images.gif: added transparent pixel support
parent
e9c780ba28
commit
bb71143054
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@ -37,9 +37,7 @@ ERROR: unknown-extension n ;
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ERROR: gif-unexpected-eof ;
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TUPLE: graphics-control-extension
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label block-size raw-data
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packed delay-time color-index
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block-terminator ;
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flags delay-time transparent-color-index ;
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TUPLE: image-descriptor
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left top width height flags first-code-size ;
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@ -67,6 +65,8 @@ CONSTANT: graphic-control-extension HEX: f9
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CONSTANT: comment-extension HEX: fe
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CONSTANT: application-extension HEX: ff
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CONSTANT: trailer HEX: 3b
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CONSTANT: graphic-control-extension-block-size HEX: 04
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CONSTANT: block-terminator HEX: 00
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: <loading-gif> ( -- loading-gif )
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\ loading-gif new
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@ -101,9 +101,11 @@ M: input-port stream-peek1
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: read-graphic-control-extension ( -- graphic-control-extension )
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\ graphics-control-extension new
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1 read le> [ >>block-size ] [ read ] bi
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>>raw-data
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1 read le> >>block-terminator ;
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1 read le> graphic-control-extension-block-size assert=
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1 read le> >>flags
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2 read le> >>delay-time
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1 read le> >>transparent-color-index
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1 read le> block-terminator assert= ;
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: read-plain-text-extension ( -- plain-text-extension )
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\ plain-text-extension new
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@ -147,6 +149,8 @@ ERROR: unimplemented message ;
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: interlaced? ( image -- ? ) flags>> 6 bit? ; inline
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: sort? ( image -- ? ) flags>> 5 bit? ; inline
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: color-table-size ( image -- ? ) flags>> 3 bits 1 + 2^ 3 * ; inline
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: transparency? ( image -- ? )
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graphic-control-extensions>> first flags>> 0 bit? ; inline
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: color-resolution ( image -- ? ) flags>> -4 shift 3 bits ; inline
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@ -225,18 +229,26 @@ ERROR: unhandled-data byte ;
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[ compressed-bytes>> ] bi
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lzw-uncompress ;
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: apply-palette ( indexes palette -- bitmap )
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[ nth 255 suffix ] curry V{ } map-as concat ;
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: colorize ( index palette transparent-index/f -- seq )
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pick = [ 2drop B{ 0 0 0 0 } ] [ nth 255 suffix ] if ;
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: apply-palette ( indexes palette transparent-index/f -- bitmap )
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[ colorize ] 2curry V{ } map-as concat ;
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: dimensions ( loading-gif -- dim )
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[ image-descriptor>> width>> ] [ image-descriptor>> height>> ] bi 2array ;
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: ?transparent-color-index ( loading-gif -- index/f )
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dup transparency?
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[ graphic-control-extensions>> first transparent-color-index>> ]
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[ drop f ] if ;
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: loading-gif>image ( loading-gif -- image )
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[ <image> ] dip
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[ dimensions >>dim ]
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[ drop RGBA >>component-order ubyte-components >>component-type ]
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[
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[ decompress ] [ global-color-table>> ] bi
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[ decompress ] [ global-color-table>> ] [ ?transparent-color-index ] tri
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apply-palette >>bitmap
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] tri ;
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