Take pixel ratio into account for graph cache. (#1405)

* Take pixel ratio into account for graph cache.

src/Cutter.pro

@@ -311,7 +311,8 @@ SOURCES += \
     common/BasicBlockHighlighter.cpp \
     dialogs/LinkTypeDialog.cpp \
     common/UpdateWorker.cpp \
-    widgets/MemoryDockWidget.cpp
+    widgets/MemoryDockWidget.cpp \
+    common/HighDpiPixmap.cpp
 
 HEADERS  += \
     core/Cutter.h \
@@ -428,7 +429,8 @@ HEADERS  += \
     common/BasicBlockHighlighter.h \
     common/UpdateWorker.h \
     dialogs/LinkTypeDialog.h \
-    widgets/MemoryDockWidget.h
+    widgets/MemoryDockWidget.h \
+    common/HighDpiPixmap.h
 
 FORMS    += \
     dialogs/AboutDialog.ui \

src/CutterApplication.cpp

@@ -29,6 +29,7 @@ CutterApplication::CutterApplication(int &argc, char **argv) : QApplication(argc
     setApplicationVersion(CUTTER_VERSION_FULL);
     setWindowIcon(QIcon(":/img/cutter.svg"));
     setAttribute(Qt::AA_DontShowIconsInMenus);
+    setAttribute(Qt::AA_UseHighDpiPixmaps);
     setLayoutDirection(Qt::LeftToRight);
 
     // WARN!!! Put initialization code below this line. Code above this line is mandatory to be run First

src/common/HighDpiPixmap.cpp

@@ -0,0 +1,23 @@
+#include "common/HighDpiPixmap.h"
+
+#include <QGuiApplication>
+#include <QScreen>
+
+static qreal GetDevicePixelRatio(qreal devicePixelRatio)
+{
+    if (devicePixelRatio > 0) {
+        return devicePixelRatio;
+    }
+    qreal ratio = 1;
+    for (auto screen : QGuiApplication::screens()) {
+        ratio = std::max(ratio, screen->devicePixelRatio());
+    }
+    return ratio;
+}
+
+HighDpiPixmap::HighDpiPixmap(int width, int height, qreal devicePixelRatio)
+    : QPixmap(int(width * GetDevicePixelRatio(devicePixelRatio)),
+              int(height * GetDevicePixelRatio(devicePixelRatio)))
+{
+    setDevicePixelRatio(GetDevicePixelRatio(devicePixelRatio));
+}

src/common/HighDpiPixmap.h

@@ -0,0 +1,11 @@
+#ifndef HIGHDPIPIXMAP_H
+#define HIGHDPIPIXMAP_H
+
+#include <QPixmap>
+class HighDpiPixmap : public QPixmap
+{
+public:
+    HighDpiPixmap(int width, int height, qreal devicePixelRatio = -1);
+};
+
+#endif // HIGHDPIPIXMAP_H

src/dialogs/NewFileDialog.cpp

@@ -4,6 +4,7 @@
 #include "dialogs/AboutDialog.h"
 #include "ui_NewfileDialog.h"
 #include "common/Helpers.h"
+#include "common/HighDpiPixmap.h"
 
 #include <QFileDialog>
 #include <QtGui>
@@ -33,7 +34,7 @@ static QIcon getIconFor(const QString &str, int pos)
     int w = 64;
     int h = 64;
 
-    QPixmap pixmap(w, h);
+    HighDpiPixmap pixmap(w, h);
     pixmap.fill(Qt::transparent);
 
     QPainter pixPaint(&pixmap);

src/widgets/GraphView.cpp

@@ -381,11 +381,13 @@ QPolygonF GraphView::recalculatePolygon(QPolygonF polygon)
 void GraphView::paintEvent(QPaintEvent *event)
 {
     Q_UNUSED(event);
-    if (useCache) {
+    qreal dpr = devicePixelRatioF();
+    if (useCache && qFuzzyCompare(dpr, pixmap.devicePixelRatioF())) {
         drawGraph();
         return;
     }
-    pixmap = QPixmap(viewport()->width(), viewport()->height());
+    pixmap = QPixmap(int(viewport()->width() * dpr), int(viewport()->height() * dpr));
+    pixmap.setDevicePixelRatio(dpr);
     QPainter p(&pixmap);
 
     p.setRenderHint(QPainter::Antialiasing);
@@ -393,9 +395,8 @@ void GraphView::paintEvent(QPaintEvent *event)
     int render_width = viewport()->width();
     int render_height = viewport()->height();
 
-    QRect viewportRect(viewport()->rect().topLeft(), viewport()->rect().bottomRight() - QPoint(1, 1));
     p.setBrush(backgroundColor);
-    p.drawRect(viewportRect);
+    p.drawRect(viewport()->rect());
     p.setBrush(Qt::black);
 
     p.scale(current_scale, current_scale);
@@ -448,7 +449,8 @@ void GraphView::paintEvent(QPaintEvent *event)
 void GraphView::drawGraph()
 {
     QRectF target(0.0, 0.0, viewport()->width(), viewport()->height());
-    QRectF source(0.0, 0.0, viewport()->width(), viewport()->height());
+    QRectF source(0.0, 0.0, viewport()->width() * pixmap.devicePixelRatioF(),
+                  viewport()->height() * pixmap.devicePixelRatioF());
     QPainter p(viewport());
     p.drawPixmap(target, pixmap, source);
 }