Issue 559: Cleartype text not rendered correctly with opacity applied
http://code.google.com/p/chromium/issues/detail?id=559

Comment #8 by [EMAIL PROTECTED]:
Please note that the PNG opacity problem occurs when opacity of the  
bounding object is changed.  That is,
when opacity of a bounding object (such as a DIV) is less than 100%, any  
PNG rendered in that bounding
object will be rendered incorrectly.  This is very bad for any kind of  
procedural image manipulation, including
opacity effects.  One cannot fade objects containing PNG images in and out  
by varying the opacity, for
example, if the PNG images have any transparency to them, as Chrome will  
not render those images properly.
This is a very serious rendering issue for Chrome that is not demonstrated  
by any other major browser.  The
primary statement above included the following statement:

"Although this color is replaced when we composite, the antialiased edges  
around any text or images will have
been composited on the wrong color and will look bad."

Actually any pixel that is at less than 100% opacity in the PNG image  
itself appears to get drawn in your magic
color AND at 100% opacity until the containing object has a CSS opacity of  
100%.  Verify this for yourself:

1) Create a PNG image with a transparent region... something like a round  
button with a gradient drop
shadow on a transparent BG.  Save this as a PNG24.

2) Place the button into a DIV on a page, or apply it as a CSS background  
property.

3) Under script control, vary the opacity of the containing DIV.

You will observe that the transparent areas of the PNG will render in your  
magic color, at 100% opacity, until
the opacity of the containing object reaches 100%.  At this point, the PNG  
will render properly.

Frankly speaking, I do not believe this problem is likely to be just one of  
your compositing engine failing to
deal with anti-aliased edges properly.

I'd be happy to set you up with specific test cases if that will help.



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