135 lines
3.7 KiB
C
135 lines
3.7 KiB
C
/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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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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