Fixes to Color Balance node:

* The Lift/Gamma/Gain formula previously was incorrect, fixed this and 
removed conversions - now the RNA values are the same as what goes into 
the formula.
* Because of this, added the ability for the Value slider to map to a wider range 
than 0.0-1.0. The black/white gradient remains the same, in this case just 
indicating darker/brighter rather than absolute colour values. Also added ability 
for color wheels to be locked at full brightness (useful for this case, where the 
color value itself is dark).
* Added an alternate formula - offset/power/slope (asc-cdl). This fits the standard 
Color Decision List formula, here for compatibility with other systems, though 
default Lift/Gamma/Gain is easier to use and gives nicer results.

1 files changed, 10 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index d9e8f6f55d2..aeea7d4a354 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -1577,6 +1577,11 @@ void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, rcti *rect)
 	rgb_to_hsv(rgb[0], rgb[1], rgb[2], hsv, hsv+1, hsv+2);
 	copy_v3_v3(hsvo, hsv);
 	
+	/* exception: if 'lock' is set (stored in but->a2),
+	 * lock the value of the color wheel to 1.
+	 * Useful for color correction tools where you're only interested in hue. */
+	if (but->a2) hsv[2] = 1.f;
+	
 	hsv_to_rgb(0.f, 0.f, hsv[2], colcent, colcent+1, colcent+2);
 	
 	glShadeModel(GL_SMOOTH);
@@ -1793,7 +1798,7 @@ static void ui_draw_but_HSV_v(uiBut *but, rcti *rect)
 	uiWidgetBase wtb;
 	float rad= 0.5f*(rect->xmax - rect->xmin);
 	float x, y;
-	float rgb[3], hsv[3], v;
+	float rgb[3], hsv[3], v, range;
 	int color_profile = but->block->color_profile;
 	
 	if (but->rnaprop) {
@@ -1808,6 +1813,10 @@ static void ui_draw_but_HSV_v(uiBut *but, rcti *rect)
 	
 	if (color_profile)
 		v = linearrgb_to_srgb(v);
+
+	/* map v from property range to [0,1] */
+	range = but->softmax - but->softmin;
+	v =	(v - but->softmin)/range;
 	
 	widget_init(&wtb);