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253 lines
7.3 KiB
253 lines
7.3 KiB
/* |
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* wrtarga.c |
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* |
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* Copyright (C) 1991-1996, Thomas G. Lane. |
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* This file is part of the Independent JPEG Group's software. |
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* For conditions of distribution and use, see the accompanying README file. |
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* |
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* This file contains routines to write output images in Targa format. |
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* |
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* These routines may need modification for non-Unix environments or |
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* specialized applications. As they stand, they assume output to |
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* an ordinary stdio stream. |
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* |
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* Based on code contributed by Lee Daniel Crocker. |
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*/ |
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#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */ |
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#ifdef TARGA_SUPPORTED |
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/* |
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* To support 12-bit JPEG data, we'd have to scale output down to 8 bits. |
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* This is not yet implemented. |
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*/ |
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#if BITS_IN_JSAMPLE != 8 |
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Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */ |
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#endif |
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/* |
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* The output buffer needs to be writable by fwrite(). On PCs, we must |
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* allocate the buffer in near data space, because we are assuming small-data |
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* memory model, wherein fwrite() can't reach far memory. If you need to |
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* process very wide images on a PC, you might have to compile in large-memory |
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* model, or else replace fwrite() with a putc() loop --- which will be much |
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* slower. |
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*/ |
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/* Private version of data destination object */ |
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typedef struct { |
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struct djpeg_dest_struct pub; /* public fields */ |
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char *iobuffer; /* physical I/O buffer */ |
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JDIMENSION buffer_width; /* width of one row */ |
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} tga_dest_struct; |
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typedef tga_dest_struct * tga_dest_ptr; |
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LOCAL(void) |
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write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors) |
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/* Create and write a Targa header */ |
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{ |
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char targaheader[18]; |
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/* Set unused fields of header to 0 */ |
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MEMZERO(targaheader, SIZEOF(targaheader)); |
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if (num_colors > 0) { |
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targaheader[1] = 1; /* color map type 1 */ |
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targaheader[5] = (char) (num_colors & 0xFF); |
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targaheader[6] = (char) (num_colors >> 8); |
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targaheader[7] = 24; /* 24 bits per cmap entry */ |
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} |
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targaheader[12] = (char) (cinfo->output_width & 0xFF); |
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targaheader[13] = (char) (cinfo->output_width >> 8); |
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targaheader[14] = (char) (cinfo->output_height & 0xFF); |
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targaheader[15] = (char) (cinfo->output_height >> 8); |
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targaheader[17] = 0x20; /* Top-down, non-interlaced */ |
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if (cinfo->out_color_space == JCS_GRAYSCALE) { |
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targaheader[2] = 3; /* image type = uncompressed gray-scale */ |
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targaheader[16] = 8; /* bits per pixel */ |
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} else { /* must be RGB */ |
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if (num_colors > 0) { |
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targaheader[2] = 1; /* image type = colormapped RGB */ |
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targaheader[16] = 8; |
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} else { |
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targaheader[2] = 2; /* image type = uncompressed RGB */ |
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targaheader[16] = 24; |
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} |
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} |
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if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18) |
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ERREXIT(cinfo, JERR_FILE_WRITE); |
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} |
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/* |
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* Write some pixel data. |
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* In this module rows_supplied will always be 1. |
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*/ |
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METHODDEF(void) |
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put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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JDIMENSION rows_supplied) |
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/* used for unquantized full-color output */ |
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{ |
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tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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register JSAMPROW inptr; |
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register char * outptr; |
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register JDIMENSION col; |
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inptr = dest->pub.buffer[0]; |
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outptr = dest->iobuffer; |
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for (col = cinfo->output_width; col > 0; col--) { |
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outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */ |
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outptr[1] = (char) GETJSAMPLE(inptr[1]); |
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outptr[2] = (char) GETJSAMPLE(inptr[0]); |
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inptr += 3, outptr += 3; |
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} |
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(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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} |
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METHODDEF(void) |
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put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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JDIMENSION rows_supplied) |
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/* used for grayscale OR quantized color output */ |
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{ |
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tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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register JSAMPROW inptr; |
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register char * outptr; |
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register JDIMENSION col; |
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inptr = dest->pub.buffer[0]; |
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outptr = dest->iobuffer; |
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for (col = cinfo->output_width; col > 0; col--) { |
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*outptr++ = (char) GETJSAMPLE(*inptr++); |
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} |
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(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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} |
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/* |
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* Write some demapped pixel data when color quantization is in effect. |
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* For Targa, this is only applied to grayscale data. |
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*/ |
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METHODDEF(void) |
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put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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JDIMENSION rows_supplied) |
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{ |
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tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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register JSAMPROW inptr; |
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register char * outptr; |
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register JSAMPROW color_map0 = cinfo->colormap[0]; |
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register JDIMENSION col; |
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inptr = dest->pub.buffer[0]; |
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outptr = dest->iobuffer; |
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for (col = cinfo->output_width; col > 0; col--) { |
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*outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]); |
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} |
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(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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} |
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/* |
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* Startup: write the file header. |
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*/ |
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METHODDEF(void) |
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start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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{ |
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tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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int num_colors, i; |
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FILE *outfile; |
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if (cinfo->out_color_space == JCS_GRAYSCALE) { |
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/* Targa doesn't have a mapped grayscale format, so we will */ |
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/* demap quantized gray output. Never emit a colormap. */ |
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write_header(cinfo, dinfo, 0); |
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if (cinfo->quantize_colors) |
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dest->pub.put_pixel_rows = put_demapped_gray; |
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else |
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dest->pub.put_pixel_rows = put_gray_rows; |
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} else if (cinfo->out_color_space == JCS_RGB) { |
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if (cinfo->quantize_colors) { |
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/* We only support 8-bit colormap indexes, so only 256 colors */ |
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num_colors = cinfo->actual_number_of_colors; |
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if (num_colors > 256) |
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ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors); |
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write_header(cinfo, dinfo, num_colors); |
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/* Write the colormap. Note Targa uses BGR byte order */ |
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outfile = dest->pub.output_file; |
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for (i = 0; i < num_colors; i++) { |
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putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile); |
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putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile); |
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putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile); |
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} |
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dest->pub.put_pixel_rows = put_gray_rows; |
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} else { |
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write_header(cinfo, dinfo, 0); |
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dest->pub.put_pixel_rows = put_pixel_rows; |
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} |
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} else { |
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ERREXIT(cinfo, JERR_TGA_COLORSPACE); |
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} |
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} |
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/* |
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* Finish up at the end of the file. |
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*/ |
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METHODDEF(void) |
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finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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{ |
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/* Make sure we wrote the output file OK */ |
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fflush(dinfo->output_file); |
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if (ferror(dinfo->output_file)) |
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ERREXIT(cinfo, JERR_FILE_WRITE); |
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} |
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/* |
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* The module selection routine for Targa format output. |
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*/ |
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GLOBAL(djpeg_dest_ptr) |
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jinit_write_targa (j_decompress_ptr cinfo) |
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{ |
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tga_dest_ptr dest; |
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/* Create module interface object, fill in method pointers */ |
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dest = (tga_dest_ptr) |
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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SIZEOF(tga_dest_struct)); |
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dest->pub.start_output = start_output_tga; |
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dest->pub.finish_output = finish_output_tga; |
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/* Calculate output image dimensions so we can allocate space */ |
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jpeg_calc_output_dimensions(cinfo); |
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/* Create I/O buffer. Note we make this near on a PC. */ |
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dest->buffer_width = cinfo->output_width * cinfo->output_components; |
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dest->iobuffer = (char *) |
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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(size_t) (dest->buffer_width * SIZEOF(char))); |
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/* Create decompressor output buffer. */ |
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dest->pub.buffer = (*cinfo->mem->alloc_sarray) |
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((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1); |
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dest->pub.buffer_height = 1; |
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return (djpeg_dest_ptr) dest; |
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} |
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#endif /* TARGA_SUPPORTED */
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