Qt案例之利用QImage类实现对图像的基本操作（图像显示、图像缩放、图像旋转）.zip

#include "widget.h" #include "ui_widget.h" #include<QDebug> Widget::Widget(QWidget *parent) : QWidget(parent) , ui(new Ui::Widget) { ui->setupUi(this); ui->horizontalSlider->setVisible(false);//设置滑动条默认为不显示 } Widget::~Widget() { delete ui; } //选择图像 void Widget::on_Choose_clicked() { QString path=QFileDialog::getOpenFileName(this,tr("选择图像"),"E:\\image\\",tr("Images (*.png *.bmp *.jpg *.tif *.GIF )")); if(path.isEmpty()) { return; } else { if(! ( img.load(path) ) ) //加载图像 { QMessageBox::information(this,tr("打开图像失败"),tr("打开图像失败!")); //delete img; return; } //img.load(path); ui->imagelabel->setPixmap(QPixmap::fromImage(img)); } } //图像缩放 void Widget::on_Zoom_clicked() { QImage* imgScaled = new QImage; int width=ui->imagelabel->width()/2; int height=ui->imagelabel->height()/2; *imgScaled=img.scaled(width,height,Qt::KeepAspectRatio);//对半缩放 ui->imagelabel->setPixmap(QPixmap::fromImage(*imgScaled)); } //图像旋转 void Widget::on_Rotate_clicked() { ui->horizontalSlider->setVisible(true);//显示滑动条 } //滑动条值变化 void Widget::on_horizontalSlider_valueChanged(int value) { qDebug()<<value;//输出旋转角度 QImage* imgRatate = new QImage; QMatrix matrix; matrix.rotate(value); *imgRatate = img.transformed(matrix); ui->imagelabel->setPixmap(QPixmap::fromImage(*imgRatate)); }