Suckless Farbfeld support

src/farbfeld.c

@@ -0,0 +1,146 @@
+#include "meh.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <assert.h>
+
+/* #define DEBUG */
+
+struct farbfeld_header_t {
+	unsigned char magic[8]; /* magic bytes "farbfeld" */
+	uint32_t width; /* image width in pixels (BE) */
+	uint32_t height; /* image height in pixels (BE) */
+};
+
+#define FARBFELD_MAGIC_LEN 8
+static unsigned char FARBFELD_MAGIC[FARBFELD_MAGIC_LEN] = "farbfeld";
+
+struct farbfeld_rgba_t {
+	uint16_t r, g, b, a;
+};
+
+struct farbfeld_t{
+	struct image img;
+	FILE *f;
+	struct farbfeld_header_t header;
+};
+
+struct image *farbfeld_open(FILE *f){
+	struct farbfeld_t *q;
+	uint32_t buf;
+
+#ifdef DEBUG
+	printf("farbfeld_open start\n");
+#endif
+
+	rewind(f);
+	q = malloc(sizeof(struct farbfeld_t));
+	if(!q) return NULL;
+	q->f = f;
+
+	/* read header */
+	if(fread(q->header.magic, 1, FARBFELD_MAGIC_LEN, f) != FARBFELD_MAGIC_LEN)
+		return NULL;
+	if(memcmp(q->header.magic, FARBFELD_MAGIC, FARBFELD_MAGIC_LEN) != 0)
+		return NULL;
+	if(fread(&buf, 1, 4, f) != 4)
+		return NULL;
+	q->header.width = ntohl(buf);
+#ifdef DEBUG
+	printf("width: %d\n", q->header.width);
+#endif
+	if(q->header.width == 0)
+		return NULL;
+	if(fread(&buf, 1, 4, f) != 4)
+		return NULL;
+	q->header.height = ntohl(buf);
+#ifdef DEBUG
+	printf("height: %d\n", q->header.height);
+#endif
+	if(q->header.height == 0)
+		return NULL;
+
+	q->img.bufwidth = q->header.width;
+	/* we add one row to the output buffer, so we can put the sentinel there,
+	 * below we make sure we don't write pixels after we past the last row.
+	 */
+	q->img.bufheight = q->header.height+1;
+
+	q->img.fmt = &farbfeld;
+
+	return (struct image *)q;
+}
+
+int farbfeld_read(struct image *img){
+	struct farbfeld_t *q = (struct farbfeld_t *)img;
+	uint16_t buf[4];
+	uint32_t ptr = 0;
+	struct farbfeld_rgba_t pixel;
+	uint32_t rows, cols;
+
+#ifdef DEBUG
+	printf("farbfeld_read start\n");
+#endif
+
+	rows = 0;
+	cols = 0;
+
+	while(1){
+		if(fread(buf, 1, 8, q->f) != 1) {
+			if(feof(q->f)){
+				fprintf(stderr, "EOF seen, premature end of image? %d, %d\n", rows, cols);
+				goto END;
+			}
+		}
+		pixel.r = ntohs(buf[0]);
+		pixel.g = ntohs(buf[1]);
+		pixel.b = ntohs(buf[2]);
+		pixel.a = ntohs(buf[3]);
+
+#ifdef DEBUG
+		fprintf(stderr, "PIXEL(%d,%d) = RGBA(%d,%d,%d,%d)\n", rows, cols, pixel.r, pixel.g, pixel.b, pixel.a);
+#endif
+		float alpha = pixel.a / 65535;
+		img->buf[ptr++] = ( alpha * pixel.r ) / 257;
+		img->buf[ptr++] = ( alpha * pixel.g ) / 257;
+		img->buf[ptr++] = ( alpha * pixel.b ) / 257;
+#ifdef DEBUG
+		fprintf(stderr, "BUF(%d,%d)=(%d,%d,%d)\n", rows, cols, img->buf[ptr-3], img->buf[ptr-2], img->buf[ptr-1]);
+#endif
+
+		cols++;
+		if(cols >= q->header.width){
+			cols=0;
+			rows++;
+			if(rows >= q->header.height){
+				goto END;
+			}
+		}
+	}
+
+END:
+#ifdef DEBUG
+	fprintf(stderr,"THE END\n");
+#endif
+	img->state |= LOADED | SLOWLOADED;
+
+	return 0;
+}
+
+void farbfeld_close(struct image *img){
+	struct farbfeld_t *q = (struct farbfeld_t *)img;
+
+#ifdef DEBUG
+	printf("farbfeld_close start\n");
+#endif
+	fclose(q->f);
+}
+
+struct imageformat farbfeld = {
+	farbfeld_open,
+	NULL,
+	farbfeld_read,
+	farbfeld_close
+};

src/main.c

@@ -22,6 +22,7 @@ static struct imageformat *formats[] = {
 	&libpng,
 	&netpbm,
 	&giflib, /* HACK! make gif last (uses read()) */
+	&farbfeld,
 	&imagemagick,
 	NULL
 };

src/meh.h

@@ -72,6 +72,7 @@ extern struct imageformat libpng;
 extern struct imageformat bmp;
 extern struct imageformat netpbm;
 extern struct imageformat imagemagick;
+extern struct imageformat farbfeld;
 
 extern int width, height;
 extern struct image *curimg;