mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-15 19:33:59 +03:00
3cf7852e03
git-svn-id: svn://kolibrios.org@5131 a494cfbc-eb01-0410-851d-a64ba20cac60
243 lines
6.9 KiB
C
243 lines
6.9 KiB
C
/*
|
|
IMGLIB: An example image loading library for use with SDL
|
|
Copyright (C) 1999 Sam Lantinga
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2 of the License, or (at your option) any later version.
|
|
|
|
This library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with this library; if not, write to the Free
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
Sam Lantinga
|
|
5635-34 Springhouse Dr.
|
|
Pleasanton, CA 94588 (USA)
|
|
slouken@devolution.com
|
|
*/
|
|
|
|
/* This is a JPEG image file loading framework */
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "SDL_image.h"
|
|
|
|
#ifdef LOAD_JPG
|
|
|
|
#include <jpeglib.h>
|
|
|
|
/* Define this for fast loading and not as good image quality */
|
|
/*#define FAST_JPEG*/
|
|
|
|
/* See if an image is contained in a data source */
|
|
int IMG_isJPG(SDL_RWops *src)
|
|
{
|
|
int is_JPG;
|
|
Uint8 magic[4];
|
|
|
|
is_JPG = 0;
|
|
if ( SDL_RWread(src, magic, 2, 1) ) {
|
|
if ( (magic[0] == 0xFF) && (magic[1] == 0xD8) ) {
|
|
SDL_RWread(src, magic, 4, 1);
|
|
SDL_RWread(src, magic, 4, 1);
|
|
if ( memcmp((char *)magic, "JFIF", 4) == 0 ) {
|
|
is_JPG = 1;
|
|
}
|
|
}
|
|
}
|
|
return(is_JPG);
|
|
}
|
|
|
|
#define INPUT_BUFFER_SIZE 4096
|
|
typedef struct {
|
|
struct jpeg_source_mgr pub;
|
|
|
|
SDL_RWops *ctx;
|
|
Uint8 buffer[INPUT_BUFFER_SIZE];
|
|
} my_source_mgr;
|
|
|
|
/*
|
|
* Initialize source --- called by jpeg_read_header
|
|
* before any data is actually read.
|
|
*/
|
|
static void init_source (j_decompress_ptr cinfo)
|
|
{
|
|
/* We don't actually need to do anything */
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Fill the input buffer --- called whenever buffer is emptied.
|
|
*/
|
|
static int fill_input_buffer (j_decompress_ptr cinfo)
|
|
{
|
|
my_source_mgr * src = (my_source_mgr *) cinfo->src;
|
|
int nbytes;
|
|
|
|
nbytes = SDL_RWread(src->ctx, src->buffer, 1, INPUT_BUFFER_SIZE);
|
|
if (nbytes <= 0) {
|
|
/* Insert a fake EOI marker */
|
|
src->buffer[0] = (Uint8) 0xFF;
|
|
src->buffer[1] = (Uint8) JPEG_EOI;
|
|
nbytes = 2;
|
|
}
|
|
src->pub.next_input_byte = src->buffer;
|
|
src->pub.bytes_in_buffer = nbytes;
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/*
|
|
* Skip data --- used to skip over a potentially large amount of
|
|
* uninteresting data (such as an APPn marker).
|
|
*
|
|
* Writers of suspendable-input applications must note that skip_input_data
|
|
* is not granted the right to give a suspension return. If the skip extends
|
|
* beyond the data currently in the buffer, the buffer can be marked empty so
|
|
* that the next read will cause a fill_input_buffer call that can suspend.
|
|
* Arranging for additional bytes to be discarded before reloading the input
|
|
* buffer is the application writer's problem.
|
|
*/
|
|
static void skip_input_data (j_decompress_ptr cinfo, long num_bytes)
|
|
{
|
|
my_source_mgr * src = (my_source_mgr *) cinfo->src;
|
|
|
|
/* Just a dumb implementation for now. Could use fseek() except
|
|
* it doesn't work on pipes. Not clear that being smart is worth
|
|
* any trouble anyway --- large skips are infrequent.
|
|
*/
|
|
if (num_bytes > 0) {
|
|
while (num_bytes > (long) src->pub.bytes_in_buffer) {
|
|
num_bytes -= (long) src->pub.bytes_in_buffer;
|
|
(void) src->pub.fill_input_buffer(cinfo);
|
|
/* note we assume that fill_input_buffer will never
|
|
* return FALSE, so suspension need not be handled.
|
|
*/
|
|
}
|
|
src->pub.next_input_byte += (size_t) num_bytes;
|
|
src->pub.bytes_in_buffer -= (size_t) num_bytes;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Terminate source --- called by jpeg_finish_decompress
|
|
* after all data has been read.
|
|
*/
|
|
static void term_source (j_decompress_ptr cinfo)
|
|
{
|
|
/* We don't actually need to do anything */
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Prepare for input from a stdio stream.
|
|
* The caller must have already opened the stream, and is responsible
|
|
* for closing it after finishing decompression.
|
|
*/
|
|
static void jpeg_SDL_RW_src (j_decompress_ptr cinfo, SDL_RWops *ctx)
|
|
{
|
|
my_source_mgr *src;
|
|
|
|
/* The source object and input buffer are made permanent so that a series
|
|
* of JPEG images can be read from the same file by calling jpeg_stdio_src
|
|
* only before the first one. (If we discarded the buffer at the end of
|
|
* one image, we'd likely lose the start of the next one.)
|
|
* This makes it unsafe to use this manager and a different source
|
|
* manager serially with the same JPEG object. Caveat programmer.
|
|
*/
|
|
if (cinfo->src == NULL) { /* first time for this JPEG object? */
|
|
cinfo->src = (struct jpeg_source_mgr *)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
|
|
sizeof(my_source_mgr));
|
|
src = (my_source_mgr *) cinfo->src;
|
|
}
|
|
|
|
src = (my_source_mgr *) cinfo->src;
|
|
src->pub.init_source = init_source;
|
|
src->pub.fill_input_buffer = fill_input_buffer;
|
|
src->pub.skip_input_data = skip_input_data;
|
|
src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
|
|
src->pub.term_source = term_source;
|
|
src->ctx = ctx;
|
|
src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
|
|
src->pub.next_input_byte = NULL; /* until buffer loaded */
|
|
}
|
|
|
|
/* Load a JPEG type image from an SDL datasource */
|
|
SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
|
|
{
|
|
struct jpeg_error_mgr errmgr;
|
|
struct jpeg_decompress_struct cinfo;
|
|
JSAMPROW rowptr[1];
|
|
SDL_Surface *surface;
|
|
|
|
/* Create a decompression structure and load the JPEG header */
|
|
cinfo.err = jpeg_std_error(&errmgr);
|
|
jpeg_create_decompress(&cinfo);
|
|
jpeg_SDL_RW_src(&cinfo, src);
|
|
jpeg_read_header(&cinfo, TRUE);
|
|
|
|
/* Set 24-bit RGB output */
|
|
cinfo.out_color_space = JCS_RGB;
|
|
cinfo.quantize_colors = FALSE;
|
|
#ifdef FAST_JPEG
|
|
cinfo.scale_num = 1;
|
|
cinfo.scale_denom = 1;
|
|
cinfo.dct_method = JDCT_FASTEST;
|
|
cinfo.do_fancy_upsampling = FALSE;
|
|
#endif
|
|
jpeg_calc_output_dimensions(&cinfo);
|
|
|
|
/* Allocate an output surface to hold the image */
|
|
surface = SDL_AllocSurface(SDL_SWSURFACE,
|
|
cinfo.output_width, cinfo.output_height, 24,
|
|
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
|
|
0x0000FF, 0x00FF00, 0xFF0000,
|
|
#else
|
|
0xFF0000, 0x00FF00, 0x0000FF,
|
|
#endif
|
|
0);
|
|
if ( surface == NULL ) {
|
|
IMG_SetError("Out of memory");
|
|
goto done;
|
|
}
|
|
|
|
/* Decompress the image */
|
|
jpeg_start_decompress(&cinfo);
|
|
while ( cinfo.output_scanline < cinfo.output_height ) {
|
|
rowptr[0] = (JSAMPROW)(Uint8 *)surface->pixels +
|
|
cinfo.output_scanline * surface->pitch;
|
|
jpeg_read_scanlines(&cinfo, rowptr, (JDIMENSION) 1);
|
|
}
|
|
jpeg_finish_decompress(&cinfo);
|
|
|
|
/* Clean up and return */
|
|
done:
|
|
jpeg_destroy_decompress(&cinfo);
|
|
return(surface);
|
|
}
|
|
|
|
#else
|
|
|
|
/* See if an image is contained in a data source */
|
|
int IMG_isJPG(SDL_RWops *src)
|
|
{
|
|
return(0);
|
|
}
|
|
|
|
/* Load a JPEG type image from an SDL datasource */
|
|
SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
|
|
{
|
|
return(NULL);
|
|
}
|
|
|
|
#endif /* LOAD_JPG */
|