#ifndef HAVE_WRITE_JPEG_H
#define HAVE_WRITE_JPEG_H
#ifndef WRITE_DATA_ERROR
# define WRITE_DATA_ERROR -1
#endif
#ifndef WRITE_DATA_OK
# define WRITE_DATA_OK 0
#endif
#ifndef MAX_JPG_COM_LENGTH
# define MAX_JPG_COM_LENGTH 65000L /* must be <= 65533 in any case */
#endif
/* Allow C++ Portability */
// #ifdef __cplusplus
extern "C" {
// #endif
/* write a JPEG file */
extern int write_jpg (const char *file_name, /* Name of file to be
written */
unsigned char *datap, /* pointer to
image data array */
int width, /*
Image width */
int height, /*
Image height */
int depth, /*
Image depth, valid values 1(mono), 3(RGB) */
char *keyword, /*
Keyword to use in COM chunk (may be NULL) */
char *description); /* String to
use in COM chunk (may be NULL) */
// return zero for success, -1 for error
/* NOTE: As a special case, setting quality to 0 just uses the default
settings */
extern void set_jpg_quality (int quality); /* Set image quality param (0
- 100) */
extern int get_jpg_quality (void); /* Read current quality setting */
/* Allow C++ Portability */
// #ifdef __cplusplus
}
// #endif
#endif /* HAVE_WRITE_JPEG_H */
#include <cstring>
using std::strlen;
#include <cstdlib>
using std::malloc;
using std::free;
#include <cstdio>
using std::fopen;
extern "C" {
#ifdef WIN32
#include <jpeg/jpeglib.h>
#else
#include <jpeglib.h>
#endif
}
#include "write_jpg.h"
/* Holds Global quality setting - accessed only by the accessor methods
provided */
static int quality = 0; /* Image quality param (0 - 100) (0 uses lib
defaults) */
/***********************************************************************/
void set_jpg_quality (int iv)
{
if (iv < 0) iv = 0;
else if (iv > 100) iv = 100;
quality = iv;
}
/********************************************************************************/
int get_jpg_quality (void)
{
return quality;
}
/********************************************************************************/
int write_jpg (const char *file_name, // Name of file to be written
unsigned char *datap, // pointer to
image data array
int width, //
Image width
int height, //
Image height
int depth, //
Image depth,valid values 1(mono), 3(RGB)
char *keyword, //
Keyword to use in COM chunk (may be NULL)
char *description) // String to
use in COM chunk (may be NULL)
{
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
FILE *outfile; /* target file */
JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */
int row_stride; /* physical row width in image
buffer */
char *com_block_txt; /* Used to hold any COM block we write
out */
/* Only handle RGB or Greyscale images for now */
if ((depth != 3) && (depth != 1))
{
return WRITE_DATA_ERROR;
}
com_block_txt = NULL;
/* Setup jpeg error handling */
cinfo.err = jpeg_std_error (&jerr);
/* Now we can initialise the JPEG compression object. */
jpeg_create_compress (&cinfo);
/* Open the output file */
if ((outfile = fopen (file_name, "wb")) == NULL)
{
//fprintf (stderr, "can't open %s\n", file_name);
return WRITE_DATA_ERROR;
}
jpeg_stdio_dest (&cinfo, outfile);
/* Setup compression parameters */
cinfo.image_width = width; /* image width and height, in
pixels */
cinfo.image_height = height;
cinfo.input_components = depth; /* number of bytes per pixel */
if (depth == 3)
{
cinfo.in_color_space = JCS_RGB; /* RGB input image */
}
else
{
cinfo.in_color_space = JCS_GRAYSCALE; /* Greyscale input image
*/
}
/* Now use the library routine to set default compression parameters. */
jpeg_set_defaults (&cinfo);
j_compress_ptr pI= &cinfo;
/* Do we want to override the default compression quality? */
if (quality > 10) jpeg_set_quality(pI, quality, TRUE);
/* Start compressor */
jpeg_start_compress (pI, 1);
/* Now we have started the compressor, do we have a COM chunk to write
out? */
if ((keyword != NULL) && (description != NULL))
{
unsigned int ulen = strlen(keyword) + strlen(description);
if ((ulen > 0) && (ulen < MAX_JPG_COM_LENGTH))
{
com_block_txt = (char*) malloc(ulen + 8);
sprintf(com_block_txt, "%s: %s", keyword, description);
jpeg_write_marker(&cinfo, JPEG_COM,
(JOCTET*)com_block_txt,
strlen(com_block_txt));
}
}
/* Cycle through the input data, writing out the image */
row_stride = width * depth; /* JSAMPLEs per row in image_buffer */
while (cinfo.next_scanline < cinfo.image_height)
{ /* For each data line... */
row_pointer[0] = &datap[cinfo.next_scanline * row_stride];
jpeg_write_scanlines (&cinfo, row_pointer, 1);
}
/* Finish compression */
jpeg_finish_compress (&cinfo);
/* Now close the output file. */
fclose (outfile);
/* Free the JPEG compression object and other allocated memory */
jpeg_destroy_compress (&cinfo);
if (com_block_txt) free(com_block_txt);
/* And we're done! */
return WRITE_DATA_OK;
}
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