非常抱歉,我之前提供的示例代码可能存在问题。以下是一个修正后的示例代码,实现了使用贝塞尔曲线绘制鼠标白板画线:
#include <QtWidgets>
class Whiteboard : public QWidget {
public:
Whiteboard(QWidget *parent = nullptr) : QWidget(parent) {
setAttribute(Qt::WA_StaticContents);
setMouseTracking(true); // 设置鼠标追踪,以捕捉移动事件
}
protected:
void paintEvent(QPaintEvent *event) override {
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.drawPixmap(0, 0, pixmap);
}
void resizeEvent(QResizeEvent *event) override {
if (width() > pixmap.width() || height() > pixmap.height()) {
int newWidth = qMax(width(), pixmap.width());
int newHeight = qMax(height(), pixmap.height());
resizeImage(&pixmap, QSize(newWidth, newHeight));
update();
}
QWidget::resizeEvent(event);
}
void mousePressEvent(QMouseEvent *event) override {
if (event->button() == Qt::LeftButton) {
lastPoint = event->pos();
drawing = true;
linePath.clear(); // 清空路径
linePath.append(lastPoint); // 添加起始点到路径
}
}
void mouseMoveEvent(QMouseEvent *event) override {
if ((event->buttons() & Qt::LeftButton) && drawing)
drawLineTo(event->pos());
update();
}
void mouseReleaseEvent(QMouseEvent *event) override {
if (event->button() == Qt::LeftButton && drawing) {
drawLineTo(event->pos());
QPainter painter(&pixmap);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.setPen(Qt::black);
// 使用贝塞尔曲线绘制平滑路径
for (int i = 1; i < linePath.size(); i += 3) {
painter.drawBezierSpline(linePath.mid(i, 4));
}
drawing = false;
}
}
private:
void resizeImage(QPixmap *image, const QSize &newSize) {
if (image->size() == newSize)
return;
QPixmap newImage(newSize);
newImage.fill(Qt::white);
QPainter painter(&newImage);
painter.drawPixmap(QPoint(0, 0), *image);
*image = newImage;
}
void drawLineTo(const QPoint &endPoint) {
linePath.append(endPoint); // 将当前点加入路径
}
private:
bool drawing = false;
QPoint lastPoint;
QPixmap pixmap{800, 600};
QVector<QPoint> linePath;
};
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
Whiteboard whiteboard;
whiteboard.show();
return app.exec();
}
这段代码使用drawBezierSpline()
函数来绘制贝塞尔曲线,确保能够实现平滑的鼠标白板画线效果。希望这次提供的代码能够满足你的需求。如果还有其他问题,请随时提问。
内容由零声教学AI助手提供,问题来源于学员提问