1/* Copyright (c) 2013-2014 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "util/png-io.h"
  7
  8#ifdef USE_PNG
  9
 10#include "vfs.h"
 11
 12static void _pngWrite(png_structp png, png_bytep buffer, png_size_t size) {
 13	struct VFile* vf = png_get_io_ptr(png);
 14	size_t written = vf->write(vf, buffer, size);
 15	if (written != size) {
 16		png_error(png, "Could not write PNG");
 17	}
 18}
 19
 20static void _pngRead(png_structp png, png_bytep buffer, png_size_t size) {
 21	struct VFile* vf = png_get_io_ptr(png);
 22	size_t read = vf->read(vf, buffer, size);
 23	if (read != size) {
 24		png_error(png, "Could not read PNG");
 25	}
 26}
 27
 28png_structp PNGWriteOpen(struct VFile* source) {
 29	png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
 30	if (!png) {
 31		return 0;
 32	}
 33	if (setjmp(png_jmpbuf(png))) {
 34		png_destroy_write_struct(&png, 0);
 35		return 0;
 36	}
 37	png_set_write_fn(png, source, _pngWrite, 0);
 38	return png;
 39}
 40
 41png_infop PNGWriteHeader(png_structp png, unsigned width, unsigned height) {
 42	png_infop info = png_create_info_struct(png);
 43	if (!info) {
 44		return 0;
 45	}
 46	if (setjmp(png_jmpbuf(png))) {
 47		return 0;
 48	}
 49	png_set_IHDR(png, info, width, height, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 50	png_write_info(png, info);
 51	return info;
 52}
 53
 54bool PNGWritePixels(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels) {
 55	png_bytep row = malloc(sizeof(png_byte) * width * 3);
 56	if (!row) {
 57		return false;
 58	}
 59	const png_byte* pixelData = pixels;
 60	if (setjmp(png_jmpbuf(png))) {
 61		free(row);
 62		return false;
 63	}
 64	unsigned i;
 65	for (i = 0; i < height; ++i) {
 66		unsigned x;
 67		for (x = 0; x < width; ++x) {
 68#ifdef __BIG_ENDIAN__
 69			row[x * 3] = pixelData[stride * i * 4 + x * 4 + 3];
 70			row[x * 3 + 1] = pixelData[stride * i * 4 + x * 4 + 2];
 71			row[x * 3 + 2] = pixelData[stride * i * 4 + x * 4 + 1];
 72#else
 73			row[x * 3] = pixelData[stride * i * 4 + x * 4];
 74			row[x * 3 + 1] = pixelData[stride * i * 4 + x * 4 + 1];
 75			row[x * 3 + 2] = pixelData[stride * i * 4 + x * 4 + 2];
 76#endif
 77		}
 78		png_write_row(png, row);
 79	}
 80	free(row);
 81	return true;
 82}
 83
 84bool PNGWriteCustomChunk(png_structp png, const char* name, size_t size, void* data) {
 85	char realName[5];
 86	strncpy(realName, name, 4);
 87	realName[0] = tolower(realName[0]);
 88	realName[1] = tolower(realName[1]);
 89	realName[4] = '\0';
 90	if (setjmp(png_jmpbuf(png))) {
 91		return false;
 92	}
 93	png_write_chunk(png, (png_bytep) realName, data, size);
 94	return true;
 95}
 96
 97void PNGWriteClose(png_structp png, png_infop info) {
 98	if (!setjmp(png_jmpbuf(png))) {
 99		png_write_end(png, info);
100	}
101	png_destroy_write_struct(&png, &info);
102}
103
104bool isPNG(struct VFile* source) {
105	png_byte header[PNG_HEADER_BYTES];
106	source->read(source, header, PNG_HEADER_BYTES);
107	return !png_sig_cmp(header, 0, PNG_HEADER_BYTES);
108}
109
110png_structp PNGReadOpen(struct VFile* source, unsigned offset) {
111	png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
112	if (!png) {
113		return 0;
114	}
115	if (setjmp(png_jmpbuf(png))) {
116		png_destroy_read_struct(&png, 0, 0);
117		return 0;
118	}
119	png_set_read_fn(png, source, _pngRead);
120	png_set_sig_bytes(png, offset);
121	return png;
122}
123
124bool PNGInstallChunkHandler(png_structp png, void* context, ChunkHandler handler, const char* chunkName) {
125	if (setjmp(png_jmpbuf(png))) {
126		return false;
127	}
128	png_set_read_user_chunk_fn(png, context, handler);
129	int len = strlen(chunkName);
130	int chunks = 0;
131	char* chunkList = strdup(chunkName);
132	int i;
133	for (i = 4; i <= len; i += 5) {
134		chunkList[i] = '\0';
135		++chunks;
136	}
137	png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS, (png_bytep) chunkList, chunks);
138	free(chunkList);
139	return true;
140}
141
142bool PNGReadHeader(png_structp png, png_infop info) {
143	if (setjmp(png_jmpbuf(png))) {
144		return false;
145	}
146	png_read_info(png, info);
147	return true;
148}
149
150bool PNGIgnorePixels(png_structp png, png_infop info) {
151	if (setjmp(png_jmpbuf(png))) {
152		return false;
153	}
154
155	unsigned height = png_get_image_height(png, info);
156	unsigned i;
157	for (i = 0; i < height; ++i) {
158		png_read_row(png, 0, 0);
159	}
160	return true;
161}
162
163bool PNGReadPixels(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride) {
164	if (setjmp(png_jmpbuf(png))) {
165		return false;
166	}
167
168	uint8_t* pixelData = pixels;
169	unsigned pngHeight = png_get_image_height(png, info);
170	if (height < pngHeight) {
171		pngHeight = height;
172	}
173
174	unsigned pngWidth = png_get_image_width(png, info);
175	if (width < pngWidth) {
176		pngWidth = width;
177	}
178
179	unsigned i;
180	png_bytep row = malloc(png_get_rowbytes(png, info));
181	for (i = 0; i < pngHeight; ++i) {
182		png_read_row(png, row, 0);
183		unsigned x;
184		for (x = 0; x < pngWidth; ++x) {
185#if __BIG_ENDIAN__
186			pixelData[stride * i * 4 + x * 4 + 3] = row[x * 3];
187			pixelData[stride * i * 4 + x * 4 + 2] = row[x * 3 + 1];
188			pixelData[stride * i * 4 + x * 4 + 1] = row[x * 3 + 2];
189			pixelData[stride * i * 4 + x * 4] = 0xFF;
190#else
191			pixelData[stride * i * 4 + x * 4] = row[x * 3];
192			pixelData[stride * i * 4 + x * 4 + 1] = row[x * 3 + 1];
193			pixelData[stride * i * 4 + x * 4 + 2] = row[x * 3 + 2];
194			pixelData[stride * i * 4 + x * 4 + 3] = 0xFF;
195#endif
196		}
197	}
198	free(row);
199	return true;
200}
201
202bool PNGReadFooter(png_structp png, png_infop end) {
203	if (setjmp(png_jmpbuf(png))) {
204		return false;
205	}
206	png_read_end(png, end);
207	return true;
208}
209
210void PNGReadClose(png_structp png, png_infop info, png_infop end) {
211	png_destroy_read_struct(&png, &info, &end);
212}
213
214#endif