Qt编写自定义控件1

前言

汽车仪表盘几乎是qt写仪表盘控件中最常见的，一般来说先要求美工做好设计图，然后设计效果图给到程序员，由程序员根据效果来实现，主要靠贴图，这种方法有个好处就是做出来的效果比较逼真，和真实效果图基本上保持一致，而且程序员也不会那么累，基本上入门级别的程序员都可以搞定，效率比较高，缺点是如果用户需要更改某个部件的颜色，比如指针的颜色等，需要重新做效果图贴图才能实现，比较麻烦，还有一点就是如果效果图原图不是很大，则遇到特殊分辨率情况下，可能会有失真的情况，被强制拉伸等。

我一贯都喜欢用painter来绘制，以规避后面几点的缺点，也可以锻炼下自己的审美能力，所谓心中有坐标，万物皆painter。

实现的功能

• 1:可设置范围值支持负数值
• 2:可设置精确度最大支持小数点后3位
• 3:可设置大刻度数量/小刻度数量
• 4:可设置开始旋转角度/结束旋转角度
• 5:可设置是否启用动画效果以及动画效果每次移动的步长
• 6:可设置外圆背景/内圆背景/饼圆三种颜色/刻度尺颜色/文字颜色
• 7:自适应窗体拉伸刻度尺和文字自动缩放
• 8:可自由拓展各种渐变色各圆的半径
• 9:三色圆环按照比例设置范围角度 用户可以自由设置三色占用比例
• 10:圆环样式可选择 三色圆环 当前圆环
• 11:指示器样式可选择 圆形指示器 指针指示器 圆角指针指示器 三角形指示器

效果图

核心代码

void GaugeCar::paintEvent(QPaintEvent *)
{
 int width = this->width();
 int height = this->height();
 int side = qMin(width height);
 //绘制准备工作启用反锯齿平移坐标轴中心等比例缩放
 QPainter painter(this);
 painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
 painter.translate(width / 2 height / 2);
 painter.scale(side / 200.0 side / 200.0);
 //绘制外圆
 drawOuterCircle(&painter);
 //绘制内圆
 drawInnerCircle(&painter);
 //绘制饼圆
 drawColorPie(&painter);
 //绘制覆盖圆 用以遮住饼圆多余部分
 drawCoverCircle(&painter);
 //绘制刻度线
 drawScale(&painter);
 //绘制刻度值
 drawScaleNum(&painter);
 //根据指示器形状绘制指示器
 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);
 }
 //绘制指针中心圆外边框
 drawRoundCircle(&painter);
 //绘制指针中心圆
 drawCenterCircle(&painter);
 //绘制当前值
 drawValue(&painter);
 //绘制遮罩层
 drawOverlay(&painter);
}
void GaugeCar::drawOuterCircle(QPainter *painter)
{
 int radius = 99;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(outerCircleColor);
 painter->drawEllipse(-radius -radius radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawInnerCircle(QPainter *painter)
{
 int radius = 90;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(innerCircleColor);
 painter->drawEllipse(-radius -radius radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawColorPie(QPainter *painter)
{
 int radius = 60;
 painter->save();
 painter->setPen(Qt::NoPen);
 QRectF rect(-radius -radius radius * 2 radius * 2);
 if (pieStyle == PieStyle_Three) {
 //计算总范围角度根据占比例自动计算三色圆环范围角度
 //可以更改比例
 double angleAll = 360.0 - startAngle - endAngle;
 double angleStart = angleAll * 0.7;
 double angleMid = angleAll * 0.15;
 double angleEnd = angleAll * 0.15;
 //增加偏移量使得看起来没有脱节
 int offset = 3;
 //绘制开始饼圆
 painter->setBrush(pieColorStart);
 painter->drawPie(rect (270 - startAngle - angleStart) * 16 angleStart * 16);
 //绘制中间饼圆
 painter->setBrush(pieColorMid);
 painter->drawPie(rect (270 - startAngle - angleStart - angleMid) * 16 + offset angleMid * 16);
 //绘制结束饼圆
 painter->setBrush(pieColorEnd);
 painter->drawPie(rect (270 - startAngle - angleStart - angleMid - angleEnd) * 16 + offset * 2 angleEnd * 16);
 } else if (pieStyle == PieStyle_Current) {
 //计算总范围角度当前值范围角度剩余值范围角度
 double angleAll = 360.0 - startAngle - endAngle;
 double angleCurrent = angleAll * ((currentValue - minValue) / (maxValue - minValue));
 double angleOther = angleAll - angleCurrent;
 //绘制当前值饼圆
 painter->setBrush(pieColorStart);
 painter->drawPie(rect (270 - startAngle - angleCurrent) * 16 angleCurrent * 16);
 //绘制剩余值饼圆
 painter->setBrush(pieColorEnd);
 painter->drawPie(rect (270 - startAngle - angleCurrent - angleOther) * 16 angleOther * 16);
 }
 painter->restore();
}
void GaugeCar::drawCoverCircle(QPainter *painter)
{
 int radius = 50;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(coverCircleColor);
 painter->drawEllipse(-radius -radius radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawScale(QPainter *painter)
{
 int radius = 72;
 painter->save();
 painter->rotate(startAngle);
 int steps = (scaleMajor * scaleMinor);
 double angleStep = (360.0 - startAngle - endAngle) / steps;
 QPen pen;
 pen.setColor(scaleColor);
 pen.setCapStyle(Qt::RoundCap);
 for (int i = 0; i <= steps; i++) {
 if (i % scaleMinor == 0) {
 pen.setWidthF(1.5);
 painter->setPen(pen);
 painter->drawLine(0 radius - 10 0 radius);
 } else {
 pen.setWidthF(0.5);
 painter->setPen(pen);
 painter->drawLine(0 radius - 5 0 radius);
 }
 painter->rotate(angleStep);
 }
 painter->restore();
}
void GaugeCar::drawScaleNum(QPainter *painter)
{
 int radius = 82;
 painter->save();
 painter->setPen(scaleColor);
 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 GaugeCar::drawPointerCircle(QPainter *painter)
{
 int radius = 6;
 int offset = 30;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(pointerColor);
 painter->rotate(startAngle);
 double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (currentValue - minValue);
 painter->rotate(degRotate);
 painter->drawEllipse(-radius radius + offset radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawPointerIndicator(QPainter *painter)
{
 int radius = 75;
 painter->save();
 painter->setOpacity(0.8);
 painter->setPen(Qt::NoPen);
 painter->setBrush(pointerColor);
 QPolygon pts;
 pts.setPoints(3 -5 0 5 0 0 radius);
 painter->rotate(startAngle);
 double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (currentValue - minValue);
 painter->rotate(degRotate);
 painter->drawConvexPolygon(pts);
 painter->restore();
}
void GaugeCar::drawPointerIndicatorR(QPainter *painter)
{
 int radius = 75;
 painter->save();
 painter->setOpacity(1.0);
 QPen pen;
 pen.setWidth(1);
 pen.setColor(pointerColor);
 painter->setPen(pen);
 painter->setBrush(pointerColor);
 QPolygon pts;
 pts.setPoints(3 -5 0 5 0 0 radius);
 painter->rotate(startAngle);
 double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (currentValue - minValue);
 painter->rotate(degRotate);
 painter->drawConvexPolygon(pts);
 //增加绘制圆角直线与之前三角形重叠形成圆角指针
 pen.setCapStyle(Qt::RoundCap);
 pen.setWidthF(4);
 painter->setPen(pen);
 painter->drawLine(0 0 0 radius);
 painter->restore();
}
void GaugeCar::drawPointerTriangle(QPainter *painter)
{
 int radius = 10;
 int offset = 38;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(pointerColor);
 QPolygon pts;
 pts.setPoints(3 -5 0 + offset 5 0 + offset 0 radius + offset);
 painter->rotate(startAngle);
 double degRotate = (360.0 - startAngle - endAngle) / (maxValue - minValue) * (currentValue - minValue);
 painter->rotate(degRotate);
 painter->drawConvexPolygon(pts);
 painter->restore();
}
void GaugeCar::drawRoundCircle(QPainter *painter)
{
 int radius = 18;
 painter->save();
 painter->setOpacity(0.8);
 painter->setPen(Qt::NoPen);
 painter->setBrush(pointerColor);
 painter->drawEllipse(-radius -radius radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawCenterCircle(QPainter *painter)
{
 int radius = 15;
 painter->save();
 painter->setPen(Qt::NoPen);
 painter->setBrush(centerCircleColor);
 painter->drawEllipse(-radius -radius radius * 2 radius * 2);
 painter->restore();
}
void GaugeCar::drawValue(QPainter *painter)
{
 int radius = 100;
 painter->save();
 painter->setPen(textColor);
 QFont font;
 font.setPixelSize(18);
 painter->setFont(font);
 QRectF textRect(-radius -radius radius * 2 radius * 2);
 QString strValue = QString("%1").arg((double)currentValue 0 'f' precision);
 painter->drawText(textRect Qt::AlignCenter strValue);
 painter->restore();
}
void GaugeCar::drawOverlay(QPainter *painter)
{
 if (!showOverlay) {
 return;
 }
 int radius = 90;
 painter->save();
 painter->setPen(Qt::NoPen);
 QPainterPath smallCircle;
 QPainterPath bigCircle;
 radius -= 1;
 smallCircle.addEllipse(-radius -radius radius * 2 radius * 2);
 radius *= 2;
 bigCircle.addEllipse(-radius -radius + 140 radius * 2 radius * 2);
 //高光的形状为小圆扣掉大圆的部分
 QPainterPath highlight = smallCircle - bigCircle;
 QLinearGradient linearGradient(0 -radius / 2 0 0);
 overlayColor.setAlpha(100);
 linearGradient.setColorAt(0.0 overlayColor);
 overlayColor.setAlpha(30);
 linearGradient.setColorAt(1.0 overlayColor);
 painter->setBrush(linearGradient);
 painter->rotate(-20);
 painter->drawPath(highlight);
 painter->restore();
}

控件介绍

1. 超过140个精美控件，涵盖了各种仪表盘、进度条、进度球、指南针、曲线图、标尺、温度计、导航条、导航栏，flatui、高亮按钮、滑动选择器、农历等。远超qwt集成的控件数量。
2. 每个类都可以独立成一个单独的控件，零耦合，每个控件一个头文件和一个实现文件，不依赖其他文件，方便单个控件以源码形式集成到项目中，较少代码量。qwt的控件类环环相扣，高度耦合，想要使用其中一个控件，必须包含所有的代码。
3. 全部纯Qt编写，QWidget+QPainter绘制，支持Qt4.6到Qt5.12的任何Qt版本，支持mingw、msvc、gcc等编译器，不乱码，可直接集成到Qt Creator中，和自带的控件一样使用，大部分效果只要设置几个属性即可，极为方便。
4. 每个控件都有一个对应的单独的包含该控件源码的DEMO，方便参考使用。同时还提供一个所有控件使用的集成的DEMO。
5. 每个控件的源代码都有详细中文注释，都按照统一设计规范编写，方便学习自定义控件的编写。
6. 每个控件默认配色和demo对应的配色都非常精美。
7. 超过120个可见控件，6个不可见控件。
8. 部分控件提供多种样式风格选择，多种指示器样式选择。
9. 所有控件自适应窗体拉伸变化。
10. 集成自定义控件属性设计器，支持拖曳设计，所见即所得，支持导入导出xml格式。
11. 自带activex控件demo，所有控件可以直接运行在ie浏览器中。
12. 集成fontawesome图形字体+阿里巴巴iconfont收藏的几百个图形字体，享受图形字体带来的乐趣。
13. 所有控件最后生成一个dll动态库文件，可以直接集成到qtcreator中拖曳设计使用。