qt实现多图加载，缩略图的放大缩小拖动，转入单图亦可放大缩小拖动。task1.zip

#include "set.h" #include <QMenu> #include <QContextMenuEvent> #include <QStyleOption> #include <QPainter> #include <QFileDialog> //#include "mainwindow.h" #include "QMenu" #include "QMenuBar" #include "QAction" #include "QMessageBox" #include "QFileDialog" #include "QDebug" #include "QListWidget" #include"mainwindow.h" ImageView::ImageView(QWidget *parent) { // m_Image.load(imgstr); } ImageView::ImageView(QString str) { // m_Image.load(imgstr); m_Image.load(str); this->setMaximumSize(1135, 800); this->setMinimumSize(1135, 800); } ImageView::~ImageView() { } void ImageView::contextMenuEvent(QContextMenuEvent *event) { QPoint pos = event->pos(); pos = this->mapToGlobal(pos); QMenu *menu = new QMenu(this); /*QAction *loadImage = new QAction(tr("Load Image")); QObject::connect(loadImage, &QAction::triggered, this, &ImageView::onLoadImage); menu->addAction(loadImage); menu->addSeparator(); */ QAction *zoomInAction = new QAction(tr("放大")); QObject::connect(zoomInAction, &QAction::triggered, this, &ImageView::onZoomInImage); menu->addAction(zoomInAction); QAction *zoomOutAction = new QAction(tr("缩小")); QObject::connect(zoomOutAction, &QAction::triggered, this, &ImageView::onZoomOutImage); menu->addAction(zoomOutAction); QAction *presetAction = new QAction(tr("图片重置")); QObject::connect(presetAction, &QAction::triggered, this, &ImageView::onPresetImage); menu->addAction(presetAction); menu->exec(pos); } void ImageView::paintEvent(QPaintEvent *event) { // 绘制样式 QStyleOption opt; opt.init(this); QPainter painter(this); style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this); if (m_Image.isNull()) return QWidget::paintEvent(event); // 根据窗口计算应该显示的图片的大小 int width = qMin(m_Image.width(), this->width()); int height = width * 1.0 / (m_Image.width() * 1.0 / m_Image.height()); height = qMin(height, this->height()); width = height * 1.0 * (m_Image.width() * 1.0 / m_Image.height()); // 平移 painter.translate(this->width() / 2 + m_XPtInterval, this->height() / 2 + m_YPtInterval); // 缩放 painter.scale(m_ZoomValue, m_ZoomValue); // 绘制图像 QRect picRect(-width / 2, -height / 2, width, height); painter.drawImage(picRect, m_Image); } void ImageView::wheelEvent(QWheelEvent *event) { int value = event->delta(); if (value > 0) onZoomInImage(); else onZoomOutImage(); this->update(); } void ImageView::mousePressEvent(QMouseEvent *event) { m_OldPos = event->pos(); m_Pressed = true; } void ImageView::mouseMoveEvent(QMouseEvent *event) { if (!m_Pressed) return QWidget::mouseMoveEvent(event); this->setCursor(Qt::SizeAllCursor); QPoint pos = event->pos(); int xPtInterval = pos.x() - m_OldPos.x(); int yPtInterval = pos.y() - m_OldPos.y(); m_XPtInterval += xPtInterval; m_YPtInterval += yPtInterval; m_OldPos = pos; this->update(); } void ImageView::mouseReleaseEvent(QMouseEvent *event) { m_Pressed = false; this->setCursor(Qt::ArrowCursor); } /*void ImageView::onLoadImage(void) { QString imageFile = QFileDialog::getOpenFileName(this, "Open Image", "./", tr("Images (*.png *.xpm *.jpg)")); QFile file(imageFile); if (!file.exists()) return; m_Image.load(imageFile); } */ void ImageView::onZoomInImage(void) { m_ZoomValue += 0.1; this->update(); } void ImageView::onZoomOutImage(void) { m_ZoomValue -= 0.1; if (m_ZoomValue <= 0) { m_ZoomValue += 0.1; return; } } void ImageView::onPresetImage(void) { m_ZoomValue = 1.0; m_XPtInterval = 0; m_YPtInterval = 0; this->update(); }