diff options
Diffstat (limited to 'libdimension-png/png.c')
| -rw-r--r-- | libdimension-png/png.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/libdimension-png/png.c b/libdimension-png/png.c new file mode 100644 index 0000000..750b5af --- /dev/null +++ b/libdimension-png/png.c @@ -0,0 +1,263 @@ +/************************************************************************* + * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> * + * * + * This file is part of Dimension. * + * * + * Dimension is free software; you can redistribute it and/or modify it * + * under the terms of the GNU Lesser General Public License as published * + * by the Free Software Foundation; either version 3 of the License, or * + * (at your option) any later version. * + * * + * Dimension is distributed in the hope that it will be useful, but * + * WITHOUT ANY WARRANTY; without even the implied warranty of * + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * + * Lesser General Public License for more details. * + * * + * You should have received a copy of the GNU Lesser General Public * + * License along with this program. If not, see * + * <http://www.gnu.org/licenses/>. * + *************************************************************************/ + +#include "dimension-png.h" +#include <png.h> +#include <setjmp.h> +#include <arpa/inet.h> +#include <stdlib.h> + +int +dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file) +{ + png_structp png_ptr; + png_infop info_ptr; + png_uint_32 width, height; + unsigned int x, y; + uint16_t *row = NULL; + dmnsn_pixel *pixel; + + width = canvas->x; + height = canvas->y; + + if (!file) return 1; + + png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); + if (!png_ptr) return 1; + + info_ptr = png_create_info_struct(png_ptr); + if (!info_ptr) { + png_destroy_write_struct(&png_ptr, NULL); + return 1; + } + + if (setjmp(png_jmpbuf(png_ptr))) { + if (row) free(row); + png_destroy_write_struct(&png_ptr, &info_ptr); + return 1; + } + + png_init_io(png_ptr, file); + + png_set_IHDR(png_ptr, info_ptr, width, height, 16, + PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE, + PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); + + png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE); + + png_set_invert_alpha(png_ptr); + png_write_info(png_ptr, info_ptr); + + if (htonl(1) != 1) { + /* We are little-endian */ + png_set_swap(png_ptr); + } + + row = malloc(4*sizeof(uint16_t)*width); + if (!row) { + png_destroy_write_struct(&png_ptr, &info_ptr); + return 1; + } + + for (y = 0; y < height; ++y) { + for (x = 0; x < width; ++x) { + /* Invert the rows. PNG coordinates are fourth quadrant. */ + pixel = canvas->pixels + (height - y - 1)*width + x; + + row[4*x] = pixel->r; + row[4*x + 1] = pixel->g; + row[4*x + 2] = pixel->b; + + if (pixel->a > pixel->t) { + row[4*x + 3] = pixel->a; + } else { + row[4*x + 3] = pixel->t; + } + } + png_write_row(png_ptr, (png_bytep)row); + } + + png_write_end(png_ptr, info_ptr); + + free(row); + png_destroy_write_struct(&png_ptr, &info_ptr); + return 0; +} + +int +dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file) +{ + png_byte header[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; + png_structp png_ptr; + png_infop info_ptr; + png_uint_32 width, height, rowbytes; + int bit_depth, color_type, interlace_type, compression_type, filter_method; + png_bytep image = NULL; + png_bytep *row_pointers = NULL; + unsigned int x, y; + dmnsn_pixel *pixel; + png_bytep png_pixel; + + /* Ensure that *canvas can always be deleted. */ + *canvas = NULL; + + if (!file) return 1; + + fread(header, 1, 8, file); + if (png_sig_cmp(header, 0, 8)) return 1; + + png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); + if (!png_ptr) return 1; + + info_ptr = png_create_info_struct(png_ptr); + if (!info_ptr) { + png_destroy_read_struct(&png_ptr, NULL, NULL); + return 1; + } + + if (setjmp(png_jmpbuf(png_ptr))) { + if (row_pointers) free(row_pointers); + if (image) free(image); + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 1; + } + + png_init_io(png_ptr, file); + png_set_sig_bytes(png_ptr, 8); + + png_read_info(png_ptr, info_ptr); + + png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, + &interlace_type, &compression_type, &filter_method); + + /* + * - Convert paletted images to RGB. + * - Convert a tRNS chunk to an alpha channel + * - Convert grayscale to RGB + * - Invert the alpha channel + */ + if (color_type == PNG_COLOR_TYPE_PALETTE) { + png_set_palette_to_rgb(png_ptr); + } + if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { + png_set_tRNS_to_alpha(png_ptr); + } + if (color_type == PNG_COLOR_TYPE_GRAY + || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { + png_set_gray_to_rgb(png_ptr); + } + png_set_invert_alpha(png_ptr); + + png_read_update_info(png_ptr, info_ptr); + rowbytes = png_get_rowbytes(png_ptr, info_ptr); + + image = malloc(rowbytes*height); + if (!image) { + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 1; + } + + row_pointers = malloc(sizeof(png_bytep)*height); + if (!row_pointers) { + free(image); + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 1; + } + + for (y = 0; y < height; ++y) { + row_pointers[y] = image + y*rowbytes; + } + + png_read_image(png_ptr, row_pointers); + + *canvas = dmnsn_new_canvas(width, height); + if (!*canvas) { + free(row_pointers); + free(image); + png_read_end(png_ptr, NULL); + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 1; + } + + if (bit_depth == 16) { + if (color_type & PNG_COLOR_MASK_ALPHA) { + for (x = 0; x < width; ++x) { + for (y = 0; y < height; ++y) { + pixel = (*canvas)->pixels + (height - y - 1)*width + x; + png_pixel = image + 8*(y*width + x); + + pixel->r = (png_pixel[0] << UINT16_C(8)) + png_pixel[1]; + pixel->g = (png_pixel[2] << UINT16_C(8)) + png_pixel[3]; + pixel->b = (png_pixel[4] << UINT16_C(8)) + png_pixel[5]; + pixel->a = (png_pixel[6] << UINT16_C(8)) + png_pixel[7]; + pixel->t = 0; + } + } + } else { + for (x = 0; x < width; ++x) { + for (y = 0; y < height; ++y) { + pixel = (*canvas)->pixels + (height - y - 1)*width + x; + png_pixel = image + 6*(y*width + x); + + pixel->r = (png_pixel[0] << UINT16_C(8)) + png_pixel[1]; + pixel->g = (png_pixel[2] << UINT16_C(8)) + png_pixel[3]; + pixel->b = (png_pixel[4] << UINT16_C(8)) + png_pixel[5]; + pixel->a = 0; + pixel->t = 0; + } + } + } + } else { + /* Bit depth is 8 */ + if (color_type & PNG_COLOR_MASK_ALPHA) { + for (x = 0; x < width; ++x) { + for (y = 0; y < height; ++y) { + pixel = (*canvas)->pixels + (height - y - 1)*width + x; + png_pixel = image + 4*(y*width + x); + + pixel->r = png_pixel[0] << UINT16_C(8); + pixel->g = png_pixel[1] << UINT16_C(8); + pixel->b = png_pixel[2] << UINT16_C(8); + pixel->a = png_pixel[3] << UINT16_C(8); + pixel->t = 0; + } + } + } else { + for (x = 0; x < width; ++x) { + for (y = 0; y < height; ++y) { + pixel = (*canvas)->pixels + (height - y - 1)*width + x; + png_pixel = image + 3*(y*width + x); + + pixel->r = png_pixel[0] << UINT16_C(8); + pixel->g = png_pixel[1] << UINT16_C(8); + pixel->b = png_pixel[2] << UINT16_C(8); + pixel->a = 0; + pixel->t = 0; + } + } + } + } + + free(row_pointers); + free(image); + png_read_end(png_ptr, NULL); + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 0; +} |