[07 Oct 2008] Brush Transparency with OS 4.1

[PEB]

Note: This is an archived post that was originally sent to the Hollywood mailing list on Tue, 07 Oct 2008 15:14:24 -0000

An interesting bug has shown up with OS 4.1 (though I'm not sure if the bug is in Hollywood or in OS 4.1). 24 bit image brushes that are set to display with one color being transparent do not display with their transparency if the screen depth is 32 bit.

Now there are two ways to make the brushes display correctly:

1) Change the depth of the brush from 24 bit to 8 bit.

OR

2) Change the screen depth from 32 bit to 16 bit.

Note that this only applies to single color masking, such as with SetBrushTransparency()---images that use the alpha channel display correctly.

So, any idea what is causing this problem?

[airsoftsoftwair]

Note: This is an archived post that was originally sent to the Hollywood mailing list on Fri, 10 Oct 2008 23:22:54 +0200

An interesting bug has shown up with OS 4.1 (though I'm not sure if the bug is in Hollywood or in OS 4.1). 24 bit image brushes that are set to display with one color being transparent do not display with their transparency if the screen depth is 32 bit.

Now there are two ways to make the brushes display correctly: 1) Change the depth of the brush from 24 bit to 8 bit. OR 2) Change the screen depth from 32 bit to 16 bit.

Note that this only applies to single color masking, such as with SetBrushTransparency()---images that use the alpha channel display correctly.

So, any idea what is causing this problem?

Just for the records: This issue is fixed. OS 4.1 sets the alpha channel bits to 0xff even if the picture is only a 24-bit image. This caused some confusion with Hollywood but I've fixed it now.