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285 lines
7.5 KiB
C
285 lines
7.5 KiB
C
/*
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* The Python Imaging Library.
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* $Id$
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*
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* coder for JPEG data
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*
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* history:
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* 1996-05-06 fl created
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* 1996-07-16 fl don't drop last block of encoded data
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* 1996-12-30 fl added quality and progressive settings
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* 1997-01-08 fl added streamtype settings
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* 1998-01-31 fl adapted to libjpeg 6a
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* 1998-07-12 fl added YCbCr support
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* 2001-04-16 fl added DPI write support
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*
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* Copyright (c) 1997-2001 by Secret Labs AB
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* Copyright (c) 1995-1997 by Fredrik Lundh
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*
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* See the README file for details on usage and redistribution.
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*/
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#include "Imaging.h"
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#ifdef HAVE_LIBJPEG
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#undef HAVE_PROTOTYPES
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#undef HAVE_STDLIB_H
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#undef HAVE_STDDEF_H
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#undef UINT8
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#undef UINT16
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#undef UINT32
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#undef INT16
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#undef INT32
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#include "Jpeg.h"
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/* -------------------------------------------------------------------- */
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/* Suspending output handler */
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/* -------------------------------------------------------------------- */
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METHODDEF(void)
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stub(j_compress_ptr cinfo)
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{
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/* empty */
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}
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METHODDEF(boolean)
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empty_output_buffer (j_compress_ptr cinfo)
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{
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/* Suspension */
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return FALSE;
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}
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GLOBAL(void)
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jpeg_buffer_dest(j_compress_ptr cinfo, JPEGDESTINATION* destination)
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{
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cinfo->dest = (void*) destination;
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destination->pub.init_destination = stub;
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destination->pub.empty_output_buffer = empty_output_buffer;
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destination->pub.term_destination = stub;
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}
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/* -------------------------------------------------------------------- */
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/* Error handler */
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/* -------------------------------------------------------------------- */
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METHODDEF(void)
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error(j_common_ptr cinfo)
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{
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JPEGERROR* error;
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error = (JPEGERROR*) cinfo->err;
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(*cinfo->err->output_message) (cinfo);
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longjmp(error->setjmp_buffer, 1);
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}
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/* -------------------------------------------------------------------- */
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/* Encoder */
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/* -------------------------------------------------------------------- */
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int
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ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
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{
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JPEGENCODERSTATE* context = (JPEGENCODERSTATE*) state->context;
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int ok;
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if (setjmp(context->error.setjmp_buffer)) {
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/* JPEG error handler */
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jpeg_destroy_compress(&context->cinfo);
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state->errcode = IMAGING_CODEC_BROKEN;
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return -1;
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}
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if (!state->state) {
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/* Setup compression context (very similar to the decoder) */
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context->cinfo.err = jpeg_std_error(&context->error.pub);
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context->error.pub.error_exit = error;
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jpeg_create_compress(&context->cinfo);
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jpeg_buffer_dest(&context->cinfo, &context->destination);
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context->extra_offset = 0;
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/* Ready to encode */
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state->state = 1;
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}
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/* Load the destination buffer */
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context->destination.pub.next_output_byte = buf;
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context->destination.pub.free_in_buffer = bytes;
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switch (state->state) {
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case 1:
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context->cinfo.image_width = state->xsize;
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context->cinfo.image_height = state->ysize;
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switch (state->bits) {
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case 8:
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context->cinfo.input_components = 1;
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context->cinfo.in_color_space = JCS_GRAYSCALE;
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break;
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case 24:
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context->cinfo.input_components = 3;
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if (strcmp(im->mode, "YCbCr") == 0)
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context->cinfo.in_color_space = JCS_YCbCr;
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else
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context->cinfo.in_color_space = JCS_RGB;
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break;
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case 32:
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context->cinfo.input_components = 4;
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context->cinfo.in_color_space = JCS_CMYK;
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break;
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default:
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state->errcode = IMAGING_CODEC_CONFIG;
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return -1;
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}
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/* Compressor configuration */
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jpeg_set_defaults(&context->cinfo);
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if (context->quality > 0)
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jpeg_set_quality(&context->cinfo, context->quality, 1);
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/* Set subsampling options */
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switch (context->subsampling)
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{
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case 0: /* 1x1 1x1 1x1 (4:4:4) : None */
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{
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context->cinfo.comp_info[0].h_samp_factor = 1;
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context->cinfo.comp_info[0].v_samp_factor = 1;
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context->cinfo.comp_info[1].h_samp_factor = 1;
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context->cinfo.comp_info[1].v_samp_factor = 1;
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context->cinfo.comp_info[2].h_samp_factor = 1;
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context->cinfo.comp_info[2].v_samp_factor = 1;
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break;
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}
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case 1: /* 2x1, 1x1, 1x1 (4:2:2) : Medium */
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{
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context->cinfo.comp_info[0].h_samp_factor = 2;
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context->cinfo.comp_info[0].v_samp_factor = 1;
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context->cinfo.comp_info[1].h_samp_factor = 1;
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context->cinfo.comp_info[1].v_samp_factor = 1;
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context->cinfo.comp_info[2].h_samp_factor = 1;
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context->cinfo.comp_info[2].v_samp_factor = 1;
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break;
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}
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case 2: /* 2x2, 1x1, 1x1 (4:1:1) : High */
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{
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context->cinfo.comp_info[0].h_samp_factor = 2;
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context->cinfo.comp_info[0].v_samp_factor = 2;
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context->cinfo.comp_info[1].h_samp_factor = 1;
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context->cinfo.comp_info[1].v_samp_factor = 1;
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context->cinfo.comp_info[2].h_samp_factor = 1;
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context->cinfo.comp_info[2].v_samp_factor = 1;
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break;
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}
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default:
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{
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/* Use the lib's default */
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break;
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}
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}
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if (context->progressive)
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jpeg_simple_progression(&context->cinfo);
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context->cinfo.smoothing_factor = context->smooth;
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context->cinfo.optimize_coding = (boolean) context->optimize;
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if (context->xdpi > 0 && context->ydpi > 0) {
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context->cinfo.density_unit = 1; /* dots per inch */
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context->cinfo.X_density = context->xdpi;
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context->cinfo.Y_density = context->ydpi;
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}
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switch (context->streamtype) {
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case 1:
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/* tables only -- not yet implemented */
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state->errcode = IMAGING_CODEC_CONFIG;
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return -1;
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case 2:
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/* image only */
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jpeg_suppress_tables(&context->cinfo, TRUE);
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jpeg_start_compress(&context->cinfo, FALSE);
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/* suppress extra section */
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context->extra_offset = context->extra_size;
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break;
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default:
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/* interchange stream */
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jpeg_start_compress(&context->cinfo, TRUE);
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break;
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}
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state->state++;
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/* fall through */
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case 2:
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if (context->extra) {
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/* copy extra buffer to output buffer */
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unsigned int n = context->extra_size - context->extra_offset;
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if (n > context->destination.pub.free_in_buffer)
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n = context->destination.pub.free_in_buffer;
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memcpy(context->destination.pub.next_output_byte,
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context->extra + context->extra_offset, n);
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context->destination.pub.next_output_byte += n;
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context->destination.pub.free_in_buffer -= n;
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context->extra_offset += n;
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if (context->extra_offset >= context->extra_size)
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state->state++;
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else
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break;
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} else
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state->state++;
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case 3:
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ok = 1;
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while (state->y < state->ysize) {
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state->shuffle(state->buffer,
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(UINT8*) im->image[state->y + state->yoff] +
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state->xoff * im->pixelsize, state->xsize);
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ok = jpeg_write_scanlines(&context->cinfo, &state->buffer, 1);
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if (ok != 1)
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break;
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state->y++;
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}
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if (ok != 1)
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break;
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state->state++;
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/* fall through */
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case 4:
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/* Finish compression */
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if (context->destination.pub.free_in_buffer < 100)
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break;
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jpeg_finish_compress(&context->cinfo);
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/* Clean up */
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if (context->extra)
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free(context->extra);
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jpeg_destroy_compress(&context->cinfo);
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/* if (jerr.pub.num_warnings) return BROKEN; */
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state->errcode = IMAGING_CODEC_END;
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break;
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}
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/* Return number of bytes in output buffer */
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return context->destination.pub.next_output_byte - buf;
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}
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const char*
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ImagingJpegVersion(void)
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{
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static char version[20];
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sprintf(version, "%d.%d", JPEG_LIB_VERSION / 10, JPEG_LIB_VERSION % 10);
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return version;
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}
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#endif
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