From 7eeac44cfb57772b244fad2c075e722459d04451 Mon Sep 17 00:00:00 2001
From: John Wiggins <jwiggins@enthought.com>
Date: Mon, 22 Feb 2021 16:57:30 +0100
Subject: [PATCH] Get the Qt Quartz backend working again

---
 enable/qt4/quartz.py | 95 +++++++++++---------------------------------
 1 file changed, 23 insertions(+), 72 deletions(-)

diff --git a/enable/qt4/quartz.py b/enable/qt4/quartz.py
index 6876bb646..7d99a9e93 100644
--- a/enable/qt4/quartz.py
+++ b/enable/qt4/quartz.py
@@ -7,10 +7,13 @@
 # is also available online at http://www.enthought.com/licenses/BSD.txt
 #
 # Thanks for using Enthought open source!
-import numpy as np
+from PIL import Image, ImageQt
+
+# Qt imports.
+from pyface.qt import QtCore, QtGui
 
 from kiva.api import Font
-from kiva.quartz import get_mac_context, ABCGI
+from kiva.quartz import ABCGI
 
 from .base_window import BaseWindow
 from .scrollbar import NativeScrollBar
@@ -18,57 +21,8 @@
 CompiledPath = ABCGI.CGMutablePath
 
 
-class GraphicsContext(ABCGI.CGLayerContext):
-    def __init__(self, size_or_array, *args, **kwds):
-        gc = kwds.pop("window_gc", None)
-        if not gc:
-            # Create a tiny base context to spawn the CGLayerContext from.
-            # We are better off making our Layer from the window gc since
-            # the data formats will match and so it will be faster to draw the
-            # layer.
-            gc = ABCGI.CGBitmapContext((1, 1))
-        if isinstance(size_or_array, np.ndarray):
-            # Initialize the layer with an image.
-            image = ABCGI.CGImage(size_or_array)
-            width = image.width
-            height = image.height
-        else:
-            # No initialization.
-            image = None
-            width, height = size_or_array
-
-        super(GraphicsContext, self).__init__(
-            (width, height), gc, *args, **kwds
-        )
-        if image is not None:
-            self.draw_image(image)
-
-    @classmethod
-    def create_from_gc(klass, gc, size_or_array, *args, **kwds):
-        return klass(size_or_array, window_gc=gc, *args, **kwds)
-
-
-class _WindowGraphicsContext(ABCGI.CGContextInABox):
-    def __init__(self, *args, **kwds):
-        super(_WindowGraphicsContext, self).__init__(*args, **kwds)
-        self._begun = False
-
-    def begin(self):
-        if self._begun:
-            return
-        self.save_state()
-        self.translate_ctm(0, self.height())
-        self.scale_ctm(1.0, -1.0)
-        self._begun = True
-
-    def end(self):
-        if self._begun:
-            self.restore_state()
-            self._begun = False
-
-    @staticmethod
-    def create_from_gc(gc, size_or_array, *args, **kwds):
-        return GraphicsContext(size_or_array, window_gc=gc, *args, **kwds)
+class GraphicsContext(ABCGI.CGBitmapContext):
+    pass
 
 
 class Window(BaseWindow):
@@ -78,27 +32,24 @@ class Window(BaseWindow):
     # 'BaseWindow' interface ###############################################
 
     def _create_gc(self, size, pix_format=None):
-        if hasattr(self.control, "winId"):
-            # From the Qt 4.7 Documentation:
-            # "On Mac OS X, the type returned depends on which framework Qt was
-            # linked against. If Qt is using Carbon, the {WId} is actually
-            # an HIViewRef. If Qt is using Cocoa, {WId} is a pointer to
-            # an NSView."
-            # get_mac_context() only works on Cocoa.
-            self.dc = get_mac_context(self.control.winId())
-            if self.dc:
-                gc = _WindowGraphicsContext(size, self.dc)
-                gc.begin()
-                return gc
-        raise NotImplementedError("Only Qt built against Cocoa is supported")
+        gc = GraphicsContext(size)
+        gc.scale_ctm(self.base_pixel_scale, self.base_pixel_scale)
+
+        return gc
 
     def _window_paint(self, event):
-        # Make sure end() is called so that the window's GC is not left in an
-        # odd state.
-        self._gc.end()
-        # Force a new gc to be created for the next paint()
-        self._gc = None
-        self.dc = None
+        if self.control is None:
+            return
+
+        # self._gc is an image context
+        w = self._gc.width()
+        h = self._gc.height()
+        pilimage = Image.frombuffer("RGBA", (w, h), self._gc,
+                                    "raw", "RGBA", 0, 1)
+        image = ImageQt.toqimage(pilimage)
+        rect = QtCore.QRectF(0, 0, self.control.width(), self.control.height())
+        painter = QtGui.QPainter(self.control)
+        painter.drawImage(rect, image)
 
 
 def font_metrics_provider():