From 26befecbf935d3819aefc125066c17082729f664 Mon Sep 17 00:00:00 2001
From: Peter Iannucci <iannucci@mit.edu>
Date: Mon, 9 May 2016 11:38:52 -0400
Subject: [PATCH] Initial HiDPI support for qt5agg backend

---
 lib/matplotlib/backends/backend_qt5.py    | 31 ++++++++++-------------
 lib/matplotlib/backends/backend_qt5agg.py |  3 +++
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/lib/matplotlib/backends/backend_qt5.py b/lib/matplotlib/backends/backend_qt5.py
index 66aed1371e8a..8476792ee5cc 100644
--- a/lib/matplotlib/backends/backend_qt5.py
+++ b/lib/matplotlib/backends/backend_qt5.py
@@ -249,10 +249,14 @@ def leaveEvent(self, event):
         QtWidgets.QApplication.restoreOverrideCursor()
         FigureCanvasBase.leave_notify_event(self, guiEvent=event)
 
+    def mouseEventCoords(self, pos):
+        x = pos.x() * self.devicePixelRatio()
+        # flip y so y=0 is bottom of canvas
+        y = self.figure.bbox.height - pos.y() * self.devicePixelRatio()
+        return x, y
+
     def mousePressEvent(self, event):
-        x = event.pos().x()
-        # flipy so y=0 is bottom of canvas
-        y = self.figure.bbox.height - event.pos().y()
+        x, y = self.mouseEventCoords(event.pos())
         button = self.buttond.get(event.button())
         if button is not None:
             FigureCanvasBase.button_press_event(self, x, y, button,
@@ -261,9 +265,7 @@ def mousePressEvent(self, event):
             print('button pressed:', event.button())
 
     def mouseDoubleClickEvent(self, event):
-        x = event.pos().x()
-        # flipy so y=0 is bottom of canvas
-        y = self.figure.bbox.height - event.pos().y()
+        x, y = self.mouseEventCoords(event.pos())
         button = self.buttond.get(event.button())
         if button is not None:
             FigureCanvasBase.button_press_event(self, x, y,
@@ -273,16 +275,12 @@ def mouseDoubleClickEvent(self, event):
             print('button doubleclicked:', event.button())
 
     def mouseMoveEvent(self, event):
-        x = event.x()
-        # flipy so y=0 is bottom of canvas
-        y = self.figure.bbox.height - event.y()
+        x, y = self.mouseEventCoords(event)
         FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=event)
         # if DEBUG: print('mouse move')
 
     def mouseReleaseEvent(self, event):
-        x = event.x()
-        # flipy so y=0 is bottom of canvas
-        y = self.figure.bbox.height - event.y()
+        x, y = self.mouseEventCoords(event)
         button = self.buttond.get(event.button())
         if button is not None:
             FigureCanvasBase.button_release_event(self, x, y, button,
@@ -291,9 +289,7 @@ def mouseReleaseEvent(self, event):
             print('button released')
 
     def wheelEvent(self, event):
-        x = event.x()
-        # flipy so y=0 is bottom of canvas
-        y = self.figure.bbox.height - event.y()
+        x, y = self.mouseEventCoords(event)
         # from QWheelEvent::delta doc
         if event.pixelDelta().x() == 0 and event.pixelDelta().y() == 0:
             steps = event.angleDelta().y() / 120
@@ -323,8 +319,9 @@ def keyReleaseEvent(self, event):
             print('key release', key)
 
     def resizeEvent(self, event):
-        w = event.size().width()
-        h = event.size().height()
+        dpi_ratio = getattr(self, '_dpi_ratio', 1)
+        w = event.size().width() * dpi_ratio
+        h = event.size().height() * dpi_ratio
         if DEBUG:
             print('resize (%d x %d)' % (w, h))
             print("FigureCanvasQt.resizeEvent(%d, %d)" % (w, h))
diff --git a/lib/matplotlib/backends/backend_qt5agg.py b/lib/matplotlib/backends/backend_qt5agg.py
index 81addae00d27..f1549701513e 100644
--- a/lib/matplotlib/backends/backend_qt5agg.py
+++ b/lib/matplotlib/backends/backend_qt5agg.py
@@ -100,6 +100,7 @@ def paintEvent(self, e):
             qImage = QtGui.QImage(stringBuffer, self.renderer.width,
                                   self.renderer.height,
                                   QtGui.QImage.Format_ARGB32)
+            qImage.setDevicePixelRatio(self._dpi_ratio)
             # get the rectangle for the image
             rect = qImage.rect()
             p = QtGui.QPainter(self)
@@ -135,6 +136,7 @@ def paintEvent(self, e):
                 stringBuffer = reg.to_string_argb()
                 qImage = QtGui.QImage(stringBuffer, w, h,
                                       QtGui.QImage.Format_ARGB32)
+                qImage.setDevicePixelRatio(self._dpi_ratio)
                 # Adjust the stringBuffer reference count to work
                 # around a memory leak bug in QImage() under PySide on
                 # Python 3.x
@@ -222,6 +224,7 @@ def __init__(self, figure):
         super(FigureCanvasQTAgg, self).__init__(figure=figure)
         self._drawRect = None
         self.blitbox = []
+        self._dpi_ratio = self.devicePixelRatio()
         self.setAttribute(QtCore.Qt.WA_OpaquePaintEvent)