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| ** This file is part of the documentation of the Qt Toolkit. |
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| |
| #include <QtWidgets> |
| |
| class MyScrollArea : public QAbstractScrollArea |
| { |
| public: |
| MyScrollArea(QWidget *w); |
| void setWidget(QWidget *w); |
| |
| protected: |
| void scrollContentsBy(int dx, int dy) override; |
| void resizeEvent(QResizeEvent *event) override; |
| |
| private: |
| void updateWidgetPosition(); |
| void updateArea(); |
| |
| QWidget *widget; |
| }; |
| |
| MyScrollArea::MyScrollArea(QWidget *widget) |
| : QAbstractScrollArea() |
| { |
| setWidget(widget); |
| } |
| |
| void MyScrollArea::setWidget(QWidget *w) |
| { |
| widget = w; |
| widget->setParent(viewport()); |
| if (!widget->testAttribute(Qt::WA_Resized)) |
| widget->resize(widget->sizeHint()); |
| |
| verticalScrollBar()->setValue(0); |
| verticalScrollBar()->setValue(0); |
| |
| updateArea(); |
| } |
| |
| void MyScrollArea::updateWidgetPosition() |
| { |
| //! [0] |
| int hvalue = horizontalScrollBar()->value(); |
| int vvalue = verticalScrollBar()->value(); |
| QPoint topLeft = viewport()->rect().topLeft(); |
| |
| widget->move(topLeft.x() - hvalue, topLeft.y() - vvalue); |
| //! [0] |
| } |
| |
| void MyScrollArea::scrollContentsBy(int dx, int dy) |
| { |
| Q_UNUSED(dx); |
| Q_UNUSED(dy); |
| updateWidgetPosition(); |
| } |
| |
| void MyScrollArea::updateArea() |
| { |
| //! [1] |
| QSize areaSize = viewport()->size(); |
| QSize widgetSize = widget->size(); |
| |
| verticalScrollBar()->setPageStep(areaSize.height()); |
| horizontalScrollBar()->setPageStep(areaSize.width()); |
| verticalScrollBar()->setRange(0, widgetSize.height() - areaSize.height()); |
| horizontalScrollBar()->setRange(0, widgetSize.width() - areaSize.width()); |
| updateWidgetPosition(); |
| //! [1] |
| } |
| |
| void MyScrollArea::resizeEvent(QResizeEvent *event) |
| { |
| Q_UNUSED(event); |
| updateArea(); |
| } |