add MultiplyBlendEffect

src/Shared/HandyControl_Shared/Resources/Effects/ColorMatrixEffect.fx

@@ -46,11 +46,6 @@ float4 main(float2 uv : TEXCOORD) : COLOR
         k, l, m, n,
         p, q, r, s
     };
-
-    float4 matrixA2 =
-    {
-        e, j, o, t
-    };
     
-    return mul(matrixA1, color) + matrixA2;
+    return mul(matrixA1, color) + float4( e, j, o, t );
 }

src/Shared/HandyControl_Shared/Resources/Effects/MultiplyBlendEffect.fx

@@ -0,0 +1,15 @@
+sampler2D background : register(s0);
+sampler2D foreground : register(s1);
+
+float4 main(float2 uv : TEXCOORD) : COLOR
+{
+	float4 b = tex2D(background, uv);
+	float4 f = tex2D(foreground, uv);
+	float4 o = b;
+
+	f.rgb *= f.a;
+	b.rgb *= b.a;
+	o.rgb = f.rgb * b.rgb + f.rgb * (1 - b.a) + b.rgb * (1 - f.a);
+
+	return o;
+}