The Trunk: Graphics-nice.161.mcz

Nicolas Cellier uploaded a new version of Graphics to project The Trunk:
http://source.squeak.org/trunk/Graphics-nice.161.mcz

==================== Summary ====================

Name: Graphics-nice.161
Author: nice
Time: 14 December 2010, 3:03:16.064 pm
UUID: aa1e48e5-5032-b14d-bc90-84db641c7257
Ancestors: Graphics-ul.160

Fix #testPngDecodingColors32.

This was because (LargePositiveInteger new: 4) ~= 0 in COG VM.
(There is no optimization in primitives for this special case).
Anyway, it is better to always normalize a LargePositiveInteger created this way.

=============== Diff against Graphics-ul.160 ===============

Item was changed:
  ----- Method: Color>>pixelValueForDepth: (in category 'conversions') -----
  pixelValueForDepth: d
  "Returns an integer representing the bits that appear in a single pixel of this color in a Form of the given depth. The depth must be one of 1, 2, 4, 8, 16, or 32. Contrast with pixelWordForDepth: and bitPatternForDepth:, which return either a 32-bit word packed with the given pixel value or a multiple-word Bitmap containing a pattern. The inverse is the class message colorFromPixelValue:depth:"
  "Details: For depths of 8 or less, the result is a colorMap index. For depths of 16 and 32, it is a direct color value with 5 or 8 bits per color component."
  "Transparency: The pixel value zero is reserved for transparent. For depths greater than 8, black maps to the darkest possible blue."
 
  | rgbBlack val |
  d = 8 ifTrue: [^ self closestPixelValue8].  "common case"
  d < 8 ifTrue: [
  d = 4 ifTrue: [^ self closestPixelValue4].
  d = 2 ifTrue: [^ self closestPixelValue2].
  d = 1 ifTrue: [^ self closestPixelValue1]].
 
  rgbBlack := 1.  "closest black that is not transparent in RGB"
 
  d = 16 ifTrue: [
  "five bits per component; top bits ignored"
  val := (((rgb bitShift: -15) bitAnd: 16r7C00) bitOr:
  ((rgb bitShift: -10) bitAnd: 16r03E0)) bitOr:
  ((rgb bitShift: -5) bitAnd: 16r001F).
  ^ val = 0 ifTrue: [rgbBlack] ifFalse: [val]].
 
  d = 32 ifTrue: [
  "eight bits per component; top 8 bits set to all ones (opaque alpha)"
  val := LargePositiveInteger new: 4.
  val at: 3 put: ((rgb bitShift: -22) bitAnd: 16rFF).
  val at: 2 put: ((rgb bitShift: -12) bitAnd: 16rFF).
  val at: 1 put: ((rgb bitShift: -2) bitAnd: 16rFF).
+ val normalize = 0 ifTrue: [val at: 1 put: 1].  "closest non-transparent black"
- val = 0 ifTrue: [val at: 1 put: 1].  "closest non-transparent black"
  val at: 4 put: 16rFF.  "opaque alpha"
+ ^ val normalize].
- ^ val].
 
  d = 12 ifTrue: [  "for indexing a color map with 4 bits per color component"
  val := (((rgb bitShift: -18) bitAnd: 16r0F00) bitOr:
  ((rgb bitShift: -12) bitAnd: 16r00F0)) bitOr:
  ((rgb bitShift: -6) bitAnd: 16r000F).
  ^ val = 0 ifTrue: [rgbBlack] ifFalse: [val]].
 
  d = 9 ifTrue: [  "for indexing a color map with 3 bits per color component"
  val := (((rgb bitShift: -21) bitAnd: 16r01C0) bitOr:
  ((rgb bitShift: -14) bitAnd: 16r0038)) bitOr:
  ((rgb bitShift: -7) bitAnd: 16r0007).
  ^ val = 0 ifTrue: [rgbBlack] ifFalse: [val]].
 
  self error: 'unknown pixel depth: ', d printString
  !