Kristian Høgsberg
14 years ago
parent
d34912c4f9
commit
b41d76c151
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/*
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* Copyright © 2011 Intel Corporation |
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* |
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* Permission to use, copy, modify, distribute, and sell this software and |
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* its documentation for any purpose is hereby granted without fee, provided |
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* that the above copyright notice appear in all copies and that both that |
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* copyright notice and this permission notice appear in supporting |
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* documentation, and that the name of the copyright holders not be used in |
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* advertising or publicity pertaining to distribution of the software |
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* without specific, written prior permission. The copyright holders make |
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* no representations about the suitability of this software for any |
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* purpose. It is provided "as is" without express or implied warranty. |
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* |
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS |
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* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND |
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* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY |
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* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER |
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* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF |
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* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <stdint.h> |
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#include <errno.h> |
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#include <png.h> |
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#include "compositor.h" |
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static inline int |
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multiply_alpha(int alpha, int color) |
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{ |
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int temp = (alpha * color) + 0x80; |
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return ((temp + (temp >> 8)) >> 8); |
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} |
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static void |
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premultiply_data(png_structp png, |
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png_row_infop row_info, |
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png_bytep data) |
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{ |
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unsigned int i; |
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png_bytep p; |
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for (i = 0, p = data; i < row_info->rowbytes; i += 4, p += 4) { |
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png_byte alpha = p[3]; |
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uint32_t w; |
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if (alpha == 0) { |
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w = 0; |
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} else { |
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png_byte red = p[0]; |
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png_byte green = p[1]; |
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png_byte blue = p[2]; |
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if (alpha != 0xff) { |
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red = multiply_alpha(alpha, red); |
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green = multiply_alpha(alpha, green); |
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blue = multiply_alpha(alpha, blue); |
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} |
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w = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0); |
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} |
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* (uint32_t *) p = w; |
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} |
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} |
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static void |
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read_func(png_structp png, png_bytep data, png_size_t size) |
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{ |
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FILE *fp = png_get_io_ptr(png); |
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if (fread(data, 1, size, fp) < 0) |
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png_error(png, NULL); |
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} |
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uint32_t * |
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wlsc_load_image(const char *filename, |
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int32_t *width_arg, int32_t *height_arg, uint32_t *stride_arg) |
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{ |
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png_struct *png; |
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png_info *info; |
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png_byte *data; |
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png_byte **row_pointers = NULL; |
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png_uint_32 width, height; |
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int depth, color_type, interlace, stride; |
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unsigned int i; |
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FILE *fp; |
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fp = fopen(filename, "rb"); |
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if (fp == NULL) |
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return NULL; |
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png = png_create_read_struct(PNG_LIBPNG_VER_STRING, |
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NULL, NULL, NULL); |
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if (!png) { |
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fclose(fp); |
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return NULL; |
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} |
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info = png_create_info_struct(png); |
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if (!info) { |
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png_destroy_read_struct(&png, &info, NULL); |
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fclose(fp); |
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return NULL; |
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} |
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png_set_read_fn(png, fp, read_func); |
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png_read_info(png, info); |
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png_get_IHDR(png, info, |
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&width, &height, &depth, |
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&color_type, &interlace, NULL, NULL); |
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if (color_type == PNG_COLOR_TYPE_PALETTE) |
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png_set_palette_to_rgb(png); |
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if (color_type == PNG_COLOR_TYPE_GRAY) |
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png_set_expand_gray_1_2_4_to_8(png); |
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if (png_get_valid(png, info, PNG_INFO_tRNS)) |
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png_set_tRNS_to_alpha(png); |
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if (depth == 16) |
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png_set_strip_16(png); |
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if (depth < 8) |
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png_set_packing(png); |
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if (color_type == PNG_COLOR_TYPE_GRAY || |
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color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
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png_set_gray_to_rgb(png); |
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if (interlace != PNG_INTERLACE_NONE) |
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png_set_interlace_handling(png); |
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png_set_filler(png, 0xff, PNG_FILLER_AFTER); |
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png_set_read_user_transform_fn(png, premultiply_data); |
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png_read_update_info(png, info); |
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png_get_IHDR(png, info, |
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&width, &height, &depth, |
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&color_type, &interlace, NULL, NULL); |
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stride = width * 4; |
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data = malloc(stride * height); |
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if (!data) { |
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png_destroy_read_struct(&png, &info, NULL); |
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fclose(fp); |
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return NULL; |
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} |
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row_pointers = malloc(height * sizeof row_pointers[0]); |
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if (row_pointers == NULL) { |
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free(data); |
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png_destroy_read_struct(&png, &info, NULL); |
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fclose(fp); |
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return NULL; |
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} |
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for (i = 0; i < height; i++) |
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row_pointers[i] = &data[i * stride]; |
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png_read_image(png, row_pointers); |
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png_read_end(png, info); |
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free(row_pointers); |
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png_destroy_read_struct(&png, &info, NULL); |
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fclose(fp); |
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*width_arg = width; |
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*height_arg = height; |
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*stride_arg = stride; |
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return (uint32_t *) data; |
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} |
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