gecko-dev/lib/libcnv/writejpg.c
1998-03-28 02:44:41 +00:00

123 lines
4.3 KiB
C

/*
* Copyright (C) 1994-1995, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
* This code was taken from an example file.
*
*/
#include "xp_core.h" //used to make library compile faster on win32 do not ifdef this or it wont work
/*writejpg.c jpeg compression wrapper for jpeg compression utilities*/
#include <stdio.h>
#include <setjmp.h>/*for error handler*/
#include "xp_core.h"/*defines of int32 ect*/
#include "ntypes.h" /* for MWContext to include libcnv.h*/
#include "libcnv.h"
#include "writejpg.h"
#include "..\jpeg\jinclude.h"
#include "..\jpeg\jpeglib.h"
//#include "jerror.h" /* get library error codes too */
/* incomming data= (RGB,RGB,RGB)*/
struct my_error_mgr {
struct jpeg_error_mgr pub; /* "public" fields */
jmp_buf setjmp_buffer; /* for return to caller */ /*must include setjmp*/
};
typedef struct my_error_mgr * my_error_ptr;
/*
* Here's the routine that will replace the standard error_exit method:
*/
void
my_error_exit (j_common_ptr cinfo)
{
/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
my_error_ptr myerr = (my_error_ptr) cinfo->err;
/* Always display the message. */
/* We could postpone this until after returning, if we chose. */
(*cinfo->err->output_message) (cinfo);
/* Return control to the setjmp point */
longjmp(myerr->setjmp_buffer, 1);
}
/*given an array of pixels, writes a jpeg file*/
CONVERT_IMAGERESULT
write_JPEG_file (CONVERT_IMG_ARRAY p_rowarray,CONVERT_IMGCONTEXT *output,CONVERT_IMG_INFO *p_imageinfo,CONVERT_CALLBACKS p_callbacks)
{
struct jpeg_compress_struct cinfo;
struct my_error_mgr jerr;
int16 row_stride; /* physical row width in image buffer */
cinfo.err = jpeg_std_error((struct jpeg_error_mgr *)&jerr);
jerr.pub.error_exit = my_error_exit;
jerr.pub.output_message=p_callbacks.m_displaybuffercallback;
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp(jerr.setjmp_buffer)) {
/* If we get here, the JPEG code has signaled an error.
* We need to clean up the JPEG object, close the input file, and return.
*/
jpeg_close_file(&cinfo);
jpeg_destroy_compress(&cinfo);
return CONVERR_JPEGERROR;
}
/* Now we can initialize the JPEG compression object. */
jpeg_create_compress(&cinfo);
/* Here we use the library-supplied code to send compressed data to a
* stdio stream.*/
jpeg_file_dest(&cinfo, output->m_filename);
cinfo.image_width = p_imageinfo->m_image_width; /* image width and height, in pixels */
cinfo.image_height = p_imageinfo->m_image_height;
cinfo.input_components = 3; /* # of color components per pixel */
cinfo.in_color_space = JCS_RGB; /* colorspace of input image */
/* Now use the library's routine to set default compression parameters.
* (You must set at least cinfo.in_color_space before calling this,
* since the defaults depend on the source color space.)
*/
jpeg_set_defaults(&cinfo);
/* Now you can set any non-default parameters you wish to.
* Here we just illustrate the use of quality (quantization table) scaling:
*/
jpeg_set_quality(&cinfo, output->m_quality, TRUE /* limit to baseline-JPEG values */);
/* Step 4: Start compressor */
/* TRUE ensures that we will write a complete interchange-JPEG file.
* Pass TRUE unless you are very sure of what you're doing.
*/
jpeg_start_compress(&cinfo, TRUE);
/* Step 5: while (scan lines remain to be written) */
/* jpeg_write_scanlines(...); */
/* Here we use the library's state variable cinfo.next_scanline as the
* loop counter, so that we don't have to keep track ourselves.
* To keep things simple, we pass one scanline per call; you can pass
* more if you wish, though.
*/
row_stride = p_imageinfo->m_image_width * 3; /* JSAMPLEs per row in image_buffer */
while (cinfo.next_scanline < cinfo.image_height)
(void) jpeg_write_scanlines(&cinfo, (JSAMPARRAY)p_rowarray, cinfo.image_height);
/* Step 6: Finish compression */
jpeg_finish_compress(&cinfo);
/* Step 7: release JPEG compression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_compress(&cinfo);
return CONV_OK;
}