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