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/*
* The Python Imaging Library.
* $Id: JpegEncode.c 2134 2004-10-06 08:55:20Z fredrik $
*
* coder for JPEG data
*
* history:
* 1996-05-06 fl created
* 1996-07-16 fl don't drop last block of encoded data
* 1996-12-30 fl added quality and progressive settings
* 1997-01-08 fl added streamtype settings
* 1998-01-31 fl adapted to libjpeg 6a
* 1998-07-12 fl added YCbCr support
* 2001-04-16 fl added DPI write support
*
* Copyright (c) 1997-2001 by Secret Labs AB
* Copyright (c) 1995-1997 by Fredrik Lundh
*
* See the README file for details on usage and redistribution.
*/
#include "Imaging.h"
#ifdef HAVE_LIBJPEG
#undef HAVE_PROTOTYPES
#undef HAVE_STDLIB_H
#undef HAVE_STDDEF_H
#undef UINT8
#undef UINT16
#undef UINT32
#undef INT16
#undef INT32
#include "Jpeg.h"
/* -------------------------------------------------------------------- */
/* Suspending output handler */
/* -------------------------------------------------------------------- */
METHODDEF(void)
stub(j_compress_ptr cinfo)
{
/* empty */
}
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
/* Suspension */
return FALSE;
}
GLOBAL(void)
jpeg_buffer_dest(j_compress_ptr cinfo, JPEGDESTINATION* destination)
{
cinfo->dest = (void*) destination;
destination->pub.init_destination = stub;
destination->pub.empty_output_buffer = empty_output_buffer;
destination->pub.term_destination = stub;
}
/* -------------------------------------------------------------------- */
/* Error handler */
/* -------------------------------------------------------------------- */
METHODDEF(void)
error(j_common_ptr cinfo)
{
JPEGERROR* error;
error = (JPEGERROR*) cinfo->err;
(*cinfo->err->output_message) (cinfo);
longjmp(error->setjmp_buffer, 1);
}
/* -------------------------------------------------------------------- */
/* Encoder */
/* -------------------------------------------------------------------- */
int
ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
JPEGENCODERSTATE* context = (JPEGENCODERSTATE*) state->context;
int ok;
if (setjmp(context->error.setjmp_buffer)) {
/* JPEG error handler */
jpeg_destroy_compress(&context->cinfo);
state->errcode = IMAGING_CODEC_BROKEN;
return -1;
}
if (!state->state) {
/* Setup compression context (very similar to the decoder) */
context->cinfo.err = jpeg_std_error(&context->error.pub);
context->error.pub.error_exit = error;
jpeg_create_compress(&context->cinfo);
jpeg_buffer_dest(&context->cinfo, &context->destination);
/* Ready to encode */
state->state = 1;
}
/* Load the destination buffer */
context->destination.pub.next_output_byte = buf;
context->destination.pub.free_in_buffer = bytes;
switch (state->state) {
case 1:
context->cinfo.image_width = state->xsize;
context->cinfo.image_height = state->ysize;
switch (state->bits) {
case 8:
context->cinfo.input_components = 1;
context->cinfo.in_color_space = JCS_GRAYSCALE;
break;
case 24:
context->cinfo.input_components = 3;
if (strcmp(im->mode, "YCbCr") == 0)
context->cinfo.in_color_space = JCS_YCbCr;
else
context->cinfo.in_color_space = JCS_RGB;
break;
case 32:
context->cinfo.input_components = 4;
context->cinfo.in_color_space = JCS_CMYK;
break;
default:
state->errcode = IMAGING_CODEC_CONFIG;
return -1;
}
/* Compressor configuration */
jpeg_set_defaults(&context->cinfo);
if (context->quality > 0)
jpeg_set_quality(&context->cinfo, context->quality, 1);
if (context->progressive)
jpeg_simple_progression(&context->cinfo);
context->cinfo.smoothing_factor = context->smooth;
context->cinfo.optimize_coding = (boolean) context->optimize;
if (context->xdpi > 0 && context->ydpi > 0) {
context->cinfo.density_unit = 1; /* dots per inch */
context->cinfo.X_density = context->xdpi;
context->cinfo.Y_density = context->ydpi;
}
switch (context->streamtype) {
case 1:
/* tables only -- not yet implemented */
state->errcode = IMAGING_CODEC_CONFIG;
return -1;
case 2:
/* image only */
jpeg_suppress_tables(&context->cinfo, TRUE);
jpeg_start_compress(&context->cinfo, FALSE);
break;
default:
/* interchange stream */
jpeg_start_compress(&context->cinfo, TRUE);
break;
}
state->state++;
/* fall through */
case 2:
ok = 1;
while (state->y < state->ysize) {
state->shuffle(state->buffer,
(UINT8*) im->image[state->y + state->yoff] +
state->xoff * im->pixelsize, state->xsize);
ok = jpeg_write_scanlines(&context->cinfo, &state->buffer, 1);
if (ok != 1)
break;
state->y++;
}
if (ok != 1)
break;
state->state++;
/* fall through */
case 3:
/* Finish compression */
if (context->destination.pub.free_in_buffer < 100)
break;
jpeg_finish_compress(&context->cinfo);
/* Clean up */
jpeg_destroy_compress(&context->cinfo);
/* if (jerr.pub.num_warnings) return BROKEN; */
state->errcode = IMAGING_CODEC_END;
break;
}
/* Return number of bytes in output buffer */
return context->destination.pub.next_output_byte - buf;
}
#endif
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