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kdelibs'KGradientSelector (./kdelibs/kdeui/kselect.h:132)

class KGradientSelector : public KSelector
{
  Q_OBJECT
public:
  KGradientSelector( Orientation o, QWidget *parent = 0L,
		     const char *name = 0L );

  void setColors( const QColor &col1, const QColor &col2 )
  {	color1 = col1; color2 = col2; }
  void setText( const QString& t1, const QString& t2 )
  {	text1 = t1; text2 = t2; }

protected:
  virtual void drawContents( QPainter * );

protected:
  QColor color1;
  QColor color2;
  QString text1;
  QString text2;
};

kdelibs'KGradientSelector::KGradientSelector() (./kdelibs/kdeui/kselect.cpp:321)

KGradientSelector::KGradientSelector( Orientation o, QWidget *parent,
		const char *name )
	: KSelector( o, parent, name )
{
	color1.setRgb( 0, 0, 0 );
	color2.setRgb( 255, 255, 255 );

	text1 = text2 = "";
}

kdelibs'KGradientSelector::drawContents() (./kdelibs/kdeui/kselect.cpp:331)

void KGradientSelector::drawContents( QPainter *painter )
{
	QImage image( contentsRect().width(), contentsRect().height(), 32 );

	QColor col;
	float scale;

	int redDiff   = color2.red() - color1.red();
	int greenDiff = color2.green() - color1.green();
	int blueDiff  = color2.blue() - color1.blue();

	if ( orientation() == Vertical )
	{
		for ( int y = 0; y < image.height(); y++ )
		{
			scale = 1.0 * y / image.height();
			col.setRgb( color1.red() + int(redDiff*scale),
						color1.green() + int(greenDiff*scale),
						color1.blue() + int(blueDiff*scale) );

			unsigned int *p = (uint *) image.scanLine( y );
			for ( int x = 0; x < image.width(); x++ )
				*p++ = col.rgb();
		}
	}
	else
	{
		unsigned int *p = (uint *) image.scanLine( 0 );

		for ( int x = 0; x < image.width(); x++ )
		{
			scale = 1.0 * x / image.width();
			col.setRgb( color1.red() + int(redDiff*scale),
						color1.green() + int(greenDiff*scale),
						color1.blue() + int(blueDiff*scale) );
			*p++ = col.rgb();
		}

		for ( int y = 1; y < image.height(); y++ )
			memcpy( image.scanLine( y ), image.scanLine( y - 1),
				 sizeof( unsigned int ) * image.width() );
	}

	QColor ditherPalette[8];

	for ( int s = 0; s < 8; s++ )
		ditherPalette[s].setRgb( color1.red() + redDiff * s / 8,
								color1.green() + greenDiff * s / 8,
								color1.blue() + blueDiff * s / 8 );

	KImageEffect::dither( image, ditherPalette, 8 );

	QPixmap p;
	p.convertFromImage( image );

	painter->drawPixmap( contentsRect().x(), contentsRect().y(), p );

	if ( orientation() == Vertical )
	{
		int yPos = contentsRect().top() + painter->fontMetrics().ascent() + 2;
		int xPos = contentsRect().left() + (contentsRect().width() -
			 painter->fontMetrics().width( text2 )) / 2;
		QPen pen( color2 );
		painter->setPen( pen );
		painter->drawText( xPos, yPos, text2 );

		yPos = contentsRect().bottom() - painter->fontMetrics().descent() - 2;
		xPos = contentsRect().left() + (contentsRect().width() - 
			painter->fontMetrics().width( text1 )) / 2;
		pen.setColor( color1 );
		painter->setPen( pen );
		painter->drawText( xPos, yPos, text1 );
	}
	else
	{
		int yPos = contentsRect().bottom()-painter->fontMetrics().descent()-2;

		QPen pen( color2 );
		painter->setPen( pen );
		painter->drawText( contentsRect().left() + 2, yPos, text1 );

		pen.setColor( color1 );
		painter->setPen( pen );
		painter->drawText( contentsRect().right() -
			 painter->fontMetrics().width( text2 ) - 2, yPos, text2 );
	}
}

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