pie.cpp

linux qt资料

#include <qpainter.h>
#include <math.h>
#include "pie.h"



//
// Construct the PieView with buttons.
//

PieView::PieView( int *n, const char **s )
{
    setCaption( "Pie in the Sky Inc." );

    nums = n;
    strs = s;
    resize( 500, 350 );
}

void PieView::restart( int *n, const char **s )
{
    nums = n;
    strs = s;
    repaint();
}





//
// This function draws a pie chart
//


 

void PieView::drawPies( QPainter *p ) // zero terminated
{


    int sum = 0;
    int n = 0;
    {
	int *ip = nums;
	while (*ip) {
	    sum += *ip++;
	    n++;
	}
	if ( !sum )
	    return;
    }
    QFont f( "times", 18, QFont::Bold );
    p->setFont( f );
    p->setPen( black );				// black pen outline

    int size;

    int apos = -90*16;
    int *val = nums;

    const int w = width();
    const int h = height();

    const int xd = w - w/5;
    const int yd = h - h/5;


    const char ** s = strs;

    QBrush back(white);




    QRect qr(0,0,70,25);
    int i = 0;
    while ((     size = *val++ )) {
	QColor c;
	c.setHsv( ( i++ * 255)/n, 255, 255 );		// rainbow effect
	p->setBrush( c );			// solid fill with color c

	int a = ( size * 360 * 16 )/sum;
	p->drawPie( w/10, h/10, xd, yd, -apos, -a );
	apos += a;

	int x = (int) (cos(M_PI*2* (double)(apos-a/2) / 5760.0) * xd/2);
	int y = (int) (sin(M_PI*2* (double)(apos-a/2) / 5760.0) * yd/2);
	qr.moveCenter( QPoint(x+w/2,y+h/2) );
	p->setBrush(back);
	if ( s ) {
	    if ( *s && **s ) {
		p->drawRect(qr);
		p->drawText(qr, AlignCenter, *s);
	    }
	    s++;
	}

    }

}

//
// Called when the widget needs to be updated.
//

void PieView::paintEvent( QPaintEvent * )
{
    QPainter paint;
    paint.begin( this );
    drawPies( &paint );
    paint.end();		
}