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_bytep) * 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			row[x * 3] = pixelData[stride * i * 4 + x * 4];
 69			row[x * 3 + 1] = pixelData[stride * i * 4 + x * 4 + 1];
 70			row[x * 3 + 2] = pixelData[stride * i * 4 + x * 4 + 2];
 71		}
 72		png_write_row(png, row);
 73	}
 74	free(row);
 75	return true;
 76}
 77
 78bool PNGWriteCustomChunk(png_structp png, const char* name, size_t size, void* data) {
 79	char realName[5];
 80	strncpy(realName, name, 4);
 81	realName[0] = tolower(realName[0]);
 82	realName[1] = tolower(realName[1]);
 83	realName[4] = '\0';
 84	if (setjmp(png_jmpbuf(png))) {
 85		return false;
 86	}
 87	png_write_chunk(png, (png_bytep) realName, data, size);
 88	return true;
 89}
 90
 91void PNGWriteClose(png_structp png, png_infop info) {
 92	if (!setjmp(png_jmpbuf(png))) {
 93		png_write_end(png, info);
 94	}
 95	png_destroy_write_struct(&png, &info);
 96}
 97
 98bool isPNG(struct VFile* source) {
 99	png_byte header[PNG_HEADER_BYTES];
100	source->read(source, header, PNG_HEADER_BYTES);
101	return !png_sig_cmp(header, 0, PNG_HEADER_BYTES);
102}
103
104png_structp PNGReadOpen(struct VFile* source, unsigned offset) {
105	png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
106	if (!png) {
107		return 0;
108	}
109	if (setjmp(png_jmpbuf(png))) {
110		png_destroy_read_struct(&png, 0, 0);
111		return 0;
112	}
113	png_set_read_fn(png, source, _pngRead);
114	png_set_sig_bytes(png, offset);
115	return png;
116}
117
118bool PNGInstallChunkHandler(png_structp png, void* context, ChunkHandler handler, const char* chunkName) {
119	if (setjmp(png_jmpbuf(png))) {
120		return false;
121	}
122	png_set_read_user_chunk_fn(png, context, handler);
123	png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS, (png_bytep) chunkName, 1);
124	return true;
125}
126
127bool PNGReadHeader(png_structp png, png_infop info) {
128	if (setjmp(png_jmpbuf(png))) {
129		return false;
130	}
131	png_read_info(png, info);
132	return true;
133}
134
135bool PNGIgnorePixels(png_structp png, png_infop info) {
136	if (setjmp(png_jmpbuf(png))) {
137		return false;
138	}
139
140	unsigned height = png_get_image_height(png, info);
141	unsigned i;
142	for (i = 0; i < height; ++i) {
143		png_read_row(png, 0, 0);
144	}
145	return true;
146}
147
148bool PNGReadPixels(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride) {
149	if (setjmp(png_jmpbuf(png))) {
150		return false;
151	}
152
153	uint8_t* pixelData = pixels;
154	unsigned pngHeight = png_get_image_height(png, info);
155	if (height < pngHeight) {
156		pngHeight = height;
157	}
158
159	unsigned pngWidth = png_get_image_width(png, info);
160	if (width < pngWidth) {
161		pngWidth = width;
162	}
163
164	unsigned i;
165	png_bytep row = malloc(png_get_rowbytes(png, info));
166	for (i = 0; i < pngHeight; ++i) {
167		png_read_row(png, row, 0);
168		unsigned x;
169		for (x = 0; x < pngWidth; ++x) {
170			pixelData[stride * i * 4 + x * 4] = row[x * 3];
171			pixelData[stride * i * 4 + x * 4 + 1] = row[x * 3 + 1];
172			pixelData[stride * i * 4 + x * 4 + 2] = row[x * 3 + 2];
173		}
174	}
175	free(row);
176	return true;
177}
178
179bool PNGReadFooter(png_structp png, png_infop end) {
180	if (setjmp(png_jmpbuf(png))) {
181		return false;
182	}
183	png_read_end(png, end);
184	return true;
185}
186
187void PNGReadClose(png_structp png, png_infop info, png_infop end) {
188	png_destroy_read_struct(&png, &info, &end);
189}
190
191#endif