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/*
* Copyright © 2011 Intel Corporation
*
* 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 copyright holders not be used in
* advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. The copyright holders make
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <png.h>
#include "compositor.h"
static inline int
multiply_alpha(int alpha, int color)
{
int temp = (alpha * color) + 0x80;
return ((temp + (temp >> 8)) >> 8);
}
static void
premultiply_data(png_structp png,
png_row_infop row_info,
png_bytep data)
{
unsigned int i;
png_bytep p;
for (i = 0, p = data; i < row_info->rowbytes; i += 4, p += 4) {
png_byte alpha = p[3];
uint32_t w;
if (alpha == 0) {
w = 0;
} else {
png_byte red = p[0];
png_byte green = p[1];
png_byte blue = p[2];
if (alpha != 0xff) {
red = multiply_alpha(alpha, red);
green = multiply_alpha(alpha, green);
blue = multiply_alpha(alpha, blue);
}
w = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
}
* (uint32_t *) p = w;
}
}
static void
read_func(png_structp png, png_bytep data, png_size_t size)
{
FILE *fp = png_get_io_ptr(png);
if (fread(data, 1, size, fp) < 0)
png_error(png, NULL);
}
WL_EXPORT uint32_t *
wlsc_load_image(const char *filename,
int32_t *width_arg, int32_t *height_arg, uint32_t *stride_arg)
{
png_struct *png;
png_info *info;
png_byte *data;
png_byte **row_pointers = NULL;
png_uint_32 width, height;
int depth, color_type, interlace, stride;
unsigned int i;
FILE *fp;
fp = fopen(filename, "rb");
if (fp == NULL)
return NULL;
png = png_create_read_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (!png) {
fclose(fp);
return NULL;
}
info = png_create_info_struct(png);
if (!info) {
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
return NULL;
}
png_set_read_fn(png, fp, read_func);
png_read_info(png, info);
png_get_IHDR(png, info,
&width, &height, &depth,
&color_type, &interlace, NULL, NULL);
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png);
if (color_type == PNG_COLOR_TYPE_GRAY)
png_set_expand_gray_1_2_4_to_8(png);
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);
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_filler(png, 0xff, PNG_FILLER_AFTER);
png_set_read_user_transform_fn(png, premultiply_data);
png_read_update_info(png, info);
png_get_IHDR(png, info,
&width, &height, &depth,
&color_type, &interlace, NULL, NULL);
stride = width * 4;
data = malloc(stride * height);
if (!data) {
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
return NULL;
}
row_pointers = malloc(height * sizeof row_pointers[0]);
if (row_pointers == NULL) {
free(data);
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
return NULL;
}
for (i = 0; i < height; i++)
row_pointers[i] = &data[i * stride];
png_read_image(png, row_pointers);
png_read_end(png, info);
free(row_pointers);
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
*width_arg = width;
*height_arg = height;
*stride_arg = stride;
return (uint32_t *) data;
}
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