blendish: added BND_DISABLED_ALPHA constant

blendish.h

@@ -199,6 +199,10 @@ typedef enum BNDcornerFlags {
 // default horizontal spacing
 #define BND_HSPACING 8
 
+// alpha of disabled widget groups
+// can be used in conjunction with nvgGlobalAlpha()
+#define BND_DISABLED_ALPHA 0.5
+
 ////////////////////////////////////////////////////////////////////////////////
 
 // set the current theme all widgets will be drawn with.

example.cpp

@@ -119,7 +119,7 @@ void drawUI(NVGcontext *vg, int item, int x, int y) {
     rect.x += x;
     rect.y += y; 
     if (uiGetState(item) == UI_FROZEN) {
-        nvgGlobalAlpha(vg, 0.5);
+        nvgGlobalAlpha(vg, BND_DISABLED_ALPHA);
     }
     if (head) {
         switch(head->subtype) {