Qt 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 * )  2 {  3     QPainter painter(this);  4  painter.setRenderHint(QPainter::Antialiasing);  5     painter.setBrush(QColor("black"));  6  painter.drawRect(rect());  7 
    drawBarIndex(0,50,painter,QColor("#7A6864"));  9     drawBarIndex(1,50,painter,QColor("#4D84AF"));  10     drawBarIndex(2,100,painter,QColor("#B8B06C"));  11     drawBarIndex(3,100,painter,QColor("#BD2799"));  12     drawBarIndex(4,100,painter,QColor("#39B708"));  13     drawBarIndex(5,100,painter,QColor("#05AA67"));  14     drawBarIndex(6,100,painter,QColor("#3408AF"));  15     drawBarIndex(7,100,painter,QColor("#980A0A"));  16     drawBarIndex(8,100,painter,QColor("#007CF8"));  17 }  18 

void qbarpainter::drawBarIndex( int index, int valus ,QPainter &painter, QColor color )  21 {  22     int w = width();  23     int h = height()/4;  24     int leftw = 100 + index*100;  25     int step = valus*h*2/100;  26 
    //bottom 椭圆
 painter.save();  29     QRectF bottomrect(leftw,h*3-10,50,15);  30     QLinearGradient bottomlinear(leftw,h*3-step,50,step);  31     bottomlinear.setColorAt(0, color);  32     bottomlinear.setColorAt(0.3, color.lighter(200));  33     bottomlinear.setColorAt(0.35, color.lighter(180));  34     bottomlinear.setColorAt(0.9, color.darker(200));  35     bottomlinear.setColorAt(1, color);  36  bottomlinear.setStart(leftw,h);  37     bottomlinear.setFinalStop(leftw+50,h);  38  painter.setPen(Qt::NoPen);  39  painter.setBrush(bottomlinear);  40  painter.drawEllipse(bottomrect);  41  painter.restore();  42 
    //背景
 painter.save();  45     QLinearGradient bgLinearGradient(leftw,h,50,h*2);  46     bgLinearGradient.setColorAt(0, QColor("#A8C0D0"));  47     bgLinearGradient.setColorAt(0.3, QColor("#CFDBE3"));  48     bgLinearGradient.setColorAt(0.35, QColor("#A2BBCC").lighter(120));  49     bgLinearGradient.setColorAt(0.9, QColor("#767775").lighter(120));  50     bgLinearGradient.setColorAt(1, QColor("#A8C0D0"));  51  bgLinearGradient.setStart(leftw,h);  52     bgLinearGradient.setFinalStop(leftw+50,h);  53 
    QRectF bgrect(leftw,h,50,h*2);  55 
 painter.fillRect(bgrect, bgLinearGradient);  57  painter.restore();  58 
    //中间
 painter.save();  61     QRectF midrect(leftw,h*3-step,50,step);  62 
    QLinearGradient midLinearGradient(leftw,h*3-step,50,step);  64     midLinearGradient.setColorAt(0, color);  65     midLinearGradient.setColorAt(0.3, color.lighter(200));  66     midLinearGradient.setColorAt(0.35, color.lighter(180));  67     midLinearGradient.setColorAt(0.9, color.darker(200));  68     midLinearGradient.setColorAt(1, color);  69  midLinearGradient.setStart(leftw,h);  70     midLinearGradient.setFinalStop(leftw+50,h);  71 
 painter.fillRect(midrect, midLinearGradient);  73  painter.restore();  74 
    ////top 椭圆
 painter.save();  77  painter.setPen(Qt::NoPen);  78     QLinearGradient fade3(leftw, h-30,50,100);  79     fade3.setColorAt(0, QColor("#A8C0D0"));  80     fade3.setColorAt(0.9, QColor("#CFDBE3"));  81     fade3.setColorAt(0.35, QColor("#A2BBCC").darker(120));  82     fade3.setColorAt(0.3, QColor("#767775").darker(120));  83     fade3.setColorAt(0, QColor("#A8C0D0"));  84     fade3.setStart(leftw,h-30);  85     fade3.setFinalStop(leftw,h+20);  86  painter.setBrush(fade3);  87     QRectF rectangle(leftw, h-9, 50, 16);  88  painter.drawEllipse(rectangle);  89  painter.restore();  90     //////////////////////////////////////////////////////////////////////////

    //mid 椭圆
 painter.save();  94     QRectF midtoprect(leftw,h*3-step-9,50.5,15);  95 
    QLinearGradient midtoplinear(leftw,h*3-step,50,step);  97     midtoplinear.setColorAt(0, color.darker(100));  98     midtoplinear.setColorAt(0.3, color.darker(100));  99     midtoplinear.setColorAt(0.35, color.darker(100)); 100     midtoplinear.setColorAt(0.9, color.darker(100)); 101     midtoplinear.setColorAt(1, color.darker(100)); 102  midtoplinear.setStart(leftw,h); 103     midtoplinear.setFinalStop(leftw+50,h); 104  painter.setPen(Qt::NoPen); 105  painter.setBrush(midtoplinear); 106  painter.drawEllipse(midtoprect); 107  painter.restore(); 108 }