1 ! Copyrigt (C) 2009 Doug Coleman, Keith Lazuka
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays combinators compression.lzw
4 constructors destructors grouping images images.loader io
5 io.binary io.buffers io.encodings.string io.encodings.utf8
6 io.ports kernel make math math.bitwise namespaces sequences ;
10 "gif" gif-image register-image-class
20 graphic-control-extensions
21 application-extensions
33 ERROR: unsupported-gif-format magic ;
34 ERROR: unknown-extension n ;
35 ERROR: gif-unexpected-eof ;
37 TUPLE: graphics-control-extension
38 flags delay-time transparent-color-index ;
40 TUPLE: image-descriptor
41 left top width height flags first-code-size ;
43 TUPLE: plain-text-extension
44 introducer label block-size text-grid-left text-grid-top text-grid-width
45 text-grid-height cell-width cell-height
46 text-fg-color-index text-bg-color-index plain-text-data ;
48 TUPLE: application-extension
49 introducer label block-size identifier authentication-code
52 TUPLE: comment-extension
53 introducer label comment-data ;
56 CONSTRUCTOR: trailer ( byte -- obj ) ;
58 CONSTANT: image-descriptor HEX: 2c
60 CONSTANT: extension-identifier HEX: 21
61 CONSTANT: plain-text-extension HEX: 01
62 CONSTANT: graphic-control-extension HEX: f9
63 CONSTANT: comment-extension HEX: fe
64 CONSTANT: application-extension HEX: ff
65 CONSTANT: trailer HEX: 3b
66 CONSTANT: graphic-control-extension-block-size HEX: 04
67 CONSTANT: block-terminator HEX: 00
69 : <loading-gif> ( -- loading-gif )
71 V{ } clone >>graphic-control-extensions
72 V{ } clone >>application-extensions
73 V{ } clone >>plain-text-extensions
74 V{ } clone >>comment-extensions
77 : (read-sub-blocks) ( -- )
78 read1 [ read , (read-sub-blocks) ] unless-zero ;
80 : read-sub-blocks ( -- bytes )
81 [ (read-sub-blocks) ] { } make B{ } concat-as ;
83 : read-image-descriptor ( -- image-descriptor )
84 \ image-descriptor new
90 1 read le> 1 + >>first-code-size ;
92 : read-graphic-control-extension ( -- graphic-control-extension )
93 \ graphics-control-extension new
94 1 read le> graphic-control-extension-block-size assert=
96 2 read le> >>delay-time
97 1 read le> >>transparent-color-index
98 1 read le> block-terminator assert= ;
100 : read-plain-text-extension ( -- plain-text-extension )
101 \ plain-text-extension new
102 1 read le> >>block-size
103 2 read le> >>text-grid-left
104 2 read le> >>text-grid-top
105 2 read le> >>text-grid-width
106 2 read le> >>text-grid-height
107 1 read le> >>cell-width
108 1 read le> >>cell-height
109 1 read le> >>text-fg-color-index
110 1 read le> >>text-bg-color-index
111 read-sub-blocks >>plain-text-data ;
113 : read-comment-extension ( -- comment-extension )
114 \ comment-extension new
115 read-sub-blocks >>comment-data ;
117 : read-application-extension ( -- read-application-extension )
118 \ application-extension new
119 1 read le> >>block-size
120 8 read utf8 decode >>identifier
121 3 read >>authentication-code
122 read-sub-blocks >>application-data ;
124 : read-gif-header ( loading-gif -- loading-gif )
125 6 read utf8 decode >>magic ;
127 ERROR: unimplemented message ;
128 : read-GIF87a ( loading-gif -- loading-gif )
129 "GIF87a" unimplemented ;
131 : read-logical-screen-descriptor ( loading-gif -- loading-gif )
135 1 read le> >>background-color
136 1 read le> >>default-aspect-ratio ;
138 : color-table? ( image -- ? ) flags>> 7 bit? ; inline
139 : interlaced? ( image -- ? ) flags>> 6 bit? ; inline
140 : sort? ( image -- ? ) flags>> 5 bit? ; inline
141 : color-table-size ( image -- ? ) flags>> 3 bits 1 + 2^ 3 * ; inline
142 : transparency? ( image -- ? )
143 graphic-control-extensions>> first flags>> 0 bit? ; inline
145 : color-resolution ( image -- ? ) flags>> -4 shift 3 bits ; inline
147 : read-global-color-table ( loading-gif -- loading-gif )
149 dup color-table-size read 3 group >>global-color-table
152 : maybe-read-local-color-table ( loading-gif -- loading-gif )
153 dup image-descriptor>> color-table? [
154 dup color-table-size read >>local-color-table
157 : read-image-data ( loading-gif -- loading-gif )
158 read-sub-blocks >>compressed-bytes ;
160 : read-table-based-image ( loading-gif -- loading-gif )
161 read-image-descriptor >>image-descriptor
162 maybe-read-local-color-table
165 : read-graphic-rendering-block ( loading-gif -- loading-gif )
166 read-table-based-image ;
168 : read-extension ( loading-gif -- loading-gif )
170 { plain-text-extension [
171 read-plain-text-extension over plain-text-extensions>> push
174 { graphic-control-extension [
175 read-graphic-control-extension
176 over graphic-control-extensions>> push
178 { comment-extension [
179 read-comment-extension over comment-extensions>> push
181 { application-extension [
182 read-application-extension over application-extensions>> push
184 { f [ gif-unexpected-eof ] }
185 [ unknown-extension ]
188 ERROR: unhandled-data byte ;
190 : read-data ( loading-gif -- loading-gif )
192 { extension-identifier [ read-extension ] }
193 { graphic-control-extension [
194 read-graphic-control-extension
195 over graphic-control-extensions>> push
197 { image-descriptor [ read-table-based-image ] }
198 { trailer [ f >>loading? ] }
202 : read-GIF89a ( loading-gif -- loading-gif )
203 read-logical-screen-descriptor
204 read-global-color-table
205 [ read-data dup loading?>> ] loop ;
207 : load-gif ( stream -- loading-gif )
210 read-gif-header dup magic>> {
211 { "GIF87a" [ read-GIF87a ] }
212 { "GIF89a" [ read-GIF89a ] }
213 [ unsupported-gif-format ]
215 ] with-input-stream ;
217 : decompress ( loading-gif -- indexes )
218 [ compressed-bytes>> ]
219 [ image-descriptor>> first-code-size>> ] bi
222 : colorize ( index palette transparent-index/f -- seq )
223 pick = [ 2drop B{ 0 0 0 0 } ] [ nth 255 suffix ] if ;
225 : apply-palette ( indexes palette transparent-index/f -- bitmap )
226 [ colorize ] 2curry V{ } map-as concat ;
228 : dimensions ( loading-gif -- dim )
229 [ image-descriptor>> width>> ] [ image-descriptor>> height>> ] bi 2array ;
231 : ?transparent-color-index ( loading-gif -- index/f )
233 [ graphic-control-extensions>> first transparent-color-index>> ]
236 : gif>image ( loading-gif -- image )
239 [ drop RGBA >>component-order ubyte-components >>component-type ]
241 [ decompress ] [ global-color-table>> ] [ ?transparent-color-index ] tri
242 apply-palette >>bitmap
245 ERROR: loading-gif-error gif-image ;
247 : ensure-loaded ( gif-image -- gif-image )
248 dup loading?>> [ loading-gif-error ] when ;
250 M: gif-image stream>image ( path gif-image -- image )
251 drop load-gif ensure-loaded gif>image ;