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PPT好看配色

Separes 03-20 17:00 阅读 2
qt

目录

1、介绍

上一篇介绍了使用OpenCV的setMouseCallback回调函数实现获取鼠标点击点的图像坐标和像素值,本篇使用鼠标事件mouseMoveEvent函数来实现实时获取鼠标的坐标和对应图像点的像素值,并将结果实时显示在label控件上。

2、效果展示

123.gif

3、实现过程

3.1 图像的加载和显示

这里加载图像并在QLabel控件上显示,我这里使用OpenCV的imread函数加载了图像,然后把图像转换成QPixmap显示在QLabel上。

    img = imread("lena.png");
    cvtColor(img, img, COLOR_BGR2RGB);
    QImage disImage = QImage((const unsigned char*)(img.data), img.cols, img.rows, QImage::Format_RGB888);
    QPixmap pix = QPixmap::fromImage(disImage);

    pix.scaled(ui->lbl_pic->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
    ui->lbl_pic->setPixmap(pix);  // label 显示图像

这里也可以直接用QPixmap的load函数加载图像和显示,然后在mouseMoveEvent函数中要通过OpenCV获取图像的像素值时,将QPixmap格式再转换成Mat类型。

3.2 设置鼠标跟踪事件激活

激活控件内鼠标跟随属性,调用setMouseTracking(true)激活后在鼠标点击控件内区域进入mouseMoveEvent函数实现鼠标跟随。
如果想不点击鼠标在控件内移动触发mouseMoveEvent函数,就需要同时设置控件和窗口的setMouseTracking(true),这样鼠标在控件内移动时可以实时跟踪鼠标事件。

    /*激活控件鼠标跟随属性,激活后在点击鼠标后进入mouseMoveEvent函数*/
    /*如果不点击鼠标时想要在控件上触发mouseMoveEvent函数,就需要同时激活控件和窗口*/
    ui->lbl_pic->setMouseTracking(true);
    setMouseTracking(true);
void Widget::mouseMoveEvent(QMouseEvent *event)
{
    QPoint pt = event->pos();
    QRect rect = ui->lbl_pic->geometry();
    if(rect.contains(pt)){
        QPoint PicPoint = QPoint(pt.x()-rect.x(), pt.y()- rect.y());
        QString str = QString("(x:%1,y:%2)").arg(PicPoint.x()).arg(PicPoint.y());
        ui->lbl_pos->setText(str);
        if(img.channels() == 1){
            int grayValue;
            switch (img.type())
            {
            case 0:
                grayValue = static_cast<int>(img.at<uchar>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 1:
                grayValue = static_cast<int>(img.at<char>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 2:
                grayValue = static_cast<int>(img.at<ushort>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 3:
                grayValue = static_cast<int>(img.at<short>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 4:
                grayValue = static_cast<int>(img.at<int>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 5:
                grayValue = static_cast<int>(img.at<float>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 6:
                grayValue = static_cast<int>(img.at<double>(Point(PicPoint.x(), PicPoint.y())));
                break;
            }
        }
        else
        {
            int value_B = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[0]);
            int value_G = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[1]);
            int value_R = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[2]);
            QString str = QString("B:%1, G:%2, R:%3").arg(value_B).arg(value_G).arg(value_R);
            ui->lbl_pix->setText(str);
        }
    }
}

3.3 实现代码

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QMouseEvent>
#include "opencv2/opencv.hpp"

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

using namespace cv;
class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

protected:
    void mouseMoveEvent(QMouseEvent *event);
private:
    Ui::Widget *ui;
    Mat img;
};
#endif // WIDGET_H
#pragma execution_character_set("utf-8")
#include "widget.h"
#include "ui_widget.h"
#include <QDebug>

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("坐标像素实时监控");
    img = imread("lena.png");
    cvtColor(img, img, COLOR_BGR2RGB);
    QImage disImage = QImage((const unsigned char*)(img.data), img.cols, img.rows, QImage::Format_RGB888);
    QPixmap pix = QPixmap::fromImage(disImage);

    pix.scaled(ui->lbl_pic->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
    // label 显示图像
    ui->lbl_pic->setPixmap(pix);
    /*激活控件鼠标跟随属性,激活后在点击鼠标后进入mouseMoveEvent函数*/
    /*如果不点击鼠标时想要在控件上触发mouseMoveEvent函数,就需要同时激活控件和窗口*/
    ui->lbl_pic->setMouseTracking(true);
    setMouseTracking(true);
}

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

void Widget::mouseMoveEvent(QMouseEvent *event)
{
    QPoint pt = event->pos();
    QRect rect = ui->lbl_pic->geometry();
    if(rect.contains(pt)){
        QPoint PicPoint = QPoint(pt.x()-rect.x(), pt.y()- rect.y());
        QString str = QString("(x:%1,y:%2)").arg(PicPoint.x()).arg(PicPoint.y());
        ui->lbl_pos->setText(str);
        if(img.channels() == 1){            //单通道图像
            int grayValue;
            switch (img.type())
            {
            case 0:
                grayValue = static_cast<int>(img.at<uchar>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 1:
                grayValue = static_cast<int>(img.at<char>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 2:
                grayValue = static_cast<int>(img.at<ushort>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 3:
                grayValue = static_cast<int>(img.at<short>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 4:
                grayValue = static_cast<int>(img.at<int>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 5:
                grayValue = static_cast<int>(img.at<float>(Point(PicPoint.x(), PicPoint.y())));
                break;
            case 6:
                grayValue = static_cast<int>(img.at<double>(Point(PicPoint.x(), PicPoint.y())));
                break;
            }
            QString str = QString("Gray Value:%1").arg(grayValue);
            ui->lbl_pix->setText(str);
        }
        else                                //多通道图像
        {
            int value_B = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[0]);
            int value_G = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[1]);
            int value_R = static_cast<int>(img.at<Vec3b>(Point(PicPoint.x(), PicPoint.y()))[2]);
            QString str = QString("B:%1, G:%2, R:%3").arg(value_B).arg(value_G).arg(value_R);
            ui->lbl_pix->setText(str);
        }
    }
}

4、源码展示

本小例程的代码放到我的开源gitte项目里,欢迎一起学习,也希望能收获你的小星星。
项目源码PixelPos_MouseFollow

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