插件控件加载了,拖曳控件也实现了,接下来就是一个最难点了,跟QtDesigner或者其他开发环境一样,能够任意自由的拉伸控件大小,移动位置,为了这个功能,还特别编写了一个控件来实现这个功能,名字叫SelectWidget描点跟随窗体控件,大致的原理就是安装事件过滤器,在生成控件的时候将该控件传入描点跟随控件,自动识别鼠标的位置,按下拉动的距离来改变控件的大小,绘制描点指示器以便用户拉伸使用。
描点跟随控件可设置是否绘制描点、边距、描点颜色、描点尺寸、描点样式 正方形+圆形、选中边框宽度,支持上下左右按键移动窗体,支持delete键删除窗体,支持八个描点改变窗体大小尺寸。
bool SelectWidget::eventFilter(QObject *watched, QEvent *event)
{
if (watched == widget) {
if (event->type() == QEvent::Resize) {
//设置当前窗体大小为跟随窗体的大小增加部分
this->resize(this->widget->size() + QSize(padding * 2, padding * 2));
} else if (event->type() == QEvent::Move) {
//将当前窗体移到偏移位置
this->move(this->widget->pos() - QPoint(padding, padding));
}
} else {
if (event->type() == QEvent::KeyPress) {
QKeyEvent *keyEvent = dynamic_cast<QKeyEvent *>(event);
if (keyEvent->key() == Qt::Key_Left) {
this->move(this->pos() - QPoint(1, 0));
} else if (keyEvent->key() == Qt::Key_Right) {
this->move(this->pos() + QPoint(1, 0));
} else if (keyEvent->key() == Qt::Key_Up) {
this->move(this->pos() - QPoint(0, 1));
} else if (keyEvent->key() == Qt::Key_Down) {
this->move(this->pos() + QPoint(0, 1));
} else if (keyEvent->key() == Qt::Key_Delete) {
emit widgetDelete(widget);
widget->deleteLater();
this->deleteLater();
widget = 0;
}
//重新设置附带窗体的位置和大小
if (widget != 0) {
widget->setGeometry(this->x() + padding, this->y() + padding, this->width() - padding * 2, this->height() - padding * 2);
}
return QWidget::eventFilter(watched, event);
}
QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
if (mouseEvent->type() == QEvent::MouseButtonPress) {
//记住当前控件坐标和宽高以及鼠标按下的坐标
rectX = this->x();
rectY = this->y();
rectW = this->width();
rectH = this->height();
lastPos = mouseEvent->pos();
//判断按下的手柄的区域位置
if (rectLeft.contains(lastPos)) {
pressedLeft = true;
} else if (rectRight.contains(lastPos)) {
pressedRight = true;
} else if (rectTop.contains(lastPos)) {
pressedTop = true;
} else if (rectBottom.contains(lastPos)) {
pressedBottom = true;
} else if (rectLeftTop.contains(lastPos)) {
pressedLeftTop = true;
} else if (rectRightTop.contains(lastPos)) {
pressedRightTop = true;
} else if (rectLeftBottom.contains(lastPos)) {
pressedLeftBottom = true;
} else if (rectRightBottom.contains(lastPos)) {
pressedRightBottom = true;
} else {
pressed = true;
}
if (widget != 0) {
emit widgetPressed(widget);
}
} else if (mouseEvent->type() == QEvent::MouseMove) {
//根据当前鼠标位置,计算XY轴移动了多少
QPoint pos = mouseEvent->pos();
int dx = pos.x() - lastPos.x();
int dy = pos.y() - lastPos.y();
//根据按下处的位置判断是否是移动控件还是拉伸控件
if (pressed) {
this->move(this->x() + dx, this->y() + dy);
} else if (pressedLeft) {
int resizeW = this->width() - dx;
if (this->minimumWidth() <= resizeW) {
this->setGeometry(this->x() + dx, rectY, resizeW, rectH);
}
} else if (pressedRight) {
this->setGeometry(rectX, rectY, rectW + dx, rectH);
} else if (pressedTop) {
int resizeH = this->height() - dy;
if (this->minimumHeight() <= resizeH) {
this->setGeometry(rectX, this->y() + dy, rectW, resizeH);
}
} else if (pressedBottom) {
this->setGeometry(rectX, rectY, rectW, rectH + dy);
} else if (pressedLeftTop) {
int resizeW = this->width() - dx;
int resizeH = this->height() - dy;
if (this->minimumWidth() <= resizeW) {
this->setGeometry(this->x() + dx, this->y(), resizeW, resizeH);
}
if (this->minimumHeight() <= resizeH) {
this->setGeometry(this->x(), this->y() + dy, resizeW, resizeH);
}
} else if (pressedRightTop) {
int resizeW = rectW + dx;
int resizeH = this->height() - dy;
if (this->minimumHeight() <= resizeH) {
this->setGeometry(this->x(), this->y() + dy, resizeW, resizeH);
}
} else if (pressedLeftBottom) {
int resizeW = this->width() - dx;
int resizeH = rectH + dy;
if (this->minimumWidth() <= resizeW) {
this->setGeometry(this->x() + dx, this->y(), resizeW, resizeH);
}
if (this->minimumHeight() <= resizeH) {
this->setGeometry(this->x(), this->y(), resizeW, resizeH);
}
} else if (pressedRightBottom) {
int resizeW = rectW + dx;
int resizeH = rectH + dy;
this->setGeometry(this->x(), this->y(), resizeW, resizeH);
}
//重新设置附带窗体的位置和大小
if (widget != 0) {
widget->setGeometry(this->x() + padding, this->y() + padding, this->width() - padding * 2, this->height() - padding * 2);
}
} else if (mouseEvent->type() == QEvent::MouseButtonRelease) {
pressed = false;
pressedLeft = false;
pressedRight = false;
pressedTop = false;
pressedBottom = false;
pressedLeftTop = false;
pressedRightTop = false;
pressedLeftBottom = false;
pressedRightBottom = false;
if (widget != 0) {
emit widgetRelease(widget);
}
}
}
return QWidget::eventFilter(watched, event);
}
void SelectWidget::resizeEvent(QResizeEvent *)
{
//重新计算八个描点的区域,描点区域的作用还有就是计算鼠标坐标是否在某一个区域内
int width = this->width();
int height = this->height();
//左侧描点区域
rectLeft = QRectF(0, height / 2 - pointSize / 2, pointSize, pointSize);
//上侧描点区域
rectTop = QRectF(width / 2 - pointSize / 2, 0, pointSize, pointSize);
//右侧描点区域
rectRight = QRectF(width - pointSize, height / 2 - pointSize / 2, pointSize, pointSize);
//下侧描点区域
rectBottom = QRectF(width / 2 - pointSize / 2, height - pointSize, pointSize, pointSize);
//左上角描点区域
rectLeftTop = QRectF(0, 0, pointSize, pointSize);
//右上角描点区域
rectRightTop = QRectF(width - pointSize, 0, pointSize, pointSize);
//左下角描点区域
rectLeftBottom = QRectF(0, height - pointSize, pointSize, pointSize);
//右下角描点区域
rectRightBottom = QRectF(width - pointSize, height - pointSize, pointSize, pointSize);
}
void SelectWidget::mouseMoveEvent(QMouseEvent *e)
{
//计算当前鼠标位置是否在某个区域内,自动更新鼠标形状
QPoint p = e->pos();
if (rectLeft.contains(p)) {
this->setCursor(Qt::SizeHorCursor);
} else if (rectTop.contains(p)) {
this->setCursor(Qt::SizeVerCursor);
} else if (rectRight.contains(p)) {
this->setCursor(Qt::SizeHorCursor);
} else if (rectBottom.contains(p)) {
this->setCursor(Qt::SizeVerCursor);
} else if (rectLeftTop.contains(p)) {
this->setCursor(Qt::SizeFDiagCursor);
} else if (rectRightTop.contains(p)) {
this->setCursor(Qt::SizeBDiagCursor);
} else if (rectLeftBottom.contains(p)) {
this->setCursor(Qt::SizeBDiagCursor);
} else if (rectRightBottom.contains(p)) {
this->setCursor(Qt::SizeFDiagCursor);
} else {
this->setCursor(Qt::ArrowCursor);
}
}