xref: /haiku/src/add-ons/translators/png/PNGTranslator.cpp (revision f5821a1aee77d3b9a979b42c68a79e50b5ebaefe)
1 /*****************************************************************************/
2 // PNGTranslator
3 // Written by Michael Wilber, OBOS Translation Kit Team
4 //
5 // PNGTranslator.cpp
6 //
7 // This BTranslator based object is for opening and writing
8 // PNG images.
9 //
10 //
11 // Copyright (c) 2003, OpenBeOS Project
12 // Copyright (c) 2009, Haiku, Inc. All rights reserved.
13 //
14 // Permission is hereby granted, free of charge, to any person obtaining a
15 // copy of this software and associated documentation files (the "Software"),
16 // to deal in the Software without restriction, including without limitation
17 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
18 // and/or sell copies of the Software, and to permit persons to whom the
19 // Software is furnished to do so, subject to the following conditions:
20 //
21 // The above copyright notice and this permission notice shall be included
22 // in all copies or substantial portions of the Software.
23 //
24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
25 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
27 // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
30 // DEALINGS IN THE SOFTWARE.
31 /*****************************************************************************/
32 
33 
34 #include "PNGTranslator.h"
35 
36 #include <stdio.h>
37 #include <string.h>
38 
39 #include <Catalog.h>
40 #include <OS.h>
41 #define PNG_NO_PEDANTIC_WARNINGS
42 #include <png.h>
43 
44 #include "PNGView.h"
45 
46 #undef B_TRANSLATION_CONTEXT
47 #define B_TRANSLATION_CONTEXT "PNGTranslator"
48 
49 // The input formats that this translator supports.
50 static const translation_format sInputFormats[] = {
51 	{
52 		B_PNG_FORMAT,
53 		B_TRANSLATOR_BITMAP,
54 		PNG_IN_QUALITY,
55 		PNG_IN_CAPABILITY,
56 		"image/png",
57 		"PNG image"
58 	},
59 	{
60 		B_PNG_FORMAT,
61 		B_TRANSLATOR_BITMAP,
62 		PNG_IN_QUALITY,
63 		PNG_IN_CAPABILITY,
64 		"image/x-png",
65 		"PNG image"
66 	},
67 	{
68 		B_TRANSLATOR_BITMAP,
69 		B_TRANSLATOR_BITMAP,
70 		BBT_IN_QUALITY,
71 		BBT_IN_CAPABILITY,
72 		"image/x-be-bitmap",
73 		"Be Bitmap Format (PNGTranslator)"
74 	}
75 };
76 
77 // The output formats that this translator supports.
78 static const translation_format sOutputFormats[] = {
79 	{
80 		B_PNG_FORMAT,
81 		B_TRANSLATOR_BITMAP,
82 		PNG_OUT_QUALITY,
83 		PNG_OUT_CAPABILITY,
84 		"image/png",
85 		"PNG image"
86 	},
87 	{
88 		B_TRANSLATOR_BITMAP,
89 		B_TRANSLATOR_BITMAP,
90 		BBT_OUT_QUALITY,
91 		BBT_OUT_CAPABILITY,
92 		"image/x-be-bitmap",
93 		"Be Bitmap Format (PNGTranslator)"
94 	}
95 };
96 
97 // Default settings for the Translator
98 static const TranSetting sDefaultSettings[] = {
99 	{B_TRANSLATOR_EXT_HEADER_ONLY, TRAN_SETTING_BOOL, false},
100 	{B_TRANSLATOR_EXT_DATA_ONLY, TRAN_SETTING_BOOL, false},
101 	{PNG_SETTING_INTERLACE, TRAN_SETTING_INT32, PNG_INTERLACE_NONE}
102 		// interlacing is off by default
103 };
104 
105 const uint32 kNumInputFormats = sizeof(sInputFormats) / sizeof(translation_format);
106 const uint32 kNumOutputFormats = sizeof(sOutputFormats) / sizeof(translation_format);
107 const uint32 kNumDefaultSettings = sizeof(sDefaultSettings) / sizeof(TranSetting);
108 
109 
110 // ---------------------------------------------------------------
111 // make_nth_translator
112 //
113 // Creates a PNGTranslator object to be used by BTranslatorRoster
114 //
115 // Preconditions:
116 //
117 // Parameters: n,		The translator to return. Since
118 //						PNGTranslator only publishes one
119 //						translator, it only returns a
120 //						PNGTranslator if n == 0
121 //
122 //             you, 	The image_id of the add-on that
123 //						contains code (not used).
124 //
125 //             flags,	Has no meaning yet, should be 0.
126 //
127 // Postconditions:
128 //
129 // Returns: NULL if n is not zero,
130 //          a new PNGTranslator if n is zero
131 // ---------------------------------------------------------------
132 BTranslator *
133 make_nth_translator(int32 n, image_id you, uint32 flags, ...)
134 {
135 	if (!n)
136 		return new PNGTranslator();
137 	else
138 		return NULL;
139 }
140 
141  /* The png_jmpbuf() macro, used in error handling, became available in
142   * libpng version 1.0.6.  If you want to be able to run your code with older
143   * versions of libpng, you must define the macro yourself (but only if it
144   * is not already defined by libpng!).
145   */
146 
147 #ifndef png_jmpbuf
148 #  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
149 #endif
150 
151 //// libpng Callback functions!
152 
153 BPositionIO *
154 get_pio(png_structp ppng)
155 {
156 	BPositionIO *pio = NULL;
157 	pio = static_cast<BPositionIO *>(png_get_io_ptr(ppng));
158 	return pio;
159 }
160 
161 void
162 pngcb_read_data(png_structp ppng, png_bytep pdata, png_size_t length)
163 {
164 	BPositionIO *pio = get_pio(ppng);
165 	pio->Read(pdata, static_cast<size_t>(length));
166 }
167 
168 void
169 pngcb_write_data(png_structp ppng, png_bytep pdata, png_size_t length)
170 {
171 	BPositionIO *pio = get_pio(ppng);
172 	pio->Write(pdata, static_cast<size_t>(length));
173 }
174 
175 void
176 pngcb_flush_data(png_structp ppng)
177 {
178 	// I don't think I really need to do anything here
179 }
180 
181 // ---------------------------------------------------------------
182 // Constructor
183 //
184 // Sets up the version info and the name of the translator so that
185 // these values can be returned when they are requested.
186 //
187 // Preconditions:
188 //
189 // Parameters:
190 //
191 // Postconditions:
192 //
193 // Returns:
194 // ---------------------------------------------------------------
195 PNGTranslator::PNGTranslator()
196 	: BaseTranslator(B_TRANSLATE("PNG images"),
197 		B_TRANSLATE("PNG image translator"),
198 		PNG_TRANSLATOR_VERSION,
199 		sInputFormats, kNumInputFormats,
200 		sOutputFormats, kNumOutputFormats,
201 		"PNGTranslator_Settings",
202 		sDefaultSettings, kNumDefaultSettings,
203 		B_TRANSLATOR_BITMAP, B_PNG_FORMAT)
204 {
205 }
206 
207 // ---------------------------------------------------------------
208 // Destructor
209 //
210 // Does nothing
211 //
212 // Preconditions:
213 //
214 // Parameters:
215 //
216 // Postconditions:
217 //
218 // Returns:
219 // ---------------------------------------------------------------
220 PNGTranslator::~PNGTranslator()
221 {
222 }
223 
224 status_t
225 identify_png_header(BPositionIO *inSource, translator_info *outInfo)
226 {
227 	const int32 kSigSize = 8;
228 	uint8 buf[kSigSize];
229 	if (inSource->Read(buf, kSigSize) != kSigSize)
230 		return B_NO_TRANSLATOR;
231 	if (png_sig_cmp(buf, 0, kSigSize))
232 		// if first 8 bytes of stream don't match PNG signature bail
233 		return B_NO_TRANSLATOR;
234 
235 	if (outInfo) {
236 		outInfo->type = B_PNG_FORMAT;
237 		outInfo->group = B_TRANSLATOR_BITMAP;
238 		outInfo->quality = PNG_IN_QUALITY;
239 		outInfo->capability = PNG_IN_CAPABILITY;
240 		strcpy(outInfo->MIME, "image/png");
241 		strlcpy(outInfo->name, B_TRANSLATE("PNG image"),
242 			sizeof(outInfo->name));
243 	}
244 
245 	return B_OK;
246 }
247 
248 // ---------------------------------------------------------------
249 // DerivedIdentify
250 //
251 // Examines the data from inSource and determines if it is in a
252 // format that this translator knows how to work with.
253 //
254 // Preconditions:
255 //
256 // Parameters:	inSource,	where the data to examine is
257 //
258 //				inFormat,	a hint about the data in inSource,
259 //							it is ignored since it is only a hint
260 //
261 //				ioExtension,	configuration settings for the
262 //								translator (not used)
263 //
264 //				outInfo,	information about what data is in
265 //							inSource and how well this translator
266 //							can handle that data is stored here
267 //
268 //				outType,	The format that the user wants
269 //							the data in inSource to be
270 //							converted to
271 //
272 // Postconditions:
273 //
274 // Returns: B_NO_TRANSLATOR,	if this translator can't handle
275 //								the data in inSource
276 //
277 // B_ERROR,	if there was an error converting the data to the host
278 //			format
279 //
280 // B_BAD_VALUE, if the settings in ioExtension are bad
281 //
282 // B_OK,	if this translator understood the data and there were
283 //			no errors found
284 //
285 // Other errors if BPositionIO::Read() returned an error value
286 // ---------------------------------------------------------------
287 status_t
288 PNGTranslator::DerivedIdentify(BPositionIO *inSource,
289 	const translation_format *inFormat, BMessage *ioExtension,
290 	translator_info *outInfo, uint32 outType)
291 {
292 	return identify_png_header(inSource, outInfo);
293 }
294 
295 status_t
296 PNGTranslator::translate_from_png_to_bits(BPositionIO *inSource,
297 	BPositionIO *outDestination)
298 {
299 	if (identify_png_header(inSource, NULL) != B_OK)
300 		return B_NO_TRANSLATOR;
301 
302 	status_t result = B_ERROR;
303 		// if a libpng errors before this is set
304 		// to a different value, the above is what
305 		// will be returned from this function
306 
307 	bool bheaderonly = false, bdataonly = false;
308 
309 	// for storing decoded PNG row data
310 	uint8 **prows = NULL, *prow = NULL;
311 	png_uint_32 nalloc = 0;
312 
313 	png_structp ppng = NULL;
314 	png_infop pinfo = NULL;
315 	while (ppng == NULL) {
316 		// create PNG read pointer with default error handling routines
317 		ppng = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
318 		if (!ppng)
319 			break;
320 		// alocate / init memory for image information
321 		pinfo = png_create_info_struct(ppng);
322 		if (!pinfo)
323 			break;
324 		// set error handling
325 		if (setjmp(png_jmpbuf(ppng)))
326 			// When an error occurs in libpng, it uses
327 			// the longjmp function to continue execution
328 			// from this point
329 			break;
330 
331 		// set read callback function
332 		png_set_read_fn(ppng, static_cast<void *>(inSource), pngcb_read_data);
333 
334 		// Read in PNG image info
335 		png_set_sig_bytes(ppng, 8);
336 		png_read_info(ppng, pinfo);
337 
338 		png_uint_32 width, height;
339 		int bit_depth, color_type, interlace_type;
340 		png_get_IHDR(ppng, pinfo, &width, &height, &bit_depth, &color_type,
341 			&interlace_type, NULL, NULL);
342 
343 		// Setup image transformations to make converting it easier
344 		bool balpha = false;
345 
346 		if (bit_depth == 16)
347 			png_set_strip_16(ppng);
348 		else if (bit_depth < 8)
349 			png_set_packing(ppng);
350 
351 		if (color_type == PNG_COLOR_TYPE_PALETTE)
352 			png_set_palette_to_rgb(ppng);
353 
354 		if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
355 			// In order to convert from low-depth gray images to RGB,
356 			// I first need to convert them to grayscale, 8 bpp
357 			png_set_expand_gray_1_2_4_to_8(ppng);
358 
359 		if (png_get_valid(ppng, pinfo, PNG_INFO_tRNS)) {
360 			// if there is transparency data in the
361 			// PNG, but not in the form of an alpha channel
362 			balpha = true;
363 			png_set_tRNS_to_alpha(ppng);
364 		}
365 
366 		// change RGB to BGR as it is in 'bits'
367 		if (color_type & PNG_COLOR_MASK_COLOR)
368 			png_set_bgr(ppng);
369 
370 		// have libpng convert gray to RGB for me
371 		if (color_type == PNG_COLOR_TYPE_GRAY ||
372 			color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
373 			png_set_gray_to_rgb(ppng);
374 
375 		if (color_type & PNG_COLOR_MASK_ALPHA)
376 			// if image contains an alpha channel
377 			balpha = true;
378 
379 		if (!balpha)
380 			// add filler byte for images without alpha
381 			// so that the pixels are 4 bytes each
382 			png_set_filler(ppng, 0xff, PNG_FILLER_AFTER);
383 
384 		// Check that transformed PNG rowbytes matches
385 		// what is expected
386 		const int32 kbytes = 4;
387 		png_uint_32 rowbytes = png_get_rowbytes(ppng, pinfo);
388 		if (rowbytes < kbytes * width)
389 			rowbytes = kbytes * width;
390 
391 		if (!bdataonly) {
392 			// Write out the data to outDestination
393 			// Construct and write Be bitmap header
394 			TranslatorBitmap bitsHeader;
395 			bitsHeader.magic = B_TRANSLATOR_BITMAP;
396 			bitsHeader.bounds.left = 0;
397 			bitsHeader.bounds.top = 0;
398 			bitsHeader.bounds.right = width - 1;
399 			bitsHeader.bounds.bottom = height - 1;
400 			bitsHeader.rowBytes = 4 * width;
401 			if (balpha)
402 				bitsHeader.colors = B_RGBA32;
403 			else
404 				bitsHeader.colors = B_RGB32;
405 			bitsHeader.dataSize = bitsHeader.rowBytes * height;
406 			if (swap_data(B_UINT32_TYPE, &bitsHeader,
407 				sizeof(TranslatorBitmap), B_SWAP_HOST_TO_BENDIAN) != B_OK) {
408 				result = B_ERROR;
409 				break;
410 			}
411 			outDestination->Write(&bitsHeader, sizeof(TranslatorBitmap));
412 
413 			if (bheaderonly) {
414 				result = B_OK;
415 				break;
416 			}
417 		}
418 
419 		if (interlace_type == PNG_INTERLACE_NONE) {
420 			// allocate buffer for storing PNG row
421 			prow = new uint8[rowbytes];
422 			if (!prow) {
423 				result = B_NO_MEMORY;
424 				break;
425 			}
426 			for (png_uint_32 i = 0; i < height; i++) {
427 				png_read_row(ppng, prow, NULL);
428 				outDestination->Write(prow, width * kbytes);
429 			}
430 			result = B_OK;
431 				// Set OK status here, because, in the event of
432 				// an error, png_read_end() will longjmp to error
433 				// handler above and not execute lines below it
434 
435 			// finish reading, pass NULL for info because I
436 			// don't need the extra data
437 			png_read_end(ppng, NULL);
438 
439 			break;
440 
441 		} else {
442 			// interlaced PNG image
443 			prows = new uint8 *[height];
444 			if (!prows) {
445 				result = B_NO_MEMORY;
446 				break;
447 			}
448 			// allocate enough memory to store the whole image
449 			for (nalloc = 0; nalloc < height; nalloc++) {
450 				prows[nalloc] = new uint8[rowbytes];
451 				if (!prows[nalloc])
452 					break;
453 			}
454 
455 			if (nalloc < height)
456 				result = B_NO_MEMORY;
457 			else {
458 				png_read_image(ppng, prows);
459 
460 				for (png_uint_32 i = 0; i < height; i++)
461 					outDestination->Write(prows[i], width * kbytes);
462 				result = B_OK;
463 					// Set OK status here, because, in the event of
464 					// an error, png_read_end() will longjmp to error
465 					// handler above and not execute lines below it
466 
467 				png_read_end(ppng, NULL);
468 			}
469 
470 			break;
471 		}
472 	}
473 
474 	if (ppng) {
475 		delete[] prow;
476 		prow = NULL;
477 
478 		// delete row pointers and array of pointers to rows
479 		while (nalloc) {
480 			nalloc--;
481 			delete[] prows[nalloc];
482 		}
483 		delete[] prows;
484 		prows = NULL;
485 
486 		// free PNG handle / info structures
487 		if (!pinfo)
488 			png_destroy_read_struct(&ppng, NULL, NULL);
489 		else
490 			png_destroy_read_struct(&ppng, &pinfo, NULL);
491 	}
492 
493 	return result;
494 }
495 
496 status_t
497 PNGTranslator::translate_from_png(BPositionIO *inSource, uint32 outType,
498 	BPositionIO *outDestination)
499 {
500 	if (outType == B_TRANSLATOR_BITMAP)
501 		return translate_from_png_to_bits(inSource, outDestination);
502 	else {
503 		// Translate from PNG to PNG
504 		translate_direct_copy(inSource, outDestination);
505 		return B_OK;
506 	}
507 }
508 
509 // Convert width pixels from pbits to PNG format, storing the
510 // result in ppng
511 status_t
512 pix_bits_to_png(uint8 *pbits, uint8 *ppng, color_space fromspace,
513 	uint32 width, const color_map *pmap, int32 bitsBytesPerPixel)
514 {
515 	status_t bytescopied = 0;
516 	uint16 val;
517 
518 	switch (fromspace) {
519 		case B_RGBA32:
520 			bytescopied = width * bitsBytesPerPixel;
521 			memcpy(ppng, pbits, bytescopied);
522 			break;
523 
524 		case B_RGB32:
525 		case B_RGB24:
526 			bytescopied = width * bitsBytesPerPixel;
527 			while (width--) {
528 				memcpy(ppng, pbits, 3);
529 				ppng += 3;
530 				pbits += bitsBytesPerPixel;
531 			}
532 			break;
533 
534 		case B_RGBA32_BIG:
535 			bytescopied = width * 4;
536 			while (width--) {
537 				ppng[0] = pbits[3];
538 				ppng[1] = pbits[2];
539 				ppng[2] = pbits[1];
540 				ppng[3] = pbits[0];
541 
542 				ppng += 4;
543 				pbits += 4;
544 			}
545 			break;
546 
547 		case B_CMYA32:
548 			bytescopied = width * 4;
549 			while (width--) {
550 				ppng[0] = 255 - pbits[2];
551 				ppng[1] = 255 - pbits[1];
552 				ppng[2] = 255 - pbits[0];
553 				ppng[3] = pbits[3];
554 
555 				ppng += 4;
556 				pbits += 4;
557 			}
558 			break;
559 
560 		case B_CMYK32:
561 		{
562 			int32 comp;
563 			bytescopied = width * 3;
564 			while (width--) {
565 				comp = 255 - pbits[2] - pbits[3];
566 				ppng[0] = (comp < 0) ? 0 : comp;
567 
568 				comp = 255 - pbits[1] - pbits[3];
569 				ppng[1] = (comp < 0) ? 0 : comp;
570 
571 				comp = 255 - pbits[0] - pbits[3];
572 				ppng[2] = (comp < 0) ? 0 : comp;
573 
574 				ppng += 3;
575 				pbits += 4;
576 			}
577 			break;
578 		}
579 
580 		case B_CMY32:
581 		case B_CMY24:
582 			bytescopied = width * 3;
583 			while (width--) {
584 				ppng[0] = 255 - pbits[2];
585 				ppng[1] = 255 - pbits[1];
586 				ppng[2] = 255 - pbits[0];
587 
588 				ppng += 3;
589 				pbits += bitsBytesPerPixel;
590 			}
591 			break;
592 
593 		case B_RGB16:
594 		case B_RGB16_BIG:
595 			bytescopied = width * 3;
596 			while (width--) {
597 				if (fromspace == B_RGB16)
598 					val = pbits[0] + (pbits[1] << 8);
599 				else
600 					val = pbits[1] + (pbits[0] << 8);
601 
602 				ppng[0] =
603 					((val & 0x1f) << 3) | ((val & 0x1f) >> 2);
604 				ppng[1] =
605 					((val & 0x7e0) >> 3) | ((val & 0x7e0) >> 9);
606 				ppng[2] =
607 					((val & 0xf800) >> 8) | ((val & 0xf800) >> 13);
608 
609 				ppng += 3;
610 				pbits += 2;
611 			}
612 			break;
613 
614 		case B_RGB15:
615 		case B_RGB15_BIG:
616 			bytescopied = width * 3;
617 			while (width--) {
618 				if (fromspace == B_RGB15)
619 					val = pbits[0] + (pbits[1] << 8);
620 				else
621 					val = pbits[1] + (pbits[0] << 8);
622 				ppng[0] =
623 					((val & 0x1f) << 3) | ((val & 0x1f) >> 2);
624 				ppng[1] =
625 					((val & 0x3e0) >> 2) | ((val & 0x3e0) >> 7);
626 				ppng[2] =
627 					((val & 0x7c00) >> 7) | ((val & 0x7c00) >> 12);
628 
629 				ppng += 3;
630 				pbits += 2;
631 			}
632 			break;
633 
634 		case B_RGBA15:
635 		case B_RGBA15_BIG:
636 			bytescopied = width * 4;
637 			while (width--) {
638 				if (fromspace == B_RGBA15)
639 					val = pbits[0] + (pbits[1] << 8);
640 				else
641 					val = pbits[1] + (pbits[0] << 8);
642 				ppng[0] =
643 					((val & 0x1f) << 3) | ((val & 0x1f) >> 2);
644 				ppng[1] =
645 					((val & 0x3e0) >> 2) | ((val & 0x3e0) >> 7);
646 				ppng[2] =
647 					((val & 0x7c00) >> 7) | ((val & 0x7c00) >> 12);
648 				ppng[3] = (val & 0x8000) ? 255 : 0;
649 
650 				ppng += 4;
651 				pbits += 2;
652 			}
653 			break;
654 
655 		case B_RGB32_BIG:
656 			bytescopied = width * 3;
657 			while (width--) {
658 				ppng[0] = pbits[3];
659 				ppng[1] = pbits[2];
660 				ppng[2] = pbits[1];
661 
662 				ppng += 3;
663 				pbits += 4;
664 			}
665 			break;
666 
667 		case B_RGB24_BIG:
668 			bytescopied = width * 3;
669 			while (width--) {
670 				ppng[0] = pbits[2];
671 				ppng[1] = pbits[1];
672 				ppng[2] = pbits[0];
673 
674 				ppng += 3;
675 				pbits += 3;
676 			}
677 			break;
678 
679 		case B_CMAP8:
680 		{
681 			rgb_color c;
682 			bytescopied = width * 3;
683 			while (width--) {
684 				c = pmap->color_list[pbits[0]];
685 				ppng[0] = c.blue;
686 				ppng[1] = c.green;
687 				ppng[2] = c.red;
688 
689 				ppng += 3;
690 				pbits++;
691 			}
692 			break;
693 		}
694 
695 		case B_GRAY8:
696 			bytescopied = width;
697 			memcpy(ppng, pbits, bytescopied);
698 			break;
699 
700 		default:
701 			bytescopied = B_ERROR;
702 			break;
703 	} // switch (fromspace)
704 
705 	return bytescopied;
706 }
707 
708 status_t
709 PNGTranslator::translate_from_bits_to_png(BPositionIO *inSource,
710 	BPositionIO *outDestination)
711 {
712 	TranslatorBitmap bitsHeader;
713 
714 	status_t result;
715 
716 	result = identify_bits_header(inSource, NULL, &bitsHeader);
717 	if (result != B_OK)
718 		return result;
719 
720 	const color_map *pmap = NULL;
721 	if (bitsHeader.colors == B_CMAP8) {
722 		pmap = system_colors();
723 		if (!pmap)
724 			return B_ERROR;
725 	}
726 
727 	png_uint_32 width, height;
728 	width = static_cast<png_uint_32>(bitsHeader.bounds.Width() + 1);
729 	height = static_cast<png_uint_32>(bitsHeader.bounds.Height() + 1);
730 
731 	int32 pngBytesPerPixel = 0;
732 	int bit_depth, color_type, interlace_type;
733 	bit_depth = 8;
734 	switch (bitsHeader.colors) {
735 		case B_RGBA32:
736 		case B_RGBA32_BIG:
737 		case B_CMYA32:
738 		case B_RGBA15:
739 		case B_RGBA15_BIG:
740 			pngBytesPerPixel = 4;
741 			color_type = PNG_COLOR_TYPE_RGB_ALPHA;
742 			break;
743 
744 		case B_RGB32:
745 		case B_RGB32_BIG:
746 		case B_RGB24:
747 		case B_RGB24_BIG:
748 		case B_CMY32:
749 		case B_CMYK32:
750 		case B_CMY24:
751 		case B_RGB16:
752 		case B_RGB16_BIG:
753 		case B_RGB15:
754 		case B_RGB15_BIG:
755 			pngBytesPerPixel = 3;
756 			color_type = PNG_COLOR_TYPE_RGB;
757 			break;
758 
759 		// ADD SUPPORT FOR B_CMAP8 HERE (later)
760 
761 		case B_GRAY8:
762 			pngBytesPerPixel = 1;
763 			color_type = PNG_COLOR_TYPE_GRAY;
764 			break;
765 
766 		default:
767 			return B_NO_TRANSLATOR;
768 	}
769 	interlace_type = fSettings->SetGetInt32(PNG_SETTING_INTERLACE);
770 
771 	int32 bitsBytesPerPixel = 0;
772 	switch (bitsHeader.colors) {
773 		case B_RGBA32:
774 		case B_RGBA32_BIG:
775 		case B_RGB32:
776 		case B_RGB32_BIG:
777 		case B_CMYA32:
778 		case B_CMYK32:
779 		case B_CMY32:
780 			bitsBytesPerPixel = 4;
781 			break;
782 
783 		case B_RGB24:
784 		case B_RGB24_BIG:
785 		case B_CMY24:
786 			bitsBytesPerPixel = 3;
787 			break;
788 
789 		case B_RGB16:
790 		case B_RGB16_BIG:
791 		case B_RGBA15:
792 		case B_RGBA15_BIG:
793 		case B_RGB15:
794 		case B_RGB15_BIG:
795 			bitsBytesPerPixel = 2;
796 			break;
797 
798 		case B_GRAY8:
799 		case B_CMAP8:
800 			bitsBytesPerPixel = 1;
801 			break;
802 
803 		default:
804 			return B_NO_TRANSLATOR;
805 	};
806 
807 	uint8 *pbitsrow = NULL, *prow = NULL;
808 		// row buffers
809 	// image buffer for writing whole png image at once
810 	uint8 **prows = NULL;
811 	png_uint_32 nalloc = 0;
812 
813 	png_structp ppng = NULL;
814 	png_infop pinfo = NULL;
815 
816 	result = B_NO_TRANSLATOR;
817 	while (ppng == NULL) {
818 		// create PNG read pointer with default error handling routines
819 		ppng = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
820 			NULL, NULL);
821 		if (!ppng) {
822 			result = B_ERROR;
823 			break;
824 		}
825 		// alocate / init memory for image information
826 		pinfo = png_create_info_struct(ppng);
827 		if (!pinfo) {
828 			result = B_ERROR;
829 			break;
830 		}
831 		// set error handling
832 		if (setjmp(png_jmpbuf(ppng))) {
833 			// When an error occurs in libpng, it uses
834 			// the longjmp function to continue execution
835 			// from this point
836 			result = B_ERROR;
837 			break;
838 		}
839 
840 		png_set_write_fn(ppng, static_cast<void *>(outDestination),
841 			pngcb_write_data, pngcb_flush_data);
842 
843 		// Allocate memory needed to buffer image data
844 		pbitsrow = new uint8[bitsHeader.rowBytes];
845 		if (!pbitsrow) {
846 			result = B_NO_MEMORY;
847 			break;
848 		}
849 		if (interlace_type == PNG_INTERLACE_NONE) {
850 			prow = new uint8[width * pngBytesPerPixel];
851 			if (!prow) {
852 				result = B_NO_MEMORY;
853 				break;
854 			}
855 		} else {
856 			prows = new uint8 *[height];
857 			if (!prows) {
858 				result = B_NO_MEMORY;
859 				break;
860 			}
861 			// allocate enough memory to store the whole image
862 			for (nalloc = 0; nalloc < height; nalloc++) {
863 				prows[nalloc] = new uint8[width * pngBytesPerPixel];
864 				if (!prows[nalloc])
865 					break;
866 			}
867 			if (nalloc < height) {
868 				result = B_NO_MEMORY;
869 				// clear out rest of the pointers,
870 				// so we don't call delete[] with invalid pointers
871 				for (; nalloc < height; nalloc++)
872 					prows[nalloc] = NULL;
873 				break;
874 			}
875 		}
876 
877 		// Specify image info
878 		png_set_IHDR(ppng, pinfo, width, height, bit_depth, color_type,
879 			interlace_type, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
880 		png_write_info(ppng, pinfo);
881 
882 		png_set_bgr(ppng);
883 
884 		// write out image data
885 		if (interlace_type == PNG_INTERLACE_NONE) {
886 			for (png_uint_32 i = 0; i < height; i++) {
887 				inSource->Read(pbitsrow, bitsHeader.rowBytes);
888 
889 				pix_bits_to_png(pbitsrow, prow, bitsHeader.colors, width,
890 					pmap, bitsBytesPerPixel);
891 
892 				png_write_row(ppng, prow);
893 			}
894 		} else {
895 			for (png_uint_32 i = 0; i < height; i++) {
896 				inSource->Read(pbitsrow, bitsHeader.rowBytes);
897 
898 				pix_bits_to_png(pbitsrow, prows[i], bitsHeader.colors, width,
899 					pmap, bitsBytesPerPixel);
900 			}
901 			png_write_image(ppng, prows);
902 		}
903 		png_write_end(ppng, NULL);
904 
905 		result = B_OK;
906 		break;
907 	}
908 
909 	if (ppng) {
910 		delete[] pbitsrow;
911 		pbitsrow = NULL;
912 
913 		delete[] prow;
914 		prow = NULL;
915 
916 		// delete row pointers and array of pointers to rows
917 		while (nalloc) {
918 			nalloc--;
919 			delete[] prows[nalloc];
920 		}
921 		delete[] prows;
922 		prows = NULL;
923 
924 		// free PNG handle / info structures
925 		if (!pinfo)
926 			png_destroy_write_struct(&ppng, NULL);
927 		else
928 			png_destroy_write_struct(&ppng, &pinfo);
929 	}
930 
931 	return result;
932 }
933 
934 // ---------------------------------------------------------------
935 // DerivedTranslate
936 //
937 // Translates the data in inSource to the type outType and stores
938 // the translated data in outDestination.
939 //
940 // Preconditions:
941 //
942 // Parameters:	inSource,	the data to be translated
943 //
944 //				inInfo,	hint about the data in inSource (not used)
945 //
946 //				ioExtension,	configuration options for the
947 //								translator
948 //
949 //				outType,	the type to convert inSource to
950 //
951 //				outDestination,	where the translated data is
952 //								put
953 //
954 //				baseType, indicates whether inSource is in the
955 //				          bits format, not in the bits format or
956 //				          is unknown
957 //
958 // Postconditions:
959 //
960 // Returns: B_BAD_VALUE, if the options in ioExtension are bad
961 //
962 // B_NO_TRANSLATOR, if this translator doesn't understand the data
963 //
964 // B_ERROR, if there was an error allocating memory or converting
965 //          data
966 //
967 // B_OK, if all went well
968 // ---------------------------------------------------------------
969 status_t
970 PNGTranslator::DerivedTranslate(BPositionIO *inSource,
971 	const translator_info *inInfo, BMessage *ioExtension, uint32 outType,
972 	BPositionIO *outDestination, int32 baseType)
973 {
974 	if (baseType == 1)
975 		// if inSource is in bits format
976 		return translate_from_bits_to_png(inSource, outDestination);
977 	else if (baseType == 0)
978 		// if inSource is NOT in bits format
979 		return translate_from_png(inSource, outType, outDestination);
980 	else
981 		return B_NO_TRANSLATOR;
982 }
983 
984 BView *
985 PNGTranslator::NewConfigView(TranslatorSettings *settings)
986 {
987 	return new PNGView(BRect(0, 0, PNG_VIEW_WIDTH, PNG_VIEW_HEIGHT),
988 		B_TRANSLATE("PNGTranslator Settings"), B_FOLLOW_ALL,
989 		B_WILL_DRAW, settings);
990 }
991 
992