Nix packaging.

.gitignore

@@ -1,3 +1,4 @@
 ff-sort
 *.png
 *.jpg
+result

Makefile

@@ -3,9 +3,10 @@
 CC ?= cc
 CFLAGS ?= -Os
 CPPFLAGS += -pedantic -Wall -Wextra
-FARBHERD=1
+FARBHERD=0
 
-DESTDIR ?= /usr/local
+PREFIX ?= /usr/local
+DESTDIR ?= /
 
 # but not this..
 CPPFLAGS += -DFARBHERD=$(FARBHERD)
@@ -14,10 +15,11 @@ BINS=ff-sort
 all: $(BINS)
 
 ff-sort: ff-sort.c
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $^
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $^ -lm
 
 install: $(BINS)
-	install $(BINS) $(DESTDIR)/bin
+	install -d $(DESTDIR)/$(PREFIX)/bin
+	install $(BINS) $(DESTDIR)/$(PREFIX)/bin
 
 clean:
 	rm -f $(BINS)

default.nix

@@ -0,0 +1,10 @@
+with import <nixpkgs> {};
+stdenv.mkDerivation {
+  src = ./.;
+  name = "ff-sort";
+  enableParallelBuilding = true;
+
+  installPhase = ''
+      make install PREFIX=$out
+    '';
+}

ff-sort.c

@@ -33,7 +33,12 @@
 	}
 
 static void usage(char* self, int status) {
-	eprintf("Usage: <farbfeld source> | %s [-x|-y] [-t type] [-l min] [-u max] [type] [args..] | <farbfeld sink>\n", self);
+	eprintf(
+		"Usage: <farbfeld source> | %s [-x|-y] [-l min] [-u max] type [args..] | <farbfeld sink>\n"
+		"Type is one of:\n"
+		"\tred/green/blue - color channel\n"
+		"\tsum - sum of the above\n"
+		"\thue/saturation/value - HSV\n", self);
 	exit(status);
 }
 
@@ -89,7 +94,6 @@ static int options;
 #define SEL_X 0
 #define SEL_Y 1
 
-static int detection = 0;
 #define SEL_BRUTE 0
 #define SEL_EDGES 1 // soon.
 
@@ -300,7 +304,7 @@ int main(int argc, char* argv[]) {
 
 	// parse arguments
 	int opt;
-	while ((opt = getopt(argc, argv, "xyrhu:l:t:")) != -1) {
+	while ((opt = getopt(argc, argv, "xyrhu:l:")) != -1) {
 		switch (opt) {
 		case 'x':
 			options = SEL_X;