Qt 标尺绘制Demo C++

#include "sliderruler.h" #include "qpainter.h" #include "qevent.h" #include "qtimer.h" #include "qdebug.h" SliderRuler::SliderRuler(QWidget *parent) : QWidget(parent) { value = 0.0; minValue = 0.0; maxValue = 100.0; precision = 0; longStep = 10; shortStep = 1; space = 20; bgColorStart = QColor(100, 100, 100); bgColorEnd = QColor(60, 60, 60); lineColor = QColor(255, 255, 255); sliderColorTop = QColor(100, 184, 255); sliderColorBottom = QColor(235, 235, 235); tipBgColor = QColor(255, 255, 255); tipTextColor = QColor(50, 50, 50); pressed = false; currentValue = 0; sliderLastPot = QPointF(space, longLineHeight / 2); } void SliderRuler::resizeEvent(QResizeEvent *) { resetVariables(); setValue(currentValue); } void SliderRuler::wheelEvent(QWheelEvent *e) { //滚动的角度,*8就是鼠标滚动的距离 int degrees = e->delta() / 8; //滚动的步数,*15就是鼠标滚动的角度 int steps = degrees / 15; //如果是正数代表为左边移动,负数代表为右边移动 if (e->orientation() == Qt::Vertical) { double value = currentValue - steps; if (steps > 0) { if (value > minValue) { setValue(value); } else { setValue(minValue); } } else { if (value < maxValue) { setValue(value); } else { setValue(maxValue); } } } } void SliderRuler::mousePressEvent(QMouseEvent *e) { if (e->button() & Qt::LeftButton) { if (sliderRect.contains(e->pos())) { pressed = true; update(); } } } void SliderRuler::mouseReleaseEvent(QMouseEvent *e) { pressed = false; update(); } void SliderRuler::mouseMoveEvent(QMouseEvent *e) { if (pressed) { if (e->pos().x() >= lineLeftPot.x() && e->pos().x() <= lineRightPot.x()) { double totalLineWidth = lineRightPot.x() - lineLeftPot.x(); double dx = e->pos().x() - lineLeftPot.x(); double ratio = (double)dx / totalLineWidth; sliderLastPot = QPointF(e->pos().x(), sliderTopPot.y()); currentValue = (maxValue - minValue) * ratio + minValue; this->value = currentValue; emit valueChanged(currentValue); update(); } } } void SliderRuler::paintEvent(QPaintEvent *) { //绘制准备工作,启用反锯齿 QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); //绘制背景 drawBg(&painter); //绘制标尺 drawRule(&painter); //绘制滑块 drawSlider(&painter); //绘制当前值的提示 drawTip(&painter); } void SliderRuler::drawBg(QPainter *painter) { painter->save(); painter->setPen(Qt::NoPen); QLinearGradient bgGradient(0, 0, 0, height()); bgGradient.setColorAt(0.0, bgColorStart); bgGradient.setColorAt(1.0, bgColorEnd); painter->setBrush(bgGradient); painter->drawRect(rect()); painter->restore(); } void SliderRuler::drawRule(QPainter *painter) { painter->save(); painter->setPen(lineColor); //绘制横向标尺底部线,居中 double initX = space; double initY = (double)height() / 2; lineLeftPot = QPointF(initX, initY); lineRightPot = QPointF(width() - initX, initY); painter->drawLine(lineLeftPot, lineRightPot); //绘制纵向标尺刻度 double length = width() - 2 * space; //计算每一格移动多少 double increment = length / (maxValue - minValue); //根据范围值绘制刻度值及刻度值 for (int i = minValue; i <= maxValue; i = i + shortStep) { if (i % longStep == 0) { QPointF topPot(initX, initY - longLineHeight); QPointF bottomPot(initX, initY); painter->drawLine(topPot, bottomPot); QString strValue = QString("%1").arg((double)i, 0, 'f', precision); double textWidth = fontMetrics().width(strValue); double textHeight = fontMetrics().height(); QPointF textPot(initX - textWidth / 2, initY + textHeight); painter->drawText(textPot, strValue); } else { QPointF topPot(initX, initY - shortLineHeight); QPointF bottomPot(initX, initY); painter->drawLine(topPot, bottomPot); } initX += increment * shortStep; } painter->restore(); } void SliderRuler::drawSlider(QPainter *painter) { painter->save(); //绘制滑块上部分三角形 sliderTopPot = QPointF(sliderLastPot.x(), lineLeftPot.y() - longLineHeight / 4); sliderLeftPot = QPointF(sliderTopPot.x() - width() / 100, sliderTopPot.y() + sliderTopHeight); sliderRightPot = QPointF(sliderTopPot.x() + width() / 100, sliderTopPot.y() + sliderTopHeight); painter->setPen(sliderColorTop); painter->setBrush(sliderColorTop); QVector<QPointF> potVec; potVec.append(sliderTopPot); potVec.append(sliderLeftPot); potVec.append(sliderRightPot); painter->drawPolygon(potVec); //绘制滑块下部分矩形 double indicatorLength = sliderRightPot.x() - sliderLeftPot.x(); QPointF handleBottomRightPot(sliderLeftPot.x() + indicatorLength, sliderLeftPot.y() + sliderBottomHeight); sliderRect = QRectF(sliderLeftPot, handleBottomRightPot); QPointF tipRectTopLeftPot(sliderRect.topRight().x() + 2, sliderRect.topRight().y()); QString strValue = QString("%1").arg(currentValue, 0, 'f', precision); double textLength = fontMetrics().width(strValue); double textHeight = fontMetrics().height(); QPointF tipRectBottomRightPot(tipRectTopLeftPot.x() + textLength + 10, tipRectTopLeftPot.y() + textHeight + 5); tipRect = QRectF(tipRectTopLeftPot, tipRectBottomRightPot); painter->setPen(sliderColorBottom); painter->setBrush(sliderColorBottom); painter->drawRect(sliderRect); painter->restore(); } void SliderRuler::drawTip(QPainter *painter) { if (!pressed) { return; } painter->save(); painter->setPen(tipTextColor); painter->setBrush(tipBgColor); painter->drawRect(tipRect); QString strValue = QString("%1").arg(currentValue, 0, 'f', precision); painter->drawText(tipRect, Qt::AlignCenter, strValue); painter->restore(); } void SliderRuler::resetVariables() { longLineHeight = height() / 5; shortLineHeight = height() / 7; sliderTopHeight = height() / 7; sliderBottomHeight = height() / 6; } void SliderRuler::setRange(double minValue, double maxValue) { //如果最小值大于或者等于最大值以及最小值小于0则不设置 if (minValue >= maxValue || minValue < 0) { return; } this->minValue = minValue; this->maxValue = maxValue; setValue(minValue); } void SliderRuler::setRange(int minValue, int maxValue) { setRange((double)minValue, (double)maxValue); } void SliderRuler::setValue(double value) { //值小于最小值或者值大于最大值则无需处理 if (value < minValue || value > maxValue) { return; } double lineWidth = width() - 2 * space; double ratio = (double)value / (maxValue - minValue); double x = lineWidth * ratio; double newX = x + space; double y = space + longLineHeight - 10; sliderLastPot = QPointF(newX, y); this->value = value; this->currentValue = value; emit valueChanged(value); update(); } void SliderRuler::setValue(int value) { setValue((double)value); } void SliderRuler::setPrecision(int precision) { this->precision = precision; update(); } void SliderRuler::setStep(int longStep, int shortStep) { //短步长不能超过长步长 if (longStep < shortStep) { return; } this->longStep = longStep; this->shortStep = shortStep; update(); } void SliderRuler::setSpace(int space) { this->space = space; update(); } void SliderRuler::setBgColor(QColor bgColorStart, QColor bgColorEnd) { this->bgColorStart = bgColorStart; this->bgColorEnd = bgColorEnd; update(); } void SliderRuler::setLineColor(QColor lineColor) { this->lineColor = lineColor; update(); } void SliderRuler::setSliderColor(QColor sliderColorTop, QColor sliderColorBottom) { this->sliderColorTop = sliderColorTop; this->sliderC