138 lines
4.0 KiB
C
138 lines
4.0 KiB
C
/*
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* Copyright (C) 2013 Glyptodon LLC
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "config.h"
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#include "palette.h"
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#include <cairo/cairo.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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guac_palette* guac_palette_alloc(cairo_surface_t* surface) {
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int x, y;
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int width = cairo_image_surface_get_width(surface);
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int height = cairo_image_surface_get_height(surface);
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int stride = cairo_image_surface_get_stride(surface);
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unsigned char* data = cairo_image_surface_get_data(surface);
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/* Allocate palette */
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guac_palette* palette = (guac_palette*) malloc(sizeof(guac_palette));
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memset(palette, 0, sizeof(guac_palette));
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for (y=0; y<height; y++) {
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for (x=0; x<width; x++) {
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/* Get pixel color */
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int color = ((uint32_t*) data)[x] & 0xFFFFFF;
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/* Calculate hash code */
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int hash = ((color & 0xFFF000) >> 12) ^ (color & 0xFFF);
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guac_palette_entry* entry;
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/* Search for open palette entry */
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for (;;) {
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entry = &(palette->entries[hash]);
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/* If we've found a free space, use it */
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if (entry->index == 0) {
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png_color* c;
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/* Stop if already at capacity */
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if (palette->size == 256) {
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guac_palette_free(palette);
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return NULL;
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}
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/* Store in palette */
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c = &(palette->colors[palette->size]);
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c->blue = (color ) & 0xFF;
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c->green = (color >> 8 ) & 0xFF;
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c->red = (color >> 16) & 0xFF;
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/* Add color to map */
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entry->index = ++palette->size;
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entry->color = color;
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break;
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}
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/* Otherwise, if already stored here, done */
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if (entry->color == color)
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break;
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/* Otherwise, collision. Move on to another bucket */
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hash = (hash+1) & 0xFFF;
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}
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}
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/* Advance to next data row */
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data += stride;
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}
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return palette;
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}
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int guac_palette_find(guac_palette* palette, int color) {
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/* Calculate hash code */
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int hash = ((color & 0xFFF000) >> 12) ^ (color & 0xFFF);
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guac_palette_entry* entry;
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/* Search for palette entry */
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for (;;) {
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entry = &(palette->entries[hash]);
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/* If we've found a free space, color not stored. */
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if (entry->index == 0)
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return -1;
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/* Otherwise, if color indeed stored here, done */
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if (entry->color == color)
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return entry->index - 1;
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/* Otherwise, collision. Move on to another bucket */
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hash = (hash+1) & 0xFFF;
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}
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}
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void guac_palette_free(guac_palette* palette) {
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free(palette);
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}
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