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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#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();
}
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