move chans

3 files changed, 36 insertions, 0 deletions

diff --git a/main.c b/main.c
index 2cf7fa0..e2977fa 100644
--- a/main.c
+++ b/main.c
@@ -20,6 +20,7 @@ main(int argc, char **argv)
 	kldImage_mod(sky, KLD_COLOR(m, m, m, 255));
 
 	kldImage_sub(cloud, sky);
+	kldImage_movechans(cloud, KLD_COLOR(3, 3, 2, -1));
 	kldImage_writePAM(cloud, stdout);
 
 	kldImage_free(sky);
diff --git a/src/image.c b/src/image.c
index aa5024a..35d6ee5 100644
--- a/src/image.c
+++ b/src/image.c
@@ -444,6 +444,35 @@ kldImage_mod(KldImage *img, KldColor mask)
 	}
 }
 
+void
+kldImage_movechans(KldImage *img, KldColor cmd)
+{
+	NULL_SAFETY();
+
+	const uint8_t cmds[4] = {
+	    (KLD_COLOR_R(cmd) <= 4) ? KLD_COLOR_R(cmd) : 1,
+	    (KLD_COLOR_G(cmd) <= 4) ? KLD_COLOR_G(cmd) : 2,
+	    (KLD_COLOR_B(cmd) <= 4) ? KLD_COLOR_B(cmd) : 3,
+	    (KLD_COLOR_A(cmd) <= 4) ? KLD_COLOR_A(cmd) : 4,
+	};
+	for (size_t i = 0; i < img->size; i++) {
+		const KldColor col = img->data[i];
+		const uint8_t chans[5] = {
+		    0,
+		    KLD_COLOR_R(col),
+		    KLD_COLOR_G(col),
+		    KLD_COLOR_B(col),
+		    KLD_COLOR_A(col)
+		};
+		img->data[i] = KLD_COLOR(
+		    chans[cmds[0]],
+		    chans[cmds[1]],
+		    chans[cmds[2]],
+		    chans[cmds[3]]
+		);
+	}
+}
+
 int
 kldImage_blend(KldImage *img, KldImage *other, float ratio)
 {
diff --git a/src/image.h b/src/image.h
index 2c6b453..95fe32f 100644
--- a/src/image.h
+++ b/src/image.h
@@ -53,6 +53,12 @@ void kldImage_bit3(KldImage *img);
 
 void kldImage_mod(KldImage *img, KldColor mask);
 
+/* cmd examples:
+ * KLD_COLOR(-1, -1, -1, -1) does nothing
+ * KLD_COLOR(2, 3, 1, -1) R->G G->B B->R A->A
+ * KLD_COLOR(4, -1, 0, 3) R->A B->0 A->B */
+void kldImage_movechans(KldImage *img, KldColor cmd);
+
 /* return -1 if sizes are not equal */
 int kldImage_blend(KldImage *img, KldImage *other, float ratio);