#endif /* HAVE_CONFIG_H */
#include "allheaders.h"
/*---------------------------------------------------------------------*
* Coloring "gray" pixels *
*---------------------------------------------------------------------*/
/*!
* \brief pixColorGrayRegions()
*
* \param[in] pixs 2, 4 or 8 bpp gray, rgb, or colormapped
* \param[in] boxa of regions in which to apply color
* \param[in] type L_PAINT_LIGHT, L_PAINT_DARK
* \param[in] thresh average value below/above which pixel is unchanged
* \param[in] rval, gval, bval new color to paint
* \return pixd, or NULL on error
*
*
* Notes:
* (1) This generates a new image, where some of the pixels in each
* box in the boxa are colorized. See pixColorGray() for usage
* with %type and %thresh. Note that %thresh is only used for
* rgb; it is ignored for colormapped images.
* (2) If the input image is colormapped, the new image will be 8 bpp
* colormapped if possible; otherwise, it will be converted
* to 32 bpp rgb. Only pixels that are strictly gray will be
* colorized.
* (3) If the input image is not colormapped, it is converted to rgb.
* A "gray" value for a pixel is determined by averaging the
* components, and the output rgb value is determined from this.
* (4) This can be used in conjunction with pixHasHighlightRed() to
* add highlight color to a grayscale image.
*
*/
PIX *
pixColorGrayRegions(PIX *pixs,
BOXA *boxa,
l_int32 type,
l_int32 thresh,
l_int32 rval,
l_int32 gval,
l_int32 bval)
{
l_int32 i, n, ncolors, ngray;
BOX *box;
PIX *pixd;
PIXCMAP *cmap;
PROCNAME("pixColorGrayRegions");
if (!pixs || pixGetDepth(pixs) == 1)
return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
if (!boxa)
return (PIX *)ERROR_PTR("boxa not defined", procName, NULL);
if (type != L_PAINT_LIGHT && type != L_PAINT_DARK)
return (PIX *)ERROR_PTR("invalid type", procName, NULL);
/* If cmapped and there is room in an 8 bpp colormap for
* expansion, convert pixs to 8 bpp, and colorize. */
cmap = pixGetColormap(pixs);
if (cmap) {
ncolors = pixcmapGetCount(cmap);
pixcmapCountGrayColors(cmap, &ngray);
if (ncolors + ngray < 255) {
pixd = pixConvertTo8(pixs, 1); /* always new image */
pixColorGrayRegionsCmap(pixd, boxa, type, rval, gval, bval);
return pixd;
}
}
/* The output will be rgb. Make sure the thresholds are valid */
if (type == L_PAINT_LIGHT) { /* thresh should be low */
if (thresh >= 255)
return (PIX *)ERROR_PTR("thresh must be < 255", procName, NULL);
if (thresh > 127)
L_WARNING("threshold set very high\n", procName);
} else { /* type == L_PAINT_DARK; thresh should be high */
if (thresh <= 0)
return (PIX *)ERROR_PTR("thresh must be > 0", procName, NULL);
if (thresh < 128)
L_WARNING("threshold set very low\n", procName);
}
pixd = pixConvertTo32(pixs); /* always new image */
n = boxaGetCount(boxa);
for (i = 0; i < n; i++) {
box = boxaGetBox(boxa, i, L_CLONE);
pixColorGray(pixd, box, type, thresh, rval, gval, bval);
boxDestroy(&box);
}
return pixd;
}
/*!
* \brief pixColorGray()
*
* \param[in] pixs 8 bpp gray, rgb or colormapped image
* \param[in] box [optional] region in which to apply color; can be NULL
* \param[in] type L_PAINT_LIGHT, L_PAINT_DARK
* \param[in] thresh average value below/above which pixel is unchanged
* \param[in] rval, gval, bval new color to paint
* \return 0 if OK; 1 on error
*
*
* Notes:
* (1) This is an in-place operation; pixs is modified.
* If pixs is colormapped, the operation will add colors to the
* colormap. Otherwise, pixs will be converted to 32 bpp rgb if
* it is initially 8 bpp gray.
* (2) If type == L_PAINT_LIGHT, it colorizes non-black pixels,
* preserving antialiasing.
* If type == L_PAINT_DARK, it colorizes non-white pixels,
* preserving antialiasing.
* (3) If box is NULL, applies function to the entire image; otherwise,
* clips the operation to the intersection of the box and pix.
* (4) If colormapped, calls pixColorGrayCmap(), which applies the
* coloring algorithm only to pixels that are strictly gray.
* (5) For RGB, determines a "gray" value by averaging; then uses this
* value, plus the input rgb target, to generate the output
* pixel values.
* (6) thresh is only used for rgb; it is ignored for colormapped pix.
* If type == L_PAINT_LIGHT, use thresh = 0 if all pixels are to
* be colored (black pixels will be unaltered).
* In situations where there are a lot of black pixels,
* setting thresh > 0 will make the function considerably
* more efficient without affecting the final result.
* If type == L_PAINT_DARK, use thresh = 255 if all pixels
* are to be colored (white pixels will be unaltered).
* In situations where there are a lot of white pixels,
* setting thresh < 255 will make the function considerably
* more efficient without affecting the final result.
*
*/
l_ok
pixColorGray(PIX *pixs,
BOX *box,
l_int32 type,
l_int32 thresh,
l_int32 rval,
l_int32 gval,
l_int32 bval)
{
l_int32 i, j, w, h, d, wpl, x1, x2, y1, y2, bw, bh;
l_int32 nrval, ngval, nbval, aveval;
l_float32 factor;
l_uint32 val32;
l_uint32 *line, *data;
PIX *pixt;
PIXCMAP *cmap;
PROCNAME("pixColorGray");
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (type != L_PAINT_LIGHT && type != L_PAINT_DARK)
return ERROR_INT("invalid type", procName, 1);
cmap = pixGetColormap(pixs);
pixGetDimensions(pixs, &w, &h, &d);
if (!cmap && d != 8 && d != 32)
return ERROR_INT("pixs not cmapped, 8 bpp or rgb", procName, 1);
if (cmap)
return pixColorGrayCmap(pixs, box, type, rval, gval, bval);
/* rgb or 8 bpp gray image; check the thresh */
if (type == L_PAINT_LIGHT) { /* thresh should be low */
if (thresh >= 255)
return ERROR_INT("thresh must be < 255; else this is a no-op",
procName, 1);
if (thresh > 127)
L_WARNING("threshold set very high\n", procName);
} else { /* type == L_PAINT_DARK; thresh should be high */
if (thresh <= 0)
return ERROR_INT("thresh must be > 0; else this is a no-op",
procName, 1);
if (thresh < 128)
L_WARNING("threshold set very low\n", procName);
}
/* In-place conversion to 32 bpp if necessary */
if (d == 8) {
pixt = pixConvertTo32(pixs);
pixTransferAllData(pixs, &pixt, 1, 0);
}
if (!box) {
x1 = y1 = 0;
x2 = w;
y2 = h;
} else {
boxGetGeometry(box, &x1, &y1, &bw, &bh);
x2 = x1 + bw - 1;
y2 = y1 + bh - 1;
}
data = pixGetData(pixs);
wpl = pixGetWpl(pixs);
factor = 1.f / 255.f;
for (i = y1; i <= y2; i++) {
if (i < 0 || i >= h)
continue;
line = data + i * wpl;
for (j = x1; j <= x2; j++) {
if (j < 0 || j >= w)
continue;
val32 = *(line + j);
aveval = ((val32 >> 24) + ((val32 >> 16) & 0xff) +
((val32 >> 8) & 0xff)) / 3;
if (type == L_PAINT_LIGHT) {
if (aveval < thresh) /* skip sufficiently dark pixels */
continue;
nrval = (l_int32)(rval * aveval * factor);
ngval = (l_int32)(gval * aveval * factor);
nbval = (l_int32)(bval * aveval * factor);
} else { /* type == L_PAINT_DARK */
if (aveval > thresh) /* skip sufficiently light pixels */
continue;
nrval = rval + (l_int32)((255. - rval) * aveval * factor);
ngval = gval + (l_int32)((255. - gval) * aveval * factor);
nbval = bval + (l_int32)((255. - bval) * aveval * factor);
}
composeRGBPixel(nrval, ngval, nbval, &val32);
*(line + j) = val32;
}
}
return 0;
}
/*!
* \brief pixColorGrayMasked()
*
* \param[in] pixs 8 bpp gray, rgb or colormapped image
* \param[in] pixm 1 bpp mask, through which to apply color
* \param[in] type L_PAINT_LIGHT, L_PAINT_DARK
* \param[in] thresh average value below/above which pixel is unchanged
* \param[in] rval, gval, bval new color to paint
* \return pixd colorized, or NULL on error
*
*
* Notes:
* (1) This generates a new image, where some of the pixels under
* FG in the mask are colorized.
* (2) See pixColorGray() for usage with %type and %thresh. Note
* that %thresh is only used for rgb; it is ignored for
* colormapped images. In most cases, the mask will be over
* the darker parts and %type == L_PAINT_DARK.
* (3) If pixs is colormapped this calls pixColorMaskedCmap(),
* which adds colors to the colormap for pixd; it only adds
* colors corresponding to strictly gray colors in the colormap.
* Otherwise, if pixs is 8 bpp gray, pixd will be 32 bpp rgb.
* (4) If pixs is 32 bpp rgb, for each pixel a "gray" value is
* found by averaging. This average is then used with the
* input rgb target to generate the output pixel values.
* (5) This can be used in conjunction with pixHasHighlightRed() to
* add highlight color to a grayscale image.
*
*/
PIX *
pixColorGrayMasked(PIX *pixs,
PIX *pixm,
l_int32 type,
l_int32 thresh,
l_int32 rval,
l_int32 gval,
l_int32 bval)
{
l_int32 i, j, w, h, d, wm, hm, wmin, hmin, wpl, wplm;
l_int32 nrval, ngval, nbval, aveval;
l_float32 factor;
l_uint32 val32;
l_uint32 *line, *data, *linem, *datam;
PIX *pixd;
PIXCMAP *cmap;
PROCNAME("pixColorGrayMasked");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!pixm || pixGetDepth(pixm) != 1)
return (PIX *)ERROR_PTR("pixm undefined or not 1 bpp", procName, NULL);
if (type != L_PAINT_LIGHT && type != L_PAINT_DARK)
return (PIX *)ERROR_PTR("invalid type", procName, NULL);
cmap = pixGetColormap(pixs);
pixGetDimensions(pixs, &w, &h, &d);
if (!cmap && d != 8 && d != 32)
return (PIX *)ERROR_PTR("pixs not cmapped, 8 bpp gray or 32 bpp",
procName, NULL);
if (cmap) {
pixd = pixCopy(NULL, pixs);
pixColorGrayMaskedCmap(pixd, pixm, type, rval, gval, bval);
return pixd;
}
/* rgb or 8 bpp gray image; check the thresh */
if (type == L_PAINT_LIGHT) { /* thresh should be low */
if (thresh >= 255)
return (PIX *)ERROR_PTR(
"thresh must be < 255; else this is a no-op", procName, NULL);
if (thresh > 127)
L_WARNING("threshold set very high\n", procName);
} else { /* type == L_PAINT_DARK; thresh should be high */
if (thresh <= 0)
return (PIX *)ERROR_PTR(
"thresh must be > 0; else this is a no-op", procName, NULL);
if (thresh < 128)
L_WARNING("threshold set very low\n", procName);
}
pixGetDimensions(pixm, &wm, &hm, NULL);
if (wm != w)
L_WARNING("wm = %d differs from w = %d\n", procName, wm, w);
if (hm != h)
L_WARNING("hm = %d differs from h = %d\n", procName, hm, h);
wmin = L_MIN(w, wm);
hmin = L_MIN(h, hm);
if (d == 8)
pixd = pixConvertTo32(pixs);
else
pixd = pixCopy(NULL, pixs);
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
datam = pixGetData(pixm);
wplm = pixGetWpl(pixm);
factor = 1.f / 255.f;
for (i = 0; i < hmin; i++) {
line = data + i * wpl;
linem = datam + i * wplm;
for (j = 0; j < wmin; j++) {
if (GET_DATA_BIT(linem, j) == 0)
continue;
val32 = *(line + j);
aveval = ((val32 >> 24) + ((val32 >> 16) & 0xff) +
((val32 >> 8) & 0xff)) / 3;
if (type == L_PAINT_LIGHT) {
if (aveval < thresh) /* skip sufficiently dark pixels */
continue;
nrval = (l_int32)(rval * aveval * factor);
ngval = (l_int32)(gval * aveval * factor);
nbval = (l_int32)(bval * aveval * factor);
} else { /* type == L_PAINT_DARK */
if (aveval > thresh) /* skip sufficiently light pixels */
continue;
nrval = rval + (l_int32)((255. - rval) * aveval * factor);
ngval = gval + (l_int32)((255. - gval) * aveval * factor);
nbval = bval + (l_int32)((255. - bval) * aveval * factor);
}
composeRGBPixel(nrval, ngval, nbval, &val32);
*(line + j) = val32;
}
}
return pixd;
}
/*------------------------------------------------------------------*
* Adjusting one or more colors to a target color *
*------------------------------------------------------------------*/
/*!
* \brief pixSnapColor()
*
* \param[in] pixd [optional]; either NULL or equal to pixs for in-place
* \param[in] pixs colormapped or 8 bpp gray or 32 bpp rgb
* \param[in] srcval color center to be selected for change: 0xrrggbb00
* \param[in] dstval target color for pixels: 0xrrggbb00
* \param[in] diff max absolute difference, applied to all components
* \return pixd with all pixels within diff of pixval set to pixval,
* or pixd on error
*
*
* Notes:
* (1) For inplace operation, call it this way:
* pixSnapColor(pixs, pixs, ... )
* (2) For generating a new pixd:
* pixd = pixSnapColor(NULL, pixs, ...)
* (3) If pixs has a colormap, it is handled by pixSnapColorCmap().
* (4) All pixels within 'diff' of 'srcval', componentwise,
* will be changed to 'dstval'.
*
*/
PIX *
pixSnapColor(PIX *pixd,
PIX *pixs,
l_uint32 srcval,
l_uint32 dstval,
l_int32 diff)
{
l_int32 val, sval, dval;
l_int32 rval, gval, bval, rsval, gsval, bsval;
l_int32 i, j, w, h, d, wpl;
l_uint32 pixel;
l_uint32 *line, *data;
PROCNAME("pixSnapColor");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && (pixd != pixs))
return (PIX *)ERROR_PTR("pixd exists, but != pixs", procName, pixd);
if (pixGetColormap(pixs))
return pixSnapColorCmap(pixd, pixs, srcval, dstval, diff);
/* pixs does not have a colormap; it must be 8 bpp gray or
* 32 bpp rgb. */
if (pixGetDepth(pixs) < 8)
return (PIX *)ERROR_PTR("pixs is < 8 bpp", procName, pixd);
/* Do the work on pixd */
if (!pixd)
pixd = pixCopy(NULL, pixs);
pixGetDimensions(pixd, &w, &h, &d);
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
if (d == 8) {
sval = srcval & 0xff;
dval = dstval & 0xff;
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
val = GET_DATA_BYTE(line, j);
if (L_ABS(val - sval) <= diff)
SET_DATA_BYTE(line, j, dval);
}
}
} else { /* d == 32 */
extractRGBValues(srcval, &rsval, &gsval, &bsval);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
pixel = *(line + j);
extractRGBValues(pixel, &rval, &gval, &bval);
if ((L_ABS(rval - rsval) <= diff) &&
(L_ABS(gval - gsval) <= diff) &&
(L_ABS(bval - bsval) <= diff))
*(line + j) = dstval; /* replace */
}
}
}
return pixd;
}
/*!
* \brief pixSnapColorCmap()
*
* \param[in] pixd [optional]; either NULL or equal to pixs for in-place
* \param[in] pixs colormapped
* \param[in] srcval color center to be selected for change: 0xrrggbb00
* \param[in] dstval target color for pixels: 0xrrggbb00
* \param[in] diff max absolute difference, applied to all components
* \return pixd with all pixels within diff of srcval set to dstval,
* or pixd on error
*
*
* Notes:
* (1) For inplace operation, call it this way:
* pixSnapCcmap(pixs, pixs, ... )
* (2) For generating a new pixd:
* pixd = pixSnapCmap(NULL, pixs, ...)
* (3) pixs must have a colormap.
* (4) All colors within 'diff' of 'srcval', componentwise,
* will be changed to 'dstval'.
*
*/
PIX *
pixSnapColorCmap(PIX *pixd,
PIX *pixs,
l_uint32 srcval,
l_uint32 dstval,
l_int32 diff)
{
l_int32 i, ncolors, index, found;
l_int32 rval, gval, bval, rsval, gsval, bsval, rdval, gdval, bdval;
l_int32 *tab;
PIX *pixm;
PIXCMAP *cmap;
PROCNAME("pixSnapColorCmap");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (!pixGetColormap(pixs))
return (PIX *)ERROR_PTR("cmap not found", procName, pixd);
if (pixd && (pixd != pixs))
return (PIX *)ERROR_PTR("pixd exists, but != pixs", procName, pixd);
if (!pixd)
pixd = pixCopy(NULL, pixs);
/* If no free colors, look for one close to the target
* that can be commandeered. */
cmap = pixGetColormap(pixd);
ncolors = pixcmapGetCount(cmap);
extractRGBValues(srcval, &rsval, &gsval, &bsval);
extractRGBValues(dstval, &rdval, &gdval, &bdval);
found = FALSE;
if (pixcmapGetFreeCount(cmap) == 0) {
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &rval, &gval, &bval);
if ((L_ABS(rval - rsval) <= diff) &&
(L_ABS(gval - gsval) <= diff) &&
(L_ABS(bval - bsval) <= diff)) {
index = i;
pixcmapResetColor(cmap, index, rdval, gdval, bdval);
found = TRUE;
break;
}
}
} else { /* just add the new color */
pixcmapAddColor(cmap, rdval, gdval, bdval);
ncolors = pixcmapGetCount(cmap);
index = ncolors - 1; /* index of new destination color */
found = TRUE;
}
if (!found) {
L_INFO("nothing to do\n", procName);
return pixd;
}
/* For each color in cmap that is close enough to srcval,
* set the tab value to 1. Then generate a 1 bpp mask with
* fg pixels for every pixel in pixd that is close enough
* to srcval (i.e., has value 1 in tab). */
if ((tab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32))) == NULL)
return (PIX *)ERROR_PTR("tab not made", procName, pixd);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &rval, &gval, &bval);
if ((L_ABS(rval - rsval) <= diff) &&
(L_ABS(gval - gsval) <= diff) &&
(L_ABS(bval - bsval) <= diff))
tab[i] = 1;
}
pixm = pixMakeMaskFromLUT(pixd, tab);
LEPT_FREE(tab);
/* Use the binary mask to set all selected pixels to
* the dest color index. */
pixSetMasked(pixd, pixm, dstval);
pixDestroy(&pixm);
/* Remove all unused colors from the colormap. */
pixRemoveUnusedColors(pixd);
return pixd;
}
/*---------------------------------------------------------------------*
* Piecewise linear color mapping based on a source/target pair *
*---------------------------------------------------------------------*/
/*!
* \brief pixLinearMapToTargetColor()
*
* \param[in] pixd [optional]; either NULL or equal to pixs for in-place
* \param[in] pixs 32 bpp rgb
* \param[in] srcval source color: 0xrrggbb00
* \param[in] dstval target color: 0xrrggbb00
* \return pixd with all pixels mapped based on the srcval/destval mapping,
* or pixd on error
*
*
* Notes:
* (1) For each component (r, b, g) separately, this does a piecewise
* linear mapping of the colors in pixs to colors in pixd.
* If rs and rd are the red src and dest components in %srcval and
* %dstval, then the range [0 ... rs] in pixs is mapped to
* [0 ... rd] in pixd. Likewise, the range [rs ... 255] in pixs
* is mapped to [rd ... 255] in pixd. And similarly for green
* and blue.
* (2) The mapping will in general change the hue of the pixels.
* However, if the src and dst targets are related by
* a transformation given by pixelFractionalShift(), the hue
* is invariant. A special case is where the dest in the
* map is white (255, 255, 255) for an arbitrary srcval.
* (3) For inplace operation, call it this way:
* pixLinearMapToTargetColor(pixs, pixs, ... );
* For generating a new pixd:
* pixd = pixLinearMapToTargetColor(NULL, pixs, ...);
* (4) See pixShiftWithInvariantHue() for a special case of this function.
*
*/
PIX *
pixLinearMapToTargetColor(PIX *pixd,
PIX *pixs,
l_uint32 srcval,
l_uint32 dstval)
{
l_int32 i, j, w, h, wpl;
l_int32 rval, gval, bval, rsval, gsval, bsval, rdval, gdval, bdval;
l_int32 *rtab, *gtab, *btab;
l_uint32 pixel;
l_uint32 *line, *data;
PROCNAME("pixLinearMapToTargetColor");
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, pixd);
if (pixd && (pixd != pixs))
return (PIX *)ERROR_PTR("pixd exists, but != pixs", procName, pixd);
/* Do the work on pixd */
if (!pixd)
pixd = pixCopy(NULL, pixs);
extractRGBValues(srcval, &rsval, &gsval, &bsval);
extractRGBValues(dstval, &rdval, &gdval, &bdval);
rsval = L_MIN(254, L_MAX(1, rsval));
gsval = L_MIN(254, L_MAX(1, gsval));
bsval = L_MIN(254, L_MAX(1, bsval));
rtab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
gtab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
btab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
if (!rtab || !gtab || !btab)
return (PIX *)ERROR_PTR("calloc fail for tab", procName, pixd);
for (i = 0; i < 256; i++) {
if (i <= rsval)
rtab[i] = (i * rdval) / rsval;
else
rtab[i] = rdval + ((255 - rdval) * (i - rsval)) / (255 - rsval);
if (i <= gsval)
gtab[i] = (i * gdval) / gsval;
else
gtab[i] = gdval + ((255 - gdval) * (i - gsval)) / (255 - gsval);
if (i <= bsval)
btab[i] = (i * bdval) / bsval;
else
btab[i] = bdval + ((255 - bdval) * (i - bsval)) / (255 - bsval);
}
pixGetDimensions(pixd, &w, &h, NULL);
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
pixel = line[j];
extractRGBValues(pixel, &rval, &gval, &bval);
composeRGBPixel(rtab[rval], gtab[gval], btab[bval], &pixel);
line[j] = pixel;
}
}
LEPT_FREE(rtab);
LEPT_FREE(gtab);
LEPT_FREE(btab);
return pixd;
}
/*!
* \brief pixelLinearMapToTargetColor()
*
* \param[in] scolor rgb source color: 0xrrggbb00
* \param[in] srcmap source mapping color: 0xrrggbb00
* \param[in] dstmap target mapping color: 0xrrggbb00
* \param[out] pdcolor rgb dest color: 0xrrggbb00
* \return 0 if OK, 1 on error
*
*
* Notes:
* (1) This does this does a piecewise linear mapping of each
* component of %scolor to %dcolor, based on the relation
* between the components of %srcmap and %dstmap. It is the
* same transformation, performed on a single color, as mapped
* on every pixel in a pix by pixLinearMapToTargetColor().
* (2) For each component, if the sval is larger than the smap,
* the dval will be pushed up from dmap towards white.
* Otherwise, dval will be pushed down from dmap towards black.
* This is because you can visualize the transformation as
* a linear stretching where smap moves to dmap, and everything
* else follows linearly with 0 and 255 fixed.
* (3) The mapping will in general change the hue of %scolor.
* However, if the %srcmap and %dstmap targets are related by
* a transformation given by pixelFractionalShift(), the hue
* will be invariant.
*
*/
l_ok
pixelLinearMapToTargetColor(l_uint32 scolor,
l_uint32 srcmap,
l_uint32 dstmap,
l_uint32 *pdcolor)
{
l_int32 srval, sgval, sbval, drval, dgval, dbval;
l_int32 srmap, sgmap, sbmap, drmap, dgmap, dbmap;
PROCNAME("pixelLinearMapToTargetColor");
if (!pdcolor)
return ERROR_INT("&dcolor not defined", procName, 1);
*pdcolor = 0;
extractRGBValues(scolor, &srval, &sgval, &sbval);
extractRGBValues(srcmap, &srmap, &sgmap, &sbmap);
extractRGBValues(dstmap, &drmap, &dgmap, &dbmap);
srmap = L_MIN(254, L_MAX(1, srmap));
sgmap = L_MIN(254, L_MAX(1, sgmap));
sbmap = L_MIN(254, L_MAX(1, sbmap));
if (srval <= srmap)
drval = (srval * drmap) / srmap;
else
drval = drmap + ((255 - drmap) * (srval - srmap)) / (255 - srmap);
if (sgval <= sgmap)
dgval = (sgval * dgmap) / sgmap;
else
dgval = dgmap + ((255 - dgmap) * (sgval - sgmap)) / (255 - sgmap);
if (sbval <= sbmap)
dbval = (sbval * dbmap) / sbmap;
else
dbval = dbmap + ((255 - dbmap) * (sbval - sbmap)) / (255 - sbmap);
composeRGBPixel(drval, dgval, dbval, pdcolor);
return 0;
}
/*------------------------------------------------------------------*
* Fractional shift of RGB towards black or white *
*------------------------------------------------------------------*/
/*!
* \brief pixShiftByComponent()
*
* \param[in] pixd [optional]; either NULL or equal to pixs for in-place
* \param[in] pixs 32 bpp rgb, cmap OK
* \param[in] srcval source color: 0xrrggbb00
* \param[in] dstval target color: 0xrrggbb00
* \return pixd with all pixels mapped based on the srcval/destval mapping,
* or pixd on error
*
*
* Notes:
* (1) For each component (r, b, g) separately, this does a linear
* mapping of the colors in pixs to colors in pixd.
* Let rs and rd be the red src and dest components in %srcval and
* %dstval, and rval is the red component of the src pixel.
* Then for all pixels in pixs, the mapping for the red
* component from pixs to pixd is:
* if (rd <= rs) (shift toward black)
* rval --> (rd/rs) * rval
* if (rd > rs) (shift toward white)
* (255 - rval) --> ((255 - rs)/(255 - rd)) * (255 - rval)
* Thus if rd <= rs, the red component of all pixels is
* mapped by the same fraction toward white, and if rd > rs,
* they are mapped by the same fraction toward black.
* This is essentially a different linear TRC (gamma = 1)
* for each component. The source and target color inputs are
* just used to generate the three fractions.
* (2) Note that this mapping differs from that in
* pixLinearMapToTargetColor(), which maps rs --> rd and does
* a piecewise stretching in between.
* (3) For inplace operation, call it this way:
* pixFractionalShiftByComponent(pixs, pixs, ... )
* (4) For generating a new pixd:
* pixd = pixLinearMapToTargetColor(NULL, pixs, ...)
* (5) A simple application is to color a grayscale image.
* A light background can be colored using srcval = 0xffffff00
* and picking a target background color for dstval.
* A dark foreground can be colored by using srcval = 0x0
* and choosing a target foreground color for dstval.
*
*/
PIX *
pixShiftByComponent(PIX *pixd,
PIX *pixs,
l_uint32 srcval,
l_uint32 dstval)
{
l_int32 i, j, w, h, wpl;
l_int32 rval, gval, bval, rsval, gsval, bsval, rdval, gdval, bdval;
l_int32 *rtab, *gtab, *btab;
l_uint32 pixel;
l_uint32 *line, *data;
PIXCMAP *cmap;
PROCNAME("pixShiftByComponent");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && (pixd != pixs))
return (PIX *)ERROR_PTR("pixd exists, but != pixs", procName, pixd);
if (pixGetDepth(pixs) != 32 && !pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs not cmapped or 32 bpp", procName, pixd);
/* Do the work on pixd */
if (!pixd)
pixd = pixCopy(NULL, pixs);
/* If colormapped, just modify it */
if ((cmap = pixGetColormap(pixd)) != NULL) {
pixcmapShiftByComponent(cmap, srcval, dstval);
return pixd;
}
extractRGBValues(srcval, &rsval, &gsval, &bsval);
extractRGBValues(dstval, &rdval, &gdval, &bdval);
rtab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
gtab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
btab = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
if (!rtab || !gtab || !btab) {
L_ERROR("calloc fail for tab\n", procName);
goto cleanup;
}
for (i = 0; i < 256; i++) {
if (rdval == rsval)
rtab[i] = i;
else if (rdval < rsval)
rtab[i] = (i * rdval) / rsval;
else
rtab[i] = 255 - (255 - rdval) * (255 - i) / (255 - rsval);
if (gdval == gsval)
gtab[i] = i;
else if (gdval < gsval)
gtab[i] = (i * gdval) / gsval;
else
gtab[i] = 255 - (255 - gdval) * (255 - i) / (255 - gsval);
if (bdval == bsval)
btab[i] = i;
else if (bdval < bsval)
btab[i] = (i * bdval) / bsval;
else
btab[i] = 255 - (255 - bdval) * (255 - i) / (255 - bsval);
}
pixGetDimensions(pixd, &w, &h, NULL);
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
pixel = line[j];
extractRGBValues(pixel, &rval, &gval, &bval);
composeRGBPixel(rtab[rval], gtab[gval], btab[bval], &pixel);
line[j] = pixel;
}
}
cleanup:
LEPT_FREE(rtab);
LEPT_FREE(gtab);
LEPT_FREE(btab);
return pixd;
}
/*!
* \brief pixelShiftByComponent()
*
* \param[in] rval, gval, bval
* \param[in] srcval source color: 0xrrggbb00
* \param[in] dstval target color: 0xrrggbb00
* \param[out] ppixel rgb value
* \return 0 if OK, 1 on error
*
*
* Notes:
* (1) This is a linear transformation that gives the same result
* on a single pixel as pixShiftByComponent() gives
* on a pix. Each component is handled separately. If
* the dest component is larger than the src, then the
* component is pushed toward 255 by the same fraction as
* the src --> dest shift.
*
*/
l_ok
pixelShiftByComponent(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_uint32 srcval,
l_uint32 dstval,
l_uint32 *ppixel)
{
l_int32 rsval, rdval, gsval, gdval, bsval, bdval, rs, gs, bs;
PROCNAME("pixelShiftByComponent");
if (!ppixel)
return ERROR_INT("&pixel defined", procName, 1);
extractRGBValues(srcval, &rsval, &gsval, &bsval);
extractRGBValues(dstval, &rdval, &gdval, &bdval);
if (rdval == rsval)
rs = rval;
else if (rdval < rsval)
rs = (rval * rdval) / rsval;
else
rs = 255 - (255 - rdval) * (255 - rval) / (255 - rsval);
if (gdval == gsval)
gs = gval;
else if (gdval < gsval)
gs = (gval * gdval) / gsval;
else
gs = 255 - (255 - gdval) * (255 - gval) / (255 - gsval);
if (bdval == bsval)
bs = bval;
else if (bdval < bsval)
bs = (bval * bdval) / bsval;
else
bs = 255 - (255 - bdval) * (255 - bval) / (255 - bsval);
composeRGBPixel(rs, gs, bs, ppixel);
return 0;
}
/*!
* \brief pixelFractionalShift()
*
* \param[in] rval red source component
* \param[in] gval green source component
* \param[in] bval blue source component
* \param[in] fract negative toward black; positive toward white
* \param[out] ppixel resulting rgb value
* \return 0 if OK, 1 on error
*
*
* Notes:
* (1) This linear transformation shifts each component a fraction
* toward either black (%fract < 0) or white (%fract > 0).
* (2) It changes the saturation and intensity, but leaves the hue
* invariant. See usage in pixLinearMapToTargetColor() and
* pixMapWithInvariantHue().
* (3) %fract is in the range [-1 .... +1]. If %fract < 0,
* saturation is increased and brightness is reduced. The
* opposite results if %fract > 0. If %fract == -1,
* the resulting pixel is black; %fract == 1 results in white.
*
*/
l_ok
pixelFractionalShift(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_float32 fract,
l_uint32 *ppixel)
{
l_int32 nrval, ngval, nbval;
PROCNAME("pixelFractionalShift");
if (!ppixel)
return ERROR_INT("&pixel defined", procName, 1);
if (fract < -1.0 || fract > 1.0)
return ERROR_INT("fraction not in [-1 ... +1]", procName, 1);
nrval = (fract < 0) ? (l_int32)((1.0 + fract) * rval + 0.5) :
rval + (l_int32)(fract * (255 - rval) + 0.5);
ngval = (fract < 0) ? (l_int32)((1.0 + fract) * gval + 0.5) :
gval + (l_int32)(fract * (255 - gval) + 0.5);
nbval = (fract < 0) ? (l_int32)((1.0 + fract) * bval + 0.5) :
bval + (l_int32)(fract * (255 - bval) + 0.5);
composeRGBPixel(nrval, ngval, nbval, ppixel);
return 0;
}
/*!
* \brief pixMapWithInvariantHue()
*
* \param[in] pixd [optional]; either NULL or equal to pixs for in-place
* \param[in] pixs 32 bpp rgb
* \param[in] srcval reference source color: 0xrrggbb00
* \param[in] fract fraction toward white of dest color
* \return pixd with all pixels mapped based on the srcval/destval mapping,
* or pixd on error
*
*
* Notes:
* (1) The combination of %srcval and %fract define the linear
* hue-preserving transformation, that is applied to all pixels.
* (2) %fract is in the range [-1 .... +1]. If %fract < 0,
* saturation is increased and brightness is reduced. The
* opposite results if %fract > 0. If %fract == -1,
* %srcval is mapped to black; if %fract == 1, it is mapped to white.
* (3) For inplace operation, call it this way:
* pixMapWithInvariatHue(pixs, pixs, ... );
* For generating a new pixd:
* pixd = pixMapWithInvariantHue(NULL, pixs, ...);
*
*/
PIX *
pixMapWithInvariantHue(PIX *pixd,
PIX *pixs,
l_uint32 srcval,
l_float32 fract)
{
l_int32 rval, gval, bval;
l_uint32 dstval;
PROCNAME("pixMapWithInvariantHue");
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, pixd);
if (pixd && (pixd != pixs))
return (PIX *)ERROR_PTR("pixd exists, but != pixs", procName, pixd);
if (fract < -1.0 || fract > 1.0)
return (PIX *)ERROR_PTR("fraction not in [-1 ... +1]", procName, NULL);
/* Generate the dstval that is %fract toward white from %srcval */
extractRGBValues(srcval, &rval, &gval, &bval);
pixelFractionalShift(rval, gval, bval, fract, &dstval);
/* Use the (%srcval, dstval) pair to define the linear transform */
return pixLinearMapToTargetColor(pixd, pixs, srcval, dstval);
}