Subject: bug#2843: 23.0.92; Emacs.app cannot display X bitmaps

From: Alp Aker <[email-masked]>
Date: Mon, 11 Jul 2011 12:42:19 -0400 (EDT)

Peter Dyballa wrote:

> The colours of the PNG file are lighter, less saturated and the light 3D 
> shades at the NE and NW corners have less contrast to the basic colour. See 
> attached screen shot!

Ah, I misunderstood you.  Your point is that two renderings in Emacs of 
same image file look different.  This isn't Emacs's doing, though.  Cocoa 
is rendering the colors differently depending on the screen location.

Reverse the buffer/window arrangement (in the setup of your screenshot, 
put the startup buffer in the bottom window and the splash.png buffer in 
the top window) and you'll get the opposite effect: it's now the image in 
the splash.png buffer that looks more saturated.  Put the images side by 
side and they'll look equally saturated.

You can reproduce all this outside of Emacs:  Make two copies of 
splash.png and open them in a graphics editor, then try moving the windows 
around.

Why is Cocoa doing this?  I dunno.  In any case, this report should 
probably be closed.