Add map offset argument, change southbound to northbound

Passes are flipped when northbound, not southbound

README.md

@@ -71,6 +71,7 @@ Apply a falsecolor palette
 -p <path>        Path to palette
 -r               Realtime decode
 -g               Gamma adjustment (1.0 = off)
+-k               Map offset (in px, default: 0)
 ```
 
 ### Image types
@@ -89,7 +90,7 @@ Apply a falsecolor palette
  - `l`: Linear equalise
  - `d`: Denoise
  - `p`: Precipitation overlay
- - `f`: Flip image (for southbound passes)
+ - `f`: Flip image (for northbound passes)
  - `c`: Crop noise from ends of image
 
 ## Realtime decoding

common.h

@@ -47,6 +47,7 @@ typedef struct {
 	char *filename; // Output filename
 	char *palette; // Filename of palette
 	float gamma; // Gamma
+	int mapOffset;
 } options_t;
 
 enum imagetypes {

image.c

@@ -306,7 +306,7 @@ void denoise(float **prow, int nrow, int offset, int width){
 }
 #undef TRIG_LEVEL
 
-// Flips a channe, for southbound passes
+// Flips a channel, for northbound passes
 void flipImage(image_t *img, int width, int offset){
 	for(int y = 1; y < img->nrow; y++){
 		for(int x = 1; x < ceil(width / 2.0); x++){

main.c

@@ -75,11 +75,11 @@ int main(int argc, char **argv) {
 		usage();
 	}
 
-	options_t opts = { "r", "", 19, "", ".", 0, "", "", 1.0 };
+	options_t opts = { "r", "", 19, "", ".", 0, "", "", 1.0, 0 };
 
 	// Parse arguments
 	int opt;
-	while ((opt = getopt(argc, argv, "o:m:d:i:s:e:p:g:r")) != EOF) {
+	while ((opt = getopt(argc, argv, "o:m:d:i:s:e:p:g:k:r")) != EOF) {
 		switch (opt) {
 			case 'd':
 				opts.path = optarg;
@@ -112,6 +112,9 @@ int main(int argc, char **argv) {
 			case 'g':
 				opts.gamma = atof(optarg);
 				break;
+			case 'k':
+				opts.mapOffset = atoi(optarg);
+				break;
 			default:
 				usage();
 		}
@@ -216,7 +219,7 @@ static int processAudio(char *filename, options_t *opts){
 		denoise(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
 	}
 
-	// Flip, for southbound passes
+	// Flip, for northbound passes
 	if(CONTAINS(opts->effects, Flip_Image)){
 		flipImage(&img, CH_WIDTH, CHA_OFFSET);
 		flipImage(&img, CH_WIDTH, CHB_OFFSET);
@@ -345,6 +348,7 @@ static void usage(void) {
 	" -p <path>        Path to palette\n"
 	" -r               Realtime decode\n"
 	" -g               Gamma adjustment (1.0 = off)\n"
+	" -k               Map offset (in px, default: 0)"
 	"\nRefer to the README for more infomation\n");
 
 	exit(EINVAL);

pngio.c

@@ -429,7 +429,7 @@ int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, c
 
 	// Map stuff
 	if(opts->map != NULL && opts->map[0] != '\0'){
-		if(!mapOverlay(opts->map, crow, img->nrow, img->zenith, CONTAINS(opts->type, MCIR))){
+		if(!mapOverlay(opts->map, crow, img->nrow, img->zenith+opts->mapOffset, CONTAINS(opts->type, MCIR))){
 			fprintf(stderr, "Skipping MCIR generation.\n");
 			return 0;
 		}