guacamole-spice-protocol/src/libguac/palette.c
2016-03-28 20:39:19 -07:00

135 lines
3.7 KiB
C

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#include "config.h"
#include "palette.h"
#include <cairo/cairo.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
guac_palette* guac_palette_alloc(cairo_surface_t* surface) {
int x, y;
int width = cairo_image_surface_get_width(surface);
int height = cairo_image_surface_get_height(surface);
int stride = cairo_image_surface_get_stride(surface);
unsigned char* data = cairo_image_surface_get_data(surface);
/* Allocate palette */
guac_palette* palette = (guac_palette*) malloc(sizeof(guac_palette));
memset(palette, 0, sizeof(guac_palette));
for (y=0; y<height; y++) {
for (x=0; x<width; x++) {
/* Get pixel color */
int color = ((uint32_t*) data)[x] & 0xFFFFFF;
/* Calculate hash code */
int hash = ((color & 0xFFF000) >> 12) ^ (color & 0xFFF);
guac_palette_entry* entry;
/* Search for open palette entry */
for (;;) {
entry = &(palette->entries[hash]);
/* If we've found a free space, use it */
if (entry->index == 0) {
png_color* c;
/* Stop if already at capacity */
if (palette->size == 256) {
guac_palette_free(palette);
return NULL;
}
/* Store in palette */
c = &(palette->colors[palette->size]);
c->blue = (color ) & 0xFF;
c->green = (color >> 8 ) & 0xFF;
c->red = (color >> 16) & 0xFF;
/* Add color to map */
entry->index = ++palette->size;
entry->color = color;
break;
}
/* Otherwise, if already stored here, done */
if (entry->color == color)
break;
/* Otherwise, collision. Move on to another bucket */
hash = (hash+1) & 0xFFF;
}
}
/* Advance to next data row */
data += stride;
}
return palette;
}
int guac_palette_find(guac_palette* palette, int color) {
/* Calculate hash code */
int hash = ((color & 0xFFF000) >> 12) ^ (color & 0xFFF);
guac_palette_entry* entry;
/* Search for palette entry */
for (;;) {
entry = &(palette->entries[hash]);
/* If we've found a free space, color not stored. */
if (entry->index == 0)
return -1;
/* Otherwise, if color indeed stored here, done */
if (entry->color == color)
return entry->index - 1;
/* Otherwise, collision. Move on to another bucket */
hash = (hash+1) & 0xFFF;
}
}
void guac_palette_free(guac_palette* palette) {
free(palette);
}