[BUG][FIX][TEST] BitBlt alpha compositing ([sm][approved])

Doug Way dway at riskmetrics.com
Wed Apr 9 18:11:38 UTC 2003


I also verified that the simulated tests pass, at least.

- Doug Way


Andreas Raab wrote:
> 
> Hi Folks,
> 
> Attached is a test+fix for alpha compositing in BitBlt. It turns out that
> when you're using Form>>blend (aka: alpha compositing) the resulting alpha
> values are not at all what they should be. VERY problematic for stuff like
> anti-aliasing.
> 
> [Note to harvesters: Please consider integration ASAP. This presence of this
> fix in the appropriate VMs will be critical for Croquet].
> 
> Cheers,
>   - Andreas
> 
>   ------------------------------------------------------------------------------
>                          Name: BBCompositing.2.cs
>    BBCompositing.2.cs    Type: ChangeSet (application/x-unknown-content-type-cs_auto_file)
>                      Encoding: quoted-printable
> 
>                      Name: BitBltTests.st
>    BitBltTests.st    Type: unspecified type (application/octet-stream)
>                  Encoding: quoted-printable
> 
>   ------------------------------------------------------------------------------



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