/* Copyright (C) Joachim Eibl 2003
   Licence: GNU GPL version 2 */

QImage smoothResize( int xSize, int ySize, QImage& inputImg )
{
	if( inputImg.isNull() )
		return inputImg;

	QImage outputImg;
	
	outputImg.create(xSize, ySize, 32);
	
	int inWidth = inputImg.width();
	int inHeight = inputImg.height();

	double xFactor = (double)xSize/inWidth;
	double yFactor = (double)ySize/inHeight;
	
	for ( int x=0; x<xSize; ++x )
	{
		for ( int y=0; y<ySize; ++y )
		{
			double xOrig = x / xFactor;
			double yOrig = y / yFactor;
			double dx = xOrig - floor( xOrig );
			double dy = yOrig - floor( yOrig );
			double f1 = (1-dx)*(1-dy);   // Interpolation
			double f2 = dx * (1-dy);
			double f3 = (1-dx)*dy;
			double f4 = dx*dy;
			
			int xo = min(int(floor(xOrig)),inWidth-1);
			int yo = min(int(floor(yOrig)),inHeight-1);
			int xo1 = min(int(floor(xOrig))+1,inWidth-1);
			int yo1 = min(int(floor(yOrig))+1,inHeight-1);
			
			QRgb c1 = inputImg.pixel( xo, yo );
			QRgb c2 = inputImg.pixel( xo1, yo );
			QRgb c3 = inputImg.pixel( xo, yo1 );
			QRgb c4 = inputImg.pixel( xo1, yo1 );

			int r=int( f1*qRed(c1)+f2*qRed(c2)+f3*qRed(c3)+f4*qRed(c4) );
			int g=int( f1*qGreen(c1)+f2*qGreen(c2)+f3*qGreen(c3)+f4*qGreen(c4));
			int b=int( f1*qBlue(c1)+f2*qBlue(c2)+f3*qBlue(c3)+f4*qBlue(c4) );
			
			outputImg.setPixel( x,y, qRgb(r,g,b) );
		}
	}
	
	return outputImg;
}


void kscaletest::paintEvent(QPaintEvent*)
{
	QImage orig = QImage();
	
	orig.load("/opt/kdecvs/share/icons/hicolor/16x16/actions/reload_page.png");
	
	QImage scaled = orig.scale(100,100);
	QImage smoothScaled = orig.smoothScale(100,100);
	QImage smoothResized = smoothResize(100,100, orig);
	QPainter p(this);
	
	p.drawImage(0,0,orig);
	p.drawImage(20,0,scaled);
	p.drawImage(140,0,smoothScaled);
	p.drawImage(250,0,smoothResized);
}