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-rw-r--r--libdimension-png/png.c328
1 files changed, 0 insertions, 328 deletions
diff --git a/libdimension-png/png.c b/libdimension-png/png.c
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--- 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;
-}