paintarea.cpp

Linux窗口程序设计__Qt4精彩实例分析上面的源代码第二部分.以循序渐进的方式进行源代码,包括Qt4下面的图形与图画对话框QMainWindow的源代码.

#include "paintarea.h"

PaintArea::PaintArea(QWidget *parent)
{
    shape = Line;

    QPalette p = palette();
    p.setColor(QPalette::Window,Qt::white);
    setPalette(p);
    setAutoFillBackground(true);
    
    setMinimumSize(400,400);
}

void PaintArea::setShape(Shape s)
{
    shape = s;
    update();
}

void PaintArea::setPen(QPen p)
{
    pen = p;
    update();
}

void PaintArea::setBrush(QBrush b)
{
    brush = b;
    update();
}

void PaintArea::paintEvent(QPaintEvent *)
{
    QPainter p(this);
    p.setPen(pen);
    p.setBrush(brush);
    
    QRect rect(50,100,300,200);
    
    static const QPoint points[4] = {
         QPoint(150, 100),
         QPoint(300, 150),
         QPoint(350, 250),
         QPoint(100, 300)
     };
     
    int startAngle = 30 * 16;
    int spanAngle = 120 * 16;
     
    QPainterPath path;
    path.addRect(150,150,100,100);
    path.moveTo(100,100);
    path.cubicTo(300,100,200,200,300,300);
    path.cubicTo(100,300,200,200,100,100);
    
    
    switch(shape)
    {
    case Line:
        p.drawLine(rect.topLeft(),rect.bottomRight());
        break;
    case Rectangle:
        p.drawRect(rect);
        break;
    case RoundRect:
        p.drawRoundRect(rect);
        break;
    case Ellipse:
        p.drawEllipse(rect);
        break;
    case Polygon:
        p.drawPolygon(points,4);
        break;
    case Polyline:
        p.drawPolyline(points,4);
        break;
    case Points:
        p.drawPoints(points,4);
        break;
    case Arc:
        p.drawArc(rect,startAngle,spanAngle);
        break;
    case Path:
        p.drawPath(path);
        break;
    case Text:
        p.drawText(rect,Qt::AlignCenter,tr("Hello Qt!"));
        break;
    case Pixmap:
        p.drawPixmap(150,150,QPixmap(":/images/butterfly.png"));
        break;
    default:
    	break;
    }
}