examples/graphicsview/portedcanvas/blendshadow.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/graphicsview/portedcanvas/blendshadow.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,94 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#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" );
+}
+
+