sys: added color module

sys/Makefile

@@ -91,5 +91,8 @@ endif
 ifneq (,$(filter oneway_malloc,$(USEMODULE)))
     DIRS += oneway-malloc
 endif
+ifneq (,$(filter color,$(USEMODULE)))
+    DIRS += color
+endif
 
 include $(RIOTBASE)/Makefile.base

sys/color/Makefile

@@ -0,0 +1,2 @@
+MODULE = color
+include $(RIOTBASE)/Makefile.base

sys/color/color.c

@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup     sys_color
+ * @{
+ *
+ * @file
+ * @brief       Implementation of color module
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include "color.h"
+
+
+void color_rgb2hsv(color_rgb_t *rgb, color_hsv_t *hsv)
+{
+    float rd, gd, bd, delta, rc, gc, bc;
+
+    /* norm RGB colors to the range [0 - 1.0] */
+    rd = (float)rgb->r / 255.0f;
+    gd = (float)rgb->g / 255.0f;
+    bd = (float)rgb->b / 255.0f;
+
+    /* find value as maximum of the three colors */
+    if (rd >= gd) {
+        hsv->v = (rd >= bd) ? rd : bd;
+    }
+    else {
+        hsv->v = (gd >= bd) ? gd : bd;
+    }
+
+    /* compute delta from value and minimum of the three RGB colors */
+    if (rd <= gd) {
+        delta = (rd <= bd) ? (hsv->v - rd) : (hsv->v - bd);
+    }
+    else {
+        delta = (gd <= bd) ? (hsv->v - gd) : (hsv->v - bd);
+    }
+
+    /* find the saturation from value and delta */
+    hsv->s = (hsv->v != 0.0f) ? (delta / hsv->v) : 0x0f;
+
+    /* compute hue */
+    hsv->h = 0.0f;
+    if (hsv->s != 0.0) {
+        rc = (hsv->v - rd) / delta;
+        gc = (hsv->v - gd) / delta;
+        bc = (hsv->v - bd) / delta;
+
+        if (rd == hsv->v) {
+            hsv->h = bc - gc;
+        }
+        else if (gd == hsv->v) {
+            hsv->h = 2.0f + rc - bc;
+        }
+        else {
+            hsv->h = 4.0f + gc - rc;
+        }
+        hsv->h *= 60.0f;
+        if (hsv->h < 0.0f) {
+            hsv->h += 360.0;
+        }
+    }
+}
+
+void color_hsv2rgb(color_hsv_t *hsv, color_rgb_t *rgb)
+{
+    int i;
+    float aa, bb, cc, f, h;
+
+    if (hsv->s == 0.0f) {
+        rgb->r = (uint8_t)(hsv->v * 255.0f);
+        rgb->g = (uint8_t)(hsv->v * 255.0f);
+        rgb->b = (uint8_t)(hsv->v * 255.0f);
+    }
+    else {
+        h = (hsv->h == 360.0f) ? 0.0 : hsv->h;
+        h /= 60.0f;
+        i = (int)h;
+        f = h - i;
+        aa = hsv->v * (1.0f - hsv->s);
+        bb = hsv->v * (1.0f - (hsv->s * f));
+        cc = hsv->v * (1.0f - (hsv->s * (1.0f - f)));
+
+        switch (i) {
+            case 0:
+                rgb->r = (uint8_t)(hsv->v * 255.0f);
+                rgb->g = (uint8_t)(cc * 255.0f);
+                rgb->b = (uint8_t)(aa * 255.0f);
+                break;
+            case 1:
+                rgb->r = (uint8_t)(bb * 255.0f);
+                rgb->g = (uint8_t)(hsv->v * 255.0f);
+                rgb->b = (uint8_t)(aa * 255.0f);
+                break;
+            case 2:
+                rgb->r = (uint8_t)(aa * 255.0f);
+                rgb->g = (uint8_t)(hsv->v * 255.0f);
+                rgb->b = (uint8_t)(cc * 255.0f);
+                break;
+            case 3:
+                rgb->r = (uint8_t)(aa * 255.0f);
+                rgb->g = (uint8_t)(bb * 255.0f);
+                rgb->b = (uint8_t)(hsv->v * 255.0f);
+                break;
+            case 4:
+                rgb->r = (uint8_t)(cc * 255.0f);
+                rgb->g = (uint8_t)(aa * 255.0f);
+                rgb->b = (uint8_t)(hsv->v * 255.0f);
+                break;
+            case 5:
+                rgb->r = (uint8_t)(hsv->v * 255.0f);
+                rgb->g = (uint8_t)(aa * 255.0f);
+                rgb->b = (uint8_t)(bb * 255.0f);
+                break;
+        }
+    }
+}

sys/include/color.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @defgroup    sys_color Module for handling colors
+ * @ingroup     sys
+ * @brief       The color sys module supports handling RGB and HSV color
+ * @{
+ *
+ * @file
+ * @brief       Headers for the color handling module
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef __COLOR_H
+#define __COLOR_H
+
+#include <stdint.h>
+
+/**
+ * @name Data-structure describing a RGB color
+ */
+typedef struct {
+    uint8_t r;          /**< red value      [0 - 255] */
+    uint8_t g;          /**< green value    [0 - 255] */
+    uint8_t b;          /**< blue value     [0 - 255] */
+} color_rgb_t;
+
+/**
+ * @name Data-structure for holding HSV colors
+ */
+typedef struct {
+    float h;            /**< hue value        [0.0 - 360.0] */
+    float s;            /**< saturation value [0.0 - 1.0] */
+    float v;            /**< value            [0.0 - 1.0] */
+} color_hsv_t;
+
+
+/**
+ * @brief Convert RGB color to HSV color
+ *
+ * @param[in] rgb       Input color encoded in RGB space
+ * @param[out] hsv      Output color encoded in HSV space
+ */
+void color_rgb2hsv(color_rgb_t *rgb, color_hsv_t *hsv);
+
+/**
+ * @brief Convert HSV color to RGB color
+ *
+ * @param[in] hsv       Input color encoded in HSV space
+ * @param[out] rgb      Output color encoded in RGB space
+ */
+void color_hsv2rgb(color_hsv_t *hsv, color_rgb_t *rgb);
+
+#endif /* __COLOR_H */
+/** @} */