[etoys-dev] Etoys: Graphics-kfr.5.mcz

[commits at source.squeak.org]

Karl Ramberg uploaded a new version of Graphics to project Etoys:
http://source.squeak.org/etoys/Graphics-kfr.5.mcz

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

Name: Graphics-kfr.5
Author: kfr
Time: 17 June 2010, 12:16:10 am
UUID: 24e1cba9-4f7b-c440-8a5d-84a3f37b2450
Ancestors: Graphics-Richo.4

SQ-597

Animated Gif has several basic bugs

Fix by Jerome Peace


=============== Diff against Graphics-Richo.4 ===============

Item was changed:
  ----- Method: GIFReadWriter>>readBitData (in category 'private-decoding') -----
  readBitData
  	"using modified Lempel-Ziv Welch algorithm."
  
  	| outCodes outCount bitMask initCodeSize code curCode oldCode inCode finChar i bytes f c packedBits hasLocalColor localColorSize maxOutCodes |
  
  	maxOutCodes _ 4096.
  	offset := self readWord at self readWord. "Image Left at Image Top"
  	width _ self readWord.
  	height _ self readWord.
  
  	"---
  	Local Color Table Flag        1 Bit
  	Interlace Flag                1 Bit
  	Sort Flag                     1 Bit
  	Reserved                      2 Bits
  	Size of Local Color Table     3 Bits
  	----"
  	packedBits _ self next.
  	interlace _ (packedBits bitAnd: 16r40) ~= 0.
  	hasLocalColor _ (packedBits bitAnd: 16r80) ~= 0.
  	localColorSize _ 1 bitShift: ((packedBits bitAnd: 16r7) + 1).
  	hasLocalColor ifTrue: [localColorTable _ self readColorTable: localColorSize].
  
  	pass _ 0.
  	xpos _ 0.
  	ypos _ 0.
  	rowByteSize _ ((width + 3) // 4) * 4.
  	remainBitCount _ 0.
  	bufByte _ 0.
  	bufStream _ ReadStream on: ByteArray new.
  
  	outCodes _ ByteArray new: maxOutCodes + 1.
  	outCount _ 0.
+ 	
- 	bitMask _ (1 bitShift: bitsPerPixel) - 1.
  	prefixTable _ Array new: 4096.
  	suffixTable _ Array new: 4096.
  
  	initCodeSize _ self next.
+ 	bitMask _ (1 bitShift: initCodeSize ) - 1.
- 
  	self setParameters: initCodeSize.
  	bitsPerPixel > 8 ifTrue: [^self error: 'never heard of a GIF that deep'].
  	bytes _ ByteArray new: rowByteSize * height.
  	[(code _ self readCode) = eoiCode] whileFalse:
  		[code = clearCode
  			ifTrue:
  				[self setParameters: initCodeSize.
  				curCode _ oldCode _ code _ self readCode.
  				finChar _ curCode bitAnd: bitMask.
  				"Horrible hack to avoid running off the end of the bitmap.  Seems to cure problem reading some gifs!!? tk 6/24/97 20:16"
  				xpos = 0 ifTrue: [
  						ypos < height ifTrue: [
  							bytes at: (ypos * rowByteSize) + xpos + 1 put: finChar]]
  					ifFalse: [bytes at: (ypos * rowByteSize) + xpos + 1 put: finChar].
  				self updatePixelPosition]
  			ifFalse:
  				[curCode _ inCode _ code.
  				curCode >= freeCode ifTrue:
  					[curCode _ oldCode.
  					outCodes at: (outCount _ outCount + 1) put: finChar].
  				[curCode > bitMask] whileTrue:
  					[outCount > maxOutCodes
  						ifTrue: [^self error: 'corrupt GIF file (OutCount)'].
  					outCodes at: (outCount _ outCount + 1)
  						put: (suffixTable at: curCode + 1).
  					curCode _ prefixTable at: curCode + 1].
  				finChar _ curCode bitAnd: bitMask.
  				outCodes at: (outCount _ outCount + 1) put: finChar.
  				i _ outCount.
  				[i > 0] whileTrue:
  					["self writePixel: (outCodes at: i) to: bits"
  					bytes at: (ypos * rowByteSize) + xpos + 1 put: (outCodes at: i).
  					self updatePixelPosition.
  					i _ i - 1].
  				outCount _ 0.
  				prefixTable at: freeCode + 1 put: oldCode.
  				suffixTable at: freeCode + 1 put: finChar.
  				oldCode _ inCode.
  				freeCode _ freeCode + 1.
  				self checkCodeSize]].
  	prefixTable _ suffixTable _ nil.
  
  	f _ ColorForm extent: width at height depth: 8.
  	f bits copyFromByteArray: bytes.
  	"Squeak can handle depths 1, 2, 4, and 8"
  	bitsPerPixel > 4 ifTrue: [^ f].
  	"reduce depth to save space"
  	c _ ColorForm extent: width at height
  		depth: (bitsPerPixel = 3 ifTrue: [4] ifFalse: [bitsPerPixel]).
  	f displayOn: c.
  	^ c
  !