Re-arrange code

declare `get_color_from_theme()` to be available in common.h
prepare to consolidate color and interpolation methods

gtk2/common_cgtk.h

@@ -61,7 +61,7 @@ static void get_color_from_gtk (GdkColor *c, int which) {
 static float   robtk_colorcache[3][4];
 static bool    robtk_colorcached[3] = { false, false, false };
 
-void get_color_from_theme (int which, float *col) {
+static void get_color_from_theme (int which, float *col) {
 	GdkColor color;
 	assert(which >= 0 && which <= 2);
 

robtk.h

@@ -297,14 +297,7 @@ static void rect_combine(const cairo_rectangle_t *r1, const cairo_rectangle_t *r
 	dest->y = dest_y;
 }
 
-static float rtk_hue2rgb(const float p, const float q, float t) {
-	if(t < 0.f) t += 1.f;
-	if(t > 1.f) t -= 1.f;
-	if(t < 1.f/6.f) return p + (q - p) * 6.f * t;
-	if(t < 1.f/2.f) return q;
-	if(t < 2.f/3.f) return p + (q - p) * (2.f/3.f - t) * 6.f;
-	return p;
-}
+static void get_color_from_theme (int which, float *col);
 
 #include "rtk/style.h"
 #include "rtk/common.h"

rtk/common.h

@@ -23,6 +23,15 @@
 #include <string.h>
 #include <math.h>
 
+static float rtk_hue2rgb(const float p, const float q, float t) {
+	if(t < 0.f) t += 1.f;
+	if(t > 1.f) t -= 1.f;
+	if(t < 1.f/6.f) return p + (q - p) * 6.f * t;
+	if(t < 1.f/2.f) return q;
+	if(t < 2.f/3.f) return p + (q - p) * (2.f/3.f - t) * 6.f;
+	return p;
+}
+
 static void get_interpolate_color (float* c, const float* c1, const float* c2, float f) {
 	assert (f >= 0.f && f <= 1.f);
 	c[0] = c1[0] + f * (c2[0] - c1[0]);