Composite Quesiton

[Huang, FrankR]

Morton, thanks.
I have used OVER operation to produce what I want on RS690 platform. But in the geode driver, I found that it can not do the SRC and OVER rendering correctly. 
I am now firstly focusing the SRC operation. From your explanation, a (1,0,1,0) to (0,0,0,0) transfer is done outside the 20x20 mask region. Is it done by Xserver or driver? I think it is done by driver, is it correct? 
Any reference code to see how the driver to handle it? I want to fix the bug in the geode driver.


Thanks,
Frank


-----Original Message-----
From: Jonathan Morton [mailto:jonathan.morton at movial.com] 
Sent: 2010年5月17日 19:15
To: Huang, FrankR
Cc: xorg-devel at lists.x.org
Subject: Re: Composite Quesiton

On Mon, 2010-05-17 at 17:39 +0800, Huang, FrankR wrote:
>             You can imagine the result of this test. I attached the
> result of this application. I can understand the green part , but for
> the black part, I have no idea. Is it all solid to black???

The (src IN mask) part essentially modifies the "input" side of the
equation to a green-black pattern, actually a (1,0,1,0) to (0,0,0,0)
ARGB vector pattern.  Using the SRC operator then causes this to be
literally copied to the destination.

If you want the mask to limit the area of influence of the green,
producing a green-white result rather than a green-black pattern, you
need to use the OVER operator.

If you want the mask to extend beyond the 20x20 square, you need to set
the Repeat property on it as well as the source.

-- 
------
From: Jonathan Morton
      jonathan.morton at movial.com