#ifndef IMAGEVIEWWIDGET_HPP
#define IMAGEVIEWWIDGET_HPP
#include <QWidget>
#include <QPixmap>
#include <QPainter>
#include <QWheelEvent>
#include <QResizeEvent>
class ImageViewWidget : public QWidget
{
Q_OBJECT
public:
explicit ImageViewWidget(QWidget* parrent = nullptr);
~ImageViewWidget();
// 加载图片
bool loadImage(const QString& image_path);
// 设置pixmap
void setPixmap(const QPixmap& pixmap);
// 获取pixmap
QPixmap pixmap() const;
// 放大
void zoomIn(double factor = 1.1);
// 缩小
void zoomOut(double factor = 0.9);
// 重置
void resetZoom();
// 适应窗口
void fitToWindow();
// 获取当前缩放比例
double getScaleFactor() const;
protected:
void paintEvent(QPaintEvent* event) override;
void resizeEvent(QResizeEvent* event) override;
void wheelEvent(QWheelEvent* evennt) override;
void mousePressEvent(QMouseEvent* event) override;
void mouseMoveEvent(QMouseEvent *event) override;
void mouseReleaseEvent(QMouseEvent *event) override;
private:
QPixmap m_original_pixmap;
QPixmap m_scaled_pixmap;
double m_scaled_factor;
bool m_is_dragging;
QPoint m_last_mouse_point;
QPointF m_image_offset;
void updateScaledPixmap();
void adjustOffset();
};
#endif // IMAGEVIEWWIDGET_HPP
#include "ImageViewWidget.hpp"
#include <QPainter>
#include <QDebug>
#include <QGuiApplication>
ImageViewWidget::ImageViewWidget(QWidget* parrent):QWidget(parrent), m_scaled_factor(1.0), m_is_dragging(false)
{
}
ImageViewWidget::~ImageViewWidget()
{
}
void ImageViewWidget::paintEvent(QPaintEvent *event)
{
Q_UNUSED(event);
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.setRenderHint(QPainter::SmoothPixmapTransform, true);
if (m_scaled_pixmap.isNull()) {
painter.drawText(rect(), Qt::AlignCenter, tr("No Image Loaded"));
return;
}
int x = (width() - m_scaled_pixmap.width()) / 2 + m_image_offset.x();
int y = (height() - m_scaled_pixmap.height()) / 2 + m_image_offset.y();
painter.drawPixmap(x, y, m_scaled_pixmap);
}
void ImageViewWidget::resizeEvent(QResizeEvent *event)
{
Q_UNUSED(event);
if (!m_original_pixmap.isNull()) {
updateScaledPixmap();
adjustOffset();
update();
}
}
void ImageViewWidget::wheelEvent(QWheelEvent *event)
{
if (m_original_pixmap.isNull()) {
event->ignore();
return;
}
int angleDelta = event->angleDelta().y();
QPointF mousePosInWidget = event->position();
QPointF imageTopLeftInWidget((width() - m_scaled_pixmap.width()) / 2.0 + m_image_offset.x(),
(height() - m_scaled_pixmap.height()) / 2.0 + m_image_offset.y());
QPointF mousePosOnImage = (mousePosInWidget - imageTopLeftInWidget) / m_scaled_factor;
if (angleDelta > 0) {
zoomIn();
} else if (angleDelta < 0) {
zoomOut();
}
QPointF newImageTopLeftInWidget = mousePosInWidget - (mousePosOnImage * m_scaled_factor);
m_image_offset.setX(newImageTopLeftInWidget.x() - (width() - m_original_pixmap.width() * m_scaled_factor) / 2.0);
m_image_offset.setY(newImageTopLeftInWidget.y() - (height() - m_original_pixmap.height() * m_scaled_factor) / 2.0);
adjustOffset();
updateScaledPixmap();
update();
event->accept();
}
void ImageViewWidget::mousePressEvent(QMouseEvent* event)
{
if (event->button() == Qt::LeftButton && !m_original_pixmap.isNull())
{
m_is_dragging = true;
m_last_mouse_point = event->pos();
setCursor(Qt::ClosedHandCursor);
event->accept();
} else {
event->ignore(); // 如果不是左键或者没有图片，则忽略事件
}
}
void ImageViewWidget::mouseMoveEvent(QMouseEvent *event)
{
if (m_is_dragging && (event->buttons() & Qt::LeftButton))
{
QPoint current_mouse_pos = event->pos();
QPointF delta = current_mouse_pos - m_last_mouse_point;
m_image_offset += delta;
m_last_mouse_point = current_mouse_pos;
adjustOffset();
update();
event->accept();
} else {
event->ignore();
}
}
void ImageViewWidget::mouseReleaseEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton && m_is_dragging)
{
m_is_dragging = false;
setCursor(Qt::ArrowCursor);
event->accept();
}
else
{
event->ignore();
}
}
bool ImageViewWidget::loadImage(const QString &image_path)
{
QPixmap new_pixmap(image_path);
if(new_pixmap.isNull())
{
qWarning() << "Failed to load image:" << image_path;
m_original_pixmap = QPixmap();
m_scaled_pixmap = QPixmap();
m_scaled_factor = 1.0;
m_image_offset = QPointF(0,0);
update();
return false;
}
setPixmap(new_pixmap);
return true;
}
QPixmap ImageViewWidget::pixmap() const
{
return m_original_pixmap;
}
void ImageViewWidget::setPixmap(const QPixmap &pixmap)
{
m_original_pixmap = pixmap;
m_scaled_pixmap = m_original_pixmap.scaled(
m_original_pixmap.size() * m_scaled_factor,
Qt::KeepAspectRatio,
Qt::SmoothTransformation
);
m_image_offset = QPointF(0, 0);
fitToWindow();
}
double ImageViewWidget::getScaleFactor() const
{
return m_scaled_factor;
}
void ImageViewWidget::fitToWindow()
{
if (m_original_pixmap.isNull() || width() == 0 || height() == 0) {
m_scaled_factor = 1.0;
updateScaledPixmap();
update();
return;
}
double wRatio = (double)width() / m_original_pixmap.width();
double hRatio = (double)height() / m_original_pixmap.height();
m_scaled_factor = qMin(wRatio, hRatio);
m_image_offset = QPointF(0,0);
updateScaledPixmap();
update();
}
void ImageViewWidget::zoomIn(double factor)
{
if (m_original_pixmap.isNull())
{
return;
}
m_scaled_factor *= factor;
updateScaledPixmap();
update();
}
void ImageViewWidget::zoomOut(double factor)
{
if (m_original_pixmap.isNull()) return;
m_scaled_factor *= factor;
if (m_scaled_factor < 0.01) m_scaled_factor = 0.01;
updateScaledPixmap();
update();
}
void ImageViewWidget::resetZoom()
{
if (m_original_pixmap.isNull()) return;
m_scaled_factor = 1.0;
m_image_offset = QPointF(0,0);
updateScaledPixmap();
update();
}
void ImageViewWidget::updateScaledPixmap()
{
if (m_original_pixmap.isNull())
{
if (!m_scaled_pixmap.isNull())
{
m_scaled_pixmap = QPixmap();
}
return;
}
if (m_scaled_factor <= 0) {
qWarning() << "updateScaledPixmap: Invalid scale factor " << m_scaled_factor << ". Using 1.0 instead.";
m_scaled_factor = 1.0; // Or some other sensible default / minimum
}
// 根据 m_scaleFactor 缩放原始图片
// 使用 Qt::SmoothTransformation 来获得更好的缩放质量
m_scaled_pixmap = m_original_pixmap.scaled(
m_original_pixmap.size() * m_scaled_factor,
Qt::KeepAspectRatio,
Qt::SmoothTransformation
);
adjustOffset();
}
void ImageViewWidget::adjustOffset()
{
if (m_scaled_pixmap.isNull()) return;
QRectF imageRectInWidget(
(width() - m_scaled_pixmap.width()) / 2.0 + m_image_offset.x(),
(height() - m_scaled_pixmap.height()) / 2.0 + m_image_offset.y(),
m_scaled_pixmap.width(),
m_scaled_pixmap.height()
);
QRectF widgetRect(0,0, width(), height());
if (m_scaled_pixmap.width() < width())
{
double allowableXOffset = (width() - m_scaled_pixmap.width()) / 2.0;
m_image_offset.setX(qBound(-allowableXOffset, m_image_offset.x(), allowableXOffset));
}
else
{
double minXOffset = width() - m_scaled_pixmap.width() - (width() - m_scaled_pixmap.width()) / 2.0;
double maxXOffset = -(width() - m_scaled_pixmap.width()) / 2.0;
m_image_offset.setX(qBound(minXOffset, m_image_offset.x(), maxXOffset));
}
if (m_scaled_pixmap.height() < height())
{
double allowableYOffset = (height() - m_scaled_pixmap.height()) / 2.0;
m_image_offset.setY(qBound(-allowableYOffset, m_image_offset.y(), allowableYOffset));
}
else
{
double minYOffset = height() - m_scaled_pixmap.height() - (height() - m_scaled_pixmap.height()) / 2.0;
double maxYOffset = -(height() - m_scaled_pixmap.height()) / 2.0;
m_image_offset.setY(qBound(minYOffset, m_image_offset.y(), maxYOffset));
}
}
