Add pythonized versions for new doc snippets

docs/sphinx/rest_substitutions/snippets/python/converted/wx.BitmapBundleImpl.DoGetPreferredSize.1.py

@@ -0,0 +1,28 @@
+
+    class MyCustomBitmapBundleImpl(wx.BitmapBundleImpl):
+
+        def GetDefaultSize():
+            return wx.Size(32, 32)
+
+        def GetPreferredBitmapSizeAtScale(self, scale):
+            return self.DoGetPreferredSize(scale)
+
+        def GetBitmap(self, size):
+            # For consistency with GetNextAvailableScale(), we must have
+            # bitmap variants for 32, 48 and 64px sizes.
+            availableSizes =  [32, 48, 64]
+            if (size.y <= 64)
+                ... get the bitmap from somewhere ...
+            else:
+                n = self.GetIndexToUpscale(size)
+                bitmap = ... get bitmap for availableSizes[n] ...
+                wx.Bitmap.Rescale(bitmap, size)
+            return bitmap
+
+        def GetNextAvailableScale(self, idx):
+            # The zero marks the end of available scales, and it this method
+            # won't be called again after the zero is returned.
+            availableScales =  [1.0, 1.5, 2.0, 0]
+            scale = availableScales[idx]
+            idx += 1
+            return (scale, idx)

docs/sphinx/rest_substitutions/snippets/python/converted/wx.MemoryDC.3.py

@@ -0,0 +1,12 @@
+
+    class MyWindow(wx.Window):
+        ...
+        def OnPaint(self, event):
+        bmp = wx.Bitmap();
+        bmp.CreateWithDIPSize(self.GetClientSize(), self.GetDPIScaleFactor())
+
+        memdc = wx.MemoryDC(bmp)
+        ... use memdc to draw on the bitmap ...
+
+        dc = wx.PaintDC(self)
+        dc.DrawBitmap(bmp, wx.Point(0, 0))