make alpha blend level adjustable, and fixed an overflow bug

svn-id: r5958

2 files changed, 11 insertions, 12 deletions

diff --git a/gui/newgui.cpp b/gui/newgui.cpp
index 4b57bca753..ec7fb3802d 100644
--- a/gui/newgui.cpp
+++ b/gui/newgui.cpp
@@ -315,24 +315,23 @@ void NewGui::line(int x, int y, int x2, int y2, int16 color)
 	}
 }
 
-void NewGui::blendRect(int x, int y, int w, int h, int16 color)
+void NewGui::blendRect(int x, int y, int w, int h, int16 color, int level)
 {
-	#define ALPHA_LEVEL	3
-	uint8 r, g, b;
+	int r, g, b;
 	uint8 ar, ag, ab;
-	_system->colorToRBG(color, r, g, b);
-	
-	r *= ALPHA_LEVEL;
-	g *= ALPHA_LEVEL;
-	b *= ALPHA_LEVEL;
+	_system->colorToRBG(color, ar, ag, ab);
+	r = ar * level;
+	g = ag * level;
+	b = ab * level;
+
 	int16 *ptr = getBasePtr(x, y);
 
 	while (h--) {
 		for (int i = 0; i < w; i++) {
 			_system->colorToRBG(ptr[i], ar, ag, ab);
-			ptr[i] = _system->RBGToColor((ar+r)/(ALPHA_LEVEL+1),
-										 (ag+g)/(ALPHA_LEVEL+1),
-										 (ab+b)/(ALPHA_LEVEL+1));
+			ptr[i] = _system->RBGToColor((ar+r)/(level+1),
+										 (ag+g)/(level+1),
+										 (ab+b)/(level+1));
 		}
 		ptr += _screenPitch;
 	}
diff --git a/gui/newgui.h b/gui/newgui.h
index 7c5dba1ae8..90de55a933 100644
--- a/gui/newgui.h
+++ b/gui/newgui.h
@@ -128,7 +128,7 @@ public:
 	int16 *getBasePtr(int x, int y);
 	void box(int x, int y, int width, int height, bool inverted = false);
 	void line(int x, int y, int x2, int y2, int16 color);
-	void blendRect(int x, int y, int w, int h, int16 color);
+	void blendRect(int x, int y, int w, int h, int16 color, int level = 3);
 	void fillRect(int x, int y, int w, int h, int16 color);
 	void checkerRect(int x, int y, int w, int h, int16 color);
 	void frameRect(int x, int y, int w, int h, int16 color);