Qt实现3D饼图

实现思路：采取画多个圆进行叠加实现3D的效果（参考另外的一个博客内容，忘记具体是哪个了）。

效果1：

代码实现：

void CPieWidget::drawDefault3DPie( QPainter *painter ){qreal sum = getSumValue();int radius = m_radius; //直径//QRect rect = m_pierect;//(w/2-radius/2,h/2-radius/2,radius,radius);painter->save();QPoint centerp = m_pierect.center();QTransform tr;tr.translate(centerp.x(),centerp.y());tr.rotate(-20,Qt::ZAxis);tr.rotate(0,Qt::YAxis);painter->setTransform(tr);QRect rect(-radius/2,-radius/2,radius,radius);//画底图int dep = 20/*radius/30*/;QPen pen;pen.setWidthF(0.2);painter->setPen(pen);//painter->setPen(Qt::NoPen);QStringList keylist = m_datamap.keys();for (int j = 0 ; j < dep; ++j){qreal index = 30;  //启始位置int colorindex = 0;for (int i = 0; i < keylist.count(); ++i){qreal v = m_datamap.value(keylist.at(i));v =v/sum*(360);QRect newrect = rect;if (m_explodedindex == i || m_isexploded){QPoint newcenter = newrect.center();int midangel = index+v/2;QPoint tp = getMovePoint(midangel);newcenter += tp;newrect.moveCenter(newcenter);}QPoint cp = newrect.center() + QPoint(j/2,-j);newrect.moveCenter(cp);QPoint centerPoint = newrect.center();QColor firstColor = m_colorlist.at(colorindex);QRadialGradient firstGradient(centerPoint, radius/2);if (j == 19){firstGradient.setColorAt(0, firstColor.lighter(120));firstGradient.setColorAt(1.0, firstColor.lighter(100));}elsefirstGradient.setColorAt(1.0, firstColor.dark(150));painter->setBrush(firstGradient);painter->drawPie(newrect, index * 16, v * 16);index+=v;colorindex++;if (colorindex==m_colorlist.count()){colorindex = 0;}}}painter->restore();}

效果2：

代码如下：

void CPieWidget::drawDount3DPie( QPainter *painter ){qreal sum = getSumValue();int radius = m_radius; //直径QPoint centerp = m_pierect.center();painter->save();QTransform tr;tr.translate(centerp.x(),centerp.y());tr.rotate(-20,Qt::ZAxis);tr.rotate(0,Qt::YAxis);painter->setTransform(tr);//QRect rect(w/2-radius/2,h/2-radius/2,radius,radius);QRect rect(-radius/2,-radius/2,radius,radius);//画底图int dep = 20/*radius/30*/;QPen pen;pen.setWidthF(0.2);painter->setPen(pen);painter->setPen(Qt::NoPen);QStringList keylist = m_datamap.keys();for (int j = 0 ; j < dep; ++j){qreal index = 30;  //启始位置int colorindex = 0;for (int i = 0; i < keylist.count(); ++i){qreal v = m_datamap.value(keylist.at(i));v =v/sum*(360);QRect newrect = rect;if (m_explodedindex == i || m_isexploded){QPoint newcenter = newrect.center();int midangel = index+v/2;QPoint tp = getMovePoint(midangel);newcenter += tp;newrect.moveCenter(newcenter);}QPoint cp = newrect.center() + QPoint(j/2,-j);newrect.moveCenter(cp);QPoint centerPoint = newrect.center();QColor firstColor = m_colorlist.at(colorindex);QRadialGradient firstGradient(centerPoint, radius/2);firstGradient.setColorAt(0, Qt::transparent);firstGradient.setColorAt(0.6, Qt::transparent);if (j == 19){firstGradient.setColorAt(0.61, firstColor.lighter(120));firstGradient.setColorAt(1.0, firstColor.lighter(100));}else{firstGradient.setColorAt(0.61, firstColor.dark(120));firstGradient.setColorAt(1.0, firstColor.dark(150));}painter->setBrush(firstGradient);painter->drawPie(newrect, index * 16, v * 16);index+=v;colorindex++;if (colorindex==m_colorlist.count()){colorindex = 0;}}}painter->restore();}

相关变量说明

QHash<QString,float> m_datamap;
QList<QColor> m_colorlist;

QRect m_pierect;
QRect m_legendrect;
int m_radius;

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这种方式实现可能会影响效率，因为循环画了多次。