X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/ab1f7d2aa9cb1857cf87e105ebbd36a92676bbde..75736a9c818f10e49b51506d967759fbecb4fa66:/wxPython/docs/MigrationGuide.txt

diff --git a/wxPython/docs/MigrationGuide.txt b/wxPython/docs/MigrationGuide.txt
index 79d79ae383..ec3f973675 100644
--- a/wxPython/docs/MigrationGuide.txt
+++ b/wxPython/docs/MigrationGuide.txt
@@ -53,9 +53,10 @@ operation unless you first have created an app object, (even on
 Windows where most anything was possible before.)
 
 **[Changed in 2.5.2.0]** All the Window and GDI (pen, bitmap, etc.)
-classes and also many toplevel functions will now check that a wx.App
-object has already been created and will raise a wx.PyNoAppError
-exception if not.
+class constructors and also many toplevel functions and static methods
+will now check that a wx.App object has already been created and will
+raise a wx.PyNoAppError exception if not.
+
 
 
 
@@ -590,6 +591,36 @@ provided by the makers of the ActiveX control that you are using.
 
 
 
+
+PNG Images
+----------
+
+Prior to 2.5 the PNG image handler would convert all alpha channel
+information to a mask when the image was loaded.  Pixels that were
+more than halfway transparent would be made fully transparent by the
+mask and the rest would be made fully opaque.
+
+In 2.5 the image handler has been updated to preserve the alpha
+channel and will now only create a mask when all the pixels in the
+image are either fully transparent or fully opaque.  In addition, the
+wx.DC.DrawBitmap and wx.DC.Blit methods are able to correctly blend
+the pixels in the image with partially transparent alpha values.
+(Currently only on MSW and Mac, if anybody knows how to do it for GTK
+then please submit a patch!)
+
+If you are using a PNG with an alpha channel but you need to have a
+wx.Mask like you automatically got in 2.4 then you can do one of the
+following:
+
+    * Edit the image and make all the partially transparent pixels be
+      fully transparent.
+
+    * Use a different image type.
+
+    * Set a mask based on colour after you load the image.
+
+
+
 OGL is dead! LONG LIVE OGL!
 ---------------------------