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GIFReader.st
changeset 882 2913420cab5a
parent 809 0d39cb7c21a9
child 888 69628f75a4b8 
--- a/GIFReader.st	Tue Mar 31 11:42:45 1998 +0200
+++ b/GIFReader.st	Wed Apr 01 14:17:37 1998 +0200
@@ -308,7 +308,7 @@
 !
 
 fromStream:aStream
-    "read a stream containing a GIF image.
+    "read a stream containing a GIF image (or an image sequence).
      Leave image description in instance variables."
 
     |byte index flag count fileColorMap
@@ -408,7 +408,7 @@
                     self buildMaskFromColor:maskPixel
                 ].
 
-                imageSequence add:(self image).
+                imageSequence add:(self makeImage).
 
                 aStream atEnd ifTrue:[
                     atEnd := true.
@@ -418,7 +418,7 @@
     ].
 
     "Modified: / 5.7.1996 / 17:32:01 / stefan"
-    "Modified: / 3.2.1998 / 17:53:37 / cg"
+    "Modified: / 1.4.1998 / 14:17:26 / cg"
 !
 
 makeGreyscale
@@ -445,7 +445,7 @@
 !
 
 readExtension:aStream
-    "get gif89 extension - this is currently ignored"
+    "get gif89 extension"
 
     |type blockSize subBlockSize
      aspNum aspDen left top width height cWidth cHeight fg bg
@@ -455,127 +455,127 @@
 
     type := aStream nextByte.
     type == $R asciiValue ifTrue:[
-	"/
-	"/ Ratio extension
-	"/
-	'GIFREADER [info]: ratio extension ignored' infoPrintCR.
-	blockSize := aStream nextByte.
-	(blockSize == 2) ifTrue:[
-	    aspNum := aStream nextByte.
-	    aspDen := aStream nextByte
-	] ifFalse:[
-	    aStream skip:blockSize
-	].
-	"/ eat subblocks
+        "/
+        "/ Ratio extension
+        "/
+        'GIFREADER [info]: ratio extension ignored' infoPrintCR.
+        blockSize := aStream nextByte.
+        (blockSize == 2) ifTrue:[
+            aspNum := aStream nextByte.
+            aspDen := aStream nextByte
+        ] ifFalse:[
+            aStream skip:blockSize
+        ].
+        "/ eat subblocks
         
-	[(subBlockSize := aStream nextByte) > 0] whileTrue:[
-	    aStream skip:subBlockSize
-	].
-	^ self
+        [(subBlockSize := aStream nextByte) > 0] whileTrue:[
+            aStream skip:subBlockSize
+        ].
+        ^ self
     ].
 
     type == 16r01 ifTrue:[
-	"/
-	"/ plaintext extension
-	"/
+        "/
+        "/ plaintext extension
+        "/
 "/        'GIFREADER [info]: plaintext extension ignored' infoPrintCR.
-	subBlockSize := aStream nextByte.
-	left := aStream nextShortMSB:false.
-	top := aStream nextShortMSB:false.
-	width := aStream nextShortMSB:false.
-	height := aStream nextShortMSB:false.
-	cWidth := aStream nextByte.
-	cHeight := aStream nextByte.
-	fg := aStream nextByte.
-	bg := aStream nextByte.
-	aStream skip:12.
-	[(subBlockSize := aStream nextByte) > 0] whileTrue:[
-	    aStream skip:subBlockSize
-	].
-	^ self
+        subBlockSize := aStream nextByte.
+        left := aStream nextShortMSB:false.
+        top := aStream nextShortMSB:false.
+        width := aStream nextShortMSB:false.
+        height := aStream nextShortMSB:false.
+        cWidth := aStream nextByte.
+        cHeight := aStream nextByte.
+        fg := aStream nextByte.
+        bg := aStream nextByte.
+        aStream skip:12.
+        [(subBlockSize := aStream nextByte) > 0] whileTrue:[
+            aStream skip:subBlockSize
+        ].
+        ^ self
     ].
 
     type == 16rF9 ifTrue:[
-	"/
-	"/ graphic control extension
-	"/
+        "/
+        "/ graphic control extension
+        "/
 "/        'GIFREADER [info]: graphic control extension ignored' infoPrintCR.
 
-	[(subBlockSize := aStream nextByte) ~~ 0] whileTrue:[
-	    "/ type bitAnd:1 means: animationMask is transparent pixel
-	    "/ to be implemented in Image ...
+        [(subBlockSize := aStream nextByte) ~~ 0] whileTrue:[
+            "/ type bitAnd:1 means: animationMask is transparent pixel
+            "/ to be implemented in Image ...
 
-	    animationType := aStream nextByte.
-	    animationTime := aStream nextShortMSB:false.
-	    animationMask := aStream nextByte.
-	    subBlockSize := subBlockSize - 4.
+            animationType := aStream nextByte.
+            animationTime := aStream nextShortMSB:false.
+            animationMask := aStream nextByte.
+            subBlockSize := subBlockSize - 4.
 
-	   (animationType bitTest: 1) ifTrue:[
-		maskPixel := animationMask.
+           (animationType bitTest: 1) ifTrue:[
+                maskPixel := animationMask.
 "/                'GIFREADER [info]: mask: ' infoPrint. (maskPixel printStringRadix:16) infoPrintCR.
-	    ].
+            ].
 "/            'GIFREADER [info]: animationTime: ' infoPrint. (animationTime * (1/100)) infoPrintCR.
 
-	    subBlockSize ~~ 0 ifTrue:[
-		aStream skip:subBlockSize
-	    ].
-	].
-	^ self
+            subBlockSize ~~ 0 ifTrue:[
+                aStream skip:subBlockSize
+            ].
+        ].
+        ^ self
     ].
 
     type == 16rFE ifTrue:[
-	"/
-	"/ comment extension
-	"/
+        "/
+        "/ comment extension
+        "/
 "/        'GIFREADER [info]: comment extension ignored' infoPrintCR.
-	[(blockSize := aStream nextByte) ~~ 0] whileTrue:[
-	    aStream skip:blockSize
-	].
-	^ self
+        [(blockSize := aStream nextByte) ~~ 0] whileTrue:[
+            aStream skip:blockSize
+        ].
+        ^ self
     ].
 
     type == 16rFF ifTrue:[
-	"/
-	"/  application extension
-	"/
-	subBlockSize := aStream nextByte.
-	appID := (aStream nextBytes:8 ) asString.
-	appAUTH := aStream nextBytes:3.
+        "/
+        "/  application extension
+        "/
+        subBlockSize := aStream nextByte.
+        appID := (aStream nextBytes:8 ) asString.
+        appAUTH := aStream nextBytes:3.
 
-	subBlockSize := aStream nextByte.
+        subBlockSize := aStream nextByte.
 
-	ok := false.
-	appID = 'NETSCAPE' ifTrue:[
-	    appAUTH asString = '2.0' ifTrue:[
-		subBlockSize == 3 ifTrue:[
-		    b := aStream nextByte.
-		    iterationCount := aStream nextShortMSB:false.
-		    subBlockSize := aStream nextByte.
-		    ok := true.
-		]
-	    ]
-	].
+        ok := false.
+        appID = 'NETSCAPE' ifTrue:[
+            appAUTH asString = '2.0' ifTrue:[
+                subBlockSize == 3 ifTrue:[
+                    b := aStream nextByte.
+                    iterationCount := aStream nextShortMSB:false.
+                    subBlockSize := aStream nextByte.
+                    ok := true.
+                ]
+            ]
+        ].
 
-	ok ifFalse:[
-	    ('GIFREADER [info]: application extension (' , appID , ') ignored') infoPrintCR.
-	].
+        ok ifFalse:[
+            ('GIFREADER [info]: application extension (' , appID , ') ignored') infoPrintCR.
+        ].
 
-	[subBlockSize > 0] whileTrue:[
-	    aStream skip:subBlockSize.
-	    subBlockSize := aStream nextByte.
-	].
-	^ self
+        [subBlockSize > 0] whileTrue:[
+            aStream skip:subBlockSize.
+            subBlockSize := aStream nextByte.
+        ].
+        ^ self
     ].
 
     type == 16r2C ifTrue:[
-	"/
-	"/  image descriptor extension
-	"/
-	'GIFREADER [info]: image descriptor extension ignored' infoPrintCR.
-	[(subBlockSize := aStream nextByte) > 0] whileTrue:[
-	    aStream skip:subBlockSize
-	].
-	^ self
+        "/
+        "/  image descriptor extension
+        "/
+        'GIFREADER [info]: image descriptor extension ignored' infoPrintCR.
+        [(subBlockSize := aStream nextByte) > 0] whileTrue:[
+            aStream skip:subBlockSize
+        ].
+        ^ self
     ].
 
     "/
@@ -583,13 +583,15 @@
     "/
     'GIFREADER [info]: unknown extension ignored' infoPrintCR.
     [(subBlockSize := aStream nextByte) > 0] whileTrue:[
-	aStream skip:subBlockSize
+        aStream skip:subBlockSize
     ]
 
-    "Modified: 24.7.1997 / 18:02:49 / cg"
+    "Modified: / 1.4.1998 / 14:00:37 / cg"
 !
 
 readImage:aStream
+    "read a single image from aStream."
+
     |leftOffs topOffs flag interlaced hasLocalColorMap bitsPerPixel colorMapSize
      codeLen compressedData compressedSize index count h tmp srcOffset dstOffset
      initialBuffSize|
@@ -601,7 +603,7 @@
     height := aStream nextShortMSB:false.
 
     dimensionCallBack notNil ifTrue:[
-	dimensionCallBack value:self
+        dimensionCallBack value:self
     ].
 
 "/
@@ -618,24 +620,24 @@
     "if image has a local colormap, this one is used"
 
     hasLocalColorMap ifTrue:[
-	"local descr. overwrites"
-	bitsPerPixel := (flag bitAnd:2r00000111) + 1.
-	colorMapSize := 1 bitShift:bitsPerPixel.
-	"overwrite colormap"
-	self readColorMap:colorMapSize.
-	colorMap := Colormap 
-			redVector:redMap 
-			greenVector:greenMap 
-			blueVector:blueMap.
+        "local descr. overwrites"
+        bitsPerPixel := (flag bitAnd:2r00000111) + 1.
+        colorMapSize := 1 bitShift:bitsPerPixel.
+        "overwrite colormap"
+        self readColorMap:colorMapSize.
+        colorMap := Colormap 
+                        redVector:redMap 
+                        greenVector:greenMap 
+                        blueVector:blueMap.
     ].
 
 
     "get codelen for decompression"
     codeLen := aStream nextByte.
     (aStream respondsTo:#fileSize) ifTrue:[
-	initialBuffSize := aStream fileSize.
+        initialBuffSize := aStream fileSize.
     ] ifFalse:[
-	initialBuffSize := 512.
+        initialBuffSize := 512.
     ].
     compressedData := ByteArray uninitializedNew:initialBuffSize.
 
@@ -651,9 +653,9 @@
             compressedData := t.
         ].
 
-	aStream nextBytes:count into:compressedData startingAt:index blockSize:4096.
-	index := index + count.
-	count := aStream nextByte
+        aStream nextBytes:count into:compressedData startingAt:index blockSize:4096.
+        index := index + count.
+        count := aStream nextByte
     ].
     compressedSize := index - 1.
 
@@ -662,58 +664,58 @@
 "/    'GIFReader: decompressing ...' infoPrintCR.
 
     self class decompressGIFFrom:compressedData
-			   count:compressedSize
-			    into:data
-		      startingAt:1
-			 codeLen:(codeLen + 1).
+                           count:compressedSize
+                            into:data
+                      startingAt:1
+                         codeLen:(codeLen + 1).
 
     interlaced ifTrue:[
 "/    'GIFREADER: deinterlacing ...' infoPrintCR.
-	tmp := ByteArray uninitializedNew:(data size).
+        tmp := ByteArray uninitializedNew:(data size).
 
-	"phase 1: 0, 8, 16, 24, ..."
+        "phase 1: 0, 8, 16, 24, ..."
 
-	srcOffset := 1.
-	0 to:(h - 1) by:8 do:[:dstRow |
-	    dstOffset := dstRow * width + 1.
-	    tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
-		       with:data startingAt:srcOffset.
-	    srcOffset := srcOffset + width.
-	].
+        srcOffset := 1.
+        0 to:(h - 1) by:8 do:[:dstRow |
+            dstOffset := dstRow * width + 1.
+            tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
+                       with:data startingAt:srcOffset.
+            srcOffset := srcOffset + width.
+        ].
 
-	"phase 2: 4, 12, 20, 28, ..."
+        "phase 2: 4, 12, 20, 28, ..."
 
-	4 to:(h - 1) by:8 do:[:dstRow |
-	    dstOffset := dstRow * width + 1.
-	    tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
-		       with:data startingAt:srcOffset.
-	    srcOffset := srcOffset + width.
-	].
+        4 to:(h - 1) by:8 do:[:dstRow |
+            dstOffset := dstRow * width + 1.
+            tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
+                       with:data startingAt:srcOffset.
+            srcOffset := srcOffset + width.
+        ].
 
-	"phase 3: 2, 6, 10, 14, ..."
+        "phase 3: 2, 6, 10, 14, ..."
 
-	2 to:(h - 1) by:4 do:[:dstRow |
-	    dstOffset := dstRow * width + 1.
-	    tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
-		       with:data startingAt:srcOffset.
-	    srcOffset := srcOffset + width.
-	].
+        2 to:(h - 1) by:4 do:[:dstRow |
+            dstOffset := dstRow * width + 1.
+            tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
+                       with:data startingAt:srcOffset.
+            srcOffset := srcOffset + width.
+        ].
 
-	"phase 4: 1, 3, 5, 7, ..."
+        "phase 4: 1, 3, 5, 7, ..."
 
-	1 to:(h - 1) by:2 do:[:dstRow |
-	    dstOffset := dstRow * width + 1.
-	    tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
-		       with:data startingAt:srcOffset.
-	    srcOffset := srcOffset + width.
-	].
+        1 to:(h - 1) by:2 do:[:dstRow |
+            dstOffset := dstRow * width + 1.
+            tmp replaceFrom:dstOffset to:(dstOffset + width - 1)
+                       with:data startingAt:srcOffset.
+            srcOffset := srcOffset + width.
+        ].
 
-	data := tmp.
-	tmp := nil.
+        data := tmp.
+        tmp := nil.
     ].
 
-    "Modified: / 13.1.1998 / 10:41:05 / cg"
     "Created: / 13.1.1998 / 10:44:05 / cg"
+    "Modified: / 1.4.1998 / 14:00:27 / cg"
 ! !
 
 !GIFReader methodsFor:'writing to file'!
@@ -939,6 +941,6 @@
 !GIFReader class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libview2/GIFReader.st,v 1.67 1998-02-03 16:54:19 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libview2/GIFReader.st,v 1.68 1998-04-01 12:17:37 cg Exp $'
 ! !
 GIFReader initialize!
hg/stx-libview2