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/******************************************************************************
* $Id$
*
* Project: MapServer
* Purpose: MapCache tile caching support file: high level image format I/O
* Author: Thomas Bonfort and the MapServer team.
*
******************************************************************************
* Copyright (c) 1996-2011 Regents of the University of Minnesota.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies of this Software or works derived from this Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#include "mapcache.h"
#include <png.h>
#include <jpeglib.h>
/**\addtogroup imageio*/
/** @{ */
int mapcache_imageio_is_valid_format(mapcache_context *ctx, mapcache_buffer *buffer)
{
mapcache_image_format_type t = mapcache_imageio_header_sniff(ctx,buffer);
if(t==GC_PNG || t==GC_JPEG) {
return MAPCACHE_TRUE;
} else {
return MAPCACHE_FALSE;
}
}
mapcache_image_format_type mapcache_imageio_header_sniff(mapcache_context *ctx, mapcache_buffer *buffer)
{
if(!buffer) {
return GC_UNKNOWN;
}
if(buffer->size >= 8 && png_sig_cmp((png_bytep)buffer->buf, 0, 8) == 0) {
return GC_PNG;
} else if(buffer->size >= 2 && ((unsigned char*)buffer->buf)[0] == 0xFF && ((unsigned char*)buffer->buf)[1] == 0xD8) {
return GC_JPEG;
} else {
return GC_UNKNOWN;
}
}
mapcache_image_alpha_type mapcache_imageio_alpha_sniff(mapcache_context *ctx, mapcache_buffer *buffer)
{
const unsigned char * b = buffer->buf;
mapcache_image_format_type t = mapcache_imageio_header_sniff(ctx,buffer);
mapcache_image_alpha_type alpha_type;
switch (t) {
case GC_JPEG:
// JPEG files are opaque
alpha_type = MC_ALPHA_NO;
break;
case GC_PNG:
if (buffer->size >= 26) {
// Check color type of PNG file in IHDR chunk
if ( (b[12]|32)=='i' && (b[13]|32)=='h' && (b[14]|32)=='d' && (b[15]|32)=='r' ) {
switch (b[25]) {
case 4:
case 6:
// Gray or RGB with alpha
alpha_type = MC_ALPHA_YES;
break;
default:
// Other colortypes have no alpha channel
alpha_type = MC_ALPHA_NO;
}
}
} else {
alpha_type = MC_ALPHA_UNKNOWN;
}
break;
default:
alpha_type = MC_ALPHA_UNKNOWN;
break;
}
return alpha_type;
}
mapcache_image* mapcache_imageio_decode(mapcache_context *ctx, mapcache_buffer *buffer)
{
mapcache_image_format_type type = mapcache_imageio_header_sniff(ctx,buffer);
if(type == GC_PNG) {
return _mapcache_imageio_png_decode(ctx,buffer);
} else if(type == GC_JPEG) {
return _mapcache_imageio_jpeg_decode(ctx,buffer);
} else {
ctx->set_error(ctx, 500, "mapcache_imageio_decode: unrecognized image format");
return NULL;
}
}
void mapcache_image_create_empty(mapcache_context *ctx, mapcache_cfg *cfg)
{
unsigned int color=0;
/* create a transparent image for PNG, and a white one for jpeg */
if(cfg->default_image_format->mime_type && !strstr(cfg->default_image_format->mime_type,"png")) {
color = 0xffffffff;
}
cfg->empty_image = cfg->default_image_format->create_empty_image(ctx, cfg->default_image_format,
256,256, color);
GC_CHECK_ERROR(ctx);
}
void mapcache_imageio_decode_to_image(mapcache_context *ctx, mapcache_buffer *buffer,
mapcache_image *image)
{
mapcache_image_format_type type = mapcache_imageio_header_sniff(ctx,buffer);
if(type == GC_PNG) {
_mapcache_imageio_png_decode_to_image(ctx,buffer,image);
} else if(type == GC_JPEG) {
_mapcache_imageio_jpeg_decode_to_image(ctx,buffer,image);
} else {
ctx->set_error(ctx, 500, "mapcache_imageio_decode: unrecognized image format");
}
return;
}
/** @} */
/* vim: ts=2 sts=2 et sw=2
*/
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