Qt之画刻度尺入门

Qt之画刻度尺入门

效果图

上源码

#include "rulerslider.h"
#include "QPainter"
#include "math.h"

#include 
#include 
#include 

RulerSlider::RulerSlider(QWidget *parent):QSlider(parent)

{
     

    //注册过滤器

    installEventFilter(this);

    //鼠标事件追踪

    setMouseTracking(true);

    //显示当前值label

    valueLabel = new QLabel(this);

    valueLabel->setStyleSheet("background-color: rgb(0, 0, 0);font-size:14px;color:white;border:1px solid black");

    valueLabel->setAlignment(Qt::AlignCenter);

    valueLabel->hide();

    //滑块

    handleLabel = new QLabel(this);

    handleLabel->setFixedSize(20,15);

    handleLabel->raise();

    QImage image,result;

    image.load(":/images/handle.png");//temppath为图片的路径

    result = image.scaled(handleLabel->width(), handleLabel->height(),Qt::IgnoreAspectRatio, Qt::SmoothTransformation);//放缩图片，以固定大小显示

    handleLabel->setPixmap(QPixmap::fromImage(result));//在Label控件上显示图片

}

RulerSlider::~RulerSlider()

{
     

}

/**

* 绘制

* @brief RulerSlider::paintEvent

*/

void RulerSlider::paintEvent(QPaintEvent *)

{
     

    QPainter painter;

    painter.begin(this);

    //抗锯齿

    painter.setRenderHint(QPainter::Antialiasing);

    drawRulerBackgroud(&painter);

    drawSliderMark(&painter);

    painter.end();

}

/**

* 绘制尺子背景

* @brief RulerSlider::drawRulerBackgroud

* @param painter

*/

void RulerSlider::drawRulerBackgroud(QPainter *painter)

{
     

    QPointF topLeftPot3(0,0);

    QPointF bottomRightPot3(width(),height());

    painter->setPen(Qt::white);

    painter->setBrush(QColor(61,84,110));

    painter->drawRect(QRectF(topLeftPot3,bottomRightPot3));

}

/**

* 绘制刻度与值

* @brief RulerSlider::drawSliderMark

* @param painter

*/

void RulerSlider::drawSliderMark(QPainter *painter)

{
     

    painter->setPen(Qt::gray);

    painter->setBrush(QColor(128,128,128));

    //计算刻度之间的间隔最小为10

    int dis = maximum()-minimum();

    //绘制横坐标开始起点

    qreal startX = SIDEDISTANCE;

   // for (uint16_t i=minimum();i<=(minimum()+dis/singleStep());i++) {
     
    for (uint16_t i=minimum();i<=1000;i++) {
     

        //偶数

        if(i%2 == 0 && i%5 == 0){
     

            painter->drawRect(QRectF(startX,0,0.1,BIG_Y));

            //绘制刻度值

            float value = round(minimum()+((i-minimum())*singleStep()));

            QString strValue = tr("%1").arg(value);

            int fontWidth = fontMetrics().width(strValue)/2;

            painter->drawText(QPointF(startX-fontWidth,BIG_Y+15),strValue);

        }else {
     

            if(i%5 == 0){
     

                painter->drawRect(QRectF(startX,0,0.1,MIDDLE_Y));

            }else{
     

                painter->drawRect(QRectF(startX,0,0.1,SMALL_Y));

            }

        }

        startX+=sliderInterval;

    }

}

/**

* 根据鼠标位置获取当前值

* @brief RulerSlider::eventPosGetValue

* @param ev

*/

void RulerSlider::eventPosGetValue(QMouseEvent *ev)

{
     

    //光标所在矩形范围

    double posWidth = (double)width()-SIDEDISTANCER-SIDEDISTANCE;

    //鼠标光标位置

    double xpos = ev->pos().x();

    if(xpos >=SIDEDISTANCE&&xpos<=width()-SIDEDISTANCER){
     

        //根据光标计算

        double posValue = (xpos-SIDEDISTANCE)/posWidth;

        int value =round(posValue * (maximum()-minimum()) + minimum());

        handleLabel->move(xpos-handleLabel->width()/2,0);

        qDebug()<<"结果值"<<value;

        setValue(value);

    }

}

/**

* 设置slider范围

* @brief RulerSlider::setRulerSliderRange

* @param min

* @param max

*/

void RulerSlider::setRulerSliderRange(int min, int max)

{
     

    //当设置的最小值为负数或0时，设置最小值为0

    int minNum = min;

    int maxNum = max;

    if(min<=0){
     

        minNum = 0;

    }

    //当最大值与最小值之间差值

    if(max-min <= DIFFERVALUE){
     

        maxNum = min+DIFFERVALUE;

    }

    qDebug()<<"滑动条"<<value()<<minNum<<maxNum;

    setMaximum(maxNum);

    setMinimum(minNum);

    if(value()>minNum){
     

        int dis = maxNum-minNum;

        sliderInterval = (float)(width()-SIDEDISTANCE-SIDEDISTANCER)/(dis/singleStep());

        double pos = ((value()-minNum)/singleStep())*sliderInterval+SIDEDISTANCE;

        handleLabel->move(pos-handleLabel->width()/2,0);

    }else {
     

        handleLabel->move(SIDEDISTANCE-handleLabel->width()/2,0);

    }

    update();

}

/**

* 设置当前值

* @brief RulerSlider::setRulerSliderValue

* @param value

*/

void RulerSlider::setRulerSliderValue(int value)

{
     

    int dis = maximum()-minimum();

    sliderInterval = (float)(width()-SIDEDISTANCE-SIDEDISTANCER)/(dis/singleStep());

    double pos = ((value-minimum())/singleStep())*sliderInterval+SIDEDISTANCE;

    handleLabel->move(pos-handleLabel->width()/2,0);

    setValue(value);

}

/**

* 鼠标移动事件

* 当mouseIsClick为true时拖动false悬停

* @brief RulerSlider::mouseFilterEvent

* @param event

*/

void RulerSlider::mouseFilterEvent(QMouseEvent *event)

{
     

    //鼠标光标位置

    double xpos = event->pos().x();

    if(xpos >=SIDEDISTANCE&&xpos<=width()-SIDEDISTANCER){
     

        if(mouseIsClick){
     

            handleLabel->move(xpos-handleLabel->width()/2,0);

            if(valueLabel->isVisible()){
     

                valueLabel->hide();

            }

        }else {
     

            //光标所在矩形范围

            double posWidth = (double)width()-SIDEDISTANCER-SIDEDISTANCE;

            //根据光标计算

            double posValue = (xpos-SIDEDISTANCE)/posWidth;

            int value =round(posValue * (maximum()-minimum()) + minimum());

            if(valueLabel->isHidden()){
     

                valueLabel->show();

            }

            if(value >= minimum() && value <= maximum()){
     

                valueLabel->setText(QString::number(value));

                valueLabel->adjustSize();

                valueLabel->move(xpos+DISTANCEMOUSE,height()-valueLabel->height());

                valueLabel->raise();

            }

        }

    }

}

/**

* 事件过滤

* @brief RulerSlider::eventFilter

* @param watched

* @param event

* @return

*/

bool RulerSlider::eventFilter(QObject *watched, QEvent *event)

{
     

    //鼠标事件

    QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);

    //鼠标离开

    if(QEvent::HoverLeave == event->type()&&!valueLabel->isHidden()){
     

        valueLabel->hide();

    }

    //鼠标悬停与拖动

    if(QEvent::HoverMove == event->type()){
     

        mouseFilterEvent(mouseEvent);

    }

    //鼠标点击事件

    if(QEvent::MouseButtonPress == event->type()){
     

        if(mouseEvent->button() & Qt::LeftButton){
     

            mouseIsClick = true;

        }

    }

    //鼠标释放事件

    if(QEvent::MouseButtonRelease == event->type()){
     

        //注意应先调用父类的鼠标点击处理事件，这样可以不影响拖动的情况

        QSlider::mouseReleaseEvent(mouseEvent);

        eventPosGetValue(mouseEvent);

        mouseIsClick = false;

    }

    return QSlider::eventFilter(watched,event);

}

.h文件

#ifndef RULERSLIDER_H
#define RULERSLIDER_H

#define SMALL_Y 5 //小刻度
#define MIDDLE_Y 7 //中刻度
#define BIG_Y 10  //大刻度
#define DIFFERVALUE 1 //最小差值(最大值与最小值的差)
#define SIDEDISTANCE 10 //尺子距离左边的距离
#define SIDEDISTANCER 50 //尺子距离右边的距离
#define HANDLEWIDTH 10 //滑块的宽度
#define HANDLEHEIGHT 15 //滑块的高度
#define MININTERVSL 10 //最小刻度之间距离
#define MAXINTERVSL 20 //最大刻度之间距离
#define DISTANCEMOUSE 20 //鼠标悬停距离箭头的位置
#include 
#include 

class RulerSlider : public QSlider

{
     

public:

    RulerSlider(QWidget *parent = nullptr);

    ~RulerSlider();

    //刻度之间的距离

    qreal sliderInterval = 1;

    //显示刻度值

    QLabel *valueLabel;

    //滑块

    QLabel *handleLabel;

    //鼠标是否点击

    bool mouseIsClick = false;

    //设置控件的范围

    void setRulerSliderRange(int min,int max);

    //设置当前值

    void setRulerSliderValue(int value);

private:

    //绘制尺子背景

    void drawRulerBackgroud(QPainter *painter);

    //绘制刻度线与值

    void drawSliderMark(QPainter *painter);

    //根据坐标位置计算当前值

    void eventPosGetValue(QMouseEvent *ev);

    //鼠标事件

    void mouseFilterEvent(QMouseEvent *event);

protected:

    //重新绘制

    void paintEvent(QPaintEvent *);

    //过滤器

    bool eventFilter(QObject *watched,QEvent *event);

};

#endif // RULERSLIDER_H

widget.cpp文件的

#include "widget.h"
#include "ui_widget.h"
#include "rulerslider.h"
#include 

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
     
    ui->setupUi(this);

     this->setWindowTitle("Ruler Measurement Tools 2020.08.22 Design By Johnson");
    RulerSlider *slider = new RulerSlider(this);

        slider->setFixedSize(this->width(),300);

        slider->setSingleStep(1);

        slider->setRulerSliderRange(0,280);

        slider->setRulerSliderValue(50);

    QObject::connect(slider,SIGNAL(valueChanged(int)),this,SLOT(sliderValueChanged(int)));



}

Widget::~Widget()
{
     
    delete ui;
}


void Widget::on_pushButton_clicked()
{
     
    QMessageBox::aboutQt(this,"about");
}

void Widget::on_pushButton_2_clicked()
{
     
    QMessageBox::warning(this,"软件架构构想","本软件的设计灵感来源于手机端尺子,此软件的开发，将彻底改变用传统实体尺子测量，继而使用电子版测量，永不坏掉，永不丢掉，一次开发，一劳永逸!2020.08.22 Design By Johnson");
}