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Diffstat (limited to 'test/read-png.c')
| -rw-r--r-- | test/read-png.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/test/read-png.c b/test/read-png.c new file mode 100644 index 000000000..23f91e831 --- /dev/null +++ b/test/read-png.c @@ -0,0 +1,166 @@ +/* + * Copyright © 2003 USC, Information Sciences Institute + * + * Permission to use, copy, modify, distribute, and sell this software + * and its documentation for any purpose is hereby granted without + * fee, provided that the above copyright notice appear in all copies + * and that both that copyright notice and this permission notice + * appear in supporting documentation, and that the name of the + * University of Southern California not be used in advertising or + * publicity pertaining to distribution of the software without + * specific, written prior permission. The University of Southern + * California makes no representations about the suitability of this + * software for any purpose. It is provided "as is" without express + * or implied warranty. + * + * THE UNIVERSITY OF SOUTHERN CALIFORNIA DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE UNIVERSITY OF + * SOUTHERN CALIFORNIA BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS + * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, + * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + * Author: Carl D. Worth <cworth@isi.edu> + */ + +#include <stdio.h> +#include <stdlib.h> +#include <png.h> + +#include "read_png.h" +#include "xmalloc.h" + +static void +premultiply_data (png_structp png, + png_row_infop row_info, + png_bytep data) +{ + int i; + + for (i = 0; i < row_info->rowbytes; i += 4) { + unsigned char *base = &data[i]; + unsigned char blue = base[0]; + unsigned char green = base[1]; + unsigned char red = base[2]; + unsigned char alpha = base[3]; + unsigned long p; + + red = (unsigned) red * (unsigned) alpha / 255; + green = (unsigned) green * (unsigned) alpha / 255; + blue = (unsigned) blue * (unsigned) alpha / 255; + p = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0); + memcpy (base, &p, sizeof (unsigned long)); + } +} + +read_png_status_t +read_png_argb32 (const char *filename, + unsigned char **data, + unsigned int *width, + unsigned int *height, + unsigned int *stride) +{ + int i; + FILE *file; + static const int PNG_SIG_SIZE = 8; + unsigned char png_sig[PNG_SIG_SIZE]; + int sig_bytes; + png_struct *png; + png_info *info; + png_uint_32 png_width, png_height; + int depth, color_type, interlace; + unsigned int pixel_size; + png_byte **row_pointers; + + file = fopen (filename, "rb"); + if (file == NULL) { + return READ_PNG_FILE_NOT_FOUND; + } + + sig_bytes = fread (png_sig, 1, PNG_SIG_SIZE, file); + if (png_check_sig (png_sig, sig_bytes) == 0) { + fclose (file); + return READ_PNG_FILE_NOT_PNG; + } + + /* XXX: Perhaps we'll want some other error handlers? */ + png = png_create_read_struct (PNG_LIBPNG_VER_STRING, + NULL, + NULL, + NULL); + if (png == NULL) { + fclose (file); + return READ_PNG_NO_MEMORY; + } + + info = png_create_info_struct (png); + if (info == NULL) { + fclose (file); + png_destroy_read_struct (&png, NULL, NULL); + return READ_PNG_NO_MEMORY; + } + + png_init_io (png, file); + png_set_sig_bytes (png, sig_bytes); + + png_read_info (png, info); + + png_get_IHDR (png, info, + &png_width, &png_height, &depth, + &color_type, &interlace, NULL, NULL); + *width = png_width; + *height = png_height; + *stride = 4 * png_width; + + + /* convert palette/gray image to rgb */ + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_palette_to_rgb (png); + + /* expand gray bit depth if needed */ + if (color_type == PNG_COLOR_TYPE_GRAY && depth < 8) + png_set_gray_1_2_4_to_8 (png); + /* transform transparency to alpha */ + if (png_get_valid(png, info, PNG_INFO_tRNS)) + png_set_tRNS_to_alpha (png); + + if (depth == 16) + png_set_strip_16 (png); + + if (depth < 8) + png_set_packing (png); + + /* convert grayscale to RGB */ + if (color_type == PNG_COLOR_TYPE_GRAY + || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_gray_to_rgb (png); + + if (interlace != PNG_INTERLACE_NONE) + png_set_interlace_handling (png); + + png_set_bgr (png); + png_set_filler (png, 0xff, PNG_FILLER_AFTER); + + png_set_read_user_transform_fn (png, premultiply_data); + + png_read_update_info (png, info); + + pixel_size = 4; + *data = xmalloc (png_width * png_height * pixel_size); + + row_pointers = malloc (png_height * sizeof(char *)); + for (i=0; i < png_height; i++) + row_pointers[i] = (png_byte *) (*data + i * png_width * pixel_size); + + png_read_image (png, row_pointers); + png_read_end (png, info); + + free (row_pointers); + fclose (file); + + png_destroy_read_struct (&png, &info, NULL); + + return READ_PNG_SUCCESS; +} |