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ID Category Severity Reproducibility Date Submitted Last Update
0007247 [Squeak] Graphics minor always 12-18-08 12:16 09-18-13 00:25
Reporter Nicolai Hess View Status public  
Assigned To tim
Priority normal Resolution fixed  
Status closed   Product Version
Summary 0007247: BitBlt Bug in alphaSourceBlendBits8
Description In alphaSourceBlendBits8 the colormask is shifted wrong number of times, if
dest display byteorder is little endian.

Test: Change your display depth to 8 bit little endian and compare
with 8 bit big endian.

To fix this :
At the end of method alphaSourceBlendBits8
srcShift should reset when 24, not 32.
..

destMSB ifTrue:[
..
] ifFalse:[
 srcShift = 32 "<--- here "
  ifTrue:[dstIndex := dstIndex + 4.
    srcShift := 0.
    dstMask := 16rFFFFFF00]
  ifFalse:[srcShift := srcShift + 8.
  dstMask := dstMask << 8 bitOr: 255].
].
            
Additional Information
Attached Files

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- Notes
(0014448 - 203 - 242 - 242 - 242 - 242 - 242)
tim
09-18-13 00:24

Looks to be a correct diagnosis to me; for MSB the srcShift will cycle through 0->8->16->24->0 but for LSB it can go 0->8->16->24->32->0 which seems likely to cause a problem.

Fixed in VMMaker-tpr.325
 

- Issue History
Date Modified Username Field Change
12-18-08 12:16 Nicolai Hess New Issue
12-18-08 12:16 Nicolai Hess Status new => assigned
12-18-08 12:16 Nicolai Hess Assigned To  => andreas
07-22-13 02:59 tim Assigned To andreas => tim
09-18-13 00:24 tim Note Added: 0014448
09-18-13 00:25 tim Status assigned => resolved
09-18-13 00:25 tim Fixed in Version  => 4.4
09-18-13 00:25 tim Resolution open => fixed
09-18-13 00:25 tim Status resolved => closed


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