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	farbfeld.5 - farbfeld - suckless image format with conversion tools
	git clone git://git.suckless.org/farbfeld
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	farbfeld.5 (4301B)
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	1 .Dd 2018-04-11
	2 .Dt FARBFELD 5
	3 .Os suckless.org
	4 .Sh NAME
	5 .Nm farbfeld
	6 .Nd suckless image format
	7 .Sh DESCRIPTION
	8 .Nm
	9 is a
	10 .Em lossless
	11 image format which is easy to parse, pipe and compress.
	12 It has the following format:
	13 .Bd -literal -offset left
	14 BYTES DESCRIPTION
	15 8 "farbfeld" magic value
	16 4 32-Bit BE unsigned integer (width)
	17 4 32-Bit BE unsigned integer (height)
	18 [2222] 4*16-Bit BE unsigned integers [RGBA] / pixel, row-major
	19 .Ed
	20 .Pp
	21 The RGB-data should be sRGB for best interoperability and not
	22 alpha-premultiplied.
	23 .Sh USAGE
	24 .Nm
	25 provides the tools
	26 .Xr 2ff 1 ,
	27 .Xr jpg2ff 1 ,
	28 .Xr png2ff 1
	29 and
	30 .Xr ff2jpg 1 ,
	31 .Xr ff2pam 1 ,
	32 .Xr ff2png 1 ,
	33 .Xr ff2ppm 1
	34 to
	35 .Em convert
	36 to and from farbfeld images respectively.
	37 .Pp
	38 .Xr bzip2 1
	39 is recommended for
	40 .Em compression ,
	41 giving results comparable with PNG for photographs and much better resul…
	42 for other image types.
	43 .sp
	44 The
	45 .Em file extension
	46 is ".ff" and compression extensions shall be
	47 appended (e.g. ".ff.bz2").
	48 .Sh MOTIVATION
	49 .Nm
	50 was created because the author was not satisfied with the boilerplate
	51 and inherent complexity involved in handling common image formats
	52 (PNG, JPEG, GIF,...), having to rely on bloated libraries while not being
	53 able to focus on the task at hand for a given image processing problem.
	54 .Sh EXAMPLES
	55 The following code listing
	56 .Em invert.c
	57 is a ready-to-use color inverter with all necessary error handling and
	58 reporting. This program can be integrated into a farbfeld pipeline as
	59 follows:
	60 .Pp
	61 $ png2ff < image.png \| invert \| ff2png > image-inverted.png
	62 .Pp
	63 It shall be noted here that due to the simplicity of the format no
	64 external libraries are needed to handle the farbfeld image data. The
	65 0BSD-License gives you the freedom to throw away the license block and
	66 just use the code as you wish. Happy hacking!
	67 .Bd -literal -offset left
	68 /*
	69 * 0BSD-License
	70 *
	71 * (c) 2017 Laslo Hunhold <[email protected]>
	72 *
	73 * Permission to use, copy, modify, and/or distribute this software for
	74 * any purpose with or without fee is hereby granted.
	75 *
	76 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
	77 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
	78 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
	79 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
	80 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	81 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
	82 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
	83 * PERFORMANCE OF THIS SOFTWARE.
	84 */
	85 #include <arpa/inet.h>
	86
	87 #include <errno.h>
	88 #include <stdint.h>
	89 #include <stdio.h>
	90 #include <string.h>
	91
	92 #define LEN(x) (sizeof (x) / sizeof *(x))
	93
	94 static void
	95 invert(uint16_t rgba[4])
	96 {
	97 rgba[0] = UINT16_MAX - rgba[0];
	98 rgba[1] = UINT16_MAX - rgba[1];
	99 rgba[2] = UINT16_MAX - rgba[2];
	100 }
	101
	102 int
	103 main(int argc, char *argv[])
	104 {
	105 uint32_t hdr[4], width, height, i, j, k;
	106 uint16_t rgba[4];
	107
	108 /* arguments */
	109 if (argc != 1) {
	110 fprintf(stderr, "usage: %s\\n", argv[0]);
	111 return 1;
	112 }
	113
	114 /* read header */
	115 if (fread(hdr, sizeof(*hdr), LEN(hdr), stdin) != LEN(hdr)) {
	116 goto readerr;
	117 }
	118 if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
	119 fprintf(stderr, "%s: invalid magic value\\n", argv[0]);
	120 return 1;
	121 }
	122 width = ntohl(hdr[2]);
	123 height = ntohl(hdr[3]);
	124
	125 /* write data */
	126 if (fwrite(hdr, sizeof(*hdr), LEN(hdr), stdout) != 4) {
	127 goto writerr;
	128 }
	129
	130 for (i = 0; i < height; i++) {
	131 for (j = 0; j < width; j++) {
	132 if (fread(rgba, sizeof(*rgba), LEN(rgba),
	133 stdin) != LEN(rgba)) {
	134 goto readerr;
	135 }
	136 for (k = 0; k < 4; k++) {
	137 rgba[k] = ntohs(rgba[k]);
	138 }
	139
	140 invert(rgba);
	141
	142 for (k = 0; k < 4; k++) {
	143 rgba[k] = htons(rgba[k]);
	144 }
	145 if (fwrite(rgba, sizeof(*rgba), LEN(rgba),
	146 stdout) != LEN(rgba)) {
	147 goto writerr;
	148 }
	149 }
	150 }
	151
	152 /* clean up */
	153 if (fclose(stdout)) {
	154 fprintf(stderr, "%s: fclose: %s\\n", argv[0],
	155 strerror(errno));
	156 return 1;
	157 }
	158
	159 return 0;
	160 readerr:
	161 fprintf(stderr, "%s: fread: Unexpected EOF\\n", argv[0]);
	162 return 1;
	163 writerr:
	164 fprintf(stderr, "%s: fwrite: %s\\n", argv[0], strerror(errno));
	165 return 1;
	166 }
	167 .Ed
	168 .Sh SEE ALSO
	169 .Xr 2ff 1 ,
	170 .Xr ff2jpg 1 ,
	171 .Xr ff2pam 1 ,
	172 .Xr ff2png 1 ,
	173 .Xr ff2ppm 1 ,
	174 .Xr jpg2ff 1 ,
	175 .Xr png2ff 1
	176 .Sh AUTHORS
	177 .An Laslo Hunhold Aq Mt [email protected]