旋轉儀表盤,通常用在須要觸摸調節設置值的場景中,其實Qt自己就提供了QDial控件具備相似的功能,本控件最大的難點不在於繪製刻度和指針等,而在於自動計算當前用戶按下處的座標轉換爲當前值,這個功能想了好久,也看了QDial的源碼,他裏邊寫的很是複雜,最後仍是參考的我打99分(100分留給本身將來寫的書,哈哈!)的Qt書籍《c++ gui qt 4編程》中的篇章才寫出來的,關鍵須要用到atan2將座標轉爲值,看來學好數學真的很重要。c++
#ifndef GAUGEDIAL_H #define GAUGEDIAL_H /** * 旋轉儀表盤控件 做者:feiyangqingyun(QQ:517216493) 2016-11-11 * 1:支持指示器樣式選擇 圓形指示器/指針指示器/圓角指針指示器/三角形指示器 * 2:支持鼠標按下旋轉改變值 * 3:支持負數刻度值 * 4:支持設置當前值及範圍值 * 5:支持左右旋轉角度設置 * 6:支持設置大刻度數量和小刻度數量 * 7:支持設置各類顏色 * 8:字號隨窗體拉伸自動變化 * 9:可設置是否顯示當前值 */ #include <QWidget> #ifdef quc #if (QT_VERSION < QT_VERSION_CHECK(5,7,0)) #include <QtDesigner/QDesignerExportWidget> #else #include <QtUiPlugin/QDesignerExportWidget> #endif class QDESIGNER_WIDGET_EXPORT GaugeDial : public QWidget #else class GaugeDial : public QWidget #endif { Q_OBJECT Q_ENUMS(PointerStyle) Q_PROPERTY(double minValue READ getMinValue WRITE setMinValue) Q_PROPERTY(double maxValue READ getMaxValue WRITE setMaxValue) Q_PROPERTY(double value READ getValue WRITE setValue) Q_PROPERTY(int precision READ getPrecision WRITE setPrecision) Q_PROPERTY(int scaleMajor READ getScaleMajor WRITE setScaleMajor) Q_PROPERTY(int scaleMinor READ getScaleMinor WRITE setScaleMinor) Q_PROPERTY(int startAngle READ getStartAngle WRITE setStartAngle) Q_PROPERTY(int endAngle READ getEndAngle WRITE setEndAngle) Q_PROPERTY(QColor darkColor READ getDarkColor WRITE setDarkColor) Q_PROPERTY(QColor lightColor READ getLightColor WRITE setLightColor) Q_PROPERTY(QColor textColor READ getTextColor WRITE setTextColor) Q_PROPERTY(bool showValue READ getShowValue WRITE setShowValue) Q_PROPERTY(PointerStyle pointerStyle READ getPointerStyle WRITE setPointerStyle) public: enum PointerStyle { PointerStyle_Circle = 0, //圓形指示器 PointerStyle_Indicator = 1, //指針指示器 PointerStyle_IndicatorR = 2, //圓角指針指示器 PointerStyle_Triangle = 3 //三角形指示器 }; explicit GaugeDial(QWidget *parent = 0); ~GaugeDial(); protected: void mousePressEvent(QMouseEvent *); void mouseReleaseEvent(QMouseEvent *); void mouseMoveEvent(QMouseEvent *); void paintEvent(QPaintEvent *); void drawScale(QPainter *painter); void drawScaleNum(QPainter *painter); void drawBorderCircle(QPainter *painter); void drawBgCircle(QPainter *painter); void drawPointerCircle(QPainter *painter); void drawPointerIndicator(QPainter *painter); void drawPointerIndicatorR(QPainter *painter); void drawPointerTriangle(QPainter *painter); void drawCenterCircle(QPainter *painter); void drawValue(QPainter *painter); private: double minValue; //最小值 double maxValue; //最大值 double value; //目標值 int precision; //精確度,小數點後幾位 int scaleMajor; //大刻度數量 int scaleMinor; //小刻度數量 int startAngle; //開始旋轉角度 int endAngle; //結束旋轉角度 QColor darkColor; //暗黑顏色 QColor lightColor; //明亮顏色 QColor textColor; //文字顏色 bool showValue; //是否顯示當前值 PointerStyle pointerStyle; //指針樣式 private: //鼠標是否按下 bool pressed; //根據鼠標按下的座標設置當前按下座標處的值 void setPressedValue(QPointF pressedPoint); public: double getMinValue() const; double getMaxValue() const; double getValue() const; int getPrecision() const; int getScaleMajor() const; int getScaleMinor() const; int getStartAngle() const; int getEndAngle() const; QColor getDarkColor() const; QColor getLightColor() const; QColor getTextColor() const; bool getShowValue() const; PointerStyle getPointerStyle() const; QSize sizeHint() const; QSize minimumSizeHint() const; public Q_SLOTS: //設置範圍值 void setRange(double minValue, double maxValue); void setRange(int minValue, int maxValue); //設置最大最小值 void setMinValue(double minValue); void setMaxValue(double maxValue); //設置目標值 void setValue(double value); void setValue(int value); //設置精確度 void setPrecision(int precision); //設置主刻度數量 void setScaleMajor(int scaleMajor); //設置小刻度數量 void setScaleMinor(int scaleMinor); //設置開始旋轉角度 void setStartAngle(int startAngle); //設置結束旋轉角度 void setEndAngle(int endAngle); //設置顏色 void setDarkColor(const QColor &darkColor); void setLightColor(const QColor &lightColor); //設置文本顏色 void setTextColor(const QColor &textColor); //設置是否顯示當前值 void setShowValue(bool showValue); //設置指針樣式 void setPointerStyle(const PointerStyle &pointerStyle); Q_SIGNALS: void valueChanged(int value); }; #endif //GAUGEDIAL_H
void GaugeDial::paintEvent(QPaintEvent *) { int width = this->width(); int height = this->height(); int side = qMin(width, height); //繪製準備工做,啓用反鋸齒,平移座標軸中心,等比例縮放 QPainter painter(this); painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing); painter.translate(width / 2, height / 2); painter.scale(side / 200.0, side / 200.0); //繪製刻度線 drawScale(&painter); //繪製刻度值 drawScaleNum(&painter); //繪製邊界凹凸圓 drawBorderCircle(&painter); //繪製背景圓 drawBgCircle(&painter); //根據指示器形狀繪製指示器 if (pointerStyle == PointerStyle_Circle) { drawPointerCircle(&painter); } else if (pointerStyle == PointerStyle_Indicator) { drawPointerIndicator(&painter); } else if (pointerStyle == PointerStyle_IndicatorR) { drawPointerIndicatorR(&painter); } else if (pointerStyle == PointerStyle_Triangle) { drawPointerTriangle(&painter); } //繪製當前值中心背景圓 drawCenterCircle(&painter); //繪製當前值 drawValue(&painter); } void GaugeDial::drawScale(QPainter *painter) { int radius = 80; painter->save(); painter->rotate(startAngle); int steps = (scaleMajor * scaleMinor); double angleStep = (360.0 - startAngle - endAngle) / steps; QPen pen; pen.setCapStyle(Qt::RoundCap); pen.setColor(textColor); for (int i = 0; i <= steps; i++) { if (i % scaleMinor == 0) { pen.setWidthF(1.5); painter->setPen(pen); painter->drawLine(0, radius - 8, 0, radius); } else { pen.setWidthF(0.5); painter->setPen(pen); painter->drawLine(0, radius - 8, 0, radius - 3); } painter->rotate(angleStep); } painter->restore(); } void GaugeDial::drawScaleNum(QPainter *painter) { int radius = 90; painter->save(); painter->setPen(textColor); double startRad = (360 - startAngle - 90) * (M_PI / 180); double deltaRad = (360 - startAngle - endAngle) * (M_PI / 180) / scaleMajor; for (int i = 0; i <= scaleMajor; i++) { double sina = qSin(startRad - i * deltaRad); double cosa = qCos(startRad - i * deltaRad); double value = 1.0 * i * ((maxValue - minValue) / scaleMajor) + minValue; QString strValue = QString("%1").arg((double)value, 0, 'f', precision); double textWidth = fontMetrics().width(strValue); double textHeight = fontMetrics().height(); int x = radius * cosa - textWidth / 2; int y = -radius * sina + textHeight / 4; painter->drawText(x, y, strValue); } painter->restore(); } void GaugeDial::drawBorderCircle(QPainter *painter) { int radius = 70; painter->save(); painter->setPen(Qt::NoPen); QLinearGradient bgGradient(0, -radius, 0, radius); bgGradient.setColorAt(0.0, darkColor); bgGradient.setColorAt(1.0, lightColor); painter->setBrush(bgGradient); painter->drawEllipse(-radius, -radius, radius * 2, radius * 2); painter->restore(); } void GaugeDial::drawBgCircle(QPainter *painter) { int radius = 60; painter->save(); painter->setPen(Qt::NoPen); QLinearGradient bgGradient(0, -radius, 0, radius); bgGradient.setColorAt(0.0, lightColor); bgGradient.setColorAt(1.0, darkColor); painter->setBrush(bgGradient); painter->drawEllipse(-radius, -radius, radius * 2, radius * 2); painter->restore(); } void GaugeDial::drawPointerCircle(QPainter *painter) { int radius = 15; int offset = 10; painter->save(); painter->setPen(Qt::NoPen); painter->rotate(startAngle); double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (value - minValue); painter->rotate(degRotate); QLinearGradient bgGradient(0, 0, radius * 2, radius * 2); bgGradient.setColorAt(0.0, darkColor); bgGradient.setColorAt(1.0, lightColor); painter->setBrush(bgGradient); painter->drawEllipse(-radius, radius + offset, radius * 2, radius * 2); painter->setPen(QPen(darkColor, 2, Qt::SolidLine, Qt::RoundCap)); painter->drawLine(0, radius * 2 + offset, 0, radius * 2 + 10 + offset); painter->restore(); } void GaugeDial::drawPointerIndicator(QPainter *painter) { int radius = 55; painter->save(); painter->setOpacity(0.8); painter->setPen(Qt::NoPen); painter->setBrush(darkColor); QPolygon pts; pts.setPoints(3, -5, 0, 5, 0, 0, radius); painter->rotate(startAngle); double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (value - minValue); painter->rotate(degRotate); painter->drawConvexPolygon(pts); painter->restore(); } void GaugeDial::drawPointerIndicatorR(QPainter *painter) { int radius = 55; painter->save(); painter->setOpacity(0.6); QPen pen; pen.setWidth(1); pen.setColor(darkColor); painter->setPen(pen); painter->setBrush(darkColor); QPolygon pts; pts.setPoints(3, -5, 0, 5, 0, 0, radius); painter->rotate(startAngle); double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (value - minValue); painter->rotate(degRotate); painter->drawConvexPolygon(pts); //增長繪製圓角直線,與以前三角形重疊,造成圓角指針 pen.setCapStyle(Qt::RoundCap); pen.setWidthF(4); painter->setPen(pen); painter->drawLine(0, 0, 0, radius); painter->restore(); } void GaugeDial::drawPointerTriangle(QPainter *painter) { int radius = 10; int offset = 45; painter->save(); painter->setPen(Qt::NoPen); painter->setBrush(darkColor); QPolygon pts; pts.setPoints(3, -radius / 2, offset, radius / 2, offset, 0, radius + offset); painter->rotate(startAngle); double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (value - minValue); painter->rotate(degRotate); painter->drawConvexPolygon(pts); painter->restore(); } void GaugeDial::drawCenterCircle(QPainter *painter) { if (!showValue) { return; } int radius = 15; painter->save(); painter->setPen(Qt::NoPen); QLinearGradient bgGradient(0, -radius, 0, radius); bgGradient.setColorAt(0.0, darkColor); bgGradient.setColorAt(1.0, lightColor); painter->setBrush(bgGradient); painter->drawEllipse(-radius, -radius, radius * 2, radius * 2); painter->restore(); } void GaugeDial::drawValue(QPainter *painter) { if (!showValue) { return; } int radius = 100; painter->save(); painter->setPen(textColor); QFont font; font.setPixelSize(12); font.setBold(true); painter->setFont(font); QRectF textRect(-radius, -radius, radius * 2, radius * 2); QString strValue = QString("%1").arg((double)value, 0, 'f', precision); painter->drawText(textRect, Qt::AlignCenter, strValue); painter->restore(); } void GaugeDial::setPressedValue(QPointF pressedPoint) { //計算總角度 double length = 360 - startAngle - endAngle; //計算最近的刻度 QPointF point = pressedPoint - rect().center(); double theta = -atan2(-point.x(), -point.y()) * 180 / M_PI; theta = theta + length / 2; //計算每個角度對應值移動多少 double increment = (maxValue - minValue) / length; double currentValue = (theta * increment) + minValue; //過濾圓弧外的值 if (currentValue <= minValue) { currentValue = minValue; } else if (currentValue >= maxValue) { currentValue = maxValue; } setValue(currentValue); }