2 * Image Library -- libpng
4 * (c) 2006 Pavel Charvat <pchar@ucw.cz>
6 * This software may be freely distributed and used according to the terms
7 * of the GNU Lesser General Public License.
13 #include "lib/mempool.h"
14 #include "lib/fastbuf.h"
15 #include "images/images.h"
16 #include "images/error.h"
17 #include "images/color.h"
18 #include "images/io-main.h"
23 struct libpng_read_data {
34 libpng_malloc(png_structp png_ptr, png_size_t size)
36 DBG("libpng_malloc(size=%u)", (uns)size);
37 return mp_alloc(png_get_mem_ptr(png_ptr), size);
41 libpng_free(png_structp png_ptr UNUSED, png_voidp ptr UNUSED)
47 libpng_read_error(png_structp png_ptr, png_const_charp msg)
49 DBG("libpng_read_error()");
50 IMAGE_ERROR(png_get_error_ptr(png_ptr), IMAGE_ERROR_READ_FAILED, "%s", msg);
51 longjmp(png_jmpbuf(png_ptr), 1);
55 libpng_write_error(png_structp png_ptr, png_const_charp msg)
57 DBG("libpng_write_error()");
58 IMAGE_ERROR(png_get_error_ptr(png_ptr), IMAGE_ERROR_WRITE_FAILED, "%s", msg);
59 longjmp(png_jmpbuf(png_ptr), 1);
63 libpng_warning(png_structp png_ptr UNUSED, png_const_charp msg UNUSED)
65 DBG("libpng_warning(): %s", (byte *)msg);
69 libpng_read_fn(png_structp png_ptr, png_bytep data, png_size_t length)
71 DBG("libpng_read_fn(len=%u)", (uns)length);
72 if (unlikely(bread((struct fastbuf *)png_get_io_ptr(png_ptr), (byte *)data, length) < length))
73 png_error(png_ptr, "Incomplete data");
77 libpng_write_fn(png_structp png_ptr, png_bytep data, png_size_t length)
79 DBG("libpng_write_fn(len=%u)", (uns)length);
80 bwrite((struct fastbuf *)png_get_io_ptr(png_ptr), (byte *)data, length);
84 libpng_flush_fn(png_structp png_ptr UNUSED)
86 DBG("libpng_flush_fn()");
90 libpng_read_cancel(struct image_io *io)
92 DBG("libpng_read_cancel()");
94 struct libpng_read_data *rd = io->read_data;
95 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
99 libpng_read_header(struct image_io *io)
101 DBG("libpng_read_header()");
103 /* Create libpng structures */
104 struct libpng_read_data *rd = io->read_data = mp_alloc(io->internal_pool, sizeof(*rd));
105 rd->png_ptr = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
106 io->context, libpng_read_error, libpng_warning,
107 io->internal_pool, libpng_malloc, libpng_free);
108 if (unlikely(!rd->png_ptr))
110 IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Cannot create libpng read structure.");
113 rd->info_ptr = png_create_info_struct(rd->png_ptr);
114 if (unlikely(!rd->info_ptr))
116 IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Cannot create libpng info structure.");
117 png_destroy_read_struct(&rd->png_ptr, NULL, NULL);
120 rd->end_ptr = png_create_info_struct(rd->png_ptr);
121 if (unlikely(!rd->end_ptr))
123 IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Cannot create libpng info structure.");
124 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, NULL);
128 /* Setup libpng longjump */
129 if (unlikely(setjmp(png_jmpbuf(rd->png_ptr))))
131 DBG("Libpng failed to read the image, longjump saved us");
132 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
136 /* Setup libpng IO */
137 png_set_read_fn(rd->png_ptr, io->fastbuf, libpng_read_fn);
138 png_set_user_limits(rd->png_ptr, image_max_dim, image_max_dim);
141 png_read_info(rd->png_ptr, rd->info_ptr);
142 png_get_IHDR(rd->png_ptr, rd->info_ptr, &rd->cols, &rd->rows, &rd->bit_depth, &rd->color_type, NULL, NULL, NULL);
144 /* Fill image_io values */
147 switch (rd->color_type)
149 case PNG_COLOR_TYPE_GRAY:
150 io->flags = COLOR_SPACE_GRAYSCALE;
151 io->number_of_colors = 1 << 8;
153 case PNG_COLOR_TYPE_GRAY_ALPHA:
154 io->flags = COLOR_SPACE_GRAYSCALE | IMAGE_ALPHA;
155 io->number_of_colors = 1 << 8;
157 case PNG_COLOR_TYPE_RGB:
158 io->flags = COLOR_SPACE_RGB;
159 io->number_of_colors = 1 << 24;
161 case PNG_COLOR_TYPE_RGB_ALPHA:
162 io->number_of_colors = 1 << 24;
163 io->flags = COLOR_SPACE_RGB | IMAGE_ALPHA;
165 case PNG_COLOR_TYPE_PALETTE:
166 io->flags = COLOR_SPACE_RGB | IMAGE_ALPHA | IMAGE_IO_HAS_PALETTE;
168 if (png_get_PLTE(rd->png_ptr, rd->info_ptr, NULL, &num_palette))
169 io->number_of_colors = num_palette;
171 io->number_of_colors = 1 << rd->bit_depth;
174 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
175 IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Unknown color type");
180 io->read_cancel = libpng_read_cancel;
185 libpng_read_data(struct image_io *io)
187 DBG("libpng_read_data()");
189 struct libpng_read_data *rd = io->read_data;
191 /* Test supported pixel formats */
192 switch (io->flags & IMAGE_COLOR_SPACE)
194 case COLOR_SPACE_GRAYSCALE:
195 case COLOR_SPACE_RGB:
198 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
199 IMAGE_ERROR(io->context, IMAGE_ERROR_INVALID_PIXEL_FORMAT, "Unsupported color space.");
203 struct image_io_read_data_internals rdi;
206 if (setjmp(png_jmpbuf(rd->png_ptr)))
208 DBG("Libpng failed to read the image, longjump saved us");
209 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
211 image_io_read_data_break(&rdi, io);
215 uns read_flags = io->flags;
217 /* Apply transformations */
218 if (rd->bit_depth == 16)
219 png_set_strip_16(rd->png_ptr);
220 switch (rd->color_type)
222 case PNG_COLOR_TYPE_PALETTE:
223 if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_GRAYSCALE)
225 png_set_palette_to_rgb(rd->png_ptr);
226 png_set_rgb_to_gray_fixed(rd->png_ptr, 1, 21267, 71514);
229 png_set_palette_to_rgb(rd->png_ptr);
230 if (!(io->flags & IMAGE_ALPHA))
232 if (io->flags & IMAGE_IO_USE_BACKGROUND)
234 png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
235 read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
237 else if ((io->flags & IMAGE_PIXEL_FORMAT) == (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
238 png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
240 png_set_strip_alpha(rd->png_ptr);
243 png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
245 case PNG_COLOR_TYPE_GRAY:
246 if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_RGB)
247 png_set_gray_to_rgb(rd->png_ptr);
248 if (io->flags & IMAGE_ALPHA)
249 png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
251 case PNG_COLOR_TYPE_GRAY_ALPHA:
252 if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_RGB)
253 png_set_gray_to_rgb(rd->png_ptr);
254 if (!(io->flags & IMAGE_ALPHA))
256 if (io->flags & IMAGE_IO_USE_BACKGROUND)
257 read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
259 png_set_strip_alpha(rd->png_ptr);
262 case PNG_COLOR_TYPE_RGB:
263 if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_GRAYSCALE)
264 png_set_rgb_to_gray_fixed(rd->png_ptr, 1, 21267, 71514);
265 if ((io->flags & IMAGE_ALPHA) || (io->flags & IMAGE_PIXEL_FORMAT) == (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
266 png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
268 case PNG_COLOR_TYPE_RGB_ALPHA:
269 if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_GRAYSCALE)
270 png_set_rgb_to_gray_fixed(rd->png_ptr, 1, 21267, 71514);
271 if (!(io->flags & IMAGE_ALPHA))
272 if (io->flags & IMAGE_IO_USE_BACKGROUND)
273 read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
274 else if ((io->flags & IMAGE_PIXEL_FORMAT) != (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
275 png_set_strip_alpha(rd->png_ptr);
280 png_read_update_info(rd->png_ptr, rd->info_ptr);
282 /* Prepare the image */
283 if (unlikely(!image_io_read_data_prepare(&rdi, io, rd->cols, rd->rows, read_flags)))
285 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
288 /* Read image data */
289 DBG("Reading image data");
290 struct image *img = rdi.image;
291 byte *pixels = img->pixels;
292 png_bytep rows[img->rows];
293 for (uns r = 0; r < img->rows; r++, pixels += img->row_size)
294 rows[r] = (png_bytep)pixels;
295 png_read_image(rd->png_ptr, rows);
296 png_read_end(rd->png_ptr, rd->end_ptr);
298 /* Destroy libpng read structure */
299 png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
301 /* Finish the image */
302 return image_io_read_data_finish(&rdi, io);
306 libpng_write(struct image_io *io)
308 DBG("libpng_write()");
310 /* Create libpng structures */
311 png_structp png_ptr = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
312 io->context, libpng_write_error, libpng_warning,
313 io->internal_pool, libpng_malloc, libpng_free);
314 if (unlikely(!png_ptr))
316 IMAGE_ERROR(io->context, IMAGE_ERROR_WRITE_FAILED, "Cannot create libpng write structure.");
319 png_infop info_ptr = png_create_info_struct(png_ptr);
320 if (unlikely(!info_ptr))
322 IMAGE_ERROR(io->context, IMAGE_ERROR_WRITE_FAILED, "Cannot create libpng info structure.");
323 png_destroy_write_struct(&png_ptr, NULL);
327 /* Setup libpng longjump */
328 if (unlikely(setjmp(png_jmpbuf(png_ptr))))
330 DBG("Libpng failed to write the image, longjump saved us.");
331 png_destroy_write_struct(&png_ptr, &info_ptr);
335 /* Setup libpng IO */
336 png_set_write_fn(png_ptr, io->fastbuf, libpng_write_fn, libpng_flush_fn);
338 /* Setup PNG parameters */
339 struct image *img = io->image;
340 switch (img->flags & IMAGE_PIXEL_FORMAT)
342 case COLOR_SPACE_GRAYSCALE | IMAGE_PIXELS_ALIGNED:
343 png_set_IHDR(png_ptr, info_ptr, img->cols, img->rows, 8, PNG_COLOR_TYPE_GRAY,
344 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
346 case COLOR_SPACE_GRAYSCALE | IMAGE_ALPHA | IMAGE_PIXELS_ALIGNED:
347 png_set_IHDR(png_ptr, info_ptr, img->cols, img->rows, 8, PNG_COLOR_TYPE_GRAY_ALPHA,
348 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
350 case COLOR_SPACE_RGB:
351 png_set_IHDR(png_ptr, info_ptr, img->cols, img->rows, 8, PNG_COLOR_TYPE_RGB,
352 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
354 case COLOR_SPACE_RGB | IMAGE_ALPHA | IMAGE_PIXELS_ALIGNED:
355 png_set_IHDR(png_ptr, info_ptr, img->cols, img->rows, 8, PNG_COLOR_TYPE_RGB_ALPHA,
356 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
358 case COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED:
359 png_set_IHDR(png_ptr, info_ptr, img->cols, img->rows, 8, PNG_COLOR_TYPE_RGB,
360 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
361 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
366 png_write_info(png_ptr, info_ptr);
369 byte *pixels = img->pixels;
370 png_bytep rows[img->rows];
371 for (uns r = 0; r < img->rows; r++, pixels += img->row_size)
372 rows[r] = (png_bytep)pixels;
373 png_write_image(png_ptr, rows);
374 png_write_end(png_ptr, info_ptr);
376 /* Free libpng structure */
377 png_destroy_write_struct(&png_ptr, &info_ptr);