summaryrefslogtreecommitdiff
path: root/riscos/gif.c
blob: 948970323387f64e0640a107516e8f39e8223061 (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
/*******************
 * GIF loader for Netsurf
 * Developed by Philip Pemberton for the Netsurf project
 *
 * Yes, this is an evil hack. You will not be tested on your understanding of
 * this code. Beware - dragons lurketh here.
 *
 * TO-DO:
 *   Add support for GIF transparency
 *   Add better error handling
 *      - especially where bad GIFs are concerned.
 *
 * $Id: gif.c,v 1.4 2003/06/06 08:06:55 philpem Exp $
 */

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "libungif/gif_lib.h"
#include "oslib/colourtrans.h"
#include "oslib/os.h"
#include "oslib/osspriteop.h"
#include "netsurf/content/content.h"
#include "netsurf/riscos/gif.h"
#include "netsurf/utils/log.h"
#include "netsurf/utils/utils.h"

/* maps colours to 256 mode colour numbers */
static os_colour_number colour_table[4096];

static int
    InterlacedOffset[] = { 0, 4, 2, 1 }, /* The way Interlaced image should. */
    InterlacedJumps[] = { 8, 8, 4, 2 };    /* be read - offsets and jumps... */


void nsgif_init(void)
{
  // Generate a colour lookup table
  // TODO: Use the PNG colour table instead of the GIF table...
	unsigned int red, green, blue;
	for (red = 0; red != 0xf; red++)
		for (green = 0; green != 0xf; green++)
			for (blue = 0; blue != 0xf; blue++)
				colour_table[red << 8 | green << 4 | blue] =
					colourtrans_return_colour_number_for_mode(
						blue << 28 | blue << 24 |
						green << 20 | green << 16 |
						red << 12 | red << 8, 21, 0);
}

// Called when Netsurf wants us to prepare to decode a GIF
void nsgif_create(struct content *c)
{
  // Clear the sprite area
  c->data.gif.sprite_area = 0;

  // Allocate some memory for the GIF file
  c->data.gif.data = xcalloc(0, 1);
  // Set the length and buffer position to zero (we haven't loaded any data
  // yet)
  c->data.gif.length = 0;
  c->data.gif.buffer_pos = 0;

  LOG(("gif object created"));
}

// Called when Netsurf has got some more data for us
void nsgif_process_data(struct content *c, char *data, unsigned long size)
{
  // We've just been given some more data!
  // Reallocate the memory block
  c->data.gif.data = xrealloc(c->data.gif.data, c->data.gif.length + size);
  // Copy the new data into our buffer
  memcpy(c->data.gif.data + c->data.gif.length, data, size);
  // Update the data length variables
  c->data.gif.length += size;
  c->size += size;
}

// This is the callback for the GIF loader. It grabs some data from the buffer
// and hands it over to Libungif.
// Returns the number of bytes successfully read from the buffer
int nsgif_input_callback(GifFileType *giffile, GifByteType *data, int length)
{
  struct content *c;

  // We need to set up the content block pointer first
  c = (struct content *)giffile->UserData;

  // Now check that there's enough data in the buffer
  if ((c->data.gif.buffer_pos + length) > c->data.gif.length)
  {
    // We don't have enough data in the buffer. Give libungif the data we've
    // got.
    memcpy(data, &c->data.gif.data[c->data.gif.buffer_pos], (c->data.gif.length - c->data.gif.buffer_pos));
    c->data.gif.buffer_pos += length;
    return (c->data.gif.length - c->data.gif.buffer_pos);
  }

  // Well, we've got enough data. Give libungif as much as it wants.
  memcpy(data, &c->data.gif.data[c->data.gif.buffer_pos], length);
  c->data.gif.buffer_pos += length;

  return length;
}

// Called when Netsurf wants us to convert the image
int nsgif_convert(struct content *c, unsigned int width, unsigned int height)
{
  char *row, **row_pointers;
  int i, j, bit_depth, color_type, log2bpp, interlace;
  unsigned int rowbytes, sprite_size;
  unsigned long width, height;
  os_palette *palette;
  os_sprite_palette *sprite_palette;
  osspriteop_area *sprite_area;
  osspriteop_header *sprite;
  // The next three lines are for vars. used by the gif decoding engine
  int recordtype, cur_row, extcode, count, got_image_data;
  GifByteType *extension;
  GifColorType *colormap;

  LOG(("Opening GIF file"));

  got_image_data = 0;   // we haven't read any image data yet

  // Now decode the GIF
  c->data.gif.giffile = DGifOpen(c, &nsgif_input_callback);
  if (c->data.gif.giffile == NULL)
  {
    LOG(("ERROR: giffile is null! error %d", GifLastError()));
    return 1;  // more graceful exit
  }

  // Start creating the sprite
  width = c->data.gif.giffile->SWidth;
  height = c->data.gif.giffile->SHeight;

  LOG(("gif image width = %d, height = %d", width, height));

  sprite_size = sizeof(*sprite_area) + sizeof(*sprite);

  // GIFs can't be more than 256 colours (8 bits).
  sprite_size += 8 * 256 + height * ((width + 3) & ~3u);

  sprite_area = xcalloc(sprite_size + 1000, 1);
  sprite_area->size = sprite_size;
  sprite_area->sprite_count = 1;
  sprite_area->first = sizeof(*sprite_area);
  sprite_area->used = sprite_size;
  sprite = (osspriteop_header *) (sprite_area + 1);
  sprite->size = sprite_size - sizeof(*sprite_area);
  strcpy(sprite->name, "gif");
  sprite->height = height -1;
  c->data.gif.sprite_area = sprite_area;
  sprite->width = ((width + 3) & ~3u) / 4 - 1;
  sprite->left_bit = 0;
  sprite->right_bit = (8 * (((width - 1) % 4) + 1)) -1;
  sprite->mask = sprite->image = sizeof(*sprite) + 8 * 256;
  sprite->mode = (os_mode) 21;
  sprite_palette = (os_sprite_palette *) (sprite + 1);
  c->data.gif.sprite_image = ((char *) sprite) + sprite->image;
  c->width = width;
  c->height = height;

  do
  {
    if (DGifGetRecordType(c->data.gif.giffile, &recordtype) == GIF_ERROR)
    {
      LOG(("gif error %d", GifLastError()));
      return(1); // more graceful exit
    }
    // TODO: ^^^ better error checking
    switch (recordtype)
    {
      case IMAGE_DESC_RECORD_TYPE:
        // The next line is used to handle animated GIFs
        if (!got_image_data)
        {
          assert(DGifGetImageDesc(c->data.gif.giffile) != GIF_ERROR);
        // TODO: ^^^ better error checking

          c->data.gif.sprite_area = sprite_area;

          if (c->data.gif.giffile->Image.Interlace)
          {
            // The image is interlaced, therefore we need to perform four
            // passes over the image
            for (count = i = 0; i < 4; i++)
            {
              LOG(("Interlaced GIF file"));
              for (j=InterlacedOffset[i]; j < height; j += InterlacedJumps[i])
              {
                LOG(("gif line %d", count));
                count++;
                assert (DGifGetLine(c->data.gif.giffile, c->data.gif.sprite_image + j * ((c->width + 3) & ~3u), width) != GIF_ERROR);
                // TODO: ^^^ better error checking
              }
            }
          }
          else
          {
            LOG(("running DGifGetLine"));
            for (i=0; i<height; i++)
            {
  //            assert(DGifGetLine(c->data.gif.giffile, c->data.gif.sprite_image + i * ((c->width + 3) & ~3u), width) != GIF_ERROR);
              if (DGifGetLine(c->data.gif.giffile, c->data.gif.sprite_image + i * ((c->width + 3) & ~3u), width) == GIF_ERROR)
              {
                LOG(("error: gif line %d - error %d", i, GifLastError()));
                LOG(("exp height = %d, width = %d", height, width));
                return 1;
              }
              // TODO: ^^^ better error checking
              LOG(("gif line %d", i));
            }
          }
          got_image_data = -1;
        } else recordtype = TERMINATE_RECORD_TYPE;
        break;
      case EXTENSION_RECORD_TYPE:
        // Skip any extension blocks in the file
        assert (DGifGetExtension(c->data.gif.giffile, &extcode, &extension) != GIF_ERROR);
        // TODO: ^^^ better error checking
        while (extension != NULL)
        {
          DGifGetExtensionNext(c->data.gif.giffile, &extension);
          // TODO: ^^^ better error checking
        }
        break;
      case TERMINATE_RECORD_TYPE:
        break;
      default:       // Should be trapped by DGifGetRecordType
        break;
    }
  } while (recordtype != TERMINATE_RECORD_TYPE);

  LOG(("all done"));

/*
   And now for the obligatory quote from "The Matrix"
   "Before you can bend the spoon, you must realise the truth."
   "And what is the truth?"
   "There is no spoon."
 */

  // Load the colour map
  colormap = (c->data.gif.giffile->Image.ColorMap ?
              c->data.gif.giffile->Image.ColorMap->Colors :
              c->data.gif.giffile->SColorMap->Colors);

  for (i=0; i < 256; i++)
    sprite_palette->entries[i].on =
    sprite_palette->entries[i].off =
      (colormap[i].Blue << 24) |
      (colormap[i].Green << 16) |
      (colormap[i].Red << 8) |
      16;

  DGifCloseFile(c->data.gif.giffile);

  c->width = width;
  c->height = height;

  c->title = xcalloc(100, 1);
  sprintf(c->title, "GIF image (%ux%u)", c->width, c->height);

//  xosspriteop_save_sprite_file(osspriteop_USER_AREA, c->data.gif.sprite_area,
//          "gif");
  return 0;
}


void nsgif_revive(struct content *c, unsigned int width, unsigned int height)
{
}


void nsgif_reformat(struct content *c, unsigned int width, unsigned int height)
{
}

// Called when Netsurf is finished with us
void nsgif_destroy(struct content *c)
{
  xfree(c->title);
  xfree(c->data.gif.sprite_area);
  xfree(c->data.gif.data);
}

// Called when Netsurf wants us to draw the image
void nsgif_redraw(struct content *c, long x, long y,
		unsigned long width, unsigned long height)
{
	/* TODO: scale to width, height */
	int size;
	osspriteop_trans_tab *table;

/* JMB - lose this, it's filling my error log up too quickly ;)

  LOG(("Redraw fired"));
*/

	xcolourtrans_generate_table_for_sprite(c->data.gif.sprite_area,
			(osspriteop_id) (c->data.gif.sprite_area + 1),
			colourtrans_CURRENT_MODE, colourtrans_CURRENT_PALETTE,
			0, colourtrans_GIVEN_SPRITE, 0, 0, &size);
	table = xcalloc(size, 1);
	xcolourtrans_generate_table_for_sprite(c->data.gif.sprite_area,
			(osspriteop_id) (c->data.gif.sprite_area + 1),
			colourtrans_CURRENT_MODE, colourtrans_CURRENT_PALETTE,
			table, colourtrans_GIVEN_SPRITE, 0, 0, 0);

	xosspriteop_put_sprite_scaled(osspriteop_PTR,
			c->data.gif.sprite_area,
			(osspriteop_id) (c->data.gif.sprite_area + 1),
			x, y, 0, 0, table);

	xfree(table);
}