From 02a6912ad42eeab316eb4982a215e8272998de6a Mon Sep 17 00:00:00 2001
From: Carsten Haitzler <raster@rasterman.com>
Date: Wed, 9 May 2001 01:57:02 +0000
Subject: [PATCH] add then :)

SVN revision: 4746
---
 src/color_helpers.c | 189 ++++++++++++++++++++++++++++++++++++++++++++
 src/color_helpers.h |   9 +++
 2 files changed, 198 insertions(+)
 create mode 100644 src/color_helpers.c
 create mode 100644 src/color_helpers.h

diff --git a/src/color_helpers.c b/src/color_helpers.c
new file mode 100644
index 0000000..0f0dc51
--- /dev/null
+++ b/src/color_helpers.c
@@ -0,0 +1,189 @@
+#include "color_helpers.h"
+/*
+ * Color space conversion helper routines
+ * Convert between rgb and hsv adn between rgb and hls
+ */
+ 
+void
+__imlib_rgb_to_hsv(int r, int g, int b, float *hue, float *saturation, float *value)
+{
+   int f;
+   float i,j,k,max,min,d;
+
+   i = ((float)r)/255.0;
+   j = ((float)g)/255.0;
+   k = ((float)b)/255.0;
+
+   f = 0;
+   max = min = i;
+   if (j>max) { max = j; f = 1; } else min = j; 
+   if (k>max) { max = k; f = 2; } else if (k<min) min = k;
+   d = max - min;
+
+   *value = max;
+   if (max!=0) *saturation = d/max; else *saturation = 0;
+   if (*saturation==0) 
+      *hue = 0;
+   else
+   {
+      switch (f)
+      {
+         case 0:
+           *hue = (j - k)/d;
+           break;
+         case 1:
+           *hue = 2 + (k - i)/d;
+           break;
+         case 2:
+           *hue = 4 + (i - j)/d;
+           break;
+      }
+      *hue *= 60.0;
+      if (*hue<0) *hue += 360.0;
+   }
+}
+
+void
+__imlib_hsv_to_rgb(float hue, float saturation, float value, int *r, int *g, int *b)
+{
+   int i,p,q,t,h;
+   float vs,vsf;
+
+   i = (int)(value*255.0);
+   if (saturation==0)
+      *r = *g = *b = i;
+   else
+   {
+      if (hue==360) hue = 0;
+      hue = hue/60.0;
+		h = (int)hue;
+      vs = value * saturation;
+		vsf = vs * (hue - h);
+      p = (int)(255.0 * (value - vs));
+      q = (int)(255.0 * (value - vsf));
+      t = (int)(255.0 * (value - vs + vsf));
+      switch (h)
+      {
+         case 0:
+           *r = i;
+			  *g = t;
+			  *b = p;
+			  break;
+         case 1:
+           *r = q;
+			  *g = i;
+			  *b = p;
+           break;
+         case 2:
+           *r = p;
+			  *g = i;
+			  *b = t;
+           break;
+         case 3:
+           *r = p;
+			  *g = q;
+			  *b = i;
+           break;
+         case 4:
+           *r = t;
+			  *g = p;
+			  *b = i;
+           break;
+         case 5:
+           *r = i;
+			  *g = p;
+			  *b = q;
+           break;
+      }
+   }
+}
+
+void
+__imlib_rgb_to_hls(int r, int g, int b, float *hue, float *lightness, float *saturation)
+{
+   int f;
+   float i,j,k,max,min,d;
+
+   i = ((float)r)/255.0;
+   j = ((float)g)/255.0;
+   k = ((float)b)/255.0;
+
+   f = 0;
+   max = min = i;
+   if (j>max) { max = j; f = 1; } else min = j; 
+   if (k>max) { max = k; f = 2; } else if (k<min) min = k;
+   d = max - min;
+
+   *lightness = (max + min)/2.0;
+   if (d==0) 
+   {
+      *saturation = 0;
+      *hue = 0;
+   } 
+   else
+   {
+      if (*lightness < 0.5) *saturation = d/(max + min); else *saturation = d/(2 - max - min);
+      switch (f)
+      {
+         case 0:
+           *hue = (j - k)/d;
+           break;
+         case 1:
+           *hue = 2 + (k - i)/d;
+           break;
+         case 2:
+           *hue = 4 + (i - j)/d;
+           break;
+      }
+      *hue *= 60.0;
+      if (*hue<0) *hue += 360.0;
+   }
+}
+
+void
+__imlib_hls_to_rgb(float hue, float lightness, float saturation, int *r, int *g, int *b)
+{
+   float m1,m2,m21,h;
+
+   if (saturation==0)
+      *r = *g = *b = (int)(lightness * 255.0);
+   else
+   {
+      if (lightness<=0.5)
+         m2 = lightness * (1 + saturation);
+      else
+         m2 = lightness + saturation + lightness * saturation;
+      m1 = 2 * lightness - m2;
+      m21 = m2 - m1;
+      h = hue + 120;
+      if (h>360) h -= 360; else if (h<0) h += 360;
+      if (h<60)
+         *r = (int)(255.0 * (m1 + m21 * h/60.0));
+      else if (h<180)
+         *r = (int)(255.0 * m2);
+      else if (h<240)
+         *r = (int)(255.0 * (m1 + m21 * (240.0 - h)/60.0));
+      else
+         *r = (int)(255.0 * m1);
+      h = hue;
+      if (h>360) h -= 360; else if (h<0) h += 360;
+      if (h<60)
+         *g = (int)(255.0 * (m1 + m21 * h/60.0));
+      else if (h<180)
+         *g = (int)(255.0 * m2);
+      else if (h<240)
+         *g = (int)(255.0 * (m1 + m21 * (240.0 - h)/60.0));
+      else
+         *g = (int)(255.0 * m1);
+      h = hue - 120;
+      if (h>360) h -= 360; else if (h<0) h += 360;
+      if (h<60)
+         *b = (int)(255.0 * (m1 + m21 * h/60.0));
+      else if (h<180)
+         *b = (int)(255.0 * m2);
+      else if (h<240)
+         *b = (int)(255.0 * (m1 + m21 * (240.0 - h)/60.0));
+      else
+         *b = (int)(255.0 * m1);
+   }
+}
diff --git a/src/color_helpers.h b/src/color_helpers.h
new file mode 100644
index 0000000..0ed1999
--- /dev/null
+++ b/src/color_helpers.h
@@ -0,0 +1,9 @@
+#ifndef __COLOR_HELPERS 
+#define __COLOR_HELPERS 1
+
+void        __imlib_rgb_to_hsv(int r, int g, int b, float *hue, float *saturation, float *value);
+void        __imlib_hsv_to_rgb(float hue, float saturation, float value, int *r, int *g, int *b);
+void        __imlib_rgb_to_hls(int r, int g, int b, float *hue, float *lightness, float *saturation);
+void        __imlib_hls_to_rgb(float hue, float lightness, float saturation, int *r, int *g, int *b);
+
+#endif