summaryrefslogtreecommitdiffstats
path: root/libdimension/png.c
blob: 24f8afadd4480d81b628a43f8b03e13058d2aac4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
/*************************************************************************
 * Copyright (C) 2009-2014 Tavian Barnes <tavianator@tavianator.com>     *
 *                                                                       *
 * This file is part of The Dimension Library.                           *
 *                                                                       *
 * The Dimension Library is free software; you can redistribute it and/  *
 * or modify it under the terms of the GNU Lesser General Public License *
 * as published by the Free Software Foundation; either version 3 of the *
 * License, or (at your option) any later version.                       *
 *                                                                       *
 * The Dimension Library is distributed in the hope that it will be      *
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
 * Lesser General Public License for more details.                       *
 *                                                                       *
 * You should have received a copy of the GNU Lesser General Public      *
 * License along with this program.  If not, see                         *
 * <http://www.gnu.org/licenses/>.                                       *
 *************************************************************************/

/**
 * @file
 * PNG import/export.
 */

#include "dimension-internal.h"
#include <png.h>
#include <errno.h>
#include <setjmp.h>
#include <stdlib.h>
#include <stdint.h>

int
dmnsn_png_optimize_canvas(dmnsn_canvas *canvas)
{
  dmnsn_rgba16_optimize_canvas(canvas);
  return 0;
}

/// Payload type for PNG write thread callback.
typedef struct {
  dmnsn_future *future;
  const dmnsn_canvas *canvas;
  FILE *file;
} dmnsn_png_write_payload;

/// Payload type for PNG read thread callback.
typedef struct {
  dmnsn_future *future;
  dmnsn_canvas **canvas;
  dmnsn_pool *pool;
  FILE *file;
} dmnsn_png_read_payload;

/// PNG write thread callback.
static int dmnsn_png_write_canvas_thread(void *ptr);
/// PNG read thread callback.
static int dmnsn_png_read_canvas_thread(void *ptr);

int
dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file)
{
  dmnsn_future *future = dmnsn_png_write_canvas_async(canvas, file);
  return dmnsn_future_join(future);
}

dmnsn_future *
dmnsn_png_write_canvas_async(const dmnsn_canvas *canvas, FILE *file)
{
  dmnsn_future *future = dmnsn_new_future();

  dmnsn_png_write_payload *payload = DMNSN_MALLOC(dmnsn_png_write_payload);
  payload->future = future;
  payload->canvas = canvas;
  payload->file   = file;

  // Create the worker thread
  dmnsn_new_thread(future, dmnsn_png_write_canvas_thread, payload);

  return future;
}

// Read a canvas from the PNG file `file'.  Return NULL on error.
dmnsn_canvas *
dmnsn_png_read_canvas(dmnsn_pool *pool, FILE *file)
{
  dmnsn_canvas *canvas;
  dmnsn_future *future = dmnsn_png_read_canvas_async(&canvas, pool, file);
  dmnsn_future_join(future);
  return canvas;
}

// Read a canvas from a png file in the background
dmnsn_future *
dmnsn_png_read_canvas_async(dmnsn_canvas **canvas, dmnsn_pool *pool, FILE *file)
{
  dmnsn_future *future = dmnsn_new_future();
  dmnsn_png_read_payload *payload = DMNSN_MALLOC(dmnsn_png_read_payload);

  payload->future = future;
  payload->canvas = canvas;
  *payload->canvas = NULL;
  payload->pool = pool;
  payload->file = file;

  // Create the worker thread
  dmnsn_new_thread(future, dmnsn_png_read_canvas_thread, payload);

  return future;
}

//////////////////////
// Thread callbacks //
//////////////////////

// Write a PNG file
static int
dmnsn_png_write_canvas_thread(void *ptr)
{
  dmnsn_png_write_payload *payload = ptr;

  png_uint_32 width = payload->canvas->width;
  png_uint_32 height = payload->canvas->height;

  dmnsn_future_set_total(payload->future, height);

  png_structp png_ptr
    = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  if (!png_ptr) {
    // Couldn't create libpng write struct
    dmnsn_free(payload);
    return -1;
  }

  png_infop info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr) {
    // Couldn't create libpng info struct
    png_destroy_write_struct(&png_ptr, NULL);
    dmnsn_free(payload);
    return -1;
  }

  // libpng will longjmp here if it encounters an error from here on
  uint16_t *row = NULL;
  if (setjmp(png_jmpbuf(png_ptr))) {
    // libpng error
    dmnsn_free(row);
    png_destroy_write_struct(&png_ptr, &info_ptr);
    dmnsn_free(payload);
    return -1;
  }

  // Associate file with the libpng write struct
  png_init_io(png_ptr, payload->file);

  // Set header correctly for 16-bit sRGB image
  png_set_IHDR(png_ptr, info_ptr, width, height, 16,
               PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
               PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
  png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);

  // We think of transparency in the opposite way that PNG does
  png_set_invert_alpha(png_ptr);

  // Write the info struct
  png_write_info(png_ptr, info_ptr);

  if (dmnsn_is_little_endian()) {
    // We are little-endian; swap the byte order of the pixels
    png_set_swap(png_ptr);
  }

  // Check if we can optimize this
  dmnsn_canvas_optimizer *optimizer =
    dmnsn_canvas_find_optimizer(payload->canvas, dmnsn_rgba16_optimizer_fn);
  if (optimizer) {
    for (size_t y = 0; y < height; ++y) {
      // Invert the rows.  PNG coordinates are fourth quadrant.
      uint16_t *row_opt = (uint16_t *)optimizer->ptr + 4*(height - y - 1)*width;
      png_write_row(png_ptr, (png_bytep)row_opt);
      dmnsn_future_increment(payload->future);
    }

    // Finish the PNG file
    png_write_end(png_ptr, info_ptr);
    png_destroy_write_struct(&png_ptr, &info_ptr);
    dmnsn_free(payload);
    return 0;
  }

  // Allocate the temporary row of RGBA values
  row = dmnsn_malloc(4*sizeof(uint16_t)*width);

  // Write the pixels
  for (size_t y = 0; y < height; ++y) {
    for (size_t x = 0; x < width; ++x) {
      // Invert the rows.  PNG coordinates are fourth quadrant.
      dmnsn_tcolor tcolor = dmnsn_canvas_get_pixel(payload->canvas,
                                                   x, height - y - 1);
      tcolor = dmnsn_tcolor_remove_filter(tcolor);
      tcolor.c = dmnsn_color_to_sRGB(tcolor.c);
      tcolor = dmnsn_tcolor_saturate(tcolor);

      row[4*x]     = lround(tcolor.c.R*UINT16_MAX);
      row[4*x + 1] = lround(tcolor.c.G*UINT16_MAX);
      row[4*x + 2] = lround(tcolor.c.B*UINT16_MAX);
      row[4*x + 3] = lround(tcolor.T*UINT16_MAX);
    }

    // Write the row
    png_write_row(png_ptr, (png_bytep)row);
    dmnsn_future_increment(payload->future);
  }

  // Finish the PNG file
  png_write_end(png_ptr, info_ptr);

  dmnsn_free(row);
  png_destroy_write_struct(&png_ptr, &info_ptr);
  dmnsn_free(payload);
  return 0;
}

/// Thread-specific pointer to the appropriate dmnsn_future* for
/// dmnsn_png_read_row_callback.
static __thread dmnsn_future *dmnsn_tl_png_read_future;

/// Callback to increment the progress after a row has been read.
static void
dmnsn_png_read_row_callback(png_structp png_ptr, png_uint_32 row, int pass)
{
  dmnsn_future_increment(dmnsn_tl_png_read_future);
}

// Read a PNG file
static int
dmnsn_png_read_canvas_thread(void *ptr)
{
  dmnsn_png_read_payload *payload = ptr;
  dmnsn_tl_png_read_future = payload->future;

  png_byte header[8];
  if (fread(header, 1, 8, payload->file) != 8) {
    dmnsn_free(payload);
    return -1;
  }
  if (png_sig_cmp(header, 0, 8)) {
    // payload->file is not a PNG file
    dmnsn_free(payload);
    errno = EINVAL;
    return -1;
  }

  // Create the libpng read struct
  png_structp png_ptr
    = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  if (!png_ptr) {
    dmnsn_free(payload);
    return -1;
  }

  // Create the libpng info struct
  png_infop info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr) {
    png_destroy_read_struct(&png_ptr, NULL, NULL);
    dmnsn_free(payload);
    return -1;
  }

  // libpng will longjmp here if it encounters an error from here on
  png_bytep image = NULL;
  png_bytep *row_pointers = NULL;
  if (setjmp(png_jmpbuf(png_ptr))) {
    // libpng error
    dmnsn_free(row_pointers);
    dmnsn_free(image);
    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
    dmnsn_free(payload);
    return -1;
  }

  // Associate the read struct with the file, and tell it we've already checked
  // 8 bytes of signature
  png_init_io(png_ptr, payload->file);
  png_set_sig_bytes(png_ptr, 8);

  // Read the PNG header into info struct
  png_read_info(png_ptr, info_ptr);

  // Get useful information from the info struct
  png_uint_32 width, height;
  int bit_depth, color_type, interlace_type, compression_type, filter_method;
  png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
               &interlace_type, &compression_type, &filter_method);
  int number_of_passes = png_set_interlace_handling(png_ptr);

  dmnsn_future_set_total(payload->future, (number_of_passes + 1)*height);
  png_set_read_status_fn(png_ptr, dmnsn_png_read_row_callback);

  // - Convert paletted images to RGB.
  // - Convert a tRNS chunk to an alpha channel
  // - Convert grayscale to RGB
  // - Invert the alpha channel
  if (color_type == PNG_COLOR_TYPE_PALETTE) {
    png_set_palette_to_rgb(png_ptr);
  }
  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
    png_set_tRNS_to_alpha(png_ptr);
  }
  if (color_type == PNG_COLOR_TYPE_GRAY
      || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
  {
    png_set_gray_to_rgb(png_ptr);
  }
  png_set_invert_alpha(png_ptr);

  // Update the info struct
  png_read_update_info(png_ptr, info_ptr);

  // Get bytes/image row
  png_uint_32 rowbytes = png_get_rowbytes(png_ptr, info_ptr);

  // Allocate the temporary image buffer
  image = dmnsn_malloc(rowbytes*height);

  // Allocate and set an array of pointers to rows in image
  row_pointers = dmnsn_malloc(sizeof(png_bytep)*height);

  for (size_t y = 0; y < height; ++y) {
    row_pointers[y] = image + y*rowbytes;
  }

  // Read the image to memory all at once.  At the expense of greater memory
  // use, this handles interlacing for us.
  png_read_image(png_ptr, row_pointers);

  // Allocate the canvas
  *payload->canvas = dmnsn_new_canvas(payload->pool, width, height);

  // Now we convert the image to our canvas format.  This depends on the image
  // bit depth (which has been scaled up to at least 8 or 16), and the presence
  // of an alpha channel.
  for (size_t y = 0; y < height; ++y) {
    for (size_t x = 0; x < width; ++x) {
      dmnsn_tcolor tcolor;
      tcolor.F = 0.0;

      if (color_type & PNG_COLOR_MASK_ALPHA) {
        if (bit_depth == 16) {
          png_bytep png_pixel = image + 8*(y*width + x);
          tcolor.c.R = (double)((png_pixel[0] << 8) + png_pixel[1])/UINT16_MAX;
          tcolor.c.G = (double)((png_pixel[2] << 8) + png_pixel[3])/UINT16_MAX;
          tcolor.c.B = (double)((png_pixel[4] << 8) + png_pixel[5])/UINT16_MAX;
          tcolor.T   = (double)((png_pixel[6] << 8) + png_pixel[7])/UINT16_MAX;
        } else {
          png_bytep png_pixel = image + 4*(y*width + x);
          tcolor.c.R = (double)png_pixel[0]/UINT8_MAX;
          tcolor.c.G = (double)png_pixel[1]/UINT8_MAX;
          tcolor.c.B = (double)png_pixel[2]/UINT8_MAX;
          tcolor.T   = (double)png_pixel[3]/UINT8_MAX;
        }
      } else {
        tcolor.T = 0.0;

        if (bit_depth == 16) {
          png_bytep png_pixel = image + 6*(y*width + x);
          tcolor.c.R = (double)((png_pixel[0] << 8) + png_pixel[1])/UINT16_MAX;
          tcolor.c.G = (double)((png_pixel[2] << 8) + png_pixel[3])/UINT16_MAX;
          tcolor.c.B = (double)((png_pixel[4] << 8) + png_pixel[5])/UINT16_MAX;
        } else {
          png_bytep png_pixel = image + 3*(y*width + x);
          tcolor.c.R = (double)png_pixel[0]/UINT8_MAX;
          tcolor.c.G = (double)png_pixel[1]/UINT8_MAX;
          tcolor.c.B = (double)png_pixel[2]/UINT8_MAX;
        }
      }

      tcolor.c = dmnsn_color_from_sRGB(tcolor.c);
      dmnsn_canvas_set_pixel(*payload->canvas, x, height - y - 1, tcolor);
    }

    dmnsn_future_increment(payload->future);
  }

  dmnsn_free(row_pointers);
  dmnsn_free(image);
  png_read_end(png_ptr, NULL);
  png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
  dmnsn_free(payload);
  return 0;
}