diff options
Diffstat (limited to 'libdimension-png/png.c')
| -rw-r--r-- | libdimension-png/png.c | 328 |
1 files changed, 0 insertions, 328 deletions
diff --git a/libdimension-png/png.c b/libdimension-png/png.c deleted file mode 100644 index 7e9036f..0000000 --- a/libdimension-png/png.c +++ /dev/null @@ -1,328 +0,0 @@ -/************************************************************************* - * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> * - * * - * This file is part of The Dimension Library. * - * * - * The Dimension Library 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. * - * * - * The Dimension Library 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> - -/* Write a canvas to a png file, using libpng. Return 0 on success, nonzero on - failure. */ -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_color color; - dmnsn_sRGB sRGB; - - if (!file) return 1; /* file was NULL */ - - width = canvas->x; - height = canvas->y; - - png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); - if (!png_ptr) return 1; /* Couldn't create libpng write struct */ - - info_ptr = png_create_info_struct(png_ptr); - if (!info_ptr) { - /* Couldn't create libpng info struct */ - png_destroy_write_struct(&png_ptr, NULL); - return 1; - } - - /* libpng will longjmp here if it encounters an error from here on */ - if (setjmp(png_jmpbuf(png_ptr))) { - /* libpng error */ - if (row) free(row); - png_destroy_write_struct(&png_ptr, &info_ptr); - return 1; - } - - /* Associate file with the libpng write struct */ - png_init_io(png_ptr, file); - - /* Set header correctly for 16-bit sRGB image */ - 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); - - /* We think of transparency in the opposite way that PNG does */ - png_set_invert_alpha(png_ptr); - - /* Write the info struct */ - png_write_info(png_ptr, info_ptr); - - if (htonl(1) != 1) { - /* We are little-endian; swap the byte order of the pixels */ - png_set_swap(png_ptr); - } - - /* Allocate the temporary row of RGBA values */ - row = malloc(4*sizeof(uint16_t)*width); - if (!row) { - png_destroy_write_struct(&png_ptr, &info_ptr); - return 1; - } - - /* Write the pixels */ - for (y = 0; y < height; ++y) { - for (x = 0; x < width; ++x) { - /* Invert the rows. PNG coordinates are fourth quadrant. */ - color = dmnsn_get_pixel(canvas, x, height - y - 1); - sRGB = dmnsn_sRGB_from_color(color); - - /* Saturate R, G, and B to [0, UINT16_MAX] */ - - if (sRGB.R <= 0.0) { - row[4*x] = 0; - } else if (sRGB.R >= 1.0) { - row[4*x] = UINT16_MAX; - } else { - row[4*x] = sRGB.R*UINT16_MAX; - } - - if (sRGB.G <= 0.0) { - row[4*x + 1] = 0; - } else if (sRGB.G >= 1.0) { - row[4*x + 1] = UINT16_MAX; - } else { - row[4*x + 1] = sRGB.G*UINT16_MAX; - } - - if (sRGB.B <= 0.0) { - row[4*x + 2] = 0; - } else if (sRGB.B >= 1.0) { - row[4*x + 2] = UINT16_MAX; - } else { - row[4*x + 2] = sRGB.B*UINT16_MAX; - } - - /* color.filter + color.trans is in [0.0, 1.0] by definition */ - row[4*x + 3] = (color.filter + color.trans)*UINT16_MAX; - } - - /* Write the row */ - png_write_row(png_ptr, (png_bytep)row); - } - - /* Finish the PNG file */ - png_write_end(png_ptr, info_ptr); - - free(row); - png_destroy_write_struct(&png_ptr, &info_ptr); - return 0; -} - -/* Read a canvas from the PNG file `file'. Return NULL on error. */ -dmnsn_canvas * -dmnsn_png_read_canvas(FILE *file) -{ - dmnsn_canvas *canvas; - 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_color color; - dmnsn_sRGB sRGB; - png_bytep png_pixel; - - if (!file) return NULL; /* file was NULL */ - - fread(header, 1, 8, file); - if (png_sig_cmp(header, 0, 8)) return NULL; /* file is not a PNG file */ - - /* Create the libpng read struct */ - png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); - if (!png_ptr) return NULL; - - /* Create the libpng info struct */ - info_ptr = png_create_info_struct(png_ptr); - if (!info_ptr) { - png_destroy_read_struct(&png_ptr, NULL, NULL); - return NULL; - } - - /* libpng will longjmp here if it encounters an error from here on */ - if (setjmp(png_jmpbuf(png_ptr))) { - /* libpng error */ - if (row_pointers) free(row_pointers); - if (image) free(image); - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - return NULL; - } - - /* Associate the read struct with the file, and tell it we've already checked - 8 bytes of signature */ - png_init_io(png_ptr, file); - png_set_sig_bytes(png_ptr, 8); - - /* Read the PNG header into info struct */ - png_read_info(png_ptr, info_ptr); - - /* Get useful information from the info struct */ - 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); - - /* Update the info struct */ - png_read_update_info(png_ptr, info_ptr); - - /* Get bytes/image row */ - rowbytes = png_get_rowbytes(png_ptr, info_ptr); - - /* Allocate the temporary image buffer */ - image = malloc(rowbytes*height); - if (!image) { - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - return NULL; - } - - /* Allocate and set an array of pointers to rows in image */ - - row_pointers = malloc(sizeof(png_bytep)*height); - if (!row_pointers) { - free(image); - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - return NULL; - } - - for (y = 0; y < height; ++y) { - row_pointers[y] = image + y*rowbytes; - } - - /* Read the image to image all at once. At the expense of greater memory use, - this handles interlacing for us. */ - png_read_image(png_ptr, row_pointers); - - /* Allocate the canvas */ - 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 NULL; - } - - /* Now we convert the image to our canvas format. This depends on the image - bit depth (which has been scaled up to at least 8 or 16), and the presence - of an alpha channel. For performance reasons, the tests are outside the - loops, although that doesn't really matter for a decent compiler. */ - if (bit_depth == 16) { - if (color_type & PNG_COLOR_MASK_ALPHA) { - for (x = 0; x < width; ++x) { - for (y = 0; y < height; ++y) { - png_pixel = image + 8*(y*width + x); - - sRGB.R = ((double)((png_pixel[0] << UINT16_C(8)) + png_pixel[1])) - /UINT16_MAX; - sRGB.G = ((double)((png_pixel[2] << UINT16_C(8)) + png_pixel[3])) - /UINT16_MAX; - sRGB.B = ((double)((png_pixel[4] << UINT16_C(8)) + png_pixel[5])) - /UINT16_MAX; - - color = dmnsn_color_from_sRGB(sRGB); - color.trans = ((double)((png_pixel[6] << UINT16_C(8)) - + png_pixel[7]))/UINT16_MAX; - dmnsn_set_pixel(canvas, x, height - y - 1, color); - } - } - } else { - for (x = 0; x < width; ++x) { - for (y = 0; y < height; ++y) { - png_pixel = image + 6*(y*width + x); - - sRGB.R = ((double)((png_pixel[0] << UINT16_C(8)) + png_pixel[1])) - /UINT16_MAX; - sRGB.G = ((double)((png_pixel[2] << UINT16_C(8)) + png_pixel[3])) - /UINT16_MAX; - sRGB.B = ((double)((png_pixel[4] << UINT16_C(8)) + png_pixel[5])) - /UINT16_MAX; - - color = dmnsn_color_from_sRGB(sRGB); - dmnsn_set_pixel(canvas, x, height - y - 1, color); - } - } - } - } else { - /* Bit depth is 8 */ - if (color_type & PNG_COLOR_MASK_ALPHA) { - for (x = 0; x < width; ++x) { - for (y = 0; y < height; ++y) { - png_pixel = image + 4*(y*width + x); - - sRGB.R = ((double)png_pixel[0])/UINT8_MAX; - sRGB.G = ((double)png_pixel[1])/UINT8_MAX; - sRGB.B = ((double)png_pixel[2])/UINT8_MAX; - - color = dmnsn_color_from_sRGB(sRGB); - color.trans = ((double)png_pixel[3])/UINT8_MAX; - dmnsn_set_pixel(canvas, x, height - y - 1, color); - } - } - } else { - for (x = 0; x < width; ++x) { - for (y = 0; y < height; ++y) { - png_pixel = image + 3*(y*width + x); - - sRGB.R = ((double)png_pixel[0])/UINT8_MAX; - sRGB.G = ((double)png_pixel[1])/UINT8_MAX; - sRGB.B = ((double)png_pixel[2])/UINT8_MAX; - - color = dmnsn_color_from_sRGB(sRGB); - dmnsn_set_pixel(canvas, x, height - y - 1, color); - } - } - } - } - - free(row_pointers); - free(image); - png_read_end(png_ptr, NULL); - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - return canvas; -} |