2022/9/3——qt中实现调色板

75 阅读 0 评论 50 点赞

我是靠谱客的博主风中帆布鞋，最近开发中收集的这篇文章主要介绍2022/9/3——qt中实现调色板，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

画板的实现

1、设置画板并用白色填充

    //设置画板尺寸
    this->setFixedSize(1000,618);

    myPix = new QPixmap(this->size());
    myPix->fill(Qt::white);

2、重写鼠标按下事件、鼠标移动事件、绘画事件

void MyWnd::mousePressEvent(QMouseEvent *e)
{
    startPoint = e->pos();
}

void MyWnd::mouseMoveEvent(QMouseEvent *e)
{
    //申请一个画家类
    QPainter painter(myPix);     //依附于自定义的绘图板
    QPen pen;
    pen.setColor(color);
    pen.setWidth(size_1);
    //pen.setStyle();
    //将画笔和画家结合起来
    painter.setPen(pen);
    //开始画线
    painter.drawLine(startPoint,e->pos());
    //将当前点设为新的起点
    startPoint = e->pos();
    //实时更新
    update();
}
void MyWnd::paintEvent(QPaintEvent *)
{
    //申请一个画家，依附于this画图板
    QPainter painter(this);

    //将自定义的绘制板画到画图板上
    painter.drawPixmap(0,0,*myPix);
}

通过按钮改变颜色

   //对应的处理函数
    void MyWnd::change_Color()
    {
        color = QColorDialog::getColor(Qt::white, this);
    }
    //按钮的定义
    btn1 = new QPushButton();
    btn1->setParent(this); //设置父控件
    btn1->resize(140,60);
    btn1->move(width()/2-140, height()/2+240);
    btn1->setText("更改颜色");
    //槽函数
    connect(btn1, &QPushButton::clicked, this,&MyWnd::change_Color);

通过按钮和文本框改变画笔粗细

    //按钮的定义
    btn2 = new QPushButton("更改字体",this);
    btn2->move(btn1->width()+width()/2-140, height()/2+240);
    btn2->resize(btn1->size());
    //文本框的定义
    Lin = new QLineEdit("请输入字体尺寸",this);
    Lin->resize(btn1->size());
    Lin->move(btn1->width()+btn2->width()+width()/2-140, height()/2+240);
    //对应的处理函数
    void MyWnd::change_size()
    {
        QString val = Lin->text();
        double temp;
        temp = val.toDouble();
        if(temp<=50 && temp>=0)
        {
            size_1 = temp;
        }
    }
    //对应的槽函数
    connect(btn2, &QPushButton::clicked, this,&MyWnd::change_size);

完整代码

1、mywnd.h

#ifndef MYWND_H
#define MYWND_H

#include <QMainWindow>
#include <QPixmap>
#include <QMouseEvent>
#include <QPaintEvent>
#include <QPainter>
#include <QPen>
#include <QPoint>
#include <QPushButton>
#include <QLineEdit>
#include <QColor>
#include <QColorDialog>
#include <QString>

class MyWnd : public QMainWindow
{
    Q_OBJECT

signals:
    void singal_1();

public slots:
    void change_Color();
    void change_size();
public:
    MyWnd(QWidget *parent = nullptr);
    ~MyWnd();

    void mousePressEvent(QMouseEvent *e);
    void mouseMoveEvent(QMouseEvent *e);
    void paintEvent(QPaintEvent *);
private:
    QPixmap *myPix;       //定义绘制类的指针
    QPoint startPoint;    //画笔的起始位置

    //定义两个按钮指针
    QPushButton *btn1;
    QPushButton *btn2;

    QLineEdit *Lin;

    QColor color;

    double size_1;
};
#endif // MYWND_H

2、mywnd.cpp

#include "mywnd.h"

void MyWnd::change_Color()
{
    color = QColorDialog::getColor(Qt::white, this);
}
void MyWnd::change_size()
{
    QString val = Lin->text();
    double temp;
    temp = val.toDouble();
    if(temp<=50 && temp>=0)
    {
        size_1 = temp;
    }
}
MyWnd::MyWnd(QWidget *parent)
    : QMainWindow(parent)
{
    //设置画板尺寸
    this->setFixedSize(1000,618);

    myPix = new QPixmap(this->size());
    myPix->fill(Qt::white);

    btn1 = new QPushButton();
    btn1->setParent(this); //设置父控件
    btn1->resize(140,60);
    btn1->move(width()/2-140, height()/2+240);
    btn1->setText("更改颜色");

    btn2 = new QPushButton("更改字体",this);
    btn2->move(btn1->width()+width()/2-140, height()/2+240);
    btn2->resize(btn1->size());

    Lin = new QLineEdit("请输入字体尺寸",this);
    Lin->resize(btn1->size());
    Lin->move(btn1->width()+btn2->width()+width()/2-140, height()/2+240);

    connect(btn1, &QPushButton::clicked, this,&MyWnd::change_Color);
    connect(btn2, &QPushButton::clicked, this,&MyWnd::change_size);
}

MyWnd::~MyWnd()
{
}

void MyWnd::mousePressEvent(QMouseEvent *e)
{
    startPoint = e->pos();
}

void MyWnd::mouseMoveEvent(QMouseEvent *e)
{
    //申请一个画家类
    QPainter painter(myPix);     //依附于自定义的绘图板
    QPen pen;
    pen.setColor(color);
    pen.setWidth(size_1);
    //pen.setStyle();
    //将画笔和画家结合起来
    painter.setPen(pen);
    //开始画线
    painter.drawLine(startPoint,e->pos());
    //将当前点设为新的起点
    startPoint = e->pos();
    //实时更新
    update();
}
void MyWnd::paintEvent(QPaintEvent *)
{
    //申请一个画家，依附于this画图板
    QPainter painter(this);

    //将自定义的绘制板画到画图板上
    painter.drawPixmap(0,0,*myPix);
}