QPainter实现3d柱状图

利用QPainter实现漂亮的柱状图。看一下效果

利用渐进色实现三维的效果。
代码如下

void qbarpainter::paintEvent( QPaintEvent * )
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setBrush(QColor("black"));
    painter.drawRect(rect());

    drawBarIndex(0,50,painter,QColor("#7A6864"));
    drawBarIndex(1,50,painter,QColor("#4D84AF"));
    drawBarIndex(2,100,painter,QColor("#B8B06C"));
    drawBarIndex(3,100,painter,QColor("#BD2799"));
    drawBarIndex(4,100,painter,QColor("#39B708"));
    drawBarIndex(5,100,painter,QColor("#05AA67"));
    drawBarIndex(6,100,painter,QColor("#3408AF"));
    drawBarIndex(7,100,painter,QColor("#980A0A")); 
    drawBarIndex(8,100,painter,QColor("#007CF8")); 
}


void qbarpainter::drawBarIndex( int index, int valus ,QPainter &painter, QColor color )
{
    int w = width();
    int h = height()/4;
    int leftw = 100 + index*100;
    int step = valus*h*2/100;

    //bottom 椭圆
    painter.save();
    QRectF bottomrect(leftw,h*3-10,50,15);
    QLinearGradient bottomlinear(leftw,h*3-step,50,step);
    bottomlinear.setColorAt(0, color);
    bottomlinear.setColorAt(0.3, color.lighter(200));
    bottomlinear.setColorAt(0.35, color.lighter(180));
    bottomlinear.setColorAt(0.9, color.darker(200));
    bottomlinear.setColorAt(1, color);
    bottomlinear.setStart(leftw,h);
    bottomlinear.setFinalStop(leftw+50,h);
    painter.setPen(Qt::NoPen);
    painter.setBrush(bottomlinear);
    painter.drawEllipse(bottomrect);    
    painter.restore();

    //背景
    painter.save();
    QLinearGradient bgLinearGradient(leftw,h,50,h*2);
    bgLinearGradient.setColorAt(0, QColor("#A8C0D0"));
    bgLinearGradient.setColorAt(0.3, QColor("#CFDBE3"));
    bgLinearGradient.setColorAt(0.35, QColor("#A2BBCC").lighter(120));
    bgLinearGradient.setColorAt(0.9, QColor("#767775").lighter(120));
    bgLinearGradient.setColorAt(1, QColor("#A8C0D0"));
    bgLinearGradient.setStart(leftw,h);
    bgLinearGradient.setFinalStop(leftw+50,h);

    QRectF bgrect(leftw,h,50,h*2);

    painter.fillRect(bgrect, bgLinearGradient);
    painter.restore();

    //中间
    painter.save();
    QRectF midrect(leftw,h*3-step,50,step);

    QLinearGradient midLinearGradient(leftw,h*3-step,50,step);
    midLinearGradient.setColorAt(0, color);
    midLinearGradient.setColorAt(0.3, color.lighter(200));
    midLinearGradient.setColorAt(0.35, color.lighter(180));
    midLinearGradient.setColorAt(0.9, color.darker(200));
    midLinearGradient.setColorAt(1, color);
    midLinearGradient.setStart(leftw,h);
    midLinearGradient.setFinalStop(leftw+50,h);

    painter.fillRect(midrect, midLinearGradient);   
    painter.restore();

    ////top 椭圆
    painter.save();
    painter.setPen(Qt::NoPen);
    QLinearGradient fade3(leftw, h-30,50,100);
    fade3.setColorAt(0, QColor("#A8C0D0"));
    fade3.setColorAt(0.9, QColor("#CFDBE3"));
    fade3.setColorAt(0.35, QColor("#A2BBCC").darker(120));
    fade3.setColorAt(0.3, QColor("#767775").darker(120));
    fade3.setColorAt(0, QColor("#A8C0D0"));
    fade3.setStart(leftw,h-30);
    fade3.setFinalStop(leftw,h+20);
    painter.setBrush(fade3);
    QRectF rectangle(leftw, h-9, 50, 16);
    painter.drawEllipse(rectangle);
    painter.restore();
    //////////////////////////////////////////////////////////////////////////

    //mid 椭圆
    painter.save();
    QRectF midtoprect(leftw,h*3-step-9,50.5,15);

    QLinearGradient midtoplinear(leftw,h*3-step,50,step);
    midtoplinear.setColorAt(0, color.darker(100));
    midtoplinear.setColorAt(0.3, color.darker(100));
    midtoplinear.setColorAt(0.35, color.darker(100));
    midtoplinear.setColorAt(0.9, color.darker(100));
    midtoplinear.setColorAt(1, color.darker(100));
    midtoplinear.setStart(leftw,h);
    midtoplinear.setFinalStop(leftw+50,h);
    painter.setPen(Qt::NoPen);
    painter.setBrush(midtoplinear);
    painter.drawEllipse(midtoprect);    
    painter.restore();
}