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1 /***************************************************************************/ | |
2 /* */ | |
3 /* pngshim.c */ | |
4 /* */ | |
5 /* PNG Bitmap glyph support. */ | |
6 /* */ | |
7 /* Copyright 2013 by Google, Inc. */ | |
8 /* Written by Stuart Gill and Behdad Esfahbod. */ | |
9 /* */ | |
10 /* This file is part of the FreeType project, and may only be used, */ | |
11 /* modified, and distributed under the terms of the FreeType project */ | |
12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ | |
13 /* this file you indicate that you have read the license and */ | |
14 /* understand and accept it fully. */ | |
15 /* */ | |
16 /***************************************************************************/ | |
17 | |
18 | |
19 #include "../../include/ft2build.h" | |
20 #include "../../include/freetype/internal/ftdebug.h" | |
21 #include "../../include/freetype/internal/ftstream.h" | |
22 #include "../../include/freetype/tttags.h" | |
23 #include "../../include/freetype/config/ftstdlib.h" | |
24 | |
25 | |
26 #ifdef FT_CONFIG_OPTION_USE_PNG | |
27 | |
28 /* We always include <stjmp.h>, so make libpng shut up! */ | |
29 #define PNG_SKIP_SETJMP_CHECK 1 | |
30 #include <png.h> | |
31 #include "pngshim.h" | |
32 | |
33 #include "sferrors.h" | |
34 | |
35 | |
36 /* This code is freely based on cairo-png.c. There's so many ways */ | |
37 /* to call libpng, and the way cairo does it is defacto standard. */ | |
38 | |
39 static int | |
40 multiply_alpha( int alpha, | |
41 int color ) | |
42 { | |
43 int temp = ( alpha * color ) + 0x80; | |
44 | |
45 | |
46 return ( temp + ( temp >> 8 ) ) >> 8; | |
47 } | |
48 | |
49 | |
50 /* Premultiplies data and converts RGBA bytes => native endian. */ | |
51 static void | |
52 premultiply_data( png_structp png, | |
53 png_row_infop row_info, | |
54 png_bytep data ) | |
55 { | |
56 unsigned int i; | |
57 | |
58 FT_UNUSED( png ); | |
59 | |
60 | |
61 for ( i = 0; i < row_info->rowbytes; i += 4 ) | |
62 { | |
63 unsigned char* base = &data[i]; | |
64 unsigned int alpha = base[3]; | |
65 | |
66 | |
67 if ( alpha == 0 ) | |
68 base[0] = base[1] = base[2] = base[3] = 0; | |
69 | |
70 else | |
71 { | |
72 unsigned int red = base[0]; | |
73 unsigned int green = base[1]; | |
74 unsigned int blue = base[2]; | |
75 | |
76 | |
77 if ( alpha != 0xFF ) | |
78 { | |
79 red = multiply_alpha( alpha, red ); | |
80 green = multiply_alpha( alpha, green ); | |
81 blue = multiply_alpha( alpha, blue ); | |
82 } | |
83 | |
84 base[0] = blue; | |
85 base[1] = green; | |
86 base[2] = red; | |
87 base[3] = alpha; | |
88 } | |
89 } | |
90 } | |
91 | |
92 | |
93 /* Converts RGBx bytes to BGRA. */ | |
94 static void | |
95 convert_bytes_to_data( png_structp png, | |
96 png_row_infop row_info, | |
97 png_bytep data ) | |
98 { | |
99 unsigned int i; | |
100 | |
101 FT_UNUSED( png ); | |
102 | |
103 | |
104 for ( i = 0; i < row_info->rowbytes; i += 4 ) | |
105 { | |
106 unsigned char* base = &data[i]; | |
107 unsigned int red = base[0]; | |
108 unsigned int green = base[1]; | |
109 unsigned int blue = base[2]; | |
110 | |
111 | |
112 base[0] = blue; | |
113 base[1] = green; | |
114 base[2] = red; | |
115 base[3] = 0xFF; | |
116 } | |
117 } | |
118 | |
119 | |
120 /* Use error callback to avoid png writing to stderr. */ | |
121 static void | |
122 error_callback( png_structp png, | |
123 png_const_charp error_msg ) | |
124 { | |
125 FT_Error* error = png_get_error_ptr( png ); | |
126 | |
127 FT_UNUSED( error_msg ); | |
128 | |
129 | |
130 *error = FT_THROW( Out_Of_Memory ); | |
131 #ifdef PNG_SETJMP_SUPPORTED | |
132 longjmp( png_jmpbuf( png ), 1 ); | |
133 #endif | |
134 /* if we get here, then we have no choice but to abort ... */ | |
135 } | |
136 | |
137 | |
138 /* Use warning callback to avoid png writing to stderr. */ | |
139 static void | |
140 warning_callback( png_structp png, | |
141 png_const_charp error_msg ) | |
142 { | |
143 FT_UNUSED( png ); | |
144 FT_UNUSED( error_msg ); | |
145 | |
146 /* Just ignore warnings. */ | |
147 } | |
148 | |
149 | |
150 static void | |
151 read_data_from_FT_Stream( png_structp png, | |
152 png_bytep data, | |
153 png_size_t length ) | |
154 { | |
155 FT_Error error; | |
156 png_voidp p = png_get_io_ptr( png ); | |
157 FT_Stream stream = (FT_Stream)p; | |
158 | |
159 | |
160 if ( FT_FRAME_ENTER( length ) ) | |
161 { | |
162 FT_Error* e = png_get_error_ptr( png ); | |
163 | |
164 | |
165 *e = FT_THROW( Invalid_Stream_Read ); | |
166 png_error( png, NULL ); | |
167 | |
168 return; | |
169 } | |
170 | |
171 memcpy( data, stream->cursor, length ); | |
172 | |
173 FT_FRAME_EXIT(); | |
174 } | |
175 | |
176 | |
177 static FT_Error | |
178 Load_SBit_Png( FT_Bitmap* map, | |
179 FT_Int x_offset, | |
180 FT_Int y_offset, | |
181 FT_Int pix_bits, | |
182 TT_SBit_Metrics metrics, | |
183 FT_Memory memory, | |
184 FT_Byte* data, | |
185 FT_UInt png_len ) | |
186 { | |
187 FT_Error error = FT_Err_Ok; | |
188 FT_StreamRec stream; | |
189 | |
190 png_structp png; | |
191 png_infop info; | |
192 png_uint_32 imgWidth, imgHeight; | |
193 | |
194 int bitdepth, color_type, interlace; | |
195 FT_Int i; | |
196 png_byte* *rows; | |
197 | |
198 | |
199 if ( x_offset < 0 || x_offset + metrics->width > map->width || | |
200 y_offset < 0 || y_offset + metrics->height > map->rows || | |
201 pix_bits != 32 || map->pixel_mode != FT_PIXEL_MODE_BGRA ) | |
202 { | |
203 error = FT_THROW( Invalid_Argument ); | |
204 goto Exit; | |
205 } | |
206 | |
207 FT_Stream_OpenMemory( &stream, data, png_len ); | |
208 | |
209 png = png_create_read_struct( PNG_LIBPNG_VER_STRING, | |
210 &error, | |
211 error_callback, | |
212 warning_callback ); | |
213 if ( !png ) | |
214 { | |
215 error = FT_THROW( Out_Of_Memory ); | |
216 goto Exit; | |
217 } | |
218 | |
219 info = png_create_info_struct( png ); | |
220 if ( !info ) | |
221 { | |
222 error = FT_THROW( Out_Of_Memory ); | |
223 png_destroy_read_struct( &png, NULL, NULL ); | |
224 goto Exit; | |
225 } | |
226 | |
227 if ( ft_setjmp( png_jmpbuf( png ) ) ) | |
228 { | |
229 error = FT_THROW( Invalid_File_Format ); | |
230 goto DestroyExit; | |
231 } | |
232 | |
233 png_set_read_fn( png, &stream, read_data_from_FT_Stream ); | |
234 | |
235 png_read_info( png, info ); | |
236 png_get_IHDR( png, info, | |
237 &imgWidth, &imgHeight, | |
238 &bitdepth, &color_type, &interlace, | |
239 NULL, NULL ); | |
240 | |
241 if ( error != FT_Err_Ok || | |
242 (FT_Int)imgWidth != metrics->width || | |
243 (FT_Int)imgHeight != metrics->height ) | |
244 goto DestroyExit; | |
245 | |
246 /* convert palette/gray image to rgb */ | |
247 if ( color_type == PNG_COLOR_TYPE_PALETTE ) | |
248 png_set_palette_to_rgb( png ); | |
249 | |
250 /* expand gray bit depth if needed */ | |
251 if ( color_type == PNG_COLOR_TYPE_GRAY ) | |
252 { | |
253 #if PNG_LIBPNG_VER >= 10209 | |
254 png_set_expand_gray_1_2_4_to_8( png ); | |
255 #else | |
256 png_set_gray_1_2_4_to_8( png ); | |
257 #endif | |
258 } | |
259 | |
260 /* transform transparency to alpha */ | |
261 if ( png_get_valid(png, info, PNG_INFO_tRNS ) ) | |
262 png_set_tRNS_to_alpha( png ); | |
263 | |
264 if ( bitdepth == 16 ) | |
265 png_set_strip_16( png ); | |
266 | |
267 if ( bitdepth < 8 ) | |
268 png_set_packing( png ); | |
269 | |
270 /* convert grayscale to RGB */ | |
271 if ( color_type == PNG_COLOR_TYPE_GRAY || | |
272 color_type == PNG_COLOR_TYPE_GRAY_ALPHA ) | |
273 png_set_gray_to_rgb( png ); | |
274 | |
275 if ( interlace != PNG_INTERLACE_NONE ) | |
276 png_set_interlace_handling( png ); | |
277 | |
278 png_set_filler( png, 0xFF, PNG_FILLER_AFTER ); | |
279 | |
280 /* recheck header after setting EXPAND options */ | |
281 png_read_update_info(png, info ); | |
282 png_get_IHDR( png, info, | |
283 &imgWidth, &imgHeight, | |
284 &bitdepth, &color_type, &interlace, | |
285 NULL, NULL ); | |
286 | |
287 if ( bitdepth != 8 || | |
288 !( color_type == PNG_COLOR_TYPE_RGB || | |
289 color_type == PNG_COLOR_TYPE_RGB_ALPHA ) ) | |
290 { | |
291 error = FT_THROW( Invalid_File_Format ); | |
292 goto DestroyExit; | |
293 } | |
294 | |
295 switch ( color_type ) | |
296 { | |
297 default: | |
298 /* Shouldn't happen, but fall through. */ | |
299 | |
300 case PNG_COLOR_TYPE_RGB_ALPHA: | |
301 png_set_read_user_transform_fn( png, premultiply_data ); | |
302 break; | |
303 | |
304 case PNG_COLOR_TYPE_RGB: | |
305 /* Humm, this smells. Carry on though. */ | |
306 png_set_read_user_transform_fn( png, convert_bytes_to_data ); | |
307 break; | |
308 } | |
309 | |
310 if ( FT_NEW_ARRAY( rows, imgHeight ) ) | |
311 { | |
312 error = FT_THROW( Out_Of_Memory ); | |
313 goto DestroyExit; | |
314 } | |
315 | |
316 for ( i = 0; i < (FT_Int)imgHeight; i++ ) | |
317 rows[i] = map->buffer + ( y_offset + i ) * map->pitch + x_offset * 4; | |
318 | |
319 png_read_image( png, rows ); | |
320 | |
321 FT_FREE( rows ); | |
322 | |
323 png_read_end( png, info ); | |
324 | |
325 DestroyExit: | |
326 png_destroy_read_struct( &png, &info, NULL ); | |
327 FT_Stream_Close( &stream ); | |
328 | |
329 Exit: | |
330 return error; | |
331 } | |
332 | |
333 #endif /* FT_CONFIG_OPTION_USE_PNG */ | |
334 | |
335 | |
336 /* END */ | |
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