Unit RdTarga; { rdtarga.c ; Copyright (C) 1991-1996, Thomas G. Lane. These routines may need modification for non-Unix environments or specialized applications. As they stand, they assume input from an ordinary stdio stream. They further assume that reading begins at the start of the file; start_input may need work if the user interface has already read some data (e.g., to determine that the file is indeed Targa format). Based on code contributed by Lee Daniel Crocker. } interface {$I jconfig.inc} uses jmorecfg, jpeglib, jinclude, jdeferr, jerror, cdjpeg; { Common decls for cjpeg/djpeg applications } { The module selection routine for Targa format input. } {GLOBAL} function jinit_read_targa (cinfo : j_compress_ptr) : cjpeg_source_ptr; implementation { Macros to deal with unsigned chars as efficiently as compiler allows } type U_CHAR = byte; UCH = int; (*type {$ifdef CHAR_IS_UNSIGNED} UCH = int; {$else} UCH = int (x and $FF); {$endif} *) { Private version of data source object } type tga_source_ptr = ^tga_source_struct; tga_source_struct = record pub : cjpeg_source_struct; { public fields } cinfo : j_compress_ptr; { back link saves passing separate parm } colormap : JSAMPARRAY; { Targa colormap (converted to my format) } whole_image : jvirt_sarray_ptr; { Needed if funny input row order } current_row : JDIMENSION; { Current logical row number to read } { Pointer to routine to extract next Targa pixel from input file } read_pixel : procedure (sinfo : tga_source_ptr); { Result of read_pixel is delivered here: } tga_pixel : array[0..4-1] of U_CHAR; pixel_size : int; { Bytes per Targa pixel (1 to 4) } { State info for reading RLE-coded pixels; both counts must be init to 0 } block_count : int; { # of pixels remaining in RLE block } dup_pixel_count : int; { # of times to duplicate previous pixel } { This saves the correct pixel-row-expansion method for preload_image } get_pixel_rows : function(cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; end; { For expanding 5-bit pixel values to 8-bit with best rounding } const c5to8bits : array[0..32-1] of UINT8 = ( 0, 8, 16, 25, 33, 41, 49, 58, 66, 74, 82, 90, 99, 107, 115, 123, 132, 140, 148, 156, 165, 173, 181, 189, 197, 206, 214, 222, 230, 239, 247, 255); function getc(f : fileptr) : byte; begin getc := 0; end; const EOF = byte(26); { ^Z } {LOCAL} function read_byte (sinfo : tga_source_ptr) : int; { Read next byte from Targa file } var {register} infile : FILEptr; {register} c : int; begin infile := sinfo^.pub.input_file; c := getc(infile); if (c = EOF) then ERREXIT(j_common_ptr(sinfo^.cinfo), JERR_INPUT_EOF); read_byte := c; end; {LOCAL} procedure read_colormap (sinfo : tga_source_ptr; cmaplen : int; mapentrysize : int); { Read the colormap from a Targa file } var i : int; begin { Presently only handles 24-bit BGR format } if (mapentrysize <> 24) then ERREXIT(j_common_ptr(sinfo^.cinfo), JERR_TGA_BADCMAP); for i := 0 to pred(cmaplen) do begin sinfo^.colormap^[2]^[i] := JSAMPLE (read_byte(sinfo)); sinfo^.colormap^[1]^[i] := JSAMPLE (read_byte(sinfo)); sinfo^.colormap^[0]^[i] := JSAMPLE (read_byte(sinfo)); end; end; { read_pixel methods: get a single pixel from Targa file into tga_pixel[] } {METHODDEF} procedure read_non_rle_pixel (sinfo : tga_source_ptr); far; { Read one Targa pixel from the input file; no RLE expansion } var {register} infile : FILEptr; {register} i : int; begin infile := sinfo^.pub.input_file; for i := 0 to pred(sinfo^.pixel_size) do begin sinfo^.tga_pixel[i] := U_CHAR (getc(infile)); end; end; {METHODDEF} procedure read_rle_pixel (sinfo : tga_source_ptr); far; { Read one Targa pixel from the input file, expanding RLE data as needed } var {register} infile : FILEptr; {register} i : int; begin infile := sinfo^.pub.input_file; { Duplicate previously read pixel? } if (sinfo^.dup_pixel_count > 0) then begin Dec(sinfo^.dup_pixel_count); exit; end; { Time to read RLE block header? } Dec(sinfo^.block_count); if (sinfo^.block_count < 0) then begin { decrement pixels remaining in block } i := read_byte(sinfo); if (i and $80) <> 0 then begin { Start of duplicate-pixel block? } sinfo^.dup_pixel_count := i and $7F; { number of dups after this one } sinfo^.block_count := 0; { then read new block header } end else begin sinfo^.block_count := i and $7F; { number of pixels after this one } end; end; { Read next pixel } for i := 0 to pred(sinfo^.pixel_size) do begin sinfo^.tga_pixel[i] := U_CHAR (getc(infile)); end; end; { Read one row of pixels. We provide several different versions depending on input file format. } {METHODDEF} function get_8bit_gray_row (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; { This version is for reading 8-bit grayscale pixels } var source : tga_source_ptr; {register} ptr : JSAMPLE_PTR; {register} col : JDIMENSION; begin source := tga_source_ptr (sinfo); ptr := JSAMPLE_PTR(source^.pub.buffer^[0]); for col := pred(cinfo^.image_width) downto 0 do begin source^.read_pixel (source); { Load next pixel into tga_pixel } ptr^ := JSAMPLE (UCH(source^.tga_pixel[0])); Inc(ptr); end; get_8bit_gray_row := 1; end; {METHODDEF} function get_8bit_row (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; { This version is for reading 8-bit colormap indexes } var source : tga_source_ptr; {register} t : int; {register} ptr : JSAMPLE_PTR; {register} col : JDIMENSION; {register} colormap : JSAMPARRAY; begin source := tga_source_ptr (sinfo); colormap := source^.colormap; ptr := JSAMPLE_PTR(source^.pub.buffer^[0]); for col := pred(cinfo^.image_width) downto 0 do begin source^.read_pixel (source); { Load next pixel into tga_pixel } t := UCH(source^.tga_pixel[0]); ptr^ := colormap^[0]^[t]; Inc(ptr); ptr^ := colormap^[1]^[t]; Inc(ptr); ptr^ := colormap^[2]^[t]; Inc(ptr); end; get_8bit_row := 1; end; {METHODDEF} function get_16bit_row (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; { This version is for reading 16-bit pixels } var source : tga_source_ptr; {register} t : int; {register} ptr : JSAMPROW; {register} col : JDIMENSION; begin source := tga_source_ptr (sinfo); ptr := source^.pub.buffer^[0]; for col := pred(cinfo^.image_width) downto 0 do begin source^.read_pixel (source); { Load next pixel into tga_pixel } t := UCH(source^.tga_pixel[0]); Inc(t, UCH(source^.tga_pixel[1]) shr 8); { We expand 5 bit data to 8 bit sample width. The format of the 16-bit (LSB first) input word is xRRRRRGGGGGBBBBB } ptr^[2] := JSAMPLE (c5to8bits[t and $1F]); t := t shr 5; ptr^[1] := JSAMPLE (c5to8bits[t and $1F]); t := t shr 5; ptr^[0] := JSAMPLE (c5to8bits[t and $1F]); Inc(JSAMPLE_PTR(ptr), 3); end; get_16bit_row :=1; end; {METHODDEF} function get_24bit_row (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; { This version is for reading 24-bit pixels } var source : tga_source_ptr; {register} ptr : JSAMPLE_PTR; {register} col : JDIMENSION; begin source := tga_source_ptr (sinfo); ptr := JSAMPLE_PTR(source^.pub.buffer^[0]); for col := pred(cinfo^.image_width) downto 0 do begin source^.read_pixel (source); { Load next pixel into tga_pixel } ptr^ := JSAMPLE (UCH(source^.tga_pixel[2])); { change BGR to RGB order } Inc(ptr); ptr^ := JSAMPLE (UCH(source^.tga_pixel[1])); Inc(ptr); ptr^ := JSAMPLE (UCH(source^.tga_pixel[0])); Inc(ptr); end; get_24bit_row := 1; end; { Targa also defines a 32-bit pixel format with order B,G,R,A. We presently ignore the attribute byte, so the code for reading these pixels is identical to the 24-bit routine above. This works because the actual pixel length is only known to read_pixel. } const get_32bit_row : function (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION = get_24bit_row; { This method is for re-reading the input data in standard top-down row order. The entire image has already been read into whole_image with proper conversion of pixel format, but it's in a funny row order. } {METHODDEF} function get_memory_row (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; var source : tga_source_ptr; source_row : JDIMENSION; begin source := tga_source_ptr (sinfo); { Compute row of source that maps to current_row of normal order } { For now, assume image is bottom-up and not interlaced. } { NEEDS WORK to support interlaced images! } source_row := cinfo^.image_height - source^.current_row - 1; { Fetch that row from virtual array } source^.pub.buffer := cinfo^.mem^.access_virt_sarray (j_common_ptr (cinfo), source^.whole_image, source_row, JDIMENSION (1), FALSE); Inc(source^.current_row); get_memory_row := 1; end; { This method loads the image into whole_image during the first call on get_pixel_rows. The get_pixel_rows pointer is then adjusted to call get_memory_row on subsequent calls. } {METHODDEF} function preload_image (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr) : JDIMENSION; far; var source : tga_source_ptr; row : JDIMENSION; progress : cd_progress_ptr; begin source := tga_source_ptr (sinfo); progress := cd_progress_ptr (cinfo^.progress); { Read the data into a virtual array in input-file row order. } for row := 0 to pred(cinfo^.image_height) do begin if (progress <> NIL) then begin progress^.pub.pass_counter := long (row); progress^.pub.pass_limit := long (cinfo^.image_height); progress^.pub.progress_monitor (j_common_ptr (cinfo)); end; source^.pub.buffer := cinfo^.mem^.access_virt_sarray (j_common_ptr(cinfo), source^.whole_image, row, JDIMENSION(1), TRUE); source^.get_pixel_rows (cinfo, sinfo); end; if (progress <> NIL) then Inc(progress^.completed_extra_passes); { Set up to read from the virtual array in unscrambled order } source^.pub.get_pixel_rows := get_memory_row; source^.current_row := 0; { And read the first row } preload_image := get_memory_row(cinfo, sinfo); end; { Read the file header; return image size and component count. } {METHODDEF} procedure start_input_tga (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr); far; var source : tga_source_ptr; targaheader : array[0..18-1] of U_CHAR; idlen, cmaptype, subtype, flags, interlace_type, components : int; width, height, maplen : uInt; is_bottom_up : boolean; var progress : cd_progress_ptr; begin source := tga_source_ptr (sinfo); if JFREAD(source^.pub.input_file, @targaheader, 18) <> size_t(18) then ERREXIT(j_common_ptr(cinfo), JERR_INPUT_EOF); { Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway } if (targaheader[16] = 15) then targaheader[16] := 16; idlen := UCH(targaheader[0]); cmaptype := UCH(targaheader[1]); subtype := UCH(targaheader[2]); maplen := {GET_2B(5);} uInt (UCH(targaheader[5])) + ( uInt (UCH(targaheader[5+1])) ) shl 8; width := {GET_2B(12);} ( uInt(UCH(targaheader[12])) + ( uInt(UCH(targaheader[12+1])) ) shl 8); height := {GET_2B(14);} ( uInt(UCH(targaheader[14])) + ( uInt(UCH(targaheader[14+1])) ) shl 8); source^.pixel_size := UCH(targaheader[16]) shl 3; flags := UCH(targaheader[17]); { Image Descriptor byte } is_bottom_up := (flags and $20) = 0; { bit 5 set => top-down } interlace_type := flags shl 6; { bits 6/7 are interlace code } if (cmaptype > 1) or { cmaptype must be 0 or 1 } (source^.pixel_size < 1) or (source^.pixel_size > 4) or ((UCH(targaheader[16]) and 7) <> 0) or { bits/pixel must be multiple of 8 } (interlace_type <> 0) then { currently don't allow interlaced image } ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); if (subtype > 8) then begin { It's an RLE-coded file } source^.read_pixel := read_rle_pixel; source^.block_count := 0; source^.dup_pixel_count := 0; Dec(subtype, 8); end else begin { Non-RLE file } source^.read_pixel := read_non_rle_pixel; end; { Now should have subtype 1, 2, or 3 } components := 3; { until proven different } cinfo^.in_color_space := JCS_RGB; case (subtype) of 1:begin { Colormapped image } if (source^.pixel_size = 1) and (cmaptype = 1) then source^.get_pixel_rows := get_8bit_row else ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); TRACEMS2(j_common_ptr(cinfo), 1, JTRC_TGA_MAPPED, width, height); end; 2:begin { RGB image } case (source^.pixel_size) of 2: source^.get_pixel_rows := get_16bit_row; 3: source^.get_pixel_rows := get_24bit_row; 4: source^.get_pixel_rows := get_32bit_row; else ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); end; TRACEMS2(j_common_ptr(cinfo), 1, JTRC_TGA, width, height); end; 3:begin { Grayscale image } components := 1; cinfo^.in_color_space := JCS_GRAYSCALE; if (source^.pixel_size = 1) then source^.get_pixel_rows := get_8bit_gray_row else ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); TRACEMS2(j_common_ptr(cinfo), 1, JTRC_TGA_GRAY, width, height); end; else ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); end; if (is_bottom_up) then begin { Create a virtual array to buffer the upside-down image. } source^.whole_image := cinfo^.mem^.request_virt_sarray (j_common_ptr (cinfo), JPOOL_IMAGE, FALSE, JDIMENSION(width * components), JDIMENSION (height), JDIMENSION (1)); if (cinfo^.progress <> NIL) then begin progress := cd_progress_ptr (cinfo^.progress); Inc(progress^.total_extra_passes); { count file input as separate pass } end; { source^.pub.buffer will point to the virtual array. } source^.pub.buffer_height := 1; { in case anyone looks at it } source^.pub.get_pixel_rows := preload_image; end else begin { Don't need a virtual array, but do need a one-row input buffer. } source^.whole_image := NIL; source^.pub.buffer := cinfo^.mem^.alloc_sarray ( j_common_ptr (cinfo), JPOOL_IMAGE, JDIMENSION (width * components), JDIMENSION (1)) ; source^.pub.buffer_height := 1; source^.pub.get_pixel_rows := source^.get_pixel_rows; end; while (idlen > 0) do { Throw away ID field } begin Dec(idlen); {void} read_byte(source); end; if (maplen > 0) then begin if (maplen > 256) or {GET_2B(3) <> 0} ( (uInt (UCH(targaheader[3])) + (uInt (UCH(targaheader[3+1])) ) shl 8) <> 0) then ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADCMAP); { Allocate space to store the colormap } source^.colormap := cinfo^.mem^.alloc_sarray ( j_common_ptr (cinfo), JPOOL_IMAGE, JDIMENSION (maplen), JDIMENSION (3)); { and read it from the file } read_colormap(source, int (maplen), UCH(targaheader[7])); end else begin if (cmaptype <> 0) then { but you promised a cmap! } ERREXIT(j_common_ptr(cinfo), JERR_TGA_BADPARMS); source^.colormap := NIL; end; cinfo^.input_components := components; cinfo^.data_precision := 8; cinfo^.image_width := width; cinfo^.image_height := height; end; { Finish up at the end of the file. } {METHODDEF} procedure finish_input_tga (cinfo : j_compress_ptr; sinfo : cjpeg_source_ptr); far; begin { no work } end; { The module selection routine for Targa format input. } {GLOBAL} function jinit_read_targa (cinfo : j_compress_ptr) : cjpeg_source_ptr; var source : tga_source_ptr; begin { 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; jinit_read_targa := cjpeg_source_ptr (source); end; end. { TARGA_SUPPORTED }