203 lines
6.4 KiB
C++
203 lines
6.4 KiB
C++
#include "global.h"
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#include "SDL.h"
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#include "SDL_utils.h"
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#undef FAR /* fix for VC */
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namespace jpeg
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{
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extern "C"
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{
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#include <jpeglib.h>
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}
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}
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#include "SDL_SaveJPEG.h"
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/* Pull in JPEG library here. */
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#ifdef _XBOX
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// FIXME
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#elif defined _WINDOWS
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#pragma comment(lib, "libjpeg/jpeg.lib")
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#endif
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#define OUTPUT_BUFFER_SIZE 4096
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typedef struct {
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struct jpeg::jpeg_destination_mgr pub;
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SDL_RWops *ctx;
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Uint8 buffer[OUTPUT_BUFFER_SIZE];
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} my_destination_mgr;
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/*
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* Initialize source --- called by jpeg_read_header
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* before any data is actually read.
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*/
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static void init_destination (jpeg::j_compress_ptr cinfo)
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{
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/* We don't actually need to do anything */
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return;
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}
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/*
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* Empty the output buffer --- called whenever buffer is full.
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*/
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static jpeg::boolean empty_output_buffer (jpeg::j_compress_ptr cinfo)
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{
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my_destination_mgr * dest = (my_destination_mgr *) cinfo->dest;
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int nbytes;
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nbytes = SDL_RWwrite(dest->ctx, dest->buffer, 1, OUTPUT_BUFFER_SIZE);
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dest->pub.next_output_byte = dest->buffer;
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dest->pub.free_in_buffer = OUTPUT_BUFFER_SIZE;
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return TRUE;
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}
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/*
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* Terminate source --- called by jpeg_finish_decompress
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* after all data has been read.
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*/
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static void term_destination (jpeg::j_compress_ptr cinfo)
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{
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/* Write data remaining in the buffer */
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my_destination_mgr * dest = (my_destination_mgr *) cinfo->dest;
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int nbytes;
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nbytes = SDL_RWwrite(dest->ctx, dest->buffer, 1, OUTPUT_BUFFER_SIZE - dest->pub.free_in_buffer);
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dest->pub.next_output_byte = dest->buffer;
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dest->pub.free_in_buffer = OUTPUT_BUFFER_SIZE;
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return;
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}
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/*
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* Prepare for output to a stdio stream.
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* The caller must have already opened the stream, and is responsible
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* for closing it after finishing decompression.
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*/
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static void jpeg_SDL_RW_dest(jpeg::j_compress_ptr cinfo, SDL_RWops *ctx)
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{
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my_destination_mgr *dest;
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/* The source object and input buffer are made permanent so that a series
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* of JPEG images can be read from the same file by calling jpeg_stdio_src
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* only before the first one. (If we discarded the buffer at the end of
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* one image, we'd likely lose the start of the next one.)
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* This makes it unsafe to use this manager and a different source
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* manager serially with the same JPEG object. Caveat programmer.
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*/
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if( cinfo->dest == NULL )
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{
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/* first time for this JPEG object? */
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cinfo->dest = (struct jpeg::jpeg_destination_mgr *)
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(*cinfo->mem->alloc_small) ((jpeg::j_common_ptr) cinfo, JPOOL_PERMANENT,
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sizeof(my_destination_mgr));
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dest = (my_destination_mgr *) cinfo->dest;
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}
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dest = (my_destination_mgr *) cinfo->dest;
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dest->pub.init_destination = init_destination;
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dest->pub.empty_output_buffer = empty_output_buffer;
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dest->pub.term_destination = term_destination;
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dest->ctx = ctx;
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dest->pub.free_in_buffer = OUTPUT_BUFFER_SIZE; /* forces fill_input_buffer on first read */
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dest->pub.next_output_byte = dest->buffer; /* until buffer loaded */
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}
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/* Save a JPEG to a file. cjpeg.c and example.c from jpeglib were helpful in writing this. */
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void IMG_SaveJPG_RW( SDL_Surface *surface, SDL_RWops *dest )
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{
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SDL_Surface *dst_surface;
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if( ConvertSDLSurface( surface, dst_surface,
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surface->w, surface->h, 24, mySDL_Swap24(0xFF0000), mySDL_Swap24(0x00FF00), mySDL_Swap24(0x0000FF), 0 ) )
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surface = dst_surface;
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struct jpeg::jpeg_compress_struct cinfo;
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/* Step 1: allocate and initialize JPEG compression object */
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/* We have to set up the error handler first, in case the initialization
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* step fails. (Unlikely, but it could happen if you are out of memory.)
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* This routine fills in the contents of struct jerr, and returns jerr's
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* address which we place into the link field in cinfo.
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*/
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struct jpeg::jpeg_error_mgr jerr;
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cinfo.err = jpeg::jpeg_std_error(&jerr);
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/* Now we can initialize the JPEG compression object. */
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jpeg::jpeg_CreateCompress(&cinfo, JPEG_LIB_VERSION, \
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(size_t) sizeof(struct jpeg::jpeg_compress_struct));
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/* Step 2: specify data destination (eg, a file) */
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/* Note: steps 2 and 3 can be done in either order. */
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/* Here we use the library-supplied code to send compressed data to a
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* stdio stream. You can also write your own code to do something else.
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* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
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* requires it in order to write binary files.
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*/
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jpeg_SDL_RW_dest(&cinfo, dest);
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/* Step 3: set parameters for compression */
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/* First we supply a description of the input image.
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* Four fields of the cinfo struct must be filled in:
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*/
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cinfo.image_width = surface->w; /* image width and height, in pixels */
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cinfo.image_height = surface->h;
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cinfo.input_components = 3; /* # of color components per pixel */
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cinfo.in_color_space = jpeg::JCS_RGB; /* colorspace of input image */
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/* Now use the library's routine to set default compression parameters.
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* (You must set at least cinfo.in_color_space before calling this,
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* since the defaults depend on the source color space.)
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*/
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jpeg::jpeg_set_defaults(&cinfo);
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/* Step 4: Start compressor */
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/* TRUE ensures that we will write a complete interchange-JPEG file.
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* Pass TRUE unless you are very sure of what you're doing.
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*/
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jpeg::jpeg_start_compress(&cinfo, TRUE);
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/* Step 5: while (scan lines remain to be written) */
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/* jpeg_write_scanlines(...); */
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/* Here we use the library's state variable cinfo.next_scanline as the
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* loop counter, so that we don't have to keep track ourselves.
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* To keep things simple, we pass one scanline per call; you can pass
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* more if you wish, though.
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*/
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const int row_stride = surface->pitch; /* JSAMPLEs per row in image_buffer */
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while( cinfo.next_scanline < cinfo.image_height )
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{
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/* jpeg_write_scanlines expects an array of pointers to scanlines.
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* Here the array is only one element long, but you could pass
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* more than one scanline at a time if that's more convenient.
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*/
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jpeg::JSAMPROW row_pointer = & ((jpeg::JSAMPLE*)surface->pixels)[cinfo.next_scanline * row_stride];
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jpeg::jpeg_write_scanlines(&cinfo, &row_pointer, 1);
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}
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/* Step 6: Finish compression */
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jpeg::jpeg_finish_compress(&cinfo);
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/* After finish_compress, we can close the output file. */
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/* Step 7: release JPEG compression object */
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/* This is an important step since it will release a good deal of memory. */
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jpeg::jpeg_destroy_compress(&cinfo);
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/* And we're done! */
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if( dst_surface )
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SDL_FreeSurface( dst_surface );
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}
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