|  | Home · All Classes · Main Classes · Grouped Classes · Modules · Functions |

# blendshadow.cpp Example File
graphicsview/portedcanvas/blendshadow.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2006-2006 Trolltech ASA. All rights reserved.
        **
        ** This file is part of the example classes of the Qt Toolkit.
        **
        ** Licensees holding valid Qt Preview licenses may use this file in
        ** accordance with the Qt Preview License Agreement provided with the
        ** Software.
        **
        ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
        ** information about Qt Commercial License Agreements.
        **
        ** Contact info@trolltech.com if any conditions of this licensing are
        ** not clear to you.
        **
        ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
        ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        **
        ****************************************************************************/

        #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" );
        }