0000897: Color black is altered for 32bit forms, this leads to issues if you expect the pixel to be black when testing.

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Date Submitted

Last Update

0000897

[Squeak] Graphics

minor

always

02-24-05 10:11

10-26-05 02:32

Reporter

johnmci

View Status

public

Assigned To

Priority

normal

Resolution

open

Status

acknowledged

Product Version

3.8

Summary

0000897: Color black is altered for 32bit forms, this leads to issues if you expect the pixel to be black when testing.

Description

| form |
    form := Form extent: 10@10 depth: 32.
    form fillWithColor: Color yellow.
    form colorAt: 0@0 put: Color black.
    ^(form colorAt: 0@0) = Color black.

The problem is that we change the Color black from a zero value to a value of 1 to avoid indicating this is a transparent pixel. Later if we fetch back the pixel color it is NOT black and the test above fails since 1 <> 0. We can either ignore this problem, or consider changing the colorAt: to say value 1 at 32bit depth is really value 0, or change Color>>= to say 1 or 0 = 0.

I do recall changing the mpeg plugin to ensure black pixels have a value of 1, possible the same was done for the jpeg plugin?

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Notes
(0002981 - 68 - 68 - 68 - 68 - 68 - 68) andreas 10-26-05 02:32	I don't really see how to fix this, but it certainly is a problem...

Issue History
Date Modified	Username	Field	Change
02-24-05 10:11	johnmci	New Issue
10-25-05 05:33	andreas	Category	Kernel => Graphics
10-26-05 02:32	andreas	Note Added: 0002981
10-26-05 02:32	andreas	Status	new => acknowledged

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