From b24c7ee54647fe5c87a9a3e52de543348f505842 Mon Sep 17 00:00:00 2001
From: JonDeen <jonas@ogaard.no>
Date: Fri, 12 Jun 2015 01:40:00 +0200
Subject: [PATCH] Initial HSV

---
 libvips/colour/HSV2sRGB.c | 53 +++++++++++++++++++++++++++++++++------
 libvips/colour/sRGB2HSV.c | 12 ++++++---
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/libvips/colour/HSV2sRGB.c b/libvips/colour/HSV2sRGB.c
index f7df9d88..14c006f5 100644
--- a/libvips/colour/HSV2sRGB.c
+++ b/libvips/colour/HSV2sRGB.c
@@ -38,26 +38,65 @@
 
 #include <stdio.h>
 
+#include <math.h>
+
 #include <vips/vips.h>
 
 #include "pcolour.h"
 
+#define sixth_of_char 42.5
+#define H p[0]
+#define S p[1]
+#define V p[2]
+#define R p[0]
+#define G p[1]
+#define B p[2]
+
 typedef VipsColourCode VipsHSV2sRGB;
 typedef VipsColourCodeClass VipsHSV2sRGBClass;
 
 G_DEFINE_TYPE( VipsHSV2sRGB, vips_HSV2sRGB, VIPS_TYPE_COLOUR_CODE );
 
-static void
-vips_HSV2sRGB_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
-{
+static void vips_HSV2sRGB_line(VipsColour *colour, VipsPel *out, VipsPel **in,
+		int width) {
 	unsigned char *p = (unsigned char *) in[0];
 	unsigned char *q = (unsigned char *) out;
 	int i;
 
-	for( i = 0; i < width; i++ ) {
-		q[0] = p[0];
-		q[1] = p[1];
-		q[2] = p[2];
+
+
+	float c, x, m, s, t, u;
+	for (i = 0; i < width; i++) {
+
+		c = V* S / 255.0f;
+		x = C * (1 - abs(fmod(H / sixth_of_char, 2) - 1));
+		m = V - c;
+
+		if (H < sixth_of_char) {
+			R= (c+m);
+			G= (x+m);
+			B= (0+m);
+		} else if (H < 2*sixth_of_char) {
+			R= (x+m);
+			G= (c+m);
+			B= (0+m);
+		} else if (H < 3*sixth_of_char) {
+			R= (0+m);
+			G= (c+m);
+			B= (x+m);
+		} else if (H < 4*sixth_of_char) {
+			R= (0+m);
+			G= (x+m);
+			B= (c+m);
+		} else if (H < 5*sixth_of_char) {
+			R= (x+m);
+			G= (0+m);
+			B= (c+m);
+		} else {
+			R= (c+m);
+			G= (0+m);
+			B= (x+m);
+		}
 
 		p += 3;
 		q += 3;
diff --git a/libvips/colour/sRGB2HSV.c b/libvips/colour/sRGB2HSV.c
index 82802b09..e45aa155 100644
--- a/libvips/colour/sRGB2HSV.c
+++ b/libvips/colour/sRGB2HSV.c
@@ -58,6 +58,10 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 
 	float wrap_around_hue, secondary_diff;
 
+	#define RED		255.0f;
+	#define GREEN	85.0f;
+	#define BLUE	170.0f;
+
 
 	for( i = 0; i < width; i++ ) {
 
@@ -66,12 +70,12 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 				c_max = p[0];
 				c_min = p[1];
 				secondary_diff = p[1] - p[2];
-				wrap_around_hue = 255.0f;
+				wrap_around_hue = RED;
 			} else {
 				c_max = p[2];
 				c_min = VIPS_MIN(p[1], p[0]);
 				secondary_diff = p[0] - p[1];
-				wrap_around_hue = 170.0f;
+				wrap_around_hue = BLUE;
 			}
 		} else {
 			if (p[1] < p[0]) {
@@ -83,7 +87,7 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 				c_max = p[1];
 				c_min = VIPS_MIN(p[2], p[0]);
 				secondary_diff = p[2] - p[0];
-				wrap_around_hue = 85.0f;
+				wrap_around_hue = GREEN;
 			}
 		}
 
@@ -99,7 +103,7 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 			if (delta == 0) {
 				q[0] = 0;
 			} else {
-				q[0] = (unsigned char) (42.5f*(secondary_diff / (float) delta) + wrap_around_hue);
+				q[0] = (42.5f*(secondary_diff / (float) delta) + wrap_around_hue);
 			}
 
 			q[1] = (( delta*255.0f / (float) c_max));