#include "allheaders.h"
static void scaleColorLILow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 wpls);
static void scaleGrayLILow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 wpls);
static void scaleColor2xLILow(l_uint32 *datad, l_int32 wpld, l_uint32 *datas,
l_int32 ws, l_int32 hs, l_int32 wpls);
static void scaleColor2xLILineLow(l_uint32 *lined, l_int32 wpld,
l_uint32 *lines, l_int32 ws, l_int32 wpls,
l_int32 lastlineflag);
static void scaleGray2xLILow(l_uint32 *datad, l_int32 wpld, l_uint32 *datas,
l_int32 ws, l_int32 hs, l_int32 wpls);
static void scaleGray2xLILineLow(l_uint32 *lined, l_int32 wpld,
l_uint32 *lines, l_int32 ws, l_int32 wpls,
l_int32 lastlineflag);
static void scaleGray4xLILow(l_uint32 *datad, l_int32 wpld, l_uint32 *datas,
l_int32 ws, l_int32 hs, l_int32 wpls);
static void scaleGray4xLILineLow(l_uint32 *lined, l_int32 wpld,
l_uint32 *lines, l_int32 ws, l_int32 wpls,
l_int32 lastlineflag);
static l_int32 scaleBySamplingLow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 d, l_int32 wpls);
static l_int32 scaleSmoothLow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 d, l_int32 wpls,
l_int32 size);
static void scaleRGBToGray2Low(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 wpls,
l_float32 rwt, l_float32 gwt, l_float32 bwt);
static void scaleColorAreaMapLow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 wpls);
static void scaleGrayAreaMapLow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 wpls);
static void scaleAreaMapLow2(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 d,
l_int32 wpls);
static l_int32 scaleBinaryLow(l_uint32 *datad, l_int32 wd, l_int32 hd,
l_int32 wpld, l_uint32 *datas, l_int32 ws,
l_int32 hs, l_int32 wpls);
#ifndef NO_CONSOLE_IO
#define DEBUG_OVERFLOW 0
#define DEBUG_UNROLLING 0
#endif /* ~NO_CONSOLE_IO */
/*------------------------------------------------------------------*
* Top level scaling dispatcher *
*------------------------------------------------------------------*/
/*!
* \brief pixScale()
*
* \param[in] pixs 1, 2, 4, 8, 16 and 32 bpp
* \param[in] scalex, scaley
* \return pixd, or NULL on error
*
* This function scales 32 bpp RGB; 2, 4 or 8 bpp palette color;
* 2, 4, 8 or 16 bpp gray; and binary images.
*
* When the input has palette color, the colormap is removed and
* the result is either 8 bpp gray or 32 bpp RGB, depending on whether
* the colormap has color entries. Images with 2, 4 or 16 bpp are
* converted to 8 bpp.
*
* Because pixScale is meant to be a very simple interface to a
* number of scaling functions, including the use of unsharp masking,
* the type of scaling and the sharpening parameters are chosen
* by default. Grayscale and color images are scaled using one
* of five methods, depending on the scale factors:
* 1. antialiased subsampling (lowpass filtering followed by
* subsampling, implemented by convolution, for tiny scale factors:
* min(scalex, scaley) < 0.02.
* 2. antialiased subsampling (implemented by area mapping, for
* small scale factors:
* max(scalex, scaley) < 0.2 and min(scalex, scaley) >= 0.02.
* 3. antialiased subsampling with sharpening, for scale factors
* between 0.2 and 0.7
* 4. linear interpolation with sharpening, for scale factors between
* 0.7 and 1.4
* 5. linear interpolation without sharpening, for scale factors >= 1.4.
*
* One could use subsampling for scale factors very close to 1.0,
* because it preserves sharp edges. Linear interpolation blurs
* edges because the dest pixels will typically straddle two src edge
* pixels. Subsmpling removes entire columns and rows, so the edge is
* not blurred. However, there are two reasons for not doing this.
* First, it moves edges, so that a straight line at a large angle to
* both horizontal and vertical will have noticeable kinks where
* horizontal and vertical rasters are removed. Second, although it
* is very fast, you get good results on sharp edges by applying
* a sharpening filter.
*
* For images with sharp edges, sharpening substantially improves the
* image quality for scale factors between about 0.2 and about 2.0.
* pixScale uses a small amount of sharpening by default because
* it strengthens edge pixels that are weak due to anti-aliasing.
* The default sharpening factors are:
* * for scaling factors < 0.7: sharpfract = 0.2 sharpwidth = 1
* * for scaling factors >= 0.7: sharpfract = 0.4 sharpwidth = 2
* The cases where the sharpening halfwidth is 1 or 2 have special
* implementations and are about twice as fast as the general case.
*
* However, sharpening is computationally expensive, and one needs
* to consider the speed-quality tradeoff:
* * For upscaling of RGB images, linear interpolation plus default
* sharpening is about 5 times slower than upscaling alone.
* * For downscaling, area mapping plus default sharpening is
* about 10 times slower than downscaling alone.
* When the scale factor is larger than 1.4, the cost of sharpening,
* which is proportional to image area, is very large compared to the
* incremental quality improvement, so we cut off the default use of
* sharpening at 1.4. Thus, for scale factors greater than 1.4,
* pixScale only does linear interpolation.
*
* In many situations you will get a satisfactory result by scaling
* without sharpening: call pixScaleGeneral with %sharpfract = 0.0.
* Alternatively, if you wish to sharpen but not use the default
* value, first call pixScaleGeneral with %sharpfract = 0.0, and
* then sharpen explicitly using pixUnsharpMasking.
*
* Binary images are scaled to binary by sampling the closest pixel,
* without any low-pass filtering averaging of neighboring pixels.
* This will introduce aliasing for reductions. Aliasing can be
* prevented by using pixScaleToGray instead.
*/
PIX *
pixScale(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 sharpwidth;
l_float32 maxscale, sharpfract;
PROCNAME("pixScale");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
/* Reduce the default sharpening factors by 2 if maxscale < 0.7 */
maxscale = L_MAX(scalex, scaley);
sharpfract = (maxscale < 0.7) ? 0.2 : 0.4;
sharpwidth = (maxscale < 0.7) ? 1 : 2;
return pixScaleGeneral(pixs, scalex, scaley, sharpfract, sharpwidth);
}
/*!
* \brief pixScaleToSizeRel()
*
* \param[in] pixs
* \param[in] delw change in width, in pixels; 0 means no change
* \param[in] delh change in height, in pixels; 0 means no change
* \return pixd, or NULL on error
*/
PIX *
pixScaleToSizeRel(PIX *pixs,
l_int32 delw,
l_int32 delh)
{
l_int32 w, h, wd, hd;
PROCNAME("pixScaleToSizeRel");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (delw == 0 && delh == 0)
return pixCopy(NULL, pixs);
pixGetDimensions(pixs, &w, &h, NULL);
wd = w + delw;
hd = h + delh;
if (wd <= 0 || hd <= 0)
return (PIX *)ERROR_PTR("pix dimension reduced to 0", procName, NULL);
return pixScaleToSize(pixs, wd, hd);
}
/*!
* \brief pixScaleToSize()
*
* \param[in] pixs 1, 2, 4, 8, 16 and 32 bpp
* \param[in] wd target width; use 0 if using height as target
* \param[in] hd target height; use 0 if using width as target
* \return pixd, or NULL on error
*
*
* Notes:
* (1) The output scaled image has the dimension(s) you specify:
* * To specify the width with isotropic scaling, set %hd = 0.
* * To specify the height with isotropic scaling, set %wd = 0.
* * If both %wd and %hd are specified, the image is scaled
* (in general, anisotropically) to that size.
* * It is an error to set both %wd and %hd to 0.
*
*/
PIX *
pixScaleToSize(PIX *pixs,
l_int32 wd,
l_int32 hd)
{
l_int32 w, h;
l_float32 scalex, scaley;
PROCNAME("pixScaleToSize");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (wd <= 0 && hd <= 0)
return (PIX *)ERROR_PTR("neither wd nor hd > 0", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (wd <= 0) {
scaley = (l_float32)hd / (l_float32)h;
scalex = scaley;
} else if (hd <= 0) {
scalex = (l_float32)wd / (l_float32)w;
scaley = scalex;
} else {
scalex = (l_float32)wd / (l_float32)w;
scaley = (l_float32)hd / (l_float32)h;
}
return pixScale(pixs, scalex, scaley);
}
/*!
* \brief pixScaleToResolution()
*
* \param[in] pixs
* \param[in] target desired resolution
* \param[in] assumed assumed resolution if not defined; typ. 300.
* \param[out] pscalefact [optional] actual scaling factor used
* \return pixd, or NULL on error
*/
PIX *
pixScaleToResolution(PIX *pixs,
l_float32 target,
l_float32 assumed,
l_float32 *pscalefact)
{
l_int32 xres;
l_float32 factor;
PROCNAME("pixScaleToResolution");
if (pscalefact) *pscalefact = 1.0;
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (target <= 0)
return (PIX *)ERROR_PTR("target resolution <= 0", procName, NULL);
xres = pixGetXRes(pixs);
if (xres <= 0) {
if (assumed == 0)
return pixCopy(NULL, pixs);
xres = assumed;
}
factor = target / (l_float32)xres;
if (pscalefact) *pscalefact = factor;
return pixScale(pixs, factor, factor);
}
/*!
* \brief pixScaleGeneral()
*
* \param[in] pixs 1, 2, 4, 8, 16 and 32 bpp
* \param[in] scalex must be > 0.0
* \param[in] scaley must be > 0.0
* \param[in] sharpfract use 0.0 to skip sharpening
* \param[in] sharpwidth halfwidth of low-pass filter; typ. 1 or 2
* \return pixd, or NULL on error
*
*
* Notes:
* (1) See pixScale() for usage.
* (2) This interface may change in the future, as other special
* cases are added.
* (3) For tiny scaling factors
* minscale < 0.02: use a simple lowpass filter
* (4) The actual sharpening factors used depend on the maximum
* of the two scale factors (maxscale):
* maxscale <= 0.2: no sharpening
* 0.2 < maxscale < 1.4: uses the input parameters
* maxscale >= 1.4: no sharpening
* (5) To avoid sharpening for grayscale and color images with
* scaling factors between 0.2 and 1.4, call this function
* with %sharpfract == 0.0.
* (6) To use arbitrary sharpening in conjunction with scaling,
* call this function with %sharpfract = 0.0, and follow this
* with a call to pixUnsharpMasking() with your chosen parameters.
*
*/
PIX *
pixScaleGeneral(PIX *pixs,
l_float32 scalex,
l_float32 scaley,
l_float32 sharpfract,
l_int32 sharpwidth)
{
l_int32 d;
l_float32 maxscale, minscale;
PIX *pix1, *pix2, *pixd;
PROCNAME("pixScaleGeneral");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
d = pixGetDepth(pixs);
if (d != 1 && d != 2 && d != 4 && d != 8 && d != 16 && d != 32)
return (PIX *)ERROR_PTR("pixs not {1,2,4,8,16,32} bpp", procName, NULL);
if (scalex <= 0.0 || scaley <= 0.0)
return (PIX *)ERROR_PTR("scale factor <= 0", procName, NULL);
if (scalex == 1.0 && scaley == 1.0)
return pixCopy(NULL, pixs);
if (d == 1)
return pixScaleBinary(pixs, scalex, scaley);
/* Remove colormap; clone if possible; result is either 8 or 32 bpp */
if ((pix1 = pixConvertTo8Or32(pixs, L_CLONE, 0)) == NULL)
return (PIX *)ERROR_PTR("pix1 not made", procName, NULL);
/* Scale (up or down) */
d = pixGetDepth(pix1);
maxscale = L_MAX(scalex, scaley);
minscale = L_MIN(scalex, scaley);
if (maxscale < 0.7) { /* use low-pass filter for anti-aliasing */
if (minscale < 0.02) { /* whole-pixel low-pass filter */
pix2 = pixScaleSmooth(pix1, scalex, scaley);
} else { /* fractional pixel low-pass filter */
pix2 = pixScaleAreaMap(pix1, scalex, scaley);
}
if (maxscale > 0.2 && sharpfract > 0.0 && sharpwidth > 0) {
pixd = pixUnsharpMasking(pix2, sharpwidth, sharpfract);
} else {
pixd = pixClone(pix2);
}
} else { /* use linear interpolation */
if (d == 8) {
pix2 = pixScaleGrayLI(pix1, scalex, scaley);
} else { /* d == 32 */
pix2 = pixScaleColorLI(pix1, scalex, scaley);
}
if (maxscale < 1.4 && sharpfract > 0.0 && sharpwidth > 0) {
pixd = pixUnsharpMasking(pix2, sharpwidth, sharpfract);
} else {
pixd = pixClone(pix2);
}
}
pixDestroy(&pix1);
pixDestroy(&pix2);
pixCopyText(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
return pixd;
}
/*------------------------------------------------------------------*
* Scaling by linear interpolation *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleLI()
*
* \param[in] pixs 2, 4, 8 or 32 bpp; with or without colormap
* \param[in] scalex must be >= 0.7
* \param[in] scaley must be >= 0.7
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function should only be used when the scale factors are
* greater than or equal to 0.7, and typically greater than 1.
* If both scale factors are smaller than 0.7, we issue a warning
* and call pixScaleGeneral(), which will invoke area mapping
* without sharpening.
* (2) This works on 2, 4, 8, 16 and 32 bpp images, as well as on
* 2, 4 and 8 bpp images that have a colormap. If there is a
* colormap, it is removed to either gray or RGB, depending
* on the colormap.
* (3) This does a linear interpolation on the src image.
* (4) It dispatches to much faster implementations for
* the special cases of 2x and 4x expansion.
*
*/
PIX *
pixScaleLI(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 d;
l_float32 maxscale;
PIX *pixt, *pixd;
PROCNAME("pixScaleLI");
if (!pixs || (pixGetDepth(pixs) == 1))
return (PIX *)ERROR_PTR("pixs not defined or 1 bpp", procName, NULL);
maxscale = L_MAX(scalex, scaley);
if (maxscale < 0.7) {
L_WARNING("scaling factors < 0.7; do regular scaling\n", procName);
return pixScaleGeneral(pixs, scalex, scaley, 0.0, 0);
}
d = pixGetDepth(pixs);
if (d != 2 && d != 4 && d != 8 && d != 16 && d != 32)
return (PIX *)ERROR_PTR("pixs not {2,4,8,16,32} bpp", procName, NULL);
/* Remove colormap; clone if possible; result is either 8 or 32 bpp */
if ((pixt = pixConvertTo8Or32(pixs, L_CLONE, 0)) == NULL)
return (PIX *)ERROR_PTR("pixt not made", procName, NULL);
d = pixGetDepth(pixt);
if (d == 8)
pixd = pixScaleGrayLI(pixt, scalex, scaley);
else /* d == 32 */
pixd = pixScaleColorLI(pixt, scalex, scaley);
pixDestroy(&pixt);
pixCopyInputFormat(pixd, pixs);
return pixd;
}
/*!
* \brief pixScaleColorLI()
*
* \param[in] pixs 32 bpp, representing rgb
* \param[in] scalex must be >= 0.7
* \param[in] scaley must be >= 0.7
* \return pixd, or NULL on error
*
*
* Notes:
* (1) If both scale factors are smaller than 0.7, we issue a warning
* and call pixScaleGeneral(), which will invoke area mapping
* without sharpening. This is particularly important for
* document images with sharp edges.
* (2) For the general case, it's about 4x faster to manipulate
* the color pixels directly, rather than to make images
* out of each of the 3 components, scale each component
* using the pixScaleGrayLI(), and combine the results back
* into an rgb image.
*
*/
PIX *
pixScaleColorLI(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, wpls, wd, hd, wpld;
l_uint32 *datas, *datad;
l_float32 maxscale;
PIX *pixd;
PROCNAME("pixScaleColorLI");
if (!pixs || (pixGetDepth(pixs) != 32))
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
maxscale = L_MAX(scalex, scaley);
if (maxscale < 0.7) {
L_WARNING("scaling factors < 0.7; do regular scaling\n", procName);
return pixScaleGeneral(pixs, scalex, scaley, 0.0, 0);
}
/* Do fast special cases if possible */
if (scalex == 1.0 && scaley == 1.0)
return pixCopy(NULL, pixs);
if (scalex == 2.0 && scaley == 2.0)
return pixScaleColor2xLI(pixs);
if (scalex == 4.0 && scaley == 4.0)
return pixScaleColor4xLI(pixs);
/* General case */
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = (l_int32)(scalex * (l_float32)ws + 0.5);
hd = (l_int32)(scaley * (l_float32)hs + 0.5);
if ((pixd = pixCreate(wd, hd, 32)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleColorLILow(datad, wd, hd, wpld, datas, ws, hs, wpls);
if (pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, scalex, scaley);
pixCopyInputFormat(pixd, pixs);
return pixd;
}
/*!
* \brief pixScaleColor2xLI()
*
* \param[in] pixs 32 bpp, representing rgb
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This is a special case of linear interpolated scaling,
* for 2x upscaling. It is about 8x faster than using
* the generic pixScaleColorLI(), and about 4x faster than
* using the special 2x scale function pixScaleGray2xLI()
* on each of the three components separately.
*
*/
PIX *
pixScaleColor2xLI(PIX *pixs)
{
l_int32 ws, hs, wpls, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleColor2xLI");
if (!pixs || (pixGetDepth(pixs) != 32))
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
if ((pixd = pixCreate(2 * ws, 2 * hs, 32)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 2.0, 2.0);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleColor2xLILow(datad, wpld, datas, ws, hs, wpls);
if (pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, 2.0, 2.0);
pixCopyInputFormat(pixd, pixs);
return pixd;
}
/*!
* \brief pixScaleColor4xLI()
*
* \param[in] pixs 32 bpp, representing rgb
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This is a special case of color linear interpolated scaling,
* for 4x upscaling. It is about 3x faster than using
* the generic pixScaleColorLI().
* (2) This scales each component separately, using pixScaleGray4xLI().
* It would be about 4x faster to inline the color code properly,
* in analogy to scaleColor4xLILow(), and I leave this as
* an exercise for someone who really needs it.
*
*/
PIX *
pixScaleColor4xLI(PIX *pixs)
{
PIX *pixr, *pixg, *pixb;
PIX *pixrs, *pixgs, *pixbs;
PIX *pixd;
PROCNAME("pixScaleColor4xLI");
if (!pixs || (pixGetDepth(pixs) != 32))
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
pixr = pixGetRGBComponent(pixs, COLOR_RED);
pixrs = pixScaleGray4xLI(pixr);
pixDestroy(&pixr);
pixg = pixGetRGBComponent(pixs, COLOR_GREEN);
pixgs = pixScaleGray4xLI(pixg);
pixDestroy(&pixg);
pixb = pixGetRGBComponent(pixs, COLOR_BLUE);
pixbs = pixScaleGray4xLI(pixb);
pixDestroy(&pixb);
if ((pixd = pixCreateRGBImage(pixrs, pixgs, pixbs)) == NULL) {
L_ERROR("pixd not made\n", procName);
} else {
if (pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, 4.0, 4.0);
pixCopyInputFormat(pixd, pixs);
}
pixDestroy(&pixrs);
pixDestroy(&pixgs);
pixDestroy(&pixbs);
return pixd;
}
/*!
* \brief pixScaleGrayLI()
*
* \param[in] pixs 8 bpp grayscale, no cmap
* \param[in] scalex must be >= 0.7
* \param[in] scaley must be >= 0.7
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function is appropriate for upscaling magnification, where the
* scale factor is > 1, as well as for a small amount of downscaling
* reduction, with scale factor >= 0.7. If the scale factor is < 0.7,
* the best result is obtained by area mapping.
* (2) Here are some details:
* - For each pixel in the dest, this does a linear
* interpolation of 4 neighboring pixels in the src.
* Specifically, consider the UL corner of src and
* dest pixels. The UL corner of the dest falls within
* a src pixel, whose four corners are the UL corners
* of 4 adjacent src pixels. The value of the dest
* is taken by linear interpolation using the values of
* the four src pixels and the distance of the UL corner
* of the dest from each corner.
* - If the image is expanded so that the dest pixel is
* smaller than the src pixel, such interpolation
* is a reasonable approach. This interpolation is
* also good for a small image reduction factor that
* is not more than a 2x reduction.
* - The linear interpolation algorithm for scaling is
* identical in form to the area-mapping algorithm
* for grayscale rotation. The latter corresponds to a
* translation of each pixel without scaling.
* - This function is NOT optimal if the scaling involves
* a large reduction. If the image is significantly
* reduced, so that the dest pixel is much larger than
* the src pixels, this interpolation, which is over src
* pixels only near the UL corner of the dest pixel,
* is not going to give a good area-mapping average.
* Because area mapping for image scaling is considerably
* more computationally intensive than linear interpolation,
* we choose not to use it. For large image reduction,
* linear interpolation over adjacent src pixels
* degenerates asymptotically to subsampling. But
* subsampling without a low-pass pre-filter causes
* aliasing by the nyquist theorem. To avoid aliasing,
* a low-pass filter e.g., an averaging filter of
* size roughly equal to the dest pixel i.e., the reduction
* factor should be applied to the src before subsampling.
* - As an alternative to low-pass filtering and subsampling
* for large reduction factors, linear interpolation can
* also be done between the widely separated src pixels in
* which the corners of the dest pixel lie. This also is
* not optimal, as it samples src pixels only near the
* corners of the dest pixel, and it is not implemented.
*
*/
PIX *
pixScaleGrayLI(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, wpls, wd, hd, wpld;
l_uint32 *datas, *datad;
l_float32 maxscale;
PIX *pixd;
PROCNAME("pixScaleGrayLI");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, cmapped or not 8 bpp",
procName, NULL);
maxscale = L_MAX(scalex, scaley);
if (maxscale < 0.7) {
L_WARNING("scaling factors < 0.7; do regular scaling\n", procName);
return pixScaleGeneral(pixs, scalex, scaley, 0.0, 0);
}
/* Do fast special cases if possible */
if (scalex == 1.0 && scaley == 1.0)
return pixCopy(NULL, pixs);
if (scalex == 2.0 && scaley == 2.0)
return pixScaleGray2xLI(pixs);
if (scalex == 4.0 && scaley == 4.0)
return pixScaleGray4xLI(pixs);
/* General case */
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = (l_int32)(scalex * (l_float32)ws + 0.5);
hd = (l_int32)(scaley * (l_float32)hs + 0.5);
if ((pixd = pixCreate(wd, hd, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyText(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleGrayLILow(datad, wd, hd, wpld, datas, ws, hs, wpls);
return pixd;
}
/*!
* \brief pixScaleGray2xLI()
*
* \param[in] pixs 8 bpp grayscale, not cmapped
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This is a special case of gray linear interpolated scaling,
* for 2x upscaling. It is about 6x faster than using
* the generic pixScaleGrayLI().
*
*/
PIX *
pixScaleGray2xLI(PIX *pixs)
{
l_int32 ws, hs, wpls, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleGray2xLI");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, cmapped or not 8 bpp",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
if ((pixd = pixCreate(2 * ws, 2 * hs, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixScaleResolution(pixd, 2.0, 2.0);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleGray2xLILow(datad, wpld, datas, ws, hs, wpls);
return pixd;
}
/*!
* \brief pixScaleGray4xLI()
*
* \param[in] pixs 8 bpp grayscale, not cmapped
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This is a special case of gray linear interpolated scaling,
* for 4x upscaling. It is about 12x faster than using
* the generic pixScaleGrayLI().
*
*/
PIX *
pixScaleGray4xLI(PIX *pixs)
{
l_int32 ws, hs, wpls, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleGray4xLI");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, cmapped or not 8 bpp",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
if ((pixd = pixCreate(4 * ws, 4 * hs, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixScaleResolution(pixd, 4.0, 4.0);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleGray4xLILow(datad, wpld, datas, ws, hs, wpls);
return pixd;
}
/*------------------------------------------------------------------*
* Scale 2x followed by binarization *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleGray2xLIThresh()
*
* \param[in] pixs 8 bpp, not cmapped
* \param[in] thresh between 0 and 256
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does 2x upscale on pixs, using linear interpolation,
* followed by thresholding to binary.
* (2) Buffers are used to avoid making a large grayscale image.
*
*/
PIX *
pixScaleGray2xLIThresh(PIX *pixs,
l_int32 thresh)
{
l_int32 i, ws, hs, hsm, wd, hd, wpls, wplb, wpld;
l_uint32 *datas, *datad, *lines, *lined, *lineb;
PIX *pixd;
PROCNAME("pixScaleGray2xLIThresh");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, not 8 bpp, or cmapped",
procName, NULL);
if (thresh < 0 || thresh > 256)
return (PIX *)ERROR_PTR("thresh must be in [0, ... 256]",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
wd = 2 * ws;
hd = 2 * hs;
hsm = hs - 1;
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
/* Make line buffer for 2 lines of virtual intermediate image */
wplb = (wd + 3) / 4;
if ((lineb = (l_uint32 *)LEPT_CALLOC(2 * wplb, sizeof(l_uint32))) == NULL)
return (PIX *)ERROR_PTR("lineb not made", procName, NULL);
/* Make dest binary image */
if ((pixd = pixCreate(wd, hd, 1)) == NULL) {
LEPT_FREE(lineb);
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
}
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 2.0, 2.0);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* Do all but last src line */
for (i = 0; i < hsm; i++) {
lines = datas + i * wpls;
lined = datad + 2 * i * wpld; /* do 2 dest lines at a time */
scaleGray2xLILineLow(lineb, wplb, lines, ws, wpls, 0);
thresholdToBinaryLineLow(lined, wd, lineb, 8, thresh);
thresholdToBinaryLineLow(lined + wpld, wd, lineb + wplb, 8, thresh);
}
/* Do last src line */
lines = datas + hsm * wpls;
lined = datad + 2 * hsm * wpld;
scaleGray2xLILineLow(lineb, wplb, lines, ws, wpls, 1);
thresholdToBinaryLineLow(lined, wd, lineb, 8, thresh);
thresholdToBinaryLineLow(lined + wpld, wd, lineb + wplb, 8, thresh);
LEPT_FREE(lineb);
return pixd;
}
/*!
* \brief pixScaleGray2xLIDither()
*
* \param[in] pixs 8 bpp, not cmapped
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does 2x upscale on pixs, using linear interpolation,
* followed by Floyd-Steinberg dithering to binary.
* (2) Buffers are used to avoid making a large grayscale image.
* ~ Two line buffers are used for the src, required for the 2x
* LI upscale.
* ~ Three line buffers are used for the intermediate image.
* Two are filled with each 2xLI row operation; the third is
* needed because the upscale and dithering ops are out of sync.
*
*/
PIX *
pixScaleGray2xLIDither(PIX *pixs)
{
l_int32 i, ws, hs, hsm, wd, hd, wpls, wplb, wpld;
l_uint32 *datas, *datad;
l_uint32 *lined;
l_uint32 *lineb = NULL; /* 2 intermediate buffer lines */
l_uint32 *linebp = NULL; /* 1 intermediate buffer line */
l_uint32 *bufs = NULL; /* 2 source buffer lines */
PIX *pixd = NULL;
PROCNAME("pixScaleGray2xLIDither");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, not 8 bpp, or cmapped",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
wd = 2 * ws;
hd = 2 * hs;
hsm = hs - 1;
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
/* Make line buffers for 2 lines of src image */
if ((bufs = (l_uint32 *)LEPT_CALLOC(2 * wpls, sizeof(l_uint32))) == NULL)
return (PIX *)ERROR_PTR("bufs not made", procName, NULL);
/* Make line buffer for 2 lines of virtual intermediate image */
wplb = (wd + 3) / 4;
if ((lineb = (l_uint32 *)LEPT_CALLOC(2 * wplb, sizeof(l_uint32))) == NULL) {
L_ERROR("lineb not made\n", procName);
goto cleanup;
}
/* Make line buffer for 1 line of virtual intermediate image */
if ((linebp = (l_uint32 *)LEPT_CALLOC(wplb, sizeof(l_uint32))) == NULL) {
L_ERROR("linebp not made\n", procName);
goto cleanup;
}
/* Make dest binary image */
if ((pixd = pixCreate(wd, hd, 1)) == NULL) {
L_ERROR("pixd not made\n", procName);
goto cleanup;
}
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 2.0, 2.0);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* Start with the first src and the first dest line */
memcpy(bufs, datas, 4 * wpls); /* first src line */
memcpy(bufs + wpls, datas + wpls, 4 * wpls); /* 2nd src line */
scaleGray2xLILineLow(lineb, wplb, bufs, ws, wpls, 0); /* 2 i lines */
lined = datad;
ditherToBinaryLineLow(lined, wd, lineb, lineb + wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* 1st d line */
/* Do all but last src line */
for (i = 1; i < hsm; i++) {
memcpy(bufs, datas + i * wpls, 4 * wpls); /* i-th src line */
memcpy(bufs + wpls, datas + (i + 1) * wpls, 4 * wpls);
memcpy(linebp, lineb + wplb, 4 * wplb);
scaleGray2xLILineLow(lineb, wplb, bufs, ws, wpls, 0); /* 2 i lines */
lined = datad + 2 * i * wpld;
ditherToBinaryLineLow(lined - wpld, wd, linebp, lineb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* odd dest line */
ditherToBinaryLineLow(lined, wd, lineb, lineb + wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* even dest line */
}
/* Do the last src line and the last 3 dest lines */
memcpy(bufs, datas + hsm * wpls, 4 * wpls); /* hsm-th src line */
memcpy(linebp, lineb + wplb, 4 * wplb); /* 1 i line */
scaleGray2xLILineLow(lineb, wplb, bufs, ws, wpls, 1); /* 2 i lines */
ditherToBinaryLineLow(lined + wpld, wd, linebp, lineb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* odd dest line */
ditherToBinaryLineLow(lined + 2 * wpld, wd, lineb, lineb + wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* even dest line */
ditherToBinaryLineLow(lined + 3 * wpld, wd, lineb + wplb, NULL,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 1);
/* last dest line */
cleanup:
LEPT_FREE(bufs);
LEPT_FREE(lineb);
LEPT_FREE(linebp);
return pixd;
}
/*------------------------------------------------------------------*
* Scale 4x followed by binarization *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleGray4xLIThresh()
*
* \param[in] pixs 8 bpp
* \param[in] thresh between 0 and 256
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does 4x upscale on pixs, using linear interpolation,
* followed by thresholding to binary.
* (2) Buffers are used to avoid making a large grayscale image.
* (3) If a full 4x expanded grayscale image can be kept in memory,
* this function is only about 10% faster than separately doing
* a linear interpolation to a large grayscale image, followed
* by thresholding to binary.
*
*/
PIX *
pixScaleGray4xLIThresh(PIX *pixs,
l_int32 thresh)
{
l_int32 i, j, ws, hs, hsm, wd, hd, wpls, wplb, wpld;
l_uint32 *datas, *datad, *lines, *lined, *lineb;
PIX *pixd;
PROCNAME("pixScaleGray4xLIThresh");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, not 8 bpp, or cmapped",
procName, NULL);
if (thresh < 0 || thresh > 256)
return (PIX *)ERROR_PTR("thresh must be in [0, ... 256]",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
wd = 4 * ws;
hd = 4 * hs;
hsm = hs - 1;
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
/* Make line buffer for 4 lines of virtual intermediate image */
wplb = (wd + 3) / 4;
if ((lineb = (l_uint32 *)LEPT_CALLOC(4 * wplb, sizeof(l_uint32))) == NULL)
return (PIX *)ERROR_PTR("lineb not made", procName, NULL);
/* Make dest binary image */
if ((pixd = pixCreate(wd, hd, 1)) == NULL) {
LEPT_FREE(lineb);
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
}
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 4.0, 4.0);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* Do all but last src line */
for (i = 0; i < hsm; i++) {
lines = datas + i * wpls;
lined = datad + 4 * i * wpld; /* do 4 dest lines at a time */
scaleGray4xLILineLow(lineb, wplb, lines, ws, wpls, 0);
for (j = 0; j < 4; j++) {
thresholdToBinaryLineLow(lined + j * wpld, wd,
lineb + j * wplb, 8, thresh);
}
}
/* Do last src line */
lines = datas + hsm * wpls;
lined = datad + 4 * hsm * wpld;
scaleGray4xLILineLow(lineb, wplb, lines, ws, wpls, 1);
for (j = 0; j < 4; j++) {
thresholdToBinaryLineLow(lined + j * wpld, wd,
lineb + j * wplb, 8, thresh);
}
LEPT_FREE(lineb);
return pixd;
}
/*!
* \brief pixScaleGray4xLIDither()
*
* \param[in] pixs 8 bpp, not cmapped
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does 4x upscale on pixs, using linear interpolation,
* followed by Floyd-Steinberg dithering to binary.
* (2) Buffers are used to avoid making a large grayscale image.
* ~ Two line buffers are used for the src, required for the
* 4xLI upscale.
* ~ Five line buffers are used for the intermediate image.
* Four are filled with each 4xLI row operation; the fifth
* is needed because the upscale and dithering ops are
* out of sync.
* (3) If a full 4x expanded grayscale image can be kept in memory,
* this function is only about 5% faster than separately doing
* a linear interpolation to a large grayscale image, followed
* by error-diffusion dithering to binary.
*
*/
PIX *
pixScaleGray4xLIDither(PIX *pixs)
{
l_int32 i, j, ws, hs, hsm, wd, hd, wpls, wplb, wpld;
l_uint32 *datas, *datad;
l_uint32 *lined;
l_uint32 *lineb = NULL; /* 4 intermediate buffer lines */
l_uint32 *linebp = NULL; /* 1 intermediate buffer line */
l_uint32 *bufs = NULL; /* 2 source buffer lines */
PIX *pixd = NULL;
PROCNAME("pixScaleGray4xLIDither");
if (!pixs || pixGetDepth(pixs) != 8 || pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs undefined, not 8 bpp, or cmapped",
procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
wd = 4 * ws;
hd = 4 * hs;
hsm = hs - 1;
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
/* Make line buffers for 2 lines of src image */
if ((bufs = (l_uint32 *)LEPT_CALLOC(2 * wpls, sizeof(l_uint32))) == NULL)
return (PIX *)ERROR_PTR("bufs not made", procName, NULL);
/* Make line buffer for 4 lines of virtual intermediate image */
wplb = (wd + 3) / 4;
if ((lineb = (l_uint32 *)LEPT_CALLOC(4 * wplb, sizeof(l_uint32))) == NULL) {
L_ERROR("lineb not made\n", procName);
goto cleanup;
}
/* Make line buffer for 1 line of virtual intermediate image */
if ((linebp = (l_uint32 *)LEPT_CALLOC(wplb, sizeof(l_uint32))) == NULL) {
L_ERROR("linebp not made\n", procName);
goto cleanup;
}
/* Make dest binary image */
if ((pixd = pixCreate(wd, hd, 1)) == NULL) {
L_ERROR("pixd not made\n", procName);
goto cleanup;
}
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 4.0, 4.0);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* Start with the first src and the first 3 dest lines */
memcpy(bufs, datas, 4 * wpls); /* first src line */
memcpy(bufs + wpls, datas + wpls, 4 * wpls); /* 2nd src line */
scaleGray4xLILineLow(lineb, wplb, bufs, ws, wpls, 0); /* 4 b lines */
lined = datad;
for (j = 0; j < 3; j++) { /* first 3 d lines of Q */
ditherToBinaryLineLow(lined + j * wpld, wd, lineb + j * wplb,
lineb + (j + 1) * wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
}
/* Do all but last src line */
for (i = 1; i < hsm; i++) {
memcpy(bufs, datas + i * wpls, 4 * wpls); /* i-th src line */
memcpy(bufs + wpls, datas + (i + 1) * wpls, 4 * wpls);
memcpy(linebp, lineb + 3 * wplb, 4 * wplb);
scaleGray4xLILineLow(lineb, wplb, bufs, ws, wpls, 0); /* 4 b lines */
lined = datad + 4 * i * wpld;
ditherToBinaryLineLow(lined - wpld, wd, linebp, lineb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* 4th dest line of Q */
for (j = 0; j < 3; j++) { /* next 3 d lines of Quad */
ditherToBinaryLineLow(lined + j * wpld, wd, lineb + j * wplb,
lineb + (j + 1) * wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
}
}
/* Do the last src line and the last 5 dest lines */
memcpy(bufs, datas + hsm * wpls, 4 * wpls); /* hsm-th src line */
memcpy(linebp, lineb + 3 * wplb, 4 * wplb); /* 1 b line */
scaleGray4xLILineLow(lineb, wplb, bufs, ws, wpls, 1); /* 4 b lines */
lined = datad + 4 * hsm * wpld;
ditherToBinaryLineLow(lined - wpld, wd, linebp, lineb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
/* 4th dest line of Q */
for (j = 0; j < 3; j++) { /* next 3 d lines of Quad */
ditherToBinaryLineLow(lined + j * wpld, wd, lineb + j * wplb,
lineb + (j + 1) * wplb,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 0);
}
/* And finally, the last dest line */
ditherToBinaryLineLow(lined + 3 * wpld, wd, lineb + 3 * wplb, NULL,
DEFAULT_CLIP_LOWER_1, DEFAULT_CLIP_UPPER_1, 1);
cleanup:
LEPT_FREE(bufs);
LEPT_FREE(lineb);
LEPT_FREE(linebp);
return pixd;
}
/*------------------------------------------------------------------*
* Scaling by closest pixel sampling *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleBySampling()
*
* \param[in] pixs 1, 2, 4, 8, 16, 32 bpp
* \param[in] scalex must be > 0.0
* \param[in] scaley must be > 0.0
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function samples from the source without
* filtering. As a result, aliasing will occur for
* subsampling (%scalex and/or %scaley < 1.0).
* (2) If %scalex == 1.0 and %scaley == 1.0, returns a copy.
*
*/
PIX *
pixScaleBySampling(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, d, wpls, wd, hd, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleBySampling");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (scalex <= 0.0 || scaley <= 0.0)
return (PIX *)ERROR_PTR("scale factor <= 0", procName, NULL);
if (scalex == 1.0 && scaley == 1.0)
return pixCopy(NULL, pixs);
if ((d = pixGetDepth(pixs)) == 1)
return pixScaleBinary(pixs, scalex, scaley);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = (l_int32)(scalex * (l_float32)ws + 0.5);
hd = (l_int32)(scaley * (l_float32)hs + 0.5);
if ((pixd = pixCreate(wd, hd, d)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
pixCopyColormap(pixd, pixs);
pixCopyText(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixCopySpp(pixd, pixs);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleBySamplingLow(datad, wd, hd, wpld, datas, ws, hs, d, wpls);
if (d == 32 && pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, scalex, scaley);
return pixd;
}
/*!
* \brief pixScaleBySamplingToSize()
*
* \param[in] pixs 1, 2, 4, 8, 16 and 32 bpp
* \param[in] wd target width; use 0 if using height as target
* \param[in] hd target height; use 0 if using width as target
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This guarantees that the output scaled image has the
* dimension(s) you specify.
* ~ To specify the width with isotropic scaling, set %hd = 0.
* ~ To specify the height with isotropic scaling, set %wd = 0.
* ~ If both %wd and %hd are specified, the image is scaled
* (in general, anisotropically) to that size.
* ~ It is an error to set both %wd and %hd to 0.
*
*/
PIX *
pixScaleBySamplingToSize(PIX *pixs,
l_int32 wd,
l_int32 hd)
{
l_int32 w, h;
l_float32 scalex, scaley;
PROCNAME("pixScaleBySamplingToSize");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (wd <= 0 && hd <= 0)
return (PIX *)ERROR_PTR("neither wd nor hd > 0", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (wd <= 0) {
scaley = (l_float32)hd / (l_float32)h;
scalex = scaley;
} else if (hd <= 0) {
scalex = (l_float32)wd / (l_float32)w;
scaley = scalex;
} else {
scalex = (l_float32)wd / (l_float32)w;
scaley = (l_float32)hd / (l_float32)h;
}
return pixScaleBySampling(pixs, scalex, scaley);
}
/*!
* \brief pixScaleByIntSampling()
*
* \param[in] pixs 1, 2, 4, 8, 16, 32 bpp
* \param[in] factor integer subsampling
* \return pixd, or NULL on error
*
*
* Notes:
* (1) Simple interface to pixScaleBySampling(), for
* isotropic integer reduction.
* (2) If %factor == 1, returns a copy.
*
*/
PIX *
pixScaleByIntSampling(PIX *pixs,
l_int32 factor)
{
l_float32 scale;
PROCNAME("pixScaleByIntSampling");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (factor <= 1) {
if (factor < 1)
L_ERROR("factor must be >= 1; returning a copy\n", procName);
return pixCopy(NULL, pixs);
}
scale = 1. / (l_float32)factor;
return pixScaleBySampling(pixs, scale, scale);
}
/*------------------------------------------------------------------*
* Fast integer factor subsampling RGB to gray *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleRGBToGrayFast()
*
* \param[in] pixs 32 bpp rgb
* \param[in] factor integer reduction factor >= 1
* \param[in] color one of COLOR_RED, COLOR_GREEN, COLOR_BLUE
* \return pixd 8 bpp, or NULL on error
*
*
* Notes:
* (1) This does simultaneous subsampling by an integer factor and
* extraction of the color from the RGB pix.
* (2) It is designed for maximum speed, and is used for quickly
* generating a downsized grayscale image from a higher resolution
* RGB image. This would typically be used for image analysis.
* (3) The standard color byte order (RGBA) is assumed.
*
*/
PIX *
pixScaleRGBToGrayFast(PIX *pixs,
l_int32 factor,
l_int32 color)
{
l_int32 byteval, shift;
l_int32 i, j, ws, hs, wd, hd, wpls, wpld;
l_uint32 *datas, *words, *datad, *lined;
l_float32 scale;
PIX *pixd;
PROCNAME("pixScaleRGBToGrayFast");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("depth not 32 bpp", procName, NULL);
if (factor < 1)
return (PIX *)ERROR_PTR("factor must be >= 1", procName, NULL);
if (color == COLOR_RED)
shift = L_RED_SHIFT;
else if (color == COLOR_GREEN)
shift = L_GREEN_SHIFT;
else if (color == COLOR_BLUE)
shift = L_BLUE_SHIFT;
else
return (PIX *)ERROR_PTR("invalid color", procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = ws / factor;
hd = hs / factor;
if ((pixd = pixCreate(wd, hd, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
scale = 1. / (l_float32) factor;
pixScaleResolution(pixd, scale, scale);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < hd; i++) {
words = datas + i * factor * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++, words += factor) {
byteval = ((*words) >> shift) & 0xff;
SET_DATA_BYTE(lined, j, byteval);
}
}
return pixd;
}
/*!
* \brief pixScaleRGBToBinaryFast()
*
* \param[in] pixs 32 bpp RGB
* \param[in] factor integer reduction factor >= 1
* \param[in] thresh binarization threshold
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does simultaneous subsampling by an integer factor and
* conversion from RGB to gray to binary.
* (2) It is designed for maximum speed, and is used for quickly
* generating a downsized binary image from a higher resolution
* RGB image. This would typically be used for image analysis.
* (3) It uses the green channel to represent the RGB pixel intensity.
*
*/
PIX *
pixScaleRGBToBinaryFast(PIX *pixs,
l_int32 factor,
l_int32 thresh)
{
l_int32 byteval;
l_int32 i, j, ws, hs, wd, hd, wpls, wpld;
l_uint32 *datas, *words, *datad, *lined;
l_float32 scale;
PIX *pixd;
PROCNAME("pixScaleRGBToBinaryFast");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (factor < 1)
return (PIX *)ERROR_PTR("factor must be >= 1", procName, NULL);
if (pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("depth not 32 bpp", procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = ws / factor;
hd = hs / factor;
if ((pixd = pixCreate(wd, hd, 1)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
scale = 1. / (l_float32) factor;
pixScaleResolution(pixd, scale, scale);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < hd; i++) {
words = datas + i * factor * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++, words += factor) {
byteval = ((*words) >> L_GREEN_SHIFT) & 0xff;
if (byteval < thresh)
SET_DATA_BIT(lined, j);
}
}
return pixd;
}
/*!
* \brief pixScaleGrayToBinaryFast()
*
* \param[in] pixs 8 bpp grayscale
* \param[in] factor integer reduction factor >= 1
* \param[in] thresh binarization threshold
* \return pixd 1 bpp, or NULL on error
*
*
* Notes:
* (1) This does simultaneous subsampling by an integer factor and
* thresholding from gray to binary.
* (2) It is designed for maximum speed, and is used for quickly
* generating a downsized binary image from a higher resolution
* gray image. This would typically be used for image analysis.
*
*/
PIX *
pixScaleGrayToBinaryFast(PIX *pixs,
l_int32 factor,
l_int32 thresh)
{
l_int32 byteval;
l_int32 i, j, ws, hs, wd, hd, wpls, wpld, sj;
l_uint32 *datas, *datad, *lines, *lined;
l_float32 scale;
PIX *pixd;
PROCNAME("pixScaleGrayToBinaryFast");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (factor < 1)
return (PIX *)ERROR_PTR("factor must be >= 1", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("depth not 8 bpp", procName, NULL);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = ws / factor;
hd = hs / factor;
if ((pixd = pixCreate(wd, hd, 1)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
scale = 1. / (l_float32) factor;
pixScaleResolution(pixd, scale, scale);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < hd; i++) {
lines = datas + i * factor * wpls;
lined = datad + i * wpld;
for (j = 0, sj = 0; j < wd; j++, sj += factor) {
byteval = GET_DATA_BYTE(lines, sj);
if (byteval < thresh)
SET_DATA_BIT(lined, j);
}
}
return pixd;
}
/*------------------------------------------------------------------*
* Downscaling with (antialias) smoothing *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleSmooth()
*
* \param[in] pix 2, 4, 8 or 32 bpp; and 2, 4, 8 bpp with colormap
* \param[in] scalex must be < 0.7
* \param[in] scaley must be < 0.7
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function should only be used when the scale factors are less
* than 0.7. If either scale factor is >= 0.7, issue a warning
* and call pixScaleGeneral(), which will invoke linear interpolation
* without sharpening.
* (2) This works only on 2, 4, 8 and 32 bpp images, and if there is
* a colormap, it is removed by converting to RGB.
* (3) It does simple (flat filter) convolution, with a filter size
* commensurate with the amount of reduction, to avoid antialiasing.
* (4) It does simple subsampling after smoothing, which is appropriate
* for this range of scaling. Linear interpolation gives essentially
* the same result with more computation for these scale factors,
* so we don't use it.
* (5) The result is the same as doing a full block convolution followed by
* subsampling, but this is faster because the results of the block
* convolution are only computed at the subsampling locations.
* In fact, the computation time is approximately independent of
* the scale factor, because the convolution kernel is adjusted
* so that each source pixel is summed approximately once.
*
*/
PIX *
pixScaleSmooth(PIX *pix,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, d, wd, hd, wpls, wpld, isize;
l_uint32 val;
l_uint32 *datas, *datad;
l_float32 minscale, size;
PIX *pixs, *pixd;
PROCNAME("pixScaleSmooth");
if (!pix)
return (PIX *)ERROR_PTR("pix not defined", procName, NULL);
if (scalex >= 0.7 || scaley >= 0.7) {
L_WARNING("scaling factor not < 0.7; do regular scaling\n", procName);
return pixScaleGeneral(pix, scalex, scaley, 0.0, 0);
}
d = pixGetDepth(pix);
if (d != 2 && d != 4 && d !=8 && d != 32)
return (PIX *)ERROR_PTR("pix not 2, 4, 8 or 32 bpp", procName, NULL);
/* Remove colormap; clone if possible; result is either 8 or 32 bpp */
if ((pixs = pixConvertTo8Or32(pix, L_CLONE, 0)) == NULL)
return (PIX *)ERROR_PTR("pixs not made", procName, NULL);
d = pixGetDepth(pixs);
/* If 1.42 < 1/minscale < 2.5, use isize = 2
* If 2.5 =< 1/minscale < 3.5, use isize = 3, etc.
* Under no conditions use isize < 2 */
minscale = L_MIN(scalex, scaley);
size = 1.0 / minscale; /* ideal filter full width */
isize = L_MIN(10000, L_MAX(2, (l_int32)(size + 0.5)));
pixGetDimensions(pixs, &ws, &hs, NULL);
if ((ws < isize) || (hs < isize)) {
pixd = pixCreate(1, 1, d);
pixGetPixel(pixs, ws / 2, hs / 2, &val);
pixSetPixel(pixd, 0, 0, val);
L_WARNING("ridiculously small scaling factor %f\n", procName, minscale);
pixDestroy(&pixs);
return pixd;
}
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = L_MAX(1, (l_int32)(scalex * (l_float32)ws + 0.5));
hd = L_MAX(1, (l_int32)(scaley * (l_float32)hs + 0.5));
if ((pixd = pixCreate(wd, hd, d)) == NULL) {
pixDestroy(&pixs);
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
}
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleSmoothLow(datad, wd, hd, wpld, datas, ws, hs, d, wpls, isize);
if (d == 32 && pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, scalex, scaley);
pixDestroy(&pixs);
return pixd;
}
/*!
* \brief pixScaleSmoothToSize()
*
* \param[in] pixs 2, 4, 8 or 32 bpp; and 2, 4, 8 bpp with colormap
* \param[in] wd target width; use 0 if using height as target
* \param[in] hd target height; use 0 if using width as target
* \return pixd, or NULL on error
*
*
* Notes:
* (1) See notes in pixScaleSmooth().
* (2) The output scaled image has the dimension(s) you specify:
* - To specify the width with isotropic scaling, set %hd = 0.
* - To specify the height with isotropic scaling, set %wd = 0.
* - If both %wd and %hd are specified, the image is scaled
* (in general, anisotropically) to that size.
* - It is an error to set both %wd and %hd to 0.
*
*/
PIX *
pixScaleSmoothToSize(PIX *pixs,
l_int32 wd,
l_int32 hd)
{
l_int32 w, h;
l_float32 scalex, scaley;
PROCNAME("pixScaleSmoothToSize");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (wd <= 0 && hd <= 0)
return (PIX *)ERROR_PTR("neither wd nor hd > 0", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (wd <= 0) {
scaley = (l_float32)hd / (l_float32)h;
scalex = scaley;
} else if (hd <= 0) {
scalex = (l_float32)wd / (l_float32)w;
scaley = scalex;
} else {
scalex = (l_float32)wd / (l_float32)w;
scaley = (l_float32)hd / (l_float32)h;
}
return pixScaleSmooth(pixs, scalex, scaley);
}
/*!
* \brief pixScaleRGBToGray2()
*
* \param[in] pixs 32 bpp rgb
* \param[in] rwt, gwt, bwt must sum to 1.0
* \return pixd, 8 bpp, 2x reduced, or NULL on error
*/
PIX *
pixScaleRGBToGray2(PIX *pixs,
l_float32 rwt,
l_float32 gwt,
l_float32 bwt)
{
l_int32 wd, hd, wpls, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleRGBToGray2");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs not 32 bpp", procName, NULL);
if (rwt + gwt + bwt < 0.98 || rwt + gwt + bwt > 1.02)
return (PIX *)ERROR_PTR("sum of wts should be 1.0", procName, NULL);
wd = pixGetWidth(pixs) / 2;
hd = pixGetHeight(pixs) / 2;
wpls = pixGetWpl(pixs);
datas = pixGetData(pixs);
if ((pixd = pixCreate(wd, hd, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixScaleResolution(pixd, 0.5, 0.5);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
scaleRGBToGray2Low(datad, wd, hd, wpld, datas, wpls, rwt, gwt, bwt);
return pixd;
}
/*------------------------------------------------------------------*
* Downscaling with (antialias) area mapping *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleAreaMap()
*
* \param[in] pix 2, 4, 8 or 32 bpp; and 2, 4, 8 bpp with colormap
* \param[in] scalex must be < 0.7; minimum is 0.02
* \param[in] scaley must be < 0.7; minimum is 0.02
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This is a low-pass filter that averages over fractional pixels.
* It should only be used when the scale factors are less than 0.7.
* If either scale factor is greater than or equal to 0.7, we
* issue a warning and call pixScaleGeneral(), which will invoke
* linear interpolation without sharpening.
* (2) The minimum scale factor allowed for area mapping reduction
* is 0.02. Various overflows will occur when scale factors are
* less than about 1/256. If a scale factor smaller than 0.02
* is given, we use pixScaleSmooth(), which is a low-pass filter
* that averages over entire pixels.
* (3) This works only on 2, 4, 8 and 32 bpp images. If there is
* a colormap, it is removed by converting to RGB. In other
* cases, we issue a warning and call pixScaleGeneral().
* (4) This is faster than pixScale() because it does not do sharpening.
* (5) It does a relatively expensive area mapping computation, to
* avoid antialiasing. It is about 2x slower than pixScaleSmooth(),
* but the results are much better on fine text.
* (6) pixScaleAreaMap2() is typically about 7x faster for the special
* case of 2x reduction for color images, and about 9x faster
* for grayscale images. Surprisingly, the improvement in speed
* when using a cascade of 2x reductions for small scale factors is
* less than one might expect, and in most situations gives
* poorer image quality. But see (6).
* (7) For reductions between 0.35 and 0.5, a 2x area map reduction
* followed by using pixScaleGeneral() on a 2x larger scalefactor
* (which further reduces the image size using bilinear interpolation)
* would give a significant speed increase, with little loss of
* quality, but this is not enabled as it would break too many tests.
* For scaling factors below 0.35, scaling atomically is nearly
* as fast as using a cascade of 2x scalings, and gives
* better results.
*
*/
PIX *
pixScaleAreaMap(PIX *pix,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, d, wd, hd, wpls, wpld;
l_uint32 *datas, *datad;
l_float32 maxscale, minscale;
PIX *pixs, *pixd, *pix1, *pix2, *pix3;
PROCNAME("pixScaleAreaMap");
if (!pix)
return (PIX *)ERROR_PTR("pix not defined", procName, NULL);
d = pixGetDepth(pix);
if (d != 2 && d != 4 && d != 8 && d != 32)
return (PIX *)ERROR_PTR("pix not 2, 4, 8 or 32 bpp", procName, NULL);
minscale = L_MIN(scalex, scaley);
if (minscale < 0.02) { /* too small for area mapping */
L_WARNING("tiny scaling factor; using pixScaleSmooth()\n", procName);
return pixScaleSmooth(pix, scalex, scaley);
}
maxscale = L_MAX(scalex, scaley);
if (maxscale >= 0.7) { /* too large for area mapping */
L_WARNING("scaling factor >= 0.7; do regular scaling\n", procName);
return pixScaleGeneral(pix, scalex, scaley, 0.0, 0);
}
/* Special cases: 2x, 4x, 8x, 16x reduction */
if (scalex == 0.5 && scaley == 0.5)
return pixScaleAreaMap2(pix);
if (scalex == 0.25 && scaley == 0.25) {
pix1 = pixScaleAreaMap2(pix);
pixd = pixScaleAreaMap2(pix1);
pixDestroy(&pix1);
return pixd;
}
if (scalex == 0.125 && scaley == 0.125) {
pix1 = pixScaleAreaMap2(pix);
pix2 = pixScaleAreaMap2(pix1);
pixd = pixScaleAreaMap2(pix2);
pixDestroy(&pix1);
pixDestroy(&pix2);
return pixd;
}
if (scalex == 0.0625 && scaley == 0.0625) {
pix1 = pixScaleAreaMap2(pix);
pix2 = pixScaleAreaMap2(pix1);
pix3 = pixScaleAreaMap2(pix2);
pixd = pixScaleAreaMap2(pix3);
pixDestroy(&pix1);
pixDestroy(&pix2);
pixDestroy(&pix3);
return pixd;
}
#if 0 /* Not enabled because it breaks too many tests that rely on exact
* pixel matches. */
/* Special case where it is significantly faster to downscale first
* by 2x, with relatively little degradation in image quality. */
if (scalex > 0.35 && scalex < 0.5) {
pix1 = pixScaleAreaMap2(pix);
pixd = pixScaleAreaMap(pix1, 2.0 * scalex, 2.0 * scaley);
pixDestroy(&pix1);
return pixd;
}
#endif
/* Remove colormap if necessary.
* If 2 bpp or 4 bpp gray, convert to 8 bpp */
if ((d == 2 || d == 4 || d == 8) && pixGetColormap(pix)) {
L_WARNING("pix has colormap; removing\n", procName);
pixs = pixRemoveColormap(pix, REMOVE_CMAP_BASED_ON_SRC);
d = pixGetDepth(pixs);
} else if (d == 2 || d == 4) {
pixs = pixConvertTo8(pix, FALSE);
d = 8;
} else {
pixs = pixClone(pix);
}
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = (l_int32)(scalex * (l_float32)ws + 0.5);
hd = (l_int32)(scaley * (l_float32)hs + 0.5);
if (wd < 1 || hd < 1) {
pixDestroy(&pixs);
return (PIX *)ERROR_PTR("pixd too small", procName, NULL);
}
if ((pixd = pixCreate(wd, hd, d)) == NULL) {
pixDestroy(&pixs);
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
}
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
if (d == 8) {
scaleGrayAreaMapLow(datad, wd, hd, wpld, datas, ws, hs, wpls);
} else { /* RGB, d == 32 */
scaleColorAreaMapLow(datad, wd, hd, wpld, datas, ws, hs, wpls);
if (pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, scalex, scaley);
}
pixDestroy(&pixs);
return pixd;
}
/*!
* \brief pixScaleAreaMap2()
*
* \param[in] pix 2, 4, 8 or 32 bpp; and 2, 4, 8 bpp with colormap
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function does an area mapping (average) for 2x
* reduction.
* (2) This works only on 2, 4, 8 and 32 bpp images. If there is
* a colormap, it is removed by converting to RGB.
* (3) Compared to the general pixScaleAreaMap(), for this function
* gray processing is about 14x faster and color processing
* is about 4x faster. Consequently, pixScaleAreaMap2() is
* incorporated into the general area map scaling function,
* for the special cases of 2x, 4x, 8x and 16x reduction.
*
*/
PIX *
pixScaleAreaMap2(PIX *pix)
{
l_int32 wd, hd, d, wpls, wpld;
l_uint32 *datas, *datad;
PIX *pixs, *pixd;
PROCNAME("pixScaleAreaMap2");
if (!pix)
return (PIX *)ERROR_PTR("pix not defined", procName, NULL);
d = pixGetDepth(pix);
if (d != 2 && d != 4 && d != 8 && d != 32)
return (PIX *)ERROR_PTR("pix not 2, 4, 8 or 32 bpp", procName, NULL);
/* Remove colormap if necessary.
* If 2 bpp or 4 bpp gray, convert to 8 bpp */
if ((d == 2 || d == 4 || d == 8) && pixGetColormap(pix)) {
L_WARNING("pix has colormap; removing\n", procName);
pixs = pixRemoveColormap(pix, REMOVE_CMAP_BASED_ON_SRC);
d = pixGetDepth(pixs);
} else if (d == 2 || d == 4) {
pixs = pixConvertTo8(pix, FALSE);
d = 8;
} else {
pixs = pixClone(pix);
}
wd = pixGetWidth(pixs) / 2;
hd = pixGetHeight(pixs) / 2;
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
pixd = pixCreate(wd, hd, d);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 0.5, 0.5);
scaleAreaMapLow2(datad, wd, hd, wpld, datas, d, wpls);
if (pixGetSpp(pixs) == 4)
pixScaleAndTransferAlpha(pixd, pixs, 0.5, 0.5);
pixDestroy(&pixs);
return pixd;
}
/*!
* \brief pixScaleAreaMapToSize()
*
* \param[in] pixs 2, 4, 8 or 32 bpp; and 2, 4, 8 bpp with colormap
* \param[in] wd target width; use 0 if using height as target
* \param[in] hd target height; use 0 if using width as target
* \return pixd, or NULL on error
*
*
* Notes:
* (1) See notes in pixScaleAreaMap().
* (2) The output scaled image has the dimension(s) you specify:
* - To specify the width with isotropic scaling, set %hd = 0.
* - To specify the height with isotropic scaling, set %wd = 0.
* - If both %wd and %hd are specified, the image is scaled
* (in general, anisotropically) to that size.
* - It is an error to set both %wd and %hd to 0.
*
*/
PIX *
pixScaleAreaMapToSize(PIX *pixs,
l_int32 wd,
l_int32 hd)
{
l_int32 w, h;
l_float32 scalex, scaley;
PROCNAME("pixScaleAreaMapToSize");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (wd <= 0 && hd <= 0)
return (PIX *)ERROR_PTR("neither wd nor hd > 0", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (wd <= 0) {
scaley = (l_float32)hd / (l_float32)h;
scalex = scaley;
} else if (hd <= 0) {
scalex = (l_float32)wd / (l_float32)w;
scaley = scalex;
} else {
scalex = (l_float32)wd / (l_float32)w;
scaley = (l_float32)hd / (l_float32)h;
}
return pixScaleAreaMap(pixs, scalex, scaley);
}
/*------------------------------------------------------------------*
* Binary scaling by closest pixel sampling *
*------------------------------------------------------------------*/
/*!
* \brief pixScaleBinary()
*
* \param[in] pixs 1 bpp
* \param[in] scalex must be > 0.0
* \param[in] scaley must be > 0.0
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This function samples from the source without
* filtering. As a result, aliasing will occur for
* subsampling (scalex and scaley < 1.0).
*
*/
PIX *
pixScaleBinary(PIX *pixs,
l_float32 scalex,
l_float32 scaley)
{
l_int32 ws, hs, wpls, wd, hd, wpld;
l_uint32 *datas, *datad;
PIX *pixd;
PROCNAME("pixScaleBinary");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs must be 1 bpp", procName, NULL);
if (scalex <= 0.0 || scaley <= 0.0)
return (PIX *)ERROR_PTR("scale factor <= 0", procName, NULL);
if (scalex == 1.0 && scaley == 1.0)
return pixCopy(NULL, pixs);
pixGetDimensions(pixs, &ws, &hs, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
wd = (l_int32)(scalex * (l_float32)ws + 0.5);
hd = (l_int32)(scaley * (l_float32)hs + 0.5);
if ((pixd = pixCreate(wd, hd, 1)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyColormap(pixd, pixs);
pixCopyText(pixd, pixs);
pixCopyInputFormat(pixd, pixs);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, scalex, scaley);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
scaleBinaryLow(datad, wd, hd, wpld, datas, ws, hs, wpls);
return pixd;
}
/* ================================================================ *
* Low level static functions *
* ================================================================ */
/*------------------------------------------------------------------*
* General linear interpolated color scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleColorLILow()
*
*
* Notes:
* (1) We choose to divide each pixel into 16 x 16 sub-pixels.
* Linear interpolation is equivalent to finding the
* fractional area (i.e., number of sub-pixels divided
* by 256) associated with each of the four nearest src pixels,
* and weighting each pixel value by this fractional area.
*
*/
static void
scaleColorLILow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, j, wm2, hm2;
l_int32 xpm, ypm; /* location in src image, to 1/16 of a pixel */
l_int32 xp, yp, xf, yf; /* src pixel and pixel fraction coordinates */
l_uint32 v00r, v01r, v10r, v11r, v00g, v01g, v10g, v11g;
l_uint32 v00b, v01b, v10b, v11b, area00, area01, area10, area11;
l_uint32 pixels1, pixels2, pixels3, pixels4, pixel;
l_uint32 *lines, *lined;
l_float32 scx, scy;
/* (scx, scy) are scaling factors that are applied to the
* dest coords to get the corresponding src coords.
* We need them because we iterate over dest pixels
* and must find the corresponding set of src pixels. */
scx = 16. * (l_float32)ws / (l_float32)wd;
scy = 16. * (l_float32)hs / (l_float32)hd;
wm2 = ws - 2;
hm2 = hs - 2;
/* Iterate over the destination pixels */
for (i = 0; i < hd; i++) {
ypm = (l_int32)(scy * (l_float32)i);
yp = ypm >> 4;
yf = ypm & 0x0f;
lined = datad + i * wpld;
lines = datas + yp * wpls;
for (j = 0; j < wd; j++) {
xpm = (l_int32)(scx * (l_float32)j);
xp = xpm >> 4;
xf = xpm & 0x0f;
/* Do bilinear interpolation. This is a simple
* generalization of the calculation in scaleGrayLILow().
* Without this, we could simply subsample:
* *(lined + j) = *(lines + xp);
* which is faster but gives lousy results! */
pixels1 = *(lines + xp);
if (xp > wm2 || yp > hm2) {
if (yp > hm2 && xp <= wm2) { /* pixels near bottom */
pixels2 = *(lines + xp + 1);
pixels3 = pixels1;
pixels4 = pixels2;
} else if (xp > wm2 && yp <= hm2) { /* pixels near rt side */
pixels2 = pixels1;
pixels3 = *(lines + wpls + xp);
pixels4 = pixels3;
} else { /* pixels at LR corner */
pixels4 = pixels3 = pixels2 = pixels1;
}
} else {
pixels2 = *(lines + xp + 1);
pixels3 = *(lines + wpls + xp);
pixels4 = *(lines + wpls + xp + 1);
}
area00 = (16 - xf) * (16 - yf);
area10 = xf * (16 - yf);
area01 = (16 - xf) * yf;
area11 = xf * yf;
v00r = area00 * ((pixels1 >> L_RED_SHIFT) & 0xff);
v00g = area00 * ((pixels1 >> L_GREEN_SHIFT) & 0xff);
v00b = area00 * ((pixels1 >> L_BLUE_SHIFT) & 0xff);
v10r = area10 * ((pixels2 >> L_RED_SHIFT) & 0xff);
v10g = area10 * ((pixels2 >> L_GREEN_SHIFT) & 0xff);
v10b = area10 * ((pixels2 >> L_BLUE_SHIFT) & 0xff);
v01r = area01 * ((pixels3 >> L_RED_SHIFT) & 0xff);
v01g = area01 * ((pixels3 >> L_GREEN_SHIFT) & 0xff);
v01b = area01 * ((pixels3 >> L_BLUE_SHIFT) & 0xff);
v11r = area11 * ((pixels4 >> L_RED_SHIFT) & 0xff);
v11g = area11 * ((pixels4 >> L_GREEN_SHIFT) & 0xff);
v11b = area11 * ((pixels4 >> L_BLUE_SHIFT) & 0xff);
pixel = (((v00r + v10r + v01r + v11r + 128) << 16) & 0xff000000) |
(((v00g + v10g + v01g + v11g + 128) << 8) & 0x00ff0000) |
((v00b + v10b + v01b + v11b + 128) & 0x0000ff00);
*(lined + j) = pixel;
}
}
}
/*------------------------------------------------------------------*
* General linear interpolated gray scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleGrayLILow()
*
*
* Notes:
* (1) We choose to divide each pixel into 16 x 16 sub-pixels.
* Linear interpolation is equivalent to finding the
* fractional area (i.e., number of sub-pixels divided
* by 256) associated with each of the four nearest src pixels,
* and weighting each pixel value by this fractional area.
*
*/
static void
scaleGrayLILow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, j, wm2, hm2;
l_int32 xpm, ypm; /* location in src image, to 1/16 of a pixel */
l_int32 xp, yp, xf, yf; /* src pixel and pixel fraction coordinates */
l_int32 v00, v01, v10, v11, v00_val, v01_val, v10_val, v11_val;
l_uint8 val;
l_uint32 *lines, *lined;
l_float32 scx, scy;
/* (scx, scy) are scaling factors that are applied to the
* dest coords to get the corresponding src coords.
* We need them because we iterate over dest pixels
* and must find the corresponding set of src pixels. */
scx = 16. * (l_float32)ws / (l_float32)wd;
scy = 16. * (l_float32)hs / (l_float32)hd;
wm2 = ws - 2;
hm2 = hs - 2;
/* Iterate over the destination pixels */
for (i = 0; i < hd; i++) {
ypm = (l_int32)(scy * (l_float32)i);
yp = ypm >> 4;
yf = ypm & 0x0f;
lined = datad + i * wpld;
lines = datas + yp * wpls;
for (j = 0; j < wd; j++) {
xpm = (l_int32)(scx * (l_float32)j);
xp = xpm >> 4;
xf = xpm & 0x0f;
/* Do bilinear interpolation. Without this, we could
* simply subsample:
* SET_DATA_BYTE(lined, j, GET_DATA_BYTE(lines, xp));
* which is faster but gives lousy results! */
v00_val = GET_DATA_BYTE(lines, xp);
if (xp > wm2 || yp > hm2) {
if (yp > hm2 && xp <= wm2) { /* pixels near bottom */
v01_val = v00_val;
v10_val = GET_DATA_BYTE(lines, xp + 1);
v11_val = v10_val;
} else if (xp > wm2 && yp <= hm2) { /* pixels near rt side */
v01_val = GET_DATA_BYTE(lines + wpls, xp);
v10_val = v00_val;
v11_val = v01_val;
} else { /* pixels at LR corner */
v10_val = v01_val = v11_val = v00_val;
}
} else {
v10_val = GET_DATA_BYTE(lines, xp + 1);
v01_val = GET_DATA_BYTE(lines + wpls, xp);
v11_val = GET_DATA_BYTE(lines + wpls, xp + 1);
}
v00 = (16 - xf) * (16 - yf) * v00_val;
v10 = xf * (16 - yf) * v10_val;
v01 = (16 - xf) * yf * v01_val;
v11 = xf * yf * v11_val;
val = (l_uint8)((v00 + v01 + v10 + v11 + 128) / 256);
SET_DATA_BYTE(lined, j, val);
}
}
}
/*------------------------------------------------------------------*
* 2x linear interpolated color scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleColor2xLILow()
*
*
* Notes:
* (1) This is a special case of 2x expansion by linear
* interpolation. Each src pixel contains 4 dest pixels.
* The 4 dest pixels in src pixel 1 are numbered at
* their UL corners. The 4 dest pixels in src pixel 1
* are related to that src pixel and its 3 neighboring
* src pixels as follows:
*
* 1-----2-----|-----|-----|
* | | | | |
* | | | | |
* src 1 --> 3-----4-----| | | <-- src 2
* | | | | |
* | | | | |
* |-----|-----|-----|-----|
* | | | | |
* | | | | |
* src 3 --> | | | | | <-- src 4
* | | | | |
* | | | | |
* |-----|-----|-----|-----|
*
* dest src
* ---- ---
* dp1 = sp1
* dp2 = (sp1 + sp2) / 2
* dp3 = (sp1 + sp3) / 2
* dp4 = (sp1 + sp2 + sp3 + sp4) / 4
*
* (2) We iterate over the src pixels, and unroll the calculation
* for each set of 4 dest pixels corresponding to that src
* pixel, caching pixels for the next src pixel whenever possible.
* The method is exactly analogous to the one we use for
* scaleGray2xLILow() and its line version.
*
*/
static void
scaleColor2xLILow(l_uint32 *datad,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, hsm;
l_uint32 *lines, *lined;
hsm = hs - 1;
/* We're taking 2 src and 2 dest lines at a time,
* and for each src line, we're computing 2 dest lines.
* Call these 2 dest lines: destline1 and destline2.
* The first src line is used for destline 1.
* On all but the last src line, both src lines are
* used in the linear interpolation for destline2.
* On the last src line, both destline1 and destline2
* are computed using only that src line (because there
* isn't a lower src line). */
/* iterate over all but the last src line */
for (i = 0; i < hsm; i++) {
lines = datas + i * wpls;
lined = datad + 2 * i * wpld;
scaleColor2xLILineLow(lined, wpld, lines, ws, wpls, 0);
}
/* last src line */
lines = datas + hsm * wpls;
lined = datad + 2 * hsm * wpld;
scaleColor2xLILineLow(lined, wpld, lines, ws, wpls, 1);
}
/*!
* \brief scaleColor2xLILineLow()
*
* \param[in] lined ptr to top destline, to be made from current src line
* \param[in] wpld
* \param[in] lines ptr to current src line
* \param[in] ws
* \param[in] wpls
* \param[in] lastlineflag 1 if last src line; 0 otherwise
* \return void
*/
static void
scaleColor2xLILineLow(l_uint32 *lined,
l_int32 wpld,
l_uint32 *lines,
l_int32 ws,
l_int32 wpls,
l_int32 lastlineflag)
{
l_int32 j, jd, wsm;
l_uint32 rval1, rval2, rval3, rval4, gval1, gval2, gval3, gval4;
l_uint32 bval1, bval2, bval3, bval4;
l_uint32 pixels1, pixels2, pixels3, pixels4, pixel;
l_uint32 *linesp, *linedp;
wsm = ws - 1;
if (lastlineflag == 0) {
linesp = lines + wpls;
linedp = lined + wpld;
pixels1 = *lines;
pixels3 = *linesp;
/* initialize with v(2) and v(4) */
rval2 = pixels1 >> 24;
gval2 = (pixels1 >> 16) & 0xff;
bval2 = (pixels1 >> 8) & 0xff;
rval4 = pixels3 >> 24;
gval4 = (pixels3 >> 16) & 0xff;
bval4 = (pixels3 >> 8) & 0xff;
for (j = 0, jd = 0; j < wsm; j++, jd += 2) {
/* shift in previous src values */
rval1 = rval2;
gval1 = gval2;
bval1 = bval2;
rval3 = rval4;
gval3 = gval4;
bval3 = bval4;
/* get new src values */
pixels2 = *(lines + j + 1);
pixels4 = *(linesp + j + 1);
rval2 = pixels2 >> 24;
gval2 = (pixels2 >> 16) & 0xff;
bval2 = (pixels2 >> 8) & 0xff;
rval4 = pixels4 >> 24;
gval4 = (pixels4 >> 16) & 0xff;
bval4 = (pixels4 >> 8) & 0xff;
/* save dest values */
pixel = (rval1 << 24 | gval1 << 16 | bval1 << 8);
*(lined + jd) = pixel; /* pix 1 */
pixel = ((((rval1 + rval2) << 23) & 0xff000000) |
(((gval1 + gval2) << 15) & 0x00ff0000) |
(((bval1 + bval2) << 7) & 0x0000ff00));
*(lined + jd + 1) = pixel; /* pix 2 */
pixel = ((((rval1 + rval3) << 23) & 0xff000000) |
(((gval1 + gval3) << 15) & 0x00ff0000) |
(((bval1 + bval3) << 7) & 0x0000ff00));
*(linedp + jd) = pixel; /* pix 3 */
pixel = ((((rval1 + rval2 + rval3 + rval4) << 22) & 0xff000000) |
(((gval1 + gval2 + gval3 + gval4) << 14) & 0x00ff0000) |
(((bval1 + bval2 + bval3 + bval4) << 6) & 0x0000ff00));
*(linedp + jd + 1) = pixel; /* pix 4 */
}
/* last src pixel on line */
rval1 = rval2;
gval1 = gval2;
bval1 = bval2;
rval3 = rval4;
gval3 = gval4;
bval3 = bval4;
pixel = (rval1 << 24 | gval1 << 16 | bval1 << 8);
*(lined + 2 * wsm) = pixel; /* pix 1 */
*(lined + 2 * wsm + 1) = pixel; /* pix 2 */
pixel = ((((rval1 + rval3) << 23) & 0xff000000) |
(((gval1 + gval3) << 15) & 0x00ff0000) |
(((bval1 + bval3) << 7) & 0x0000ff00));
*(linedp + 2 * wsm) = pixel; /* pix 3 */
*(linedp + 2 * wsm + 1) = pixel; /* pix 4 */
} else { /* last row of src pixels: lastlineflag == 1 */
linedp = lined + wpld;
pixels2 = *lines;
rval2 = pixels2 >> 24;
gval2 = (pixels2 >> 16) & 0xff;
bval2 = (pixels2 >> 8) & 0xff;
for (j = 0, jd = 0; j < wsm; j++, jd += 2) {
rval1 = rval2;
gval1 = gval2;
bval1 = bval2;
pixels2 = *(lines + j + 1);
rval2 = pixels2 >> 24;
gval2 = (pixels2 >> 16) & 0xff;
bval2 = (pixels2 >> 8) & 0xff;
pixel = (rval1 << 24 | gval1 << 16 | bval1 << 8);
*(lined + jd) = pixel; /* pix 1 */
*(linedp + jd) = pixel; /* pix 2 */
pixel = ((((rval1 + rval2) << 23) & 0xff000000) |
(((gval1 + gval2) << 15) & 0x00ff0000) |
(((bval1 + bval2) << 7) & 0x0000ff00));
*(lined + jd + 1) = pixel; /* pix 3 */
*(linedp + jd + 1) = pixel; /* pix 4 */
}
rval1 = rval2;
gval1 = gval2;
bval1 = bval2;
pixel = (rval1 << 24 | gval1 << 16 | bval1 << 8);
*(lined + 2 * wsm) = pixel; /* pix 1 */
*(lined + 2 * wsm + 1) = pixel; /* pix 2 */
*(linedp + 2 * wsm) = pixel; /* pix 3 */
*(linedp + 2 * wsm + 1) = pixel; /* pix 4 */
}
}
/*------------------------------------------------------------------*
* 2x linear interpolated gray scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleGray2xLILow()
*
*
* Notes:
* (1) This is a special case of 2x expansion by linear
* interpolation. Each src pixel contains 4 dest pixels.
* The 4 dest pixels in src pixel 1 are numbered at
* their UL corners. The 4 dest pixels in src pixel 1
* are related to that src pixel and its 3 neighboring
* src pixels as follows:
*
* 1-----2-----|-----|-----|
* | | | | |
* | | | | |
* src 1 --> 3-----4-----| | | <-- src 2
* | | | | |
* | | | | |
* |-----|-----|-----|-----|
* | | | | |
* | | | | |
* src 3 --> | | | | | <-- src 4
* | | | | |
* | | | | |
* |-----|-----|-----|-----|
*
* dest src
* ---- ---
* dp1 = sp1
* dp2 = (sp1 + sp2) / 2
* dp3 = (sp1 + sp3) / 2
* dp4 = (sp1 + sp2 + sp3 + sp4) / 4
*
* (2) We iterate over the src pixels, and unroll the calculation
* for each set of 4 dest pixels corresponding to that src
* pixel, caching pixels for the next src pixel whenever possible.
*
*/
static void
scaleGray2xLILow(l_uint32 *datad,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, hsm;
l_uint32 *lines, *lined;
hsm = hs - 1;
/* We're taking 2 src and 2 dest lines at a time,
* and for each src line, we're computing 2 dest lines.
* Call these 2 dest lines: destline1 and destline2.
* The first src line is used for destline 1.
* On all but the last src line, both src lines are
* used in the linear interpolation for destline2.
* On the last src line, both destline1 and destline2
* are computed using only that src line (because there
* isn't a lower src line). */
/* iterate over all but the last src line */
for (i = 0; i < hsm; i++) {
lines = datas + i * wpls;
lined = datad + 2 * i * wpld;
scaleGray2xLILineLow(lined, wpld, lines, ws, wpls, 0);
}
/* last src line */
lines = datas + hsm * wpls;
lined = datad + 2 * hsm * wpld;
scaleGray2xLILineLow(lined, wpld, lines, ws, wpls, 1);
}
/*!
* \brief scaleGray2xLILineLow()
*
* \param[in] lined ptr to top destline, to be made from current src line
* \param[in] wpld
* \param[in] lines ptr to current src line
* \param[in] ws
* \param[in] wpls
* \param[in] lastlineflag 1 if last src line; 0 otherwise
* \return void
*/
static void
scaleGray2xLILineLow(l_uint32 *lined,
l_int32 wpld,
l_uint32 *lines,
l_int32 ws,
l_int32 wpls,
l_int32 lastlineflag)
{
l_int32 j, jd, wsm, w;
l_uint32 sval1, sval2, sval3, sval4;
l_uint32 *linesp, *linedp;
l_uint32 words, wordsp, wordd, worddp;
wsm = ws - 1;
if (lastlineflag == 0) {
linesp = lines + wpls;
linedp = lined + wpld;
/* Unroll the loop 4x and work on full words */
words = lines[0];
wordsp = linesp[0];
sval2 = (words >> 24) & 0xff;
sval4 = (wordsp >> 24) & 0xff;
for (j = 0, jd = 0, w = 0; j + 3 < wsm; j += 4, jd += 8, w++) {
/* At the top of the loop,
* words == lines[w], wordsp == linesp[w]
* and the top bytes of those have been loaded into
* sval2 and sval4. */
sval1 = sval2;
sval2 = (words >> 16) & 0xff;
sval3 = sval4;
sval4 = (wordsp >> 16) & 0xff;
wordd = (sval1 << 24) | (((sval1 + sval2) >> 1) << 16);
worddp = (((sval1 + sval3) >> 1) << 24) |
(((sval1 + sval2 + sval3 + sval4) >> 2) << 16);
sval1 = sval2;
sval2 = (words >> 8) & 0xff;
sval3 = sval4;
sval4 = (wordsp >> 8) & 0xff;
wordd |= (sval1 << 8) | ((sval1 + sval2) >> 1);
worddp |= (((sval1 + sval3) >> 1) << 8) |
((sval1 + sval2 + sval3 + sval4) >> 2);
lined[w * 2] = wordd;
linedp[w * 2] = worddp;
sval1 = sval2;
sval2 = words & 0xff;
sval3 = sval4;
sval4 = wordsp & 0xff;
wordd = (sval1 << 24) | /* pix 1 */
(((sval1 + sval2) >> 1) << 16); /* pix 2 */
worddp = (((sval1 + sval3) >> 1) << 24) | /* pix 3 */
(((sval1 + sval2 + sval3 + sval4) >> 2) << 16); /* pix 4 */
/* Load the next word as we need its first byte */
words = lines[w + 1];
wordsp = linesp[w + 1];
sval1 = sval2;
sval2 = (words >> 24) & 0xff;
sval3 = sval4;
sval4 = (wordsp >> 24) & 0xff;
wordd |= (sval1 << 8) | /* pix 1 */
((sval1 + sval2) >> 1); /* pix 2 */
worddp |= (((sval1 + sval3) >> 1) << 8) | /* pix 3 */
((sval1 + sval2 + sval3 + sval4) >> 2); /* pix 4 */
lined[w * 2 + 1] = wordd;
linedp[w * 2 + 1] = worddp;
}
/* Finish up the last word */
for (; j < wsm; j++, jd += 2) {
sval1 = sval2;
sval3 = sval4;
sval2 = GET_DATA_BYTE(lines, j + 1);
sval4 = GET_DATA_BYTE(linesp, j + 1);
SET_DATA_BYTE(lined, jd, sval1); /* pix 1 */
SET_DATA_BYTE(lined, jd + 1, (sval1 + sval2) / 2); /* pix 2 */
SET_DATA_BYTE(linedp, jd, (sval1 + sval3) / 2); /* pix 3 */
SET_DATA_BYTE(linedp, jd + 1,
(sval1 + sval2 + sval3 + sval4) / 4); /* pix 4 */
}
sval1 = sval2;
sval3 = sval4;
SET_DATA_BYTE(lined, 2 * wsm, sval1); /* pix 1 */
SET_DATA_BYTE(lined, 2 * wsm + 1, sval1); /* pix 2 */
SET_DATA_BYTE(linedp, 2 * wsm, (sval1 + sval3) / 2); /* pix 3 */
SET_DATA_BYTE(linedp, 2 * wsm + 1, (sval1 + sval3) / 2); /* pix 4 */
#if DEBUG_UNROLLING
#define CHECK_BYTE(a, b, c) if (GET_DATA_BYTE(a, b) != c) {\
lept_stderr("Error: mismatch at %d, %d vs %d\n", \
j, GET_DATA_BYTE(a, b), c); }
sval2 = GET_DATA_BYTE(lines, 0);
sval4 = GET_DATA_BYTE(linesp, 0);
for (j = 0, jd = 0; j < wsm; j++, jd += 2) {
sval1 = sval2;
sval3 = sval4;
sval2 = GET_DATA_BYTE(lines, j + 1);
sval4 = GET_DATA_BYTE(linesp, j + 1);
CHECK_BYTE(lined, jd, sval1); /* pix 1 */
CHECK_BYTE(lined, jd + 1, (sval1 + sval2) / 2); /* pix 2 */
CHECK_BYTE(linedp, jd, (sval1 + sval3) / 2); /* pix 3 */
CHECK_BYTE(linedp, jd + 1,
(sval1 + sval2 + sval3 + sval4) / 4); /* pix 4 */
}
sval1 = sval2;
sval3 = sval4;
CHECK_BYTE(lined, 2 * wsm, sval1); /* pix 1 */
CHECK_BYTE(lined, 2 * wsm + 1, sval1); /* pix 2 */
CHECK_BYTE(linedp, 2 * wsm, (sval1 + sval3) / 2); /* pix 3 */
CHECK_BYTE(linedp, 2 * wsm + 1, (sval1 + sval3) / 2); /* pix 4 */
#undef CHECK_BYTE
#endif
} else { /* last row of src pixels: lastlineflag == 1 */
linedp = lined + wpld;
sval2 = GET_DATA_BYTE(lines, 0);
for (j = 0, jd = 0; j < wsm; j++, jd += 2) {
sval1 = sval2;
sval2 = GET_DATA_BYTE(lines, j + 1);
SET_DATA_BYTE(lined, jd, sval1); /* pix 1 */
SET_DATA_BYTE(linedp, jd, sval1); /* pix 3 */
SET_DATA_BYTE(lined, jd + 1, (sval1 + sval2) / 2); /* pix 2 */
SET_DATA_BYTE(linedp, jd + 1, (sval1 + sval2) / 2); /* pix 4 */
}
sval1 = sval2;
SET_DATA_BYTE(lined, 2 * wsm, sval1); /* pix 1 */
SET_DATA_BYTE(lined, 2 * wsm + 1, sval1); /* pix 2 */
SET_DATA_BYTE(linedp, 2 * wsm, sval1); /* pix 3 */
SET_DATA_BYTE(linedp, 2 * wsm + 1, sval1); /* pix 4 */
}
}
/*------------------------------------------------------------------*
* 4x linear interpolated gray scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleGray4xLILow()
*
*
* Notes:
* (1) This is a special case of 4x expansion by linear
* interpolation. Each src pixel contains 16 dest pixels.
* The 16 dest pixels in src pixel 1 are numbered at
* their UL corners. The 16 dest pixels in src pixel 1
* are related to that src pixel and its 3 neighboring
* src pixels as follows:
*
* 1---2---3---4---|---|---|---|---|
* | | | | | | | | |
* 5---6---7---8---|---|---|---|---|
* | | | | | | | | |
* src 1 --> 9---a---b---c---|---|---|---|---| <-- src 2
* | | | | | | | | |
* d---e---f---g---|---|---|---|---|
* | | | | | | | | |
* |===|===|===|===|===|===|===|===|
* | | | | | | | | |
* |---|---|---|---|---|---|---|---|
* | | | | | | | | |
* src 3 --> |---|---|---|---|---|---|---|---| <-- src 4
* | | | | | | | | |
* |---|---|---|---|---|---|---|---|
* | | | | | | | | |
* |---|---|---|---|---|---|---|---|
*
* dest src
* ---- ---
* dp1 = sp1
* dp2 = (3 * sp1 + sp2) / 4
* dp3 = (sp1 + sp2) / 2
* dp4 = (sp1 + 3 * sp2) / 4
* dp5 = (3 * sp1 + sp3) / 4
* dp6 = (9 * sp1 + 3 * sp2 + 3 * sp3 + sp4) / 16
* dp7 = (3 * sp1 + 3 * sp2 + sp3 + sp4) / 8
* dp8 = (3 * sp1 + 9 * sp2 + 1 * sp3 + 3 * sp4) / 16
* dp9 = (sp1 + sp3) / 2
* dp10 = (3 * sp1 + sp2 + 3 * sp3 + sp4) / 8
* dp11 = (sp1 + sp2 + sp3 + sp4) / 4
* dp12 = (sp1 + 3 * sp2 + sp3 + 3 * sp4) / 8
* dp13 = (sp1 + 3 * sp3) / 4
* dp14 = (3 * sp1 + sp2 + 9 * sp3 + 3 * sp4) / 16
* dp15 = (sp1 + sp2 + 3 * sp3 + 3 * sp4) / 8
* dp16 = (sp1 + 3 * sp2 + 3 * sp3 + 9 * sp4) / 16
*
* (2) We iterate over the src pixels, and unroll the calculation
* for each set of 16 dest pixels corresponding to that src
* pixel, caching pixels for the next src pixel whenever possible.
*
*/
static void
scaleGray4xLILow(l_uint32 *datad,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, hsm;
l_uint32 *lines, *lined;
hsm = hs - 1;
/* We're taking 2 src and 4 dest lines at a time,
* and for each src line, we're computing 4 dest lines.
* Call these 4 dest lines: destline1 - destline4.
* The first src line is used for destline 1.
* Two src lines are used for all other dest lines,
* except for the last 4 dest lines, which are computed
* using only the last src line. */
/* iterate over all but the last src line */
for (i = 0; i < hsm; i++) {
lines = datas + i * wpls;
lined = datad + 4 * i * wpld;
scaleGray4xLILineLow(lined, wpld, lines, ws, wpls, 0);
}
/* last src line */
lines = datas + hsm * wpls;
lined = datad + 4 * hsm * wpld;
scaleGray4xLILineLow(lined, wpld, lines, ws, wpls, 1);
}
/*!
* \brief scaleGray4xLILineLow()
*
* \param[in] lined ptr to top destline, to be made from current src line
* \param[in] wpld
* \param[in] lines ptr to current src line
* \param[in] ws
* \param[in] wpls
* \param[in] lastlineflag 1 if last src line; 0 otherwise
* \return void
*/
static void
scaleGray4xLILineLow(l_uint32 *lined,
l_int32 wpld,
l_uint32 *lines,
l_int32 ws,
l_int32 wpls,
l_int32 lastlineflag)
{
l_int32 j, jd, wsm, wsm4;
l_int32 s1, s2, s3, s4, s1t, s2t, s3t, s4t;
l_uint32 *linesp, *linedp1, *linedp2, *linedp3;
wsm = ws - 1;
wsm4 = 4 * wsm;
if (lastlineflag == 0) {
linesp = lines + wpls;
linedp1 = lined + wpld;
linedp2 = lined + 2 * wpld;
linedp3 = lined + 3 * wpld;
s2 = GET_DATA_BYTE(lines, 0);
s4 = GET_DATA_BYTE(linesp, 0);
for (j = 0, jd = 0; j < wsm; j++, jd += 4) {
s1 = s2;
s3 = s4;
s2 = GET_DATA_BYTE(lines, j + 1);
s4 = GET_DATA_BYTE(linesp, j + 1);
s1t = 3 * s1;
s2t = 3 * s2;
s3t = 3 * s3;
s4t = 3 * s4;
SET_DATA_BYTE(lined, jd, s1); /* d1 */
SET_DATA_BYTE(lined, jd + 1, (s1t + s2) / 4); /* d2 */
SET_DATA_BYTE(lined, jd + 2, (s1 + s2) / 2); /* d3 */
SET_DATA_BYTE(lined, jd + 3, (s1 + s2t) / 4); /* d4 */
SET_DATA_BYTE(linedp1, jd, (s1t + s3) / 4); /* d5 */
SET_DATA_BYTE(linedp1, jd + 1, (9*s1 + s2t + s3t + s4) / 16); /*d6*/
SET_DATA_BYTE(linedp1, jd + 2, (s1t + s2t + s3 + s4) / 8); /* d7 */
SET_DATA_BYTE(linedp1, jd + 3, (s1t + 9*s2 + s3 + s4t) / 16);/*d8*/
SET_DATA_BYTE(linedp2, jd, (s1 + s3) / 2); /* d9 */
SET_DATA_BYTE(linedp2, jd + 1, (s1t + s2 + s3t + s4) / 8);/* d10 */
SET_DATA_BYTE(linedp2, jd + 2, (s1 + s2 + s3 + s4) / 4); /* d11 */
SET_DATA_BYTE(linedp2, jd + 3, (s1 + s2t + s3 + s4t) / 8);/* d12 */
SET_DATA_BYTE(linedp3, jd, (s1 + s3t) / 4); /* d13 */
SET_DATA_BYTE(linedp3, jd + 1, (s1t + s2 + 9*s3 + s4t) / 16);/*d14*/
SET_DATA_BYTE(linedp3, jd + 2, (s1 + s2 + s3t + s4t) / 8); /* d15 */
SET_DATA_BYTE(linedp3, jd + 3, (s1 + s2t + s3t + 9*s4) / 16);/*d16*/
}
s1 = s2;
s3 = s4;
s1t = 3 * s1;
s3t = 3 * s3;
SET_DATA_BYTE(lined, wsm4, s1); /* d1 */
SET_DATA_BYTE(lined, wsm4 + 1, s1); /* d2 */
SET_DATA_BYTE(lined, wsm4 + 2, s1); /* d3 */
SET_DATA_BYTE(lined, wsm4 + 3, s1); /* d4 */
SET_DATA_BYTE(linedp1, wsm4, (s1t + s3) / 4); /* d5 */
SET_DATA_BYTE(linedp1, wsm4 + 1, (s1t + s3) / 4); /* d6 */
SET_DATA_BYTE(linedp1, wsm4 + 2, (s1t + s3) / 4); /* d7 */
SET_DATA_BYTE(linedp1, wsm4 + 3, (s1t + s3) / 4); /* d8 */
SET_DATA_BYTE(linedp2, wsm4, (s1 + s3) / 2); /* d9 */
SET_DATA_BYTE(linedp2, wsm4 + 1, (s1 + s3) / 2); /* d10 */
SET_DATA_BYTE(linedp2, wsm4 + 2, (s1 + s3) / 2); /* d11 */
SET_DATA_BYTE(linedp2, wsm4 + 3, (s1 + s3) / 2); /* d12 */
SET_DATA_BYTE(linedp3, wsm4, (s1 + s3t) / 4); /* d13 */
SET_DATA_BYTE(linedp3, wsm4 + 1, (s1 + s3t) / 4); /* d14 */
SET_DATA_BYTE(linedp3, wsm4 + 2, (s1 + s3t) / 4); /* d15 */
SET_DATA_BYTE(linedp3, wsm4 + 3, (s1 + s3t) / 4); /* d16 */
} else { /* last row of src pixels: lastlineflag == 1 */
linedp1 = lined + wpld;
linedp2 = lined + 2 * wpld;
linedp3 = lined + 3 * wpld;
s2 = GET_DATA_BYTE(lines, 0);
for (j = 0, jd = 0; j < wsm; j++, jd += 4) {
s1 = s2;
s2 = GET_DATA_BYTE(lines, j + 1);
s1t = 3 * s1;
s2t = 3 * s2;
SET_DATA_BYTE(lined, jd, s1); /* d1 */
SET_DATA_BYTE(lined, jd + 1, (s1t + s2) / 4 ); /* d2 */
SET_DATA_BYTE(lined, jd + 2, (s1 + s2) / 2 ); /* d3 */
SET_DATA_BYTE(lined, jd + 3, (s1 + s2t) / 4 ); /* d4 */
SET_DATA_BYTE(linedp1, jd, s1); /* d5 */
SET_DATA_BYTE(linedp1, jd + 1, (s1t + s2) / 4 ); /* d6 */
SET_DATA_BYTE(linedp1, jd + 2, (s1 + s2) / 2 ); /* d7 */
SET_DATA_BYTE(linedp1, jd + 3, (s1 + s2t) / 4 ); /* d8 */
SET_DATA_BYTE(linedp2, jd, s1); /* d9 */
SET_DATA_BYTE(linedp2, jd + 1, (s1t + s2) / 4 ); /* d10 */
SET_DATA_BYTE(linedp2, jd + 2, (s1 + s2) / 2 ); /* d11 */
SET_DATA_BYTE(linedp2, jd + 3, (s1 + s2t) / 4 ); /* d12 */
SET_DATA_BYTE(linedp3, jd, s1); /* d13 */
SET_DATA_BYTE(linedp3, jd + 1, (s1t + s2) / 4 ); /* d14 */
SET_DATA_BYTE(linedp3, jd + 2, (s1 + s2) / 2 ); /* d15 */
SET_DATA_BYTE(linedp3, jd + 3, (s1 + s2t) / 4 ); /* d16 */
}
s1 = s2;
SET_DATA_BYTE(lined, wsm4, s1); /* d1 */
SET_DATA_BYTE(lined, wsm4 + 1, s1); /* d2 */
SET_DATA_BYTE(lined, wsm4 + 2, s1); /* d3 */
SET_DATA_BYTE(lined, wsm4 + 3, s1); /* d4 */
SET_DATA_BYTE(linedp1, wsm4, s1); /* d5 */
SET_DATA_BYTE(linedp1, wsm4 + 1, s1); /* d6 */
SET_DATA_BYTE(linedp1, wsm4 + 2, s1); /* d7 */
SET_DATA_BYTE(linedp1, wsm4 + 3, s1); /* d8 */
SET_DATA_BYTE(linedp2, wsm4, s1); /* d9 */
SET_DATA_BYTE(linedp2, wsm4 + 1, s1); /* d10 */
SET_DATA_BYTE(linedp2, wsm4 + 2, s1); /* d11 */
SET_DATA_BYTE(linedp2, wsm4 + 3, s1); /* d12 */
SET_DATA_BYTE(linedp3, wsm4, s1); /* d13 */
SET_DATA_BYTE(linedp3, wsm4 + 1, s1); /* d14 */
SET_DATA_BYTE(linedp3, wsm4 + 2, s1); /* d15 */
SET_DATA_BYTE(linedp3, wsm4 + 3, s1); /* d16 */
}
}
/*------------------------------------------------------------------*
* Grayscale and color scaling by closest pixel sampling *
*------------------------------------------------------------------*/
/*!
* \brief scaleBySamplingLow()
*
*
* Notes:
* (1) The dest must be cleared prior to this operation,
* and we clear it here in the low-level code.
* (2) We reuse dest pixels and dest pixel rows whenever
* possible. This speeds the upscaling; downscaling
* is done by strict subsampling and is unaffected.
* (3) Because we are sampling and not interpolating, this
* routine works directly, without conversion to full
* RGB color, for 2, 4 or 8 bpp palette color images.
*
*/
static l_int32
scaleBySamplingLow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 d,
l_int32 wpls)
{
l_int32 i, j;
l_int32 xs, prevxs, sval;
l_int32 *srow, *scol;
l_uint32 csval;
l_uint32 *lines, *prevlines, *lined, *prevlined;
l_float32 wratio, hratio;
PROCNAME("scaleBySamplingLow");
if (d != 2 && d != 4 && d !=8 && d != 16 && d != 32)
return ERROR_INT("pixel depth not supported", procName, 1);
/* Clear dest */
memset(datad, 0, 4LL * hd * wpld);
/* the source row corresponding to dest row i ==> srow[i]
* the source col corresponding to dest col j ==> scol[j] */
if ((srow = (l_int32 *)LEPT_CALLOC(hd, sizeof(l_int32))) == NULL)
return ERROR_INT("srow not made", procName, 1);
if ((scol = (l_int32 *)LEPT_CALLOC(wd, sizeof(l_int32))) == NULL) {
LEPT_FREE(srow);
return ERROR_INT("scol not made", procName, 1);
}
wratio = (l_float32)ws / (l_float32)wd;
hratio = (l_float32)hs / (l_float32)hd;
for (i = 0; i < hd; i++)
srow[i] = L_MIN((l_int32)(hratio * i + 0.5), hs - 1);
for (j = 0; j < wd; j++)
scol[j] = L_MIN((l_int32)(wratio * j + 0.5), ws - 1);
prevlines = NULL;
for (i = 0; i < hd; i++) {
lines = datas + srow[i] * wpls;
lined = datad + i * wpld;
if (lines != prevlines) { /* make dest from new source row */
prevxs = -1;
sval = 0;
csval = 0;
if (d == 2) {
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
sval = GET_DATA_DIBIT(lines, xs);
SET_DATA_DIBIT(lined, j, sval);
prevxs = xs;
} else { /* copy prev dest pix */
SET_DATA_DIBIT(lined, j, sval);
}
}
} else if (d == 4) {
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
sval = GET_DATA_QBIT(lines, xs);
SET_DATA_QBIT(lined, j, sval);
prevxs = xs;
} else { /* copy prev dest pix */
SET_DATA_QBIT(lined, j, sval);
}
}
} else if (d == 8) {
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
sval = GET_DATA_BYTE(lines, xs);
SET_DATA_BYTE(lined, j, sval);
prevxs = xs;
} else { /* copy prev dest pix */
SET_DATA_BYTE(lined, j, sval);
}
}
} else if (d == 16) {
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
sval = GET_DATA_TWO_BYTES(lines, xs);
SET_DATA_TWO_BYTES(lined, j, sval);
prevxs = xs;
} else { /* copy prev dest pix */
SET_DATA_TWO_BYTES(lined, j, sval);
}
}
} else { /* d == 32 */
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
csval = lines[xs];
lined[j] = csval;
prevxs = xs;
} else { /* copy prev dest pix */
lined[j] = csval;
}
}
}
} else { /* lines == prevlines; copy prev dest row */
prevlined = lined - wpld;
memcpy(lined, prevlined, 4 * wpld);
}
prevlines = lines;
}
LEPT_FREE(srow);
LEPT_FREE(scol);
return 0;
}
/*------------------------------------------------------------------*
* Color and grayscale downsampling with (antialias) smoothing *
*------------------------------------------------------------------*/
/*!
* \brief scaleSmoothLow()
*
*
* Notes:
* (1) This function is called on 8 or 32 bpp src and dest images.
* (2) size is the full width of the lowpass smoothing filter.
* It is correlated with the reduction ratio, being the
* nearest integer such that size is approximately equal to hs / hd.
*
*/
static l_int32
scaleSmoothLow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 d,
l_int32 wpls,
l_int32 size)
{
l_int32 i, j, m, n, xstart;
l_int32 val, rval, gval, bval;
l_int32 *srow, *scol;
l_uint32 *lines, *lined, *line, *ppixel;
l_uint32 pixel;
l_float32 wratio, hratio, norm;
PROCNAME("scaleSmoothLow");
/* Clear dest */
memset(datad, 0, 4LL * wpld * hd);
/* Each dest pixel at (j,i) is computed as the average
of size^2 corresponding src pixels.
We store the UL corner location of the square of
src pixels that correspond to dest pixel (j,i).
The are labeled by the arrays srow[i] and scol[j]. */
if ((srow = (l_int32 *)LEPT_CALLOC(hd, sizeof(l_int32))) == NULL)
return ERROR_INT("srow not made", procName, 1);
if ((scol = (l_int32 *)LEPT_CALLOC(wd, sizeof(l_int32))) == NULL) {
LEPT_FREE(srow);
return ERROR_INT("scol not made", procName, 1);
}
norm = 1. / (l_float32)(size * size);
wratio = (l_float32)ws / (l_float32)wd;
hratio = (l_float32)hs / (l_float32)hd;
for (i = 0; i < hd; i++)
srow[i] = L_MIN((l_int32)(hratio * i), hs - size);
for (j = 0; j < wd; j++)
scol[j] = L_MIN((l_int32)(wratio * j), ws - size);
/* For each dest pixel, compute average */
if (d == 8) {
for (i = 0; i < hd; i++) {
lines = datas + srow[i] * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++) {
xstart = scol[j];
val = 0;
for (m = 0; m < size; m++) {
line = lines + m * wpls;
for (n = 0; n < size; n++) {
val += GET_DATA_BYTE(line, xstart + n);
}
}
val = (l_int32)((l_float32)val * norm);
SET_DATA_BYTE(lined, j, val);
}
}
} else { /* d == 32 */
for (i = 0; i < hd; i++) {
lines = datas + srow[i] * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++) {
xstart = scol[j];
rval = gval = bval = 0;
for (m = 0; m < size; m++) {
ppixel = lines + m * wpls + xstart;
for (n = 0; n < size; n++) {
pixel = *(ppixel + n);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
}
}
rval = (l_int32)((l_float32)rval * norm);
gval = (l_int32)((l_float32)gval * norm);
bval = (l_int32)((l_float32)bval * norm);
composeRGBPixel(rval, gval, bval, lined + j);
}
}
}
LEPT_FREE(srow);
LEPT_FREE(scol);
return 0;
}
/*!
* \brief scaleRGBToGray2Low()
*
*
* Notes:
* (1) This function is called with 32 bpp RGB src and 8 bpp,
* half-resolution dest. The weights should add to 1.0.
*
*/
static void
scaleRGBToGray2Low(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 wpls,
l_float32 rwt,
l_float32 gwt,
l_float32 bwt)
{
l_int32 i, j, val, rval, gval, bval;
l_uint32 *lines, *lined;
l_uint32 pixel;
rwt *= 0.25;
gwt *= 0.25;
bwt *= 0.25;
for (i = 0; i < hd; i++) {
lines = datas + 2 * i * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++) {
/* Sum each of the color components from 4 src pixels */
pixel = *(lines + 2 * j);
rval = (pixel >> L_RED_SHIFT) & 0xff;
gval = (pixel >> L_GREEN_SHIFT) & 0xff;
bval = (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + 2 * j + 1);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + wpls + 2 * j);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + wpls + 2 * j + 1);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
/* Generate the dest byte as a weighted sum of the averages */
val = (l_int32)(rwt * rval + gwt * gval + bwt * bval);
SET_DATA_BYTE(lined, j, val);
}
}
}
/*------------------------------------------------------------------*
* General area mapped gray scaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleColorAreaMapLow()
*
*
* Notes:
* (1) This should only be used for downscaling.
* We choose to divide each pixel into 16 x 16 sub-pixels.
* This is much slower than scaleSmoothLow(), but it gives a
* better representation, esp. for downscaling factors between
* 1.5 and 5. All src pixels are subdivided into 256 sub-pixels,
* and are weighted by the number of sub-pixels covered by
* the dest pixel. This is about 2x slower than scaleSmoothLow(),
* but the results are significantly better on small text.
*
*/
static void
scaleColorAreaMapLow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, j, k, m, wm2, hm2;
l_int32 area00, area10, area01, area11, areal, arear, areat, areab;
l_int32 xu, yu; /* UL corner in src image, to 1/16 of a pixel */
l_int32 xl, yl; /* LR corner in src image, to 1/16 of a pixel */
l_int32 xup, yup, xuf, yuf; /* UL src pixel: integer and fraction */
l_int32 xlp, ylp, xlf, ylf; /* LR src pixel: integer and fraction */
l_int32 delx, dely, area;
l_int32 v00r, v00g, v00b; /* contrib. from UL src pixel */
l_int32 v01r, v01g, v01b; /* contrib. from LL src pixel */
l_int32 v10r, v10g, v10b; /* contrib from UR src pixel */
l_int32 v11r, v11g, v11b; /* contrib from LR src pixel */
l_int32 vinr, ving, vinb; /* contrib from all full interior src pixels */
l_int32 vmidr, vmidg, vmidb; /* contrib from side parts */
l_int32 rval, gval, bval;
l_uint32 pixel00, pixel10, pixel01, pixel11, pixel;
l_uint32 *lines, *lined;
l_float32 scx, scy;
/* (scx, scy) are scaling factors that are applied to the
* dest coords to get the corresponding src coords.
* We need them because we iterate over dest pixels
* and must find the corresponding set of src pixels. */
scx = 16. * (l_float32)ws / (l_float32)wd;
scy = 16. * (l_float32)hs / (l_float32)hd;
wm2 = ws - 2;
hm2 = hs - 2;
/* Iterate over the destination pixels */
for (i = 0; i < hd; i++) {
yu = (l_int32)(scy * i);
yl = (l_int32)(scy * (i + 1.0));
yup = yu >> 4;
yuf = yu & 0x0f;
ylp = yl >> 4;
ylf = yl & 0x0f;
dely = ylp - yup;
lined = datad + i * wpld;
lines = datas + yup * wpls;
for (j = 0; j < wd; j++) {
xu = (l_int32)(scx * j);
xl = (l_int32)(scx * (j + 1.0));
xup = xu >> 4;
xuf = xu & 0x0f;
xlp = xl >> 4;
xlf = xl & 0x0f;
delx = xlp - xup;
/* If near the edge, just use a src pixel value */
if (xlp > wm2 || ylp > hm2) {
*(lined + j) = *(lines + xup);
continue;
}
/* Area summed over, in subpixels. This varies
* due to the quantization, so we can't simply take
* the area to be a constant: area = scx * scy. */
area = ((16 - xuf) + 16 * (delx - 1) + xlf) *
((16 - yuf) + 16 * (dely - 1) + ylf);
/* Do area map summation */
pixel00 = *(lines + xup);
pixel10 = *(lines + xlp);
pixel01 = *(lines + dely * wpls + xup);
pixel11 = *(lines + dely * wpls + xlp);
area00 = (16 - xuf) * (16 - yuf);
area10 = xlf * (16 - yuf);
area01 = (16 - xuf) * ylf;
area11 = xlf * ylf;
v00r = area00 * ((pixel00 >> L_RED_SHIFT) & 0xff);
v00g = area00 * ((pixel00 >> L_GREEN_SHIFT) & 0xff);
v00b = area00 * ((pixel00 >> L_BLUE_SHIFT) & 0xff);
v10r = area10 * ((pixel10 >> L_RED_SHIFT) & 0xff);
v10g = area10 * ((pixel10 >> L_GREEN_SHIFT) & 0xff);
v10b = area10 * ((pixel10 >> L_BLUE_SHIFT) & 0xff);
v01r = area01 * ((pixel01 >> L_RED_SHIFT) & 0xff);
v01g = area01 * ((pixel01 >> L_GREEN_SHIFT) & 0xff);
v01b = area01 * ((pixel01 >> L_BLUE_SHIFT) & 0xff);
v11r = area11 * ((pixel11 >> L_RED_SHIFT) & 0xff);
v11g = area11 * ((pixel11 >> L_GREEN_SHIFT) & 0xff);
v11b = area11 * ((pixel11 >> L_BLUE_SHIFT) & 0xff);
vinr = ving = vinb = 0;
for (k = 1; k < dely; k++) { /* for full src pixels */
for (m = 1; m < delx; m++) {
pixel = *(lines + k * wpls + xup + m);
vinr += 256 * ((pixel >> L_RED_SHIFT) & 0xff);
ving += 256 * ((pixel >> L_GREEN_SHIFT) & 0xff);
vinb += 256 * ((pixel >> L_BLUE_SHIFT) & 0xff);
}
}
vmidr = vmidg = vmidb = 0;
areal = (16 - xuf) * 16;
arear = xlf * 16;
areat = 16 * (16 - yuf);
areab = 16 * ylf;
for (k = 1; k < dely; k++) { /* for left side */
pixel = *(lines + k * wpls + xup);
vmidr += areal * ((pixel >> L_RED_SHIFT) & 0xff);
vmidg += areal * ((pixel >> L_GREEN_SHIFT) & 0xff);
vmidb += areal * ((pixel >> L_BLUE_SHIFT) & 0xff);
}
for (k = 1; k < dely; k++) { /* for right side */
pixel = *(lines + k * wpls + xlp);
vmidr += arear * ((pixel >> L_RED_SHIFT) & 0xff);
vmidg += arear * ((pixel >> L_GREEN_SHIFT) & 0xff);
vmidb += arear * ((pixel >> L_BLUE_SHIFT) & 0xff);
}
for (m = 1; m < delx; m++) { /* for top side */
pixel = *(lines + xup + m);
vmidr += areat * ((pixel >> L_RED_SHIFT) & 0xff);
vmidg += areat * ((pixel >> L_GREEN_SHIFT) & 0xff);
vmidb += areat * ((pixel >> L_BLUE_SHIFT) & 0xff);
}
for (m = 1; m < delx; m++) { /* for bottom side */
pixel = *(lines + dely * wpls + xup + m);
vmidr += areab * ((pixel >> L_RED_SHIFT) & 0xff);
vmidg += areab * ((pixel >> L_GREEN_SHIFT) & 0xff);
vmidb += areab * ((pixel >> L_BLUE_SHIFT) & 0xff);
}
/* Sum all the contributions */
rval = (v00r + v01r + v10r + v11r + vinr + vmidr + 128) / area;
gval = (v00g + v01g + v10g + v11g + ving + vmidg + 128) / area;
bval = (v00b + v01b + v10b + v11b + vinb + vmidb + 128) / area;
#if DEBUG_OVERFLOW
if (rval > 255) lept_stderr("rval ovfl: %d\n", rval);
if (gval > 255) lept_stderr("gval ovfl: %d\n", gval);
if (bval > 255) lept_stderr("bval ovfl: %d\n", bval);
#endif /* DEBUG_OVERFLOW */
composeRGBPixel(rval, gval, bval, lined + j);
}
}
}
/*!
* \brief scaleGrayAreaMapLow()
*
*
* Notes:
* (1) This should only be used for downscaling.
* We choose to divide each pixel into 16 x 16 sub-pixels.
* This is about 2x slower than scaleSmoothLow(), but the results
* are significantly better on small text, esp. for downscaling
* factors between 1.5 and 5. All src pixels are subdivided
* into 256 sub-pixels, and are weighted by the number of
* sub-pixels covered by the dest pixel.
*
*/
static void
scaleGrayAreaMapLow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, j, k, m, wm2, hm2;
l_int32 xu, yu; /* UL corner in src image, to 1/16 of a pixel */
l_int32 xl, yl; /* LR corner in src image, to 1/16 of a pixel */
l_int32 xup, yup, xuf, yuf; /* UL src pixel: integer and fraction */
l_int32 xlp, ylp, xlf, ylf; /* LR src pixel: integer and fraction */
l_int32 delx, dely, area;
l_int32 v00; /* contrib. from UL src pixel */
l_int32 v01; /* contrib. from LL src pixel */
l_int32 v10; /* contrib from UR src pixel */
l_int32 v11; /* contrib from LR src pixel */
l_int32 vin; /* contrib from all full interior src pixels */
l_int32 vmid; /* contrib from side parts that are full in 1 direction */
l_int32 val;
l_uint32 *lines, *lined;
l_float32 scx, scy;
/* (scx, scy) are scaling factors that are applied to the
* dest coords to get the corresponding src coords.
* We need them because we iterate over dest pixels
* and must find the corresponding set of src pixels. */
scx = 16. * (l_float32)ws / (l_float32)wd;
scy = 16. * (l_float32)hs / (l_float32)hd;
wm2 = ws - 2;
hm2 = hs - 2;
/* Iterate over the destination pixels */
for (i = 0; i < hd; i++) {
yu = (l_int32)(scy * i);
yl = (l_int32)(scy * (i + 1.0));
yup = yu >> 4;
yuf = yu & 0x0f;
ylp = yl >> 4;
ylf = yl & 0x0f;
dely = ylp - yup;
lined = datad + i * wpld;
lines = datas + yup * wpls;
for (j = 0; j < wd; j++) {
xu = (l_int32)(scx * j);
xl = (l_int32)(scx * (j + 1.0));
xup = xu >> 4;
xuf = xu & 0x0f;
xlp = xl >> 4;
xlf = xl & 0x0f;
delx = xlp - xup;
/* If near the edge, just use a src pixel value */
if (xlp > wm2 || ylp > hm2) {
SET_DATA_BYTE(lined, j, GET_DATA_BYTE(lines, xup));
continue;
}
/* Area summed over, in subpixels. This varies
* due to the quantization, so we can't simply take
* the area to be a constant: area = scx * scy. */
area = ((16 - xuf) + 16 * (delx - 1) + xlf) *
((16 - yuf) + 16 * (dely - 1) + ylf);
/* Do area map summation */
v00 = (16 - xuf) * (16 - yuf) * GET_DATA_BYTE(lines, xup);
v10 = xlf * (16 - yuf) * GET_DATA_BYTE(lines, xlp);
v01 = (16 - xuf) * ylf * GET_DATA_BYTE(lines + dely * wpls, xup);
v11 = xlf * ylf * GET_DATA_BYTE(lines + dely * wpls, xlp);
for (vin = 0, k = 1; k < dely; k++) { /* for full src pixels */
for (m = 1; m < delx; m++) {
vin += 256 * GET_DATA_BYTE(lines + k * wpls, xup + m);
}
}
for (vmid = 0, k = 1; k < dely; k++) /* for left side */
vmid += (16 - xuf) * 16 * GET_DATA_BYTE(lines + k * wpls, xup);
for (k = 1; k < dely; k++) /* for right side */
vmid += xlf * 16 * GET_DATA_BYTE(lines + k * wpls, xlp);
for (m = 1; m < delx; m++) /* for top side */
vmid += 16 * (16 - yuf) * GET_DATA_BYTE(lines, xup + m);
for (m = 1; m < delx; m++) /* for bottom side */
vmid += 16 * ylf * GET_DATA_BYTE(lines + dely * wpls, xup + m);
val = (v00 + v01 + v10 + v11 + vin + vmid + 128) / area;
#if DEBUG_OVERFLOW
if (val > 255) lept_stderr("val overflow: %d\n", val);
#endif /* DEBUG_OVERFLOW */
SET_DATA_BYTE(lined, j, val);
}
}
}
/*------------------------------------------------------------------*
* 2x area mapped downscaling *
*------------------------------------------------------------------*/
/*!
* \brief scaleAreaMapLow2()
*
*
* Notes:
* (1) This function is called with either 8 bpp gray or 32 bpp RGB.
* The result is a 2x reduced dest.
*
*/
static void
scaleAreaMapLow2(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 d,
l_int32 wpls)
{
l_int32 i, j, val, rval, gval, bval;
l_uint32 *lines, *lined;
l_uint32 pixel;
if (d == 8) {
for (i = 0; i < hd; i++) {
lines = datas + 2 * i * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++) {
/* Average each dest pixel using 4 src pixels */
val = GET_DATA_BYTE(lines, 2 * j);
val += GET_DATA_BYTE(lines, 2 * j + 1);
val += GET_DATA_BYTE(lines + wpls, 2 * j);
val += GET_DATA_BYTE(lines + wpls, 2 * j + 1);
val >>= 2;
SET_DATA_BYTE(lined, j, val);
}
}
} else { /* d == 32 */
for (i = 0; i < hd; i++) {
lines = datas + 2 * i * wpls;
lined = datad + i * wpld;
for (j = 0; j < wd; j++) {
/* Average each of the color components from 4 src pixels */
pixel = *(lines + 2 * j);
rval = (pixel >> L_RED_SHIFT) & 0xff;
gval = (pixel >> L_GREEN_SHIFT) & 0xff;
bval = (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + 2 * j + 1);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + wpls + 2 * j);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
pixel = *(lines + wpls + 2 * j + 1);
rval += (pixel >> L_RED_SHIFT) & 0xff;
gval += (pixel >> L_GREEN_SHIFT) & 0xff;
bval += (pixel >> L_BLUE_SHIFT) & 0xff;
composeRGBPixel(rval >> 2, gval >> 2, bval >> 2, &pixel);
*(lined + j) = pixel;
}
}
}
}
/*------------------------------------------------------------------*
* Binary scaling by closest pixel sampling *
*------------------------------------------------------------------*/
/*
* \brief scaleBinaryLow()
*
*
* Notes:
* (1) The dest must be cleared prior to this operation,
* and we clear it here in the low-level code.
* (2) We reuse dest pixels and dest pixel rows whenever
* possible for upscaling; downscaling is done by
* strict subsampling.
*
*/
static l_int32
scaleBinaryLow(l_uint32 *datad,
l_int32 wd,
l_int32 hd,
l_int32 wpld,
l_uint32 *datas,
l_int32 ws,
l_int32 hs,
l_int32 wpls)
{
l_int32 i, j;
l_int32 xs, prevxs, sval;
l_int32 *srow, *scol;
l_uint32 *lines, *prevlines, *lined, *prevlined;
l_float32 wratio, hratio;
PROCNAME("scaleBinaryLow");
/* Clear dest */
memset(datad, 0, 4LL * hd * wpld);
/* The source row corresponding to dest row i ==> srow[i]
* The source col corresponding to dest col j ==> scol[j] */
if ((srow = (l_int32 *)LEPT_CALLOC(hd, sizeof(l_int32))) == NULL)
return ERROR_INT("srow not made", procName, 1);
if ((scol = (l_int32 *)LEPT_CALLOC(wd, sizeof(l_int32))) == NULL) {
LEPT_FREE(srow);
return ERROR_INT("scol not made", procName, 1);
}
wratio = (l_float32)ws / (l_float32)wd;
hratio = (l_float32)hs / (l_float32)hd;
for (i = 0; i < hd; i++)
srow[i] = L_MIN((l_int32)(hratio * i + 0.5), hs - 1);
for (j = 0; j < wd; j++)
scol[j] = L_MIN((l_int32)(wratio * j + 0.5), ws - 1);
prevlines = NULL;
prevxs = -1;
sval = 0;
for (i = 0; i < hd; i++) {
lines = datas + srow[i] * wpls;
lined = datad + i * wpld;
if (lines != prevlines) { /* make dest from new source row */
for (j = 0; j < wd; j++) {
xs = scol[j];
if (xs != prevxs) { /* get dest pix from source col */
if ((sval = GET_DATA_BIT(lines, xs)))
SET_DATA_BIT(lined, j);
prevxs = xs;
} else { /* copy prev dest pix, if set */
if (sval)
SET_DATA_BIT(lined, j);
}
}
} else { /* lines == prevlines; copy prev dest row */
prevlined = lined - wpld;
memcpy(lined, prevlined, 4 * wpld);
}
prevlines = lines;
}
LEPT_FREE(srow);
LEPT_FREE(scol);
return 0;
}