帮我写一个自定义QScrollArea,可以实现鼠标拖动,拖动到底后拼接最开始的地方,可以无限拖动
时间: 2024-03-27 12:40:45 浏览: 28
好的,以下是一个可以实现你所需功能的自定义QScrollArea:
customscrollarea.h:
```cpp
#ifndef CUSTOMSCROLLAREA_H
#define CUSTOMSCROLLAREA_H
#include <QScrollArea>
#include <QPixmap>
class CustomScrollArea : public QScrollArea
{
Q_OBJECT
public:
explicit CustomScrollArea(QWidget *parent = nullptr);
void setImage(const QPixmap& pixmap);
protected:
void mousePressEvent(QMouseEvent *event) override;
void mouseMoveEvent(QMouseEvent *event) override;
void paintEvent(QPaintEvent *event) override;
private:
QPoint m_lastPos;
QPixmap m_pixmap;
int m_offset;
};
#endif // CUSTOMSCROLLAREA_H
```
customscrollarea.cpp:
```cpp
#include "customscrollarea.h"
CustomScrollArea::CustomScrollArea(QWidget *parent)
: QScrollArea(parent), m_offset(0)
{
// 隐藏滚动条
setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}
void CustomScrollArea::setImage(const QPixmap& pixmap)
{
m_pixmap = pixmap;
update();
}
void CustomScrollArea::mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton) {
m_lastPos = event->pos();
}
}
void CustomScrollArea::mouseMoveEvent(QMouseEvent *event)
{
if (event->buttons() & Qt::LeftButton) {
int dx = event->pos().x() - m_lastPos.x();
m_offset += dx;
m_lastPos = event->pos();
// 如果偏移量超过了图片的宽度,则拼接到最开始的地方
if (m_offset >= m_pixmap.width()) {
m_offset -= m_pixmap.width();
} else if (m_offset < 0) {
m_offset += m_pixmap.width();
}
update();
}
}
void CustomScrollArea::paintEvent(QPaintEvent *event)
{
QPainter painter(viewport());
painter.setRenderHint(QPainter::Antialiasing);
painter.setRenderHint(QPainter::SmoothPixmapTransform);
// 绘制背景
painter.fillRect(viewport()->rect(), Qt::white);
// 绘制图片
painter.drawPixmap(m_offset, 0, m_pixmap);
if (m_offset > 0) {
painter.drawPixmap(m_offset - m_pixmap.width(), 0, m_pixmap);
}
if (m_offset + m_pixmap.width() < viewport()->width()) {
painter.drawPixmap(m_offset + m_pixmap.width(), 0, m_pixmap);
}
}
```
这个自定义QScrollArea可以实现鼠标拖动,拖动到底后拼接最开始的地方,可以无限拖动。你可以使用setImage()方法设置要显示的图片。具体使用方法可以参考以下代码:
```cpp
CustomScrollArea* scrollArea = new CustomScrollArea(this);
QPixmap pixmap("your_image_path_here");
scrollArea->setImage(pixmap);
scrollArea->setFixedSize(pixmap.size());
scrollArea->show();
```
请将"your_image_path_here"替换为你的图片路径,并且请注意设置CustomScrollArea的大小与图片的大小一致。