From cb382f87d63bdc3736696ee289875bde2ecee9e5 Mon Sep 17 00:00:00 2001
From: Alexander Volkov <a.volkov@rusbitech.ru>
Date: Thu, 25 Apr 2019 18:09:59 +0300
Subject: Add HiDPI support

Reviewers: sars, davidedmundson, ngraham

Reviewed By: sars

Differential Revision: https://phabricator.kde.org/D20821
---
 src/ImageViewer.cpp | 14 +++++++++++---
 src/main.cpp        |  1 +
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/ImageViewer.cpp b/src/ImageViewer.cpp
index 09f9b3d..5cf1439 100644
--- a/src/ImageViewer.cpp
+++ b/src/ImageViewer.cpp
@@ -87,14 +87,19 @@ void ImageViewer::setQImage(QImage *img)
     }
 
     d->img = img;
-    d->scene->setSceneRect(0, 0, img->width(), img->height());
+    const auto dpr = devicePixelRatioF();
+    d->img->setDevicePixelRatio(dpr);
+    d->scene->setSceneRect(0, 0, img->width() / dpr, img->height() / dpr);
 }
 
 // ------------------------------------------------------------------------
 void ImageViewer::drawBackground(QPainter *painter, const QRectF &rect)
 {
     painter->fillRect(rect, QColor(0x70, 0x70, 0x70));
-    painter->drawImage(rect, *d->img, rect);
+    QRectF r = rect & sceneRect();
+    const auto dpr = d->img->devicePixelRatio();
+    QRectF srcRect = QRectF(r.topLeft() * dpr, r.size() * dpr);
+    painter->drawImage(r, *d->img, srcRect);
 }
 
 // ------------------------------------------------------------------------
@@ -118,7 +123,10 @@ void ImageViewer::zoomActualSize()
 // ------------------------------------------------------------------------
 void ImageViewer::zoom2Fit()
 {
-    fitInView(d->img->rect(), Qt::KeepAspectRatio);
+    QRectF r = d->img->rect();
+    const auto dpr = d->img->devicePixelRatio();
+    r = QRectF(r.topLeft() / dpr, r.size() / dpr);
+    fitInView(r, Qt::KeepAspectRatio);
 }
 
 // ------------------------------------------------------------------------
diff --git a/src/main.cpp b/src/main.cpp
index aa704be..ae0d9b6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -34,6 +34,7 @@
 
 int main(int argc, char *argv[])
 {
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
     QApplication app(argc, argv);
 
     Kdelibs4ConfigMigrator migrate(QLatin1String("Skanlite"));
-- 
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