/****************************************************************************

**

** 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 )

{

    //shadow gets a color inversely proportional to the

    //alpha value

    s = (s*(255-as))/255;

    //then do standard blending

    return as*s + av*v -(av*as*s)/255;  

}

static inline QRgb blendShade( QRgb v, QRgb s )

{

    //pick a number: shadow is 1/3 of object

    int as = qAlpha(s)/3; 

    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 *img;

    img = new QImage( "in.png" );

    int w,h;

    int y;

    img->setAlphaBuffer( TRUE );

    *img = img->convertDepth( 32 );

    w = img->width();

    h = img->height();

#if 0

    for ( y = 0; y < h; y ++ ) {

	uint *line = (uint*)img->scanLine( y );

	for ( int x = 0; x < w; x++ ) {

	    uint pixel = line[x];

	    int r = qRed(pixel);

	    int g = qGreen(pixel);

	    int b = qBlue(pixel);

	    int min = QMIN( r, QMIN( g, b ) );

	    int max = QMAX( r, QMAX( g, b ) );

	    r -= min;

	    g -= min;

	    b -= min;

	    if ( max !=min ) {

		r = (r*255)/(max-min);

		g = (g*255)/(max-min);

		b = (b*255)/(max-min);

	    }

	    int a = 255-min;

	    a -=  (max-min)/3; //hack more transparency for colors.

	    line[x] = qRgba( r, g, b, a );

	}

    }

#endif    

    *img = img->smoothScale( w/2, h/2 );

    qDebug( "saving out.png");

    img->save( "out.png", "PNG" );

    w = img->width();

    h = img->height();

    QImage *img2 = new QImage( w, h, 32 );

    img2->setAlphaBuffer( TRUE );

    for ( y = 0; y < h; y++ ) {

	for ( int x = 0; x < w; x++ ) {

	    QRgb shader = img->pixel( x, y );

	    int as = qAlpha(shader)/3;

	    int r = (qRed(shader)*(255-as))/255;

	    int g = (qGreen(shader)*(255-as))/255;

	    int b = (qBlue(shader)*(255-as))/255;

	    img2->setPixel( x, y, qRgba(r,g,b,as) ); 

	}

    }

    img2->save( "outshade.png", "PNG" );

}