1 files changed, 53 insertions, 0 deletions
diff --git a/examples/canvas/blendshadow.cpp b/examples/canvas/blendshadow.cpp
new file mode 100644
index 0000000..44a7e5d
--- /dev/null
+++ b/examples/canvas/blendshadow.cpp
@@ -0,0 +1,53 @@
+#include <qimage.h>
+#include <qcolor.h>
+
+static inline int blendComponent( int v, int av, int s, int as )
+{
+    return as*s + av*v -(av*as*s)/255;  
+}
+    
+static inline QRgb blendShade( QRgb v, QRgb s )
+{
+    //shadow image is already reduced and blurred
+    int as = qAlpha(s); 
+    int av = qAlpha(v);
+    if ( as == 0 || av == 255 )
+	return v;
+
+    int a = as + av -(as*av)/255;
+    
+    int r = blendComponent( qRed(v),av, qRed(s), as)/a;
+    int g = blendComponent( qGreen(v),av, qGreen(s), as)/a;
+    int b = blendComponent( qBlue(v),av, qBlue(s), as)/a;
+
+    return qRgba(r,g,b,a);
+}
+
+ 
+
+int main( int*, char**)
+{
+    QImage image( "out.png" );
+    image.convertDepth( 32 );
+    QImage shade( "outshade.png" );
+    shade.convertDepth( 32 );
+    int dx = 10;
+    int dy = 5;
+	
+    int w = image.width();
+    int h = image.height();
+	
+    QImage img( w+dx, h+dy, 32 );
+    img.setAlphaBuffer( TRUE );
+
+    for ( int y = 0; y < h+dy; y++ ) {
+	for ( int x = 0; x < w+dx; x++ ) {
+	    QRgb sh =  (x<dx||y<dy) ? 0 : shade.pixel( x-dx, y-dy );
+	    QRgb pixel = (x<w&y<h) ? image.pixel( x, y ) : 0;
+	    img.setPixel( x, y, blendShade( pixel, sh ) ); 
+	}
+    }
+    img.save("blend.png", "PNG" );
+}
+
+