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[wxWidgets.git] / src / common / imagpng.cpp
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e9c4b1a2 1/////////////////////////////////////////////////////////////////////////////
27bb2b7c 2// Name: src/common/imagepng.cpp
e9c4b1a2
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3// Purpose: wxImage PNG handler
4// Author: Robert Roebling
5// RCS-ID: $Id$
6// Copyright: (c) Robert Roebling
65571936 7// Licence: wxWindows licence
e9c4b1a2
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8/////////////////////////////////////////////////////////////////////////////
9
27bb2b7c
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10// ============================================================================
11// declarations
12// ============================================================================
13
14f355c2 14#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
8f493002
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15#pragma implementation "imagpng.h"
16#endif
e9c4b1a2 17
27bb2b7c
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18// ----------------------------------------------------------------------------
19// headers
20// ----------------------------------------------------------------------------
21
e9c4b1a2
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22// For compilers that support precompilation, includes "wx.h".
23#include "wx/wxprec.h"
24
25#ifdef __BORLANDC__
ce4169a4
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26 #pragma hdrstop
27#endif
28
29#ifndef WX_PRECOMP
30 #include "wx/defs.h"
e9c4b1a2
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31#endif
32
c96ea657 33#if wxUSE_IMAGE && wxUSE_LIBPNG
ce4169a4 34
8f493002 35#include "wx/imagpng.h"
e9c4b1a2
JS
36#include "wx/bitmap.h"
37#include "wx/debug.h"
38#include "wx/log.h"
39#include "wx/app.h"
ce4169a4 40#include "png.h"
e9c4b1a2
JS
41#include "wx/filefn.h"
42#include "wx/wfstream.h"
43#include "wx/intl.h"
44#include "wx/module.h"
45
46// For memcpy
47#include <string.h>
48
49#ifdef __SALFORDC__
50#ifdef FAR
51#undef FAR
52#endif
53#endif
54
27bb2b7c
VZ
55// ----------------------------------------------------------------------------
56// constants
57// ----------------------------------------------------------------------------
58
59// image can not have any transparent pixels at all, have only 100% opaque
60// and/or 100% transparent pixels in which case a simple mask is enough to
61// store this information in wxImage or have a real alpha channel in which case
62// we need to have it in wxImage as well
63enum Transparency
64{
65 Transparency_None,
66 Transparency_Mask,
67 Transparency_Alpha
68};
69
70// ----------------------------------------------------------------------------
71// local functions
72// ----------------------------------------------------------------------------
73
74// return the kind of transparency needed for this image assuming that it does
75// have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
76static Transparency
36308e0e 77CheckTransparency(unsigned char **lines,
f7155274
VZ
78 png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
79 size_t numColBytes);
27bb2b7c
VZ
80
81// init the alpha channel for the image and fill it with 1s up to (x, y)
82static unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y);
83
84// find a free colour for the mask in the PNG data array
85static void
86FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
87 unsigned char& rMask, unsigned char& gMask, unsigned char& bMask);
e9c4b1a2 88
c9fcf581
VZ
89// is the pixel with this value of alpha a fully opaque one?
90static inline
91bool IsOpaque(unsigned char a)
92{
93 return a == 0xff;
94}
95
96// is the pixel with this value of alpha a fully transparent one?
97static inline
98bool IsTransparent(unsigned char a)
99{
100 return !a;
101}
102
27bb2b7c
VZ
103// ============================================================================
104// wxPNGHandler implementation
105// ============================================================================
e9c4b1a2 106
e9c4b1a2 107IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
e9c4b1a2 108
e30285ab 109#if wxUSE_STREAMS
9ab6ee85 110
0729bd19 111#ifndef PNGLINKAGEMODE
30e0e251
VZ
112 #ifdef __WATCOMC__
113 // we need an explicit cdecl for Watcom, at least according to
114 //
115 // http://sf.net/tracker/index.php?func=detail&aid=651492&group_id=9863&atid=109863
116 //
117 // more testing is needed for this however, please remove this comment
118 // if you can confirm that my fix works with Watcom 11
119 #define PNGLINKAGEMODE cdecl
120 #else
121 #define PNGLINKAGEMODE LINKAGEMODE
122 #endif
717b9bf2
DW
123#endif
124
bdffd806
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125
126// VS: wxPNGInfoStruct declared below is a hack that needs some explanation.
27bb2b7c
VZ
127// First, let me describe what's the problem: libpng uses jmp_buf in
128// its png_struct structure. Unfortunately, this structure is
129// compiler-specific and may vary in size, so if you use libpng compiled
bdffd806 130// as DLL with another compiler than the main executable, it may not work
27bb2b7c 131// (this is for example the case with wxMGL port and SciTech MGL library
bdffd806 132// that provides custom runtime-loadable libpng implementation with jmpbuf
27bb2b7c 133// disabled altogether). Luckily, it is still possible to use setjmp() &
bdffd806
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134// longjmp() as long as the structure is not part of png_struct.
135//
136// Sadly, there's no clean way to attach user-defined data to png_struct.
137// There is only one customizable place, png_struct.io_ptr, which is meant
27bb2b7c 138// only for I/O routines and is set with png_set_read_fn or
bdffd806
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139// png_set_write_fn. The hacky part is that we use io_ptr to store
140// a pointer to wxPNGInfoStruct that holds I/O structures _and_ jmp_buf.
141
142struct wxPNGInfoStruct
143{
144 jmp_buf jmpbuf;
145 bool verbose;
27bb2b7c 146
bdffd806
VS
147 union
148 {
149 wxInputStream *in;
150 wxOutputStream *out;
151 } stream;
152};
153
154#define WX_PNG_INFO(png_ptr) ((wxPNGInfoStruct*)png_get_io_ptr(png_ptr))
155
27bb2b7c
VZ
156// ----------------------------------------------------------------------------
157// helper functions
158// ----------------------------------------------------------------------------
bdffd806 159
90350682
VZ
160extern "C"
161{
162
e9b964cf
VS
163void PNGLINKAGEMODE wx_PNG_stream_reader( png_structp png_ptr, png_bytep data,
164 png_size_t length )
e9c4b1a2 165{
bdffd806 166 WX_PNG_INFO(png_ptr)->stream.in->Read(data, length);
e9c4b1a2
JS
167}
168
e9b964cf
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169void PNGLINKAGEMODE wx_PNG_stream_writer( png_structp png_ptr, png_bytep data,
170 png_size_t length )
e9c4b1a2 171{
bdffd806 172 WX_PNG_INFO(png_ptr)->stream.out->Write(data, length);
e9c4b1a2
JS
173}
174
deb2fec0
SB
175// from pngerror.c
176// so that the libpng doesn't send anything on stderr
177void
bdffd806 178PNGLINKAGEMODE wx_png_error(png_structp png_ptr, png_const_charp message)
deb2fec0 179{
d10c19d6 180 wxLogFatalError( wxString::FromAscii(message) );
deb2fec0
SB
181}
182
183void
bdffd806 184PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
deb2fec0 185{
d10c19d6
VZ
186 wxPNGInfoStruct *info = png_ptr ? WX_PNG_INFO(png_ptr) : NULL;
187 if ( !info || info->verbose )
2b5f62a0 188 wxLogWarning( wxString::FromAscii(message) );
deb2fec0
SB
189}
190
90350682
VZ
191} // extern "C"
192
27bb2b7c
VZ
193// ----------------------------------------------------------------------------
194// LoadFile() helpers
195// ----------------------------------------------------------------------------
196
d26d9754 197// determine the kind of transparency we need for this image: if the only alpha
c9fcf581
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198// values it has are 0 (transparent) and 0xff (opaque) then we can simply
199// create a mask for it, we should be ok with a simple mask but otherwise we
200// need a full blown alpha channel in wxImage
d26d9754
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201//
202// parameters:
36308e0e 203// lines raw PNG data
d26d9754
VZ
204// x, y starting position
205// w, h size of the image
206// numColBytes number of colour bytes (1 for grey scale, 3 for RGB)
207// (NB: alpha always follows the colour bytes)
27bb2b7c 208Transparency
36308e0e 209CheckTransparency(unsigned char **lines,
d26d9754
VZ
210 png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
211 size_t numColBytes)
27bb2b7c 212{
d26d9754
VZ
213 // suppose that a mask will suffice and check all the remaining alpha
214 // values to see if it does
36308e0e 215 for ( ; y < h; y++ )
27bb2b7c 216 {
e45cc235
RD
217 // each pixel is numColBytes+1 bytes, offset into the current line by
218 // the current x position
219 unsigned const char *ptr = lines[y] + (x * (numColBytes + 1));
36308e0e 220
c9fcf581 221 for ( png_uint_32 x2 = x; x2 < w; x2++ )
27bb2b7c 222 {
c9fcf581 223 // skip the grey or colour byte(s)
36308e0e 224 ptr += numColBytes;
27bb2b7c 225
36308e0e 226 unsigned char a2 = *ptr++;
c9fcf581
VZ
227
228 if ( !IsTransparent(a2) && !IsOpaque(a2) )
27bb2b7c 229 {
d26d9754
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230 // not fully opaque nor fully transparent, hence need alpha
231 return Transparency_Alpha;
27bb2b7c 232 }
27bb2b7c 233 }
c9fcf581
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234
235 // during the next loop iteration check all the pixels in the row
236 x = 0;
27bb2b7c
VZ
237 }
238
d26d9754
VZ
239 // mask will be enough
240 return Transparency_Mask;
27bb2b7c
VZ
241}
242
243unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
244{
245 // create alpha channel
246 image->SetAlpha();
247
248 unsigned char *alpha = image->GetAlpha();
249
250 // set alpha for the pixels we had so far
c9fcf581
VZ
251 png_uint_32 end = y * image->GetWidth() + x;
252 for ( png_uint_32 i = 0; i < end; i++ )
27bb2b7c 253 {
c9fcf581
VZ
254 // all the previous pixels were opaque
255 *alpha++ = 0xff;
27bb2b7c
VZ
256 }
257
258 return alpha;
259}
260
261void
262FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
263 unsigned char& rMask, unsigned char& gMask, unsigned char& bMask)
264{
265 // choosing the colour for the mask is more
266 // difficult: we need to iterate over the entire
267 // image for this in order to choose an unused
268 // colour (this is not very efficient but what else
269 // can we do?)
270 wxImageHistogram h;
271 unsigned nentries = 0;
272 unsigned char r2, g2, b2;
273 for ( png_uint_32 y2 = 0; y2 < height; y2++ )
274 {
275 const unsigned char *p = lines[y2];
276 for ( png_uint_32 x2 = 0; x2 < width; x2++ )
277 {
278 r2 = *p++;
279 g2 = *p++;
280 b2 = *p++;
281
282 wxImageHistogramEntry&
283 entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)];
284
285 if ( entry.value++ == 0 )
286 entry.index = nentries++;
287 }
288 }
289
290 if ( !h.FindFirstUnusedColour(&rMask, &gMask, &bMask) )
291 {
292 wxLogWarning(_("Too many colours in PNG, the image may be slightly blurred."));
293
294 // use a fixed mask colour and we'll fudge
295 // the real pixels with this colour (see
296 // below)
297 rMask = 0xfe;
298 gMask = 0;
299 bMask = 0xff;
300 }
301}
302
303// ----------------------------------------------------------------------------
304// reading PNGs
305// ----------------------------------------------------------------------------
306
307bool wxPNGHandler::DoCanRead( wxInputStream& stream )
308{
309 unsigned char hdr[4];
310
311 if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
7beb59f3 312 return false;
27bb2b7c
VZ
313
314 return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
315}
316
317// convert data from RGB to wxImage format
318static
319void CopyDataFromPNG(wxImage *image,
320 unsigned char **lines,
321 png_uint_32 width,
322 png_uint_32 height,
323 int color_type)
324{
325 Transparency transparency = Transparency_None;
326
327 // only non NULL if transparency == Transparency_Alpha
328 unsigned char *alpha = NULL;
329
330 // RGB of the mask colour if transparency == Transparency_Mask
331 // (but init them anyhow to avoid compiler warnings)
332 unsigned char rMask = 0,
333 gMask = 0,
334 bMask = 0;
335
336 unsigned char *ptrDst = image->GetData();
337 if ( !(color_type & PNG_COLOR_MASK_COLOR) )
338 {
339 // grey image: GAGAGA... where G == grey component and A == alpha
340 for ( png_uint_32 y = 0; y < height; y++ )
341 {
342 const unsigned char *ptrSrc = lines[y];
343 for ( png_uint_32 x = 0; x < width; x++ )
344 {
345 unsigned char g = *ptrSrc++;
346 unsigned char a = *ptrSrc++;
347
348 // the first time we encounter a transparent pixel we must
349 // decide about what to do about them
c9fcf581 350 if ( !IsOpaque(a) && transparency == Transparency_None )
27bb2b7c
VZ
351 {
352 // we'll need at least the mask for this image and
353 // maybe even full alpha channel info: the former is
354 // only enough if we have alpha values of 0 and 0xff
355 // only, otherwisewe need the latter
d26d9754
VZ
356 transparency = CheckTransparency
357 (
36308e0e 358 lines,
d26d9754
VZ
359 x, y,
360 width, height,
361 1
362 );
27bb2b7c
VZ
363
364 if ( transparency == Transparency_Mask )
365 {
366 // let's choose this colour for the mask: this is
367 // not a problem here as all the other pixels are
368 // grey, i.e. R == G == B which is not the case for
369 // this one so no confusion is possible
370 rMask = 0xff;
371 gMask = 0;
372 bMask = 0xff;
373 }
374 else // transparency == Transparency_Alpha
375 {
376 alpha = InitAlpha(image, x, y);
377 }
378 }
379
380 switch ( transparency )
381 {
c9fcf581
VZ
382 case Transparency_Mask:
383 if ( IsTransparent(a) )
384 {
385 *ptrDst++ = rMask;
386 *ptrDst++ = bMask;
387 *ptrDst++ = gMask;
388 break;
389 }
390 // else: !transparent
391
392 // must be opaque then as otherwise we shouldn't be
393 // using the mask at all
394 wxASSERT_MSG( IsOpaque(a), _T("logic error") );
395
396 // fall through
397
27bb2b7c 398 case Transparency_Alpha:
c9fcf581
VZ
399 if ( alpha )
400 *alpha++ = a;
27bb2b7c
VZ
401 // fall through
402
403 case Transparency_None:
404 *ptrDst++ = g;
405 *ptrDst++ = g;
406 *ptrDst++ = g;
407 break;
27bb2b7c
VZ
408 }
409 }
410 }
411 }
412 else // colour image: RGBRGB...
413 {
414 for ( png_uint_32 y = 0; y < height; y++ )
415 {
416 const unsigned char *ptrSrc = lines[y];
417 for ( png_uint_32 x = 0; x < width; x++ )
418 {
419 unsigned char r = *ptrSrc++;
420 unsigned char g = *ptrSrc++;
421 unsigned char b = *ptrSrc++;
422 unsigned char a = *ptrSrc++;
423
424 // the logic here is the same as for the grey case except
425 // where noted
c9fcf581 426 if ( !IsOpaque(a) && transparency == Transparency_None )
27bb2b7c 427 {
d26d9754
VZ
428 transparency = CheckTransparency
429 (
36308e0e 430 lines,
d26d9754
VZ
431 x, y,
432 width, height,
433 3
434 );
27bb2b7c
VZ
435
436 if ( transparency == Transparency_Mask )
437 {
438 FindMaskColour(lines, width, height,
439 rMask, gMask, bMask);
440 }
441 else // transparency == Transparency_Alpha
442 {
443 alpha = InitAlpha(image, x, y);
444 }
445
446 }
447
448 switch ( transparency )
449 {
c9fcf581
VZ
450 case Transparency_Mask:
451 if ( IsTransparent(a) )
452 {
c9fcf581
VZ
453 *ptrDst++ = rMask;
454 *ptrDst++ = bMask;
455 *ptrDst++ = gMask;
456 break;
457 }
999836aa
VZ
458 else // !transparent
459 {
460 // must be opaque then as otherwise we shouldn't be
461 // using the mask at all
462 wxASSERT_MSG( IsOpaque(a), _T("logic error") );
463
464 // if we couldn't find a unique colour for the
465 // mask, we can have real pixels with the same
466 // value as the mask and it's better to slightly
467 // change their colour than to make them
468 // transparent
469 if ( r == rMask && g == gMask && b == bMask )
470 {
471 r++;
472 }
473 }
c9fcf581
VZ
474
475 // fall through
476
27bb2b7c 477 case Transparency_Alpha:
c9fcf581
VZ
478 if ( alpha )
479 *alpha++ = a;
27bb2b7c
VZ
480 // fall through
481
482 case Transparency_None:
483 *ptrDst++ = r;
484 *ptrDst++ = g;
485 *ptrDst++ = b;
486 break;
27bb2b7c
VZ
487 }
488 }
489 }
490 }
491
492 if ( transparency == Transparency_Mask )
493 {
494 image->SetMaskColour(rMask, gMask, bMask);
495 }
496}
497
3ca6a5f0
BP
498// temporarily disable the warning C4611 (interaction between '_setjmp' and
499// C++ object destruction is non-portable) - I don't see any dtors here
500#ifdef __VISUALC__
501 #pragma warning(disable:4611)
502#endif /* VC++ */
503
27bb2b7c
VZ
504bool
505wxPNGHandler::LoadFile(wxImage *image,
506 wxInputStream& stream,
507 bool verbose,
508 int WXUNUSED(index))
e9c4b1a2
JS
509{
510 // VZ: as this function uses setjmp() the only fool proof error handling
511 // method is to use goto (setjmp is not really C++ dtors friendly...)
717b9bf2 512
27bb2b7c
VZ
513 unsigned char **lines = NULL;
514 png_infop info_ptr = (png_infop) NULL;
bdffd806
VS
515 wxPNGInfoStruct wxinfo;
516
517 wxinfo.verbose = verbose;
518 wxinfo.stream.in = &stream;
717b9bf2 519
e9c4b1a2 520 image->Destroy();
717b9bf2 521
d10c19d6
VZ
522 png_structp png_ptr = png_create_read_struct
523 (
524 PNG_LIBPNG_VER_STRING,
525 (voidp) NULL,
526 wx_png_error,
527 wx_png_warning
528 );
e9c4b1a2 529 if (!png_ptr)
27bb2b7c 530 goto error;
717b9bf2 531
bdffd806
VS
532 // NB: please see the comment near wxPNGInfoStruct declaration for
533 // explanation why this line is mandatory
e9b964cf 534 png_set_read_fn( png_ptr, &wxinfo, wx_PNG_stream_reader);
deb2fec0 535
e9c4b1a2
JS
536 info_ptr = png_create_info_struct( png_ptr );
537 if (!info_ptr)
27bb2b7c 538 goto error;
717b9bf2 539
bdffd806 540 if (setjmp(wxinfo.jmpbuf))
27bb2b7c 541 goto error;
717b9bf2 542
27bb2b7c
VZ
543 png_uint_32 i, width, height;
544 int bit_depth, color_type, interlace_type;
717b9bf2 545
e9c4b1a2
JS
546 png_read_info( png_ptr, info_ptr );
547 png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
717b9bf2 548
e9c4b1a2
JS
549 if (color_type == PNG_COLOR_TYPE_PALETTE)
550 png_set_expand( png_ptr );
717b9bf2 551
2b5f62a0
VZ
552 // Fix for Bug [ 439207 ] Monochrome PNG images come up black
553 if (bit_depth < 8)
554 png_set_expand( png_ptr );
555
e9c4b1a2
JS
556 png_set_strip_16( png_ptr );
557 png_set_packing( png_ptr );
558 if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
559 png_set_expand( png_ptr );
560 png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
717b9bf2 561
154e1ca1 562 image->Create((int)width, (int)height, (bool) false /* no need to init pixels */);
717b9bf2 563
e9c4b1a2 564 if (!image->Ok())
27bb2b7c 565 goto error;
717b9bf2 566
479cd5de 567 lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) );
27bb2b7c
VZ
568 if ( !lines )
569 goto error;
717b9bf2 570
e9c4b1a2
JS
571 for (i = 0; i < height; i++)
572 {
479cd5de 573 if ((lines[i] = (unsigned char *)malloc( (size_t)(width * (sizeof(unsigned char) * 4)))) == NULL)
e9c4b1a2
JS
574 {
575 for ( unsigned int n = 0; n < i; n++ )
576 free( lines[n] );
577 goto error;
578 }
579 }
717b9bf2 580
27bb2b7c
VZ
581 png_read_image( png_ptr, lines );
582 png_read_end( png_ptr, info_ptr );
583 png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
717b9bf2 584
27bb2b7c
VZ
585 // loaded successfully, now init wxImage with this data
586 CopyDataFromPNG(image, lines, width, height, color_type);
717b9bf2 587
27bb2b7c
VZ
588 for ( i = 0; i < height; i++ )
589 free( lines[i] );
590 free( lines );
717b9bf2 591
7beb59f3 592 return true;
95ee0ac8 593
27bb2b7c 594error:
58c837a4
RR
595 if (verbose)
596 wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
717b9bf2 597
e9c4b1a2
JS
598 if ( image->Ok() )
599 {
600 image->Destroy();
601 }
717b9bf2 602
e9c4b1a2
JS
603 if ( lines )
604 {
605 free( lines );
606 }
717b9bf2 607
e9c4b1a2
JS
608 if ( png_ptr )
609 {
610 if ( info_ptr )
611 {
612 png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
613 free(info_ptr);
614 }
615 else
616 png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
617 }
7beb59f3 618 return false;
e9c4b1a2
JS
619}
620
27bb2b7c
VZ
621// ----------------------------------------------------------------------------
622// writing PNGs
623// ----------------------------------------------------------------------------
624
deb2fec0 625bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
e9c4b1a2 626{
bdffd806 627 wxPNGInfoStruct wxinfo;
717b9bf2 628
bdffd806
VS
629 wxinfo.verbose = verbose;
630 wxinfo.stream.out = &stream;
deb2fec0 631
d10c19d6
VZ
632 png_structp png_ptr = png_create_write_struct
633 (
634 PNG_LIBPNG_VER_STRING,
635 NULL,
636 wx_png_error,
637 wx_png_warning
638 );
bdffd806
VS
639 if (!png_ptr)
640 {
641 if (verbose)
642 wxLogError(_("Couldn't save PNG image."));
7beb59f3 643 return false;
bdffd806 644 }
717b9bf2 645
bdffd806
VS
646 png_infop info_ptr = png_create_info_struct(png_ptr);
647 if (info_ptr == NULL)
648 {
649 png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
650 if (verbose)
651 wxLogError(_("Couldn't save PNG image."));
7beb59f3 652 return false;
bdffd806 653 }
717b9bf2 654
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VS
655 if (setjmp(wxinfo.jmpbuf))
656 {
657 png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
658 if (verbose)
659 wxLogError(_("Couldn't save PNG image."));
7beb59f3 660 return false;
bdffd806 661 }
717b9bf2 662
bdffd806
VS
663 // NB: please see the comment near wxPNGInfoStruct declaration for
664 // explanation why this line is mandatory
e9b964cf 665 png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL);
bdffd806
VS
666
667 png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
668 PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
669 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
670
671 png_color_8 sig_bit;
672 sig_bit.red = 8;
673 sig_bit.green = 8;
674 sig_bit.blue = 8;
675 sig_bit.alpha = 8;
676 png_set_sBIT( png_ptr, info_ptr, &sig_bit );
677 png_write_info( png_ptr, info_ptr );
678 png_set_shift( png_ptr, &sig_bit );
679 png_set_packing( png_ptr );
717b9bf2 680
bdffd806
VS
681 unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
682 if (!data)
683 {
684 png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
7beb59f3 685 return false;
bdffd806 686 }
717b9bf2 687
bdffd806
VS
688 for (int y = 0; y < image->GetHeight(); y++)
689 {
690 unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
691 for (int x = 0; x < image->GetWidth(); x++)
e9c4b1a2 692 {
bdffd806
VS
693 data[(x << 2) + 0] = *ptr++;
694 data[(x << 2) + 1] = *ptr++;
695 data[(x << 2) + 2] = *ptr++;
5f5183d3
RD
696 if ( image->HasAlpha() )
697 {
698 data[(x << 2) + 3] = image->GetAlpha(x, y);
699 }
700 else if (( !image->HasMask() ) || \
bdffd806
VS
701 (data[(x << 2) + 0] != image->GetMaskRed()) || \
702 (data[(x << 2) + 1] != image->GetMaskGreen()) || \
703 (data[(x << 2) + 2] != image->GetMaskBlue()))
e9c4b1a2 704 {
bdffd806
VS
705 data[(x << 2) + 3] = 255;
706 }
707 else
708 {
709 data[(x << 2) + 3] = 0;
e9c4b1a2 710 }
e9c4b1a2 711 }
bdffd806
VS
712 png_bytep row_ptr = data;
713 png_write_rows( png_ptr, &row_ptr, 1 );
e9c4b1a2 714 }
bdffd806
VS
715
716 free(data);
717 png_write_end( png_ptr, info_ptr );
718 png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
719
7beb59f3 720 return true;
e9c4b1a2 721}
e9c4b1a2 722
3ca6a5f0
BP
723#ifdef __VISUALC__
724 #pragma warning(default:4611)
725#endif /* VC++ */
726
9ab6ee85 727#endif // wxUSE_STREAMS
e9c4b1a2 728
9ab6ee85 729#endif // wxUSE_LIBPNG