501 lines
15 KiB
C
501 lines
15 KiB
C
/*
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* rdtarga.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 read input 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 input from
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* an ordinary stdio stream. They further assume that reading begins
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* at the start of the file; start_input may need work if the
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* user interface has already read some data (e.g., to determine that
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* the file is indeed Targa format).
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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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/* Macros to deal with unsigned chars as efficiently as compiler allows */
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#ifdef HAVE_UNSIGNED_CHAR
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typedef unsigned char U_CHAR;
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#define UCH(x) ((int) (x))
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#else /* !HAVE_UNSIGNED_CHAR */
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#ifdef CHAR_IS_UNSIGNED
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typedef char U_CHAR;
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#define UCH(x) ((int) (x))
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#else
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typedef char U_CHAR;
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#define UCH(x) ((int) (x) & 0xFF)
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#endif
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#endif /* HAVE_UNSIGNED_CHAR */
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#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
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/* Private version of data source object */
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typedef struct _tga_source_struct * tga_source_ptr;
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typedef struct _tga_source_struct {
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struct cjpeg_source_struct pub; /* public fields */
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j_compress_ptr cinfo; /* back link saves passing separate parm */
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JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
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jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
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JDIMENSION current_row; /* Current logical row number to read */
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/* Pointer to routine to extract next Targa pixel from input file */
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JMETHOD(void, read_pixel, (tga_source_ptr sinfo));
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/* Result of read_pixel is delivered here: */
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U_CHAR tga_pixel[4];
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int pixel_size; /* Bytes per Targa pixel (1 to 4) */
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/* State info for reading RLE-coded pixels; both counts must be init to 0 */
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int block_count; /* # of pixels remaining in RLE block */
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int dup_pixel_count; /* # of times to duplicate previous pixel */
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/* This saves the correct pixel-row-expansion method for preload_image */
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JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
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cjpeg_source_ptr sinfo));
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} tga_source_struct;
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/* For expanding 5-bit pixel values to 8-bit with best rounding */
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static const UINT8 c5to8bits[32] = {
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0, 8, 16, 25, 33, 41, 49, 58,
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66, 74, 82, 90, 99, 107, 115, 123,
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132, 140, 148, 156, 165, 173, 181, 189,
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197, 206, 214, 222, 230, 239, 247, 255
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};
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LOCAL(int)
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read_byte (tga_source_ptr sinfo)
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/* Read next byte from Targa file */
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{
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register FILE *infile = sinfo->pub.input_file;
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register int c;
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if ((c = getc(infile)) == EOF)
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ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
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return c;
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}
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LOCAL(void)
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read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
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/* Read the colormap from a Targa file */
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{
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int i;
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/* Presently only handles 24-bit BGR format */
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if (mapentrysize != 24)
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ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
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for (i = 0; i < cmaplen; i++) {
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sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
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sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
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sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
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}
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}
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/*
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* read_pixel methods: get a single pixel from Targa file into tga_pixel[]
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*/
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METHODDEF(void)
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read_non_rle_pixel (tga_source_ptr sinfo)
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/* Read one Targa pixel from the input file; no RLE expansion */
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{
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register FILE *infile = sinfo->pub.input_file;
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register int i;
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for (i = 0; i < sinfo->pixel_size; i++) {
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sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
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}
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}
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METHODDEF(void)
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read_rle_pixel (tga_source_ptr sinfo)
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/* Read one Targa pixel from the input file, expanding RLE data as needed */
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{
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register FILE *infile = sinfo->pub.input_file;
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register int i;
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/* Duplicate previously read pixel? */
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if (sinfo->dup_pixel_count > 0) {
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sinfo->dup_pixel_count--;
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return;
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}
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/* Time to read RLE block header? */
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if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
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i = read_byte(sinfo);
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if (i & 0x80) { /* Start of duplicate-pixel block? */
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sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
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sinfo->block_count = 0; /* then read new block header */
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} else {
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sinfo->block_count = i & 0x7F; /* number of pixels after this one */
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}
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}
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/* Read next pixel */
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for (i = 0; i < sinfo->pixel_size; i++) {
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sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
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}
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}
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/*
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* Read one row of pixels.
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*
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* We provide several different versions depending on input file format.
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*/
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METHODDEF(JDIMENSION)
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get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading 8-bit grayscale pixels */
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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register JSAMPROW ptr;
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register JDIMENSION col;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
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*ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
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}
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return 1;
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}
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METHODDEF(JDIMENSION)
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get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading 8-bit colormap indexes */
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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register int t;
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register JSAMPROW ptr;
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register JDIMENSION col;
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register JSAMPARRAY colormap = source->colormap;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
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t = UCH(source->tga_pixel[0]);
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*ptr++ = colormap[0][t];
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*ptr++ = colormap[1][t];
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*ptr++ = colormap[2][t];
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}
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return 1;
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}
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METHODDEF(JDIMENSION)
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get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading 16-bit pixels */
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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register int t;
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register JSAMPROW ptr;
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register JDIMENSION col;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
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t = UCH(source->tga_pixel[0]);
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t += UCH(source->tga_pixel[1]) << 8;
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/* We expand 5 bit data to 8 bit sample width.
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* The format of the 16-bit (LSB first) input word is
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* xRRRRRGGGGGBBBBB
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*/
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ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
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t >>= 5;
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ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
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t >>= 5;
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ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
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ptr += 3;
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}
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return 1;
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}
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METHODDEF(JDIMENSION)
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get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading 24-bit pixels */
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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register JSAMPROW ptr;
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register JDIMENSION col;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
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*ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
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*ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
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*ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
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}
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return 1;
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}
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/*
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* Targa also defines a 32-bit pixel format with order B,G,R,A.
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* We presently ignore the attribute byte, so the code for reading
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* these pixels is identical to the 24-bit routine above.
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* This works because the actual pixel length is only known to read_pixel.
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*/
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#define get_32bit_row get_24bit_row
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/*
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* This method is for re-reading the input data in standard top-down
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* row order. The entire image has already been read into whole_image
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* with proper conversion of pixel format, but it's in a funny row order.
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*/
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METHODDEF(JDIMENSION)
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get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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JDIMENSION source_row;
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/* Compute row of source that maps to current_row of normal order */
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/* For now, assume image is bottom-up and not interlaced. */
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/* NEEDS WORK to support interlaced images! */
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source_row = cinfo->image_height - source->current_row - 1;
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/* Fetch that row from virtual array */
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source->pub.buffer = (*cinfo->mem->access_virt_sarray)
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((j_common_ptr) cinfo, source->whole_image,
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source_row, (JDIMENSION) 1, FALSE);
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source->current_row++;
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return 1;
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}
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/*
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* This method loads the image into whole_image during the first call on
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* get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
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* get_memory_row on subsequent calls.
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*/
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METHODDEF(JDIMENSION)
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preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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JDIMENSION row;
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cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
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/* Read the data into a virtual array in input-file row order. */
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for (row = 0; row < cinfo->image_height; row++) {
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if (progress != NULL) {
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progress->pub.pass_counter = (long) row;
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progress->pub.pass_limit = (long) cinfo->image_height;
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(*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
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}
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source->pub.buffer = (*cinfo->mem->access_virt_sarray)
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((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE);
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(*source->get_pixel_rows) (cinfo, sinfo);
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}
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if (progress != NULL)
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progress->completed_extra_passes++;
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/* Set up to read from the virtual array in unscrambled order */
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source->pub.get_pixel_rows = get_memory_row;
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source->current_row = 0;
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/* And read the first row */
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return get_memory_row(cinfo, sinfo);
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}
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/*
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* Read the file header; return image size and component count.
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*/
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METHODDEF(void)
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start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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tga_source_ptr source = (tga_source_ptr) sinfo;
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U_CHAR targaheader[18];
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int idlen, cmaptype, subtype, flags, interlace_type, components;
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unsigned int width, height, maplen;
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boolean is_bottom_up;
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#define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \
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(((unsigned int) UCH(targaheader[offset+1])) << 8))
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if (! ReadOK(source->pub.input_file, targaheader, 18))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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/* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
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if (targaheader[16] == 15)
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targaheader[16] = 16;
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idlen = UCH(targaheader[0]);
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cmaptype = UCH(targaheader[1]);
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subtype = UCH(targaheader[2]);
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maplen = GET_2B(5);
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width = GET_2B(12);
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height = GET_2B(14);
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source->pixel_size = UCH(targaheader[16]) >> 3;
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flags = UCH(targaheader[17]); /* Image Descriptor byte */
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is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
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interlace_type = flags >> 6; /* bits 6/7 are interlace code */
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if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
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source->pixel_size < 1 || source->pixel_size > 4 ||
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(UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
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interlace_type != 0) /* currently don't allow interlaced image */
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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if (subtype > 8) {
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/* It's an RLE-coded file */
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source->read_pixel = read_rle_pixel;
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source->block_count = source->dup_pixel_count = 0;
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subtype -= 8;
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} else {
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/* Non-RLE file */
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source->read_pixel = read_non_rle_pixel;
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}
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/* Now should have subtype 1, 2, or 3 */
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components = 3; /* until proven different */
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cinfo->in_color_space = JCS_RGB;
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switch (subtype) {
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case 1: /* Colormapped image */
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if (source->pixel_size == 1 && cmaptype == 1)
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source->get_pixel_rows = get_8bit_row;
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else
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
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break;
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case 2: /* RGB image */
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switch (source->pixel_size) {
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case 2:
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source->get_pixel_rows = get_16bit_row;
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break;
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case 3:
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source->get_pixel_rows = get_24bit_row;
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break;
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case 4:
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source->get_pixel_rows = get_32bit_row;
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break;
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default:
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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break;
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}
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TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
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break;
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case 3: /* Grayscale image */
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components = 1;
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cinfo->in_color_space = JCS_GRAYSCALE;
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if (source->pixel_size == 1)
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source->get_pixel_rows = get_8bit_gray_row;
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else
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
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break;
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default:
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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break;
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}
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if (is_bottom_up) {
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/* Create a virtual array to buffer the upside-down image. */
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source->whole_image = (*cinfo->mem->request_virt_sarray)
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((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
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(JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
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if (cinfo->progress != NULL) {
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cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
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progress->total_extra_passes++; /* count file input as separate pass */
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}
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/* source->pub.buffer will point to the virtual array. */
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source->pub.buffer_height = 1; /* in case anyone looks at it */
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source->pub.get_pixel_rows = preload_image;
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} else {
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/* Don't need a virtual array, but do need a one-row input buffer. */
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source->whole_image = NULL;
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source->pub.buffer = (*cinfo->mem->alloc_sarray)
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((j_common_ptr) cinfo, JPOOL_IMAGE,
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(JDIMENSION) width * components, (JDIMENSION) 1);
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source->pub.buffer_height = 1;
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source->pub.get_pixel_rows = source->get_pixel_rows;
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}
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while (idlen--) /* Throw away ID field */
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(void) read_byte(source);
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if (maplen > 0) {
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if (maplen > 256 || GET_2B(3) != 0)
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ERREXIT(cinfo, JERR_TGA_BADCMAP);
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/* Allocate space to store the colormap */
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source->colormap = (*cinfo->mem->alloc_sarray)
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((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
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/* and read it from the file */
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read_colormap(source, (int) maplen, UCH(targaheader[7]));
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} else {
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if (cmaptype) /* but you promised a cmap! */
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ERREXIT(cinfo, JERR_TGA_BADPARMS);
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source->colormap = NULL;
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}
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cinfo->input_components = components;
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cinfo->data_precision = 8;
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cinfo->image_width = width;
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cinfo->image_height = height;
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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_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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/* no work */
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}
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/*
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* The module selection routine for Targa format input.
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*/
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GLOBAL(cjpeg_source_ptr)
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jinit_read_targa (j_compress_ptr cinfo)
|
|
{
|
|
tga_source_ptr source;
|
|
|
|
/* Create module interface object */
|
|
source = (tga_source_ptr)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
SIZEOF(tga_source_struct));
|
|
source->cinfo = cinfo; /* make back link for subroutines */
|
|
/* Fill in method ptrs, except get_pixel_rows which start_input sets */
|
|
source->pub.start_input = start_input_tga;
|
|
source->pub.finish_input = finish_input_tga;
|
|
|
|
return (cjpeg_source_ptr) source;
|
|
}
|
|
|
|
#endif /* TARGA_SUPPORTED */
|