QT环形进度条（圆形进度条）
资源内容介绍
在Qt自带的控件中，只有垂直进度条、水平进度条两种。在平时做页面开发时，有些时候会用到环形进度条，比如说：下载某个文件的下载进度。本示例使用QT实现一个自定义环形进度条。 #include "roundprogressbar.h"#include <QPainter>#include <QTransform>RoundProgressBar::RoundProgressBar(QWidget *parent) : QWidget(parent), m_min(0), m_max(100), m_value(25), m_startAngle(0), m_barStyle(StyleDonut), m_outlinePenWidth(1), m_dataPenWidth(1), m_rebuildBrush(false), m_format("%p%"), m_decimals(1), m_clockwise(true), m_baseCircleVisible(true), m_dataCircleVisible(true), m_centerCircleVisible(true), m_textVisible(true), m_updateFlags(UF_PERCENT){}RoundProgressBar::~RoundProgressBar(){}void RoundProgressBar::setStartAngle(double angle){ if (angle != m_startAngle) { m_startAngle = angle; update(); }}void RoundProgressBar::setBarStyle(RoundProgressBar::BarStyle style){ if (style != m_barStyle) { m_barStyle = style; update(); }}void RoundProgressBar::setOutlinePenWidth(double penWidth){ if (penWidth != m_outlinePenWidth) { m_outlinePenWidth = penWidth; update(); }}void RoundProgressBar::setDataPenWidth(double penWidth){ if (penWidth != m_dataPenWidth) { m_dataPenWidth = penWidth; update(); }}void RoundProgressBar::setDataColors(const QGradientStops &stopPoints){ if (stopPoints != m_gradientData) { m_gradientData = stopPoints; m_rebuildBrush = true; update(); }}void RoundProgressBar::setFormat(const QString &format){ if (format != m_format) { m_format = format; valueFormatChanged(); }}void RoundProgressBar::setDecimals(int count){ if (count >= 0 && count != m_decimals) { m_decimals = count; valueFormatChanged(); }}void RoundProgressBar::setClockwise(bool clockwise){ if(clockwise != m_clockwise) { m_clockwise = clockwise; update(); }}void RoundProgressBar::setRange(double min, double max){ m_min = min; m_max = max; if (m_max < m_min) qSwap(m_max, m_min); if (m_value < m_min) m_value = m_min; else if (m_value > m_max) m_value = m_max; update();}void RoundProgressBar::setValue(int val){ setValue((double)val);}void RoundProgressBar::setValue(double val){ if (m_value != val) { if (val < m_min) m_value = m_min; else if (val > m_max) m_value = m_max; else m_value = val; update(); }}void RoundProgressBar::setBaseCircleVisible(bool visible){ if(visible != m_baseCircleVisible) { m_baseCircleVisible = visible; update(); }}void RoundProgressBar::setDataCircleVisible(bool visible){ if(visible != m_dataCircleVisible) { m_dataCircleVisible = visible; update(); }}void RoundProgressBar::setCenterCircleVisible(bool visible){ if(visible != m_centerCircleVisible) { m_centerCircleVisible = visible; update(); }}void RoundProgressBar::setTextVisible(bool visible){ if(visible != m_textVisible) { m_textVisible = visible; update(); }}void RoundProgressBar::paintEvent(QPaintEvent *event){ Q_UNUSED(event); double outerRadius = qMin(width(), height()); QRectF baseRect(1, 1, outerRadius-2, outerRadius-2); QImage buffer(outerRadius, outerRadius, QImage::Format_ARGB32_Premultiplied); QPainter p(&buffer); p.setRenderHint(QPainter::Antialiasing); //data brush rebuildDataBrushIfNeeded(); // background drawBackground(p, buffer.rect()); // base circle if(m_baseCircleVisible) drawBase(p, baseRect); // data circle double delta = (m_max - m_min) / (m_value - m_min); if(m_dataCircleVisible) drawValue(p, baseRect, m_value, delta); // center circle double innerRadius(0); QRectF innerRect; calculateInnerRect(baseRect, outerRadius, innerRect, innerRadius); if(m_centerCircleVisible) drawInnerBackground(p, innerRect); // text if(m_textVisible) drawText(p, innerRect, innerRadius, m_value); // finally draw the bar p.end(); QTransform transform; transform.translate((width()-outerRadius)/2, (height()-outerRadius)/2); QPainter painter(this); painter.setTransform(transform); painter.fillRect(baseRect, palette().background()); painter.drawImage(0,0, buffer);}void RoundProgressBar::drawBackground(QPainter &p, const QRectF &baseRect){ p.fillRect(baseRect, palette().background());}void RoundProgressBar::drawBase(QPainter &p, const QRectF &baseRect){ switch (m_barStyle) { case StyleDonut: p.setPen(QPen(palette().shadow().color(), m_outlinePenWidth)); p.setBrush(palette().base()); p.drawEllipse(baseRect); break; case StylePie: p.setPen(QPen(palette().base().color(), m_outlinePenWidth)); p.setBrush(palette().base()); p.drawEllipse(baseRect); break; case StyleLine: p.setPen(QPen(palette().base().color(), m_outlinePenWidth)); p.setBrush(Qt::NoBrush); p.drawEllipse(baseRect.adjusted(m_outlinePenWidth/2, m_outlinePenWidth/2, -m_outlinePenWidth/2, -m_outlinePenWidth/2)); break; default: break; }}void RoundProgressBar::drawValue(QPainter &p, const QRectF &baseRect, double value, double delta){ if (value == m_min) return; // for Line style if (m_barStyle == StyleLine) { p.setPen(QPen(palette().highlight().color(), m_dataPenWidth)); p.setBrush(Qt::NoBrush); if (value == m_max) { p.drawEllipse( baseRect.adjusted(m_outlinePenWidth/2, m_outlinePenWidth/2, -m_outlinePenWidth/2, -m_outlinePenWidth/2)); } else { double arcLength = 360.0 / delta; p.drawArc( baseRect.adjusted(m_outlinePenWidth/2, m_outlinePenWidth/2, -m_outlinePenWidth/2, -m_outlinePenWidth/2), m_startAngle * 16, m_clockwise?-arcLength * 16:arcLength * 16); } return; } // for Pie and Donut styles QPainterPath dataPath; dataPath.setFillRule(Qt::WindingFill); // pie segment outer if (value == m_max) { dataPath.addEllipse(baseRect); } else { double arcLength = 360.0 / delta; dataPath.moveTo(baseRect.center()); dataPath.arcTo(baseRect, m_startAngle, m_clockwise?-arcLength:arcLength); dataPath.lineTo(baseRect.center()); } p.setBrush(palette().highlight()); p.setPen(QPen(palette().shadow().color(), m_dataPenWidth)); p.drawPath(dataPath);}void RoundProgressBar::calculateInnerRect(const QRectF &, double outerRadius, QRectF &innerRect, double &innerRadius){ // for Line and Expand styles if (m_barStyle == StyleLine) { innerRadius = outerRadius - m_outlinePenWidth; } else // for Pie and Donut styles { innerRadius = outerRadius * 0.75; } double delta = (outerRadius - innerRadius) / 2; innerRect = QRectF(delta, delta, innerRadius, innerRadius);}void RoundProgressBar::drawInnerBackground(QPainter &p, const QRectF &innerRect){ if (m_barStyle == StyleDonut) { p.setBrush(palette().alternateBase()); p.drawEllipse(innerRect); }}void RoundProgressBar::drawText(QPainter &p, const QRectF &innerRect, double innerRadius, double value){ if (m_format.isEmpty()) return; // !!! to revise QFont f(font()); f.setPixelSize(10);