44a977df7ff3180a876057100f31d33a4407e7c0
1 #define __SP_PNG_WRITE_C__
3 /*
4 * PNG file format utilities
5 *
6 * Authors:
7 * Lauris Kaplinski <lauris@kaplinski.com>
8 * Whoever wrote this example in libpng documentation
9 *
10 * Copyright (C) 1999-2002 authors
11 *
12 * Released under GNU GPL, read the file 'COPYING' for more information
13 */
15 #ifdef HAVE_CONFIG_H
16 # include "config.h"
17 #endif
19 #include <interface.h>
20 #include <libnr/nr-pixops.h>
21 #include <glib/gmessages.h>
22 #include <png.h>
23 #include "png-write.h"
24 #include "io/sys.h"
25 #include <display/nr-arena-item.h>
26 #include <display/nr-arena.h>
27 #include <document.h>
28 #include <sp-item.h>
29 #include <sp-root.h>
30 #include <sp-defs.h>
32 /* This is an example of how to use libpng to read and write PNG files.
33 * The file libpng.txt is much more verbose then this. If you have not
34 * read it, do so first. This was designed to be a starting point of an
35 * implementation. This is not officially part of libpng, and therefore
36 * does not require a copyright notice.
37 *
38 * This file does not currently compile, because it is missing certain
39 * parts, like allocating memory to hold an image. You will have to
40 * supply these parts to get it to compile. For an example of a minimal
41 * working PNG reader/writer, see pngtest.c, included in this distribution.
42 */
44 /* write a png file */
46 typedef struct SPPNGBD {
47 const guchar *px;
48 int rowstride;
49 } SPPNGBD;
51 static int
52 sp_png_get_block_stripe (const guchar **rows, int row, int num_rows, void *data)
53 {
54 SPPNGBD *bd = (SPPNGBD *) data;
56 for (int r = 0; r < num_rows; r++) {
57 rows[r] = bd->px + (row + r) * bd->rowstride;
58 }
60 return num_rows;
61 }
63 int
64 sp_png_write_rgba (const gchar *filename, const guchar *px, int width, int height, double xdpi, double ydpi, int rowstride)
65 {
66 SPPNGBD bd;
68 bd.px = px;
69 bd.rowstride = rowstride;
71 return sp_png_write_rgba_striped (filename, width, height, xdpi, ydpi, sp_png_get_block_stripe, &bd);
72 }
74 int
75 sp_png_write_rgba_striped (const gchar *filename, int width, int height, double xdpi, double ydpi,
76 int (* get_rows) (const guchar **rows, int row, int num_rows, void *data),
77 void *data)
78 {
79 FILE *fp;
80 png_structp png_ptr;
81 png_infop info_ptr;
82 png_color_8 sig_bit;
83 png_text text_ptr[3];
84 png_uint_32 r;
86 g_return_val_if_fail (filename != NULL, FALSE);
88 /* open the file */
90 Inkscape::IO::dump_fopen_call(filename, "M");
91 fp = Inkscape::IO::fopen_utf8name(filename, "wb");
92 g_return_val_if_fail (fp != NULL, FALSE);
94 /* Create and initialize the png_struct with the desired error handler
95 * functions. If you want to use the default stderr and longjump method,
96 * you can supply NULL for the last three parameters. We also check that
97 * the library version is compatible with the one used at compile time,
98 * in case we are using dynamically linked libraries. REQUIRED.
99 */
100 png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
102 if (png_ptr == NULL) {
103 fclose(fp);
104 return FALSE;
105 }
107 /* Allocate/initialize the image information data. REQUIRED */
108 info_ptr = png_create_info_struct(png_ptr);
109 if (info_ptr == NULL) {
110 fclose(fp);
111 png_destroy_write_struct(&png_ptr, NULL);
112 return FALSE;
113 }
115 /* Set error handling. REQUIRED if you aren't supplying your own
116 * error hadnling functions in the png_create_write_struct() call.
117 */
118 if (setjmp(png_ptr->jmpbuf)) {
119 /* If we get here, we had a problem reading the file */
120 fclose(fp);
121 png_destroy_write_struct(&png_ptr, &info_ptr);
122 return FALSE;
123 }
125 /* set up the output control if you are using standard C streams */
126 png_init_io(png_ptr, fp);
128 /* Set the image information here. Width and height are up to 2^31,
129 * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
130 * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
131 * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
132 * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or
133 * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
134 * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
135 */
136 png_set_IHDR(png_ptr, info_ptr,
137 width,
138 height,
139 8, /* bit_depth */
140 PNG_COLOR_TYPE_RGB_ALPHA,
141 PNG_INTERLACE_NONE,
142 PNG_COMPRESSION_TYPE_BASE,
143 PNG_FILTER_TYPE_BASE);
145 /* otherwise, if we are dealing with a color image then */
146 sig_bit.red = 8;
147 sig_bit.green = 8;
148 sig_bit.blue = 8;
149 /* if the image has an alpha channel then */
150 sig_bit.alpha = 8;
151 png_set_sBIT(png_ptr, info_ptr, &sig_bit);
153 /* Made by Inkscape comment */
154 text_ptr[0].key = "Software";
155 text_ptr[0].text = "www.inkscape.org";
156 text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
157 png_set_text(png_ptr, info_ptr, text_ptr, 1);
159 /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */
160 /* note that if sRGB is present the cHRM chunk must be ignored
161 * on read and must be written in accordance with the sRGB profile */
162 png_set_pHYs(png_ptr, info_ptr, unsigned(xdpi / 0.0254 + 0.5), unsigned(ydpi / 0.0254 + 0.5), PNG_RESOLUTION_METER);
164 /* Write the file header information. REQUIRED */
165 png_write_info(png_ptr, info_ptr);
167 /* Once we write out the header, the compression type on the text
168 * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
169 * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
170 * at the end.
171 */
173 /* set up the transformations you want. Note that these are
174 * all optional. Only call them if you want them.
175 */
177 /* --- CUT --- */
179 /* The easiest way to write the image (you may have a different memory
180 * layout, however, so choose what fits your needs best). You need to
181 * use the first method if you aren't handling interlacing yourself.
182 */
184 r = 0;
185 while (r < static_cast< png_uint_32 > (height) ) {
186 png_bytep row_pointers[64];
187 int h, n;
189 h = MIN (height - r, 64);
190 n = get_rows ((const unsigned char **) row_pointers, r, h, data);
191 if (!n) break;
192 png_write_rows (png_ptr, row_pointers, n);
193 r += n;
194 }
196 /* You can write optional chunks like tEXt, zTXt, and tIME at the end
197 * as well.
198 */
200 /* It is REQUIRED to call this to finish writing the rest of the file */
201 png_write_end(png_ptr, info_ptr);
203 /* if you allocated any text comments, free them here */
205 /* clean up after the write, and free any memory allocated */
206 png_destroy_write_struct(&png_ptr, &info_ptr);
208 /* close the file */
209 fclose(fp);
211 /* that's it */
212 return TRUE;
213 }
217 struct SPEBP {
218 int width, height, sheight;
219 guchar r, g, b, a;
220 NRArenaItem *root; // the root arena item to show; it is assumed that all unneeded items are hidden
221 guchar *px;
222 unsigned (*status)(float, void *);
223 void *data;
224 };
227 /**
228 *
229 */
230 static int
231 sp_export_get_rows(guchar const **rows, int row, int num_rows, void *data)
232 {
233 struct SPEBP *ebp = (struct SPEBP *) data;
235 if (ebp->status) {
236 if (!ebp->status((float) row / ebp->height, ebp->data)) return 0;
237 }
239 num_rows = MIN(num_rows, ebp->sheight);
240 num_rows = MIN(num_rows, ebp->height - row);
242 /* Set area of interest */
243 NRRectL bbox;
244 bbox.x0 = 0;
245 bbox.y0 = row;
246 bbox.x1 = ebp->width;
247 bbox.y1 = row + num_rows;
248 /* Update to renderable state */
249 NRGC gc(NULL);
250 nr_matrix_set_identity(&gc.transform);
252 nr_arena_item_invoke_update(ebp->root, &bbox, &gc,
253 NR_ARENA_ITEM_STATE_ALL, NR_ARENA_ITEM_STATE_NONE);
255 NRPixBlock pb;
256 nr_pixblock_setup_extern(&pb, NR_PIXBLOCK_MODE_R8G8B8A8N,
257 bbox.x0, bbox.y0, bbox.x1, bbox.y1,
258 ebp->px, 4 * ebp->width, FALSE, FALSE);
260 for (int r = 0; r < num_rows; r++) {
261 guchar *p = NR_PIXBLOCK_PX(&pb) + r * pb.rs;
262 for (int c = 0; c < ebp->width; c++) {
263 *p++ = ebp->r;
264 *p++ = ebp->g;
265 *p++ = ebp->b;
266 *p++ = ebp->a;
267 }
268 }
270 /* Render */
271 nr_arena_item_invoke_render(ebp->root, &bbox, &pb, 0);
273 for (int r = 0; r < num_rows; r++) {
274 rows[r] = NR_PIXBLOCK_PX(&pb) + r * pb.rs;
275 }
277 nr_pixblock_release(&pb);
279 return num_rows;
280 }
282 /**
283 Hide all items which are not listed in list, recursively, skipping groups and defs
284 */
285 static void
286 hide_other_items_recursively(SPObject *o, GSList *list, unsigned dkey)
287 {
288 if (SP_IS_ITEM(o)
289 && !SP_IS_DEFS(o)
290 && !SP_IS_ROOT(o)
291 && !SP_IS_GROUP(o)
292 && !g_slist_find(list, o))
293 {
294 sp_item_invoke_hide(SP_ITEM(o), dkey);
295 }
297 // recurse
298 if (!g_slist_find(list, o)) {
299 for (SPObject *child = sp_object_first_child(o) ; child != NULL; child = SP_OBJECT_NEXT(child) ) {
300 hide_other_items_recursively(child, list, dkey);
301 }
302 }
303 }
306 /**
307 * Render the SVG drawing onto a PNG raster image, then save to
308 * a file. Returns TRUE if succeeded in writing the file,
309 * FALSE otherwise.
310 */
311 int
312 sp_export_png_file(SPDocument *doc, gchar const *filename,
313 double x0, double y0, double x1, double y1,
314 unsigned width, unsigned height, double xdpi, double ydpi,
315 unsigned long bgcolor,
316 unsigned (*status)(float, void *),
317 void *data, bool force_overwrite,
318 GSList *items_only)
319 {
320 int write_status = TRUE;
321 g_return_val_if_fail(doc != NULL, FALSE);
322 g_return_val_if_fail(filename != NULL, FALSE);
323 g_return_val_if_fail(width >= 1, FALSE);
324 g_return_val_if_fail(height >= 1, FALSE);
326 if (!force_overwrite && !sp_ui_overwrite_file(filename)) {
327 return FALSE;
328 }
330 sp_document_ensure_up_to_date(doc);
332 /* Go to document coordinates */
333 gdouble t = y0;
334 y0 = sp_document_height(doc) - y1;
335 y1 = sp_document_height(doc) - t;
337 /*
338 * 1) a[0] * x0 + a[2] * y1 + a[4] = 0.0
339 * 2) a[1] * x0 + a[3] * y1 + a[5] = 0.0
340 * 3) a[0] * x1 + a[2] * y1 + a[4] = width
341 * 4) a[1] * x0 + a[3] * y0 + a[5] = height
342 * 5) a[1] = 0.0;
343 * 6) a[2] = 0.0;
344 *
345 * (1,3) a[0] * x1 - a[0] * x0 = width
346 * a[0] = width / (x1 - x0)
347 * (2,4) a[3] * y0 - a[3] * y1 = height
348 * a[3] = height / (y0 - y1)
349 * (1) a[4] = -a[0] * x0
350 * (2) a[5] = -a[3] * y1
351 */
353 NRMatrix affine;
354 affine.c[0] = width / (x1 - x0);
355 affine.c[1] = 0.0;
356 affine.c[2] = 0.0;
357 affine.c[3] = height / (y1 - y0);
358 affine.c[4] = -affine.c[0] * x0;
359 affine.c[5] = -affine.c[3] * y0;
361 //SP_PRINT_MATRIX("SVG2PNG", &affine);
363 struct SPEBP ebp;
364 ebp.width = width;
365 ebp.height = height;
366 ebp.r = NR_RGBA32_R(bgcolor);
367 ebp.g = NR_RGBA32_G(bgcolor);
368 ebp.b = NR_RGBA32_B(bgcolor);
369 ebp.a = NR_RGBA32_A(bgcolor);
371 /* Create new arena */
372 NRArena *arena = NRArena::create();
373 unsigned dkey = sp_item_display_key_new(1);
375 /* Create ArenaItems and set transform */
376 ebp.root = sp_item_invoke_show(SP_ITEM(sp_document_root(doc)), arena, dkey, SP_ITEM_SHOW_DISPLAY);
377 nr_arena_item_set_transform(NR_ARENA_ITEM(ebp.root), NR::Matrix(&affine));
379 // We show all and then hide all items we don't want, instead of showing only requested items,
380 // because that would not work if the shown item references something in defs
381 if (items_only) {
382 hide_other_items_recursively(sp_document_root(doc), items_only, dkey);
383 }
385 ebp.status = status;
386 ebp.data = data;
388 if ((width < 256) || ((width * height) < 32768)) {
389 ebp.px = nr_pixelstore_64K_new(FALSE, 0);
390 ebp.sheight = 65536 / (4 * width);
391 write_status = sp_png_write_rgba_striped(filename, width, height, xdpi, ydpi, sp_export_get_rows, &ebp);
392 nr_pixelstore_64K_free(ebp.px);
393 } else {
394 ebp.px = g_new(guchar, 4 * 64 * width);
395 ebp.sheight = 64;
396 write_status = sp_png_write_rgba_striped(filename, width, height, xdpi, ydpi, sp_export_get_rows, &ebp);
397 g_free(ebp.px);
398 }
400 // Hide items
401 sp_item_invoke_hide(SP_ITEM(sp_document_root(doc)), dkey);
403 /* Free Arena and ArenaItem */
404 nr_arena_item_unref(ebp.root);
405 nr_object_unref((NRObject *) arena);
406 return write_status;
407 }