| 1 | // Copyright (C) 2016 The Qt Company Ltd. |
|---|---|
| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause |
| 3 | |
| 4 | #include <QtWidgets> |
| 5 | |
| 6 | class MyScrollArea : public QAbstractScrollArea |
| 7 | { |
| 8 | public: |
| 9 | MyScrollArea(QWidget *w); |
| 10 | void setWidget(QWidget *w); |
| 11 | |
| 12 | protected: |
| 13 | void scrollContentsBy(int dx, int dy) override; |
| 14 | void resizeEvent(QResizeEvent *event) override; |
| 15 | |
| 16 | private: |
| 17 | void updateWidgetPosition(); |
| 18 | void updateArea(); |
| 19 | |
| 20 | QWidget *widget; |
| 21 | }; |
| 22 | |
| 23 | MyScrollArea::MyScrollArea(QWidget *widget) |
| 24 | : QAbstractScrollArea() |
| 25 | { |
| 26 | setWidget(widget); |
| 27 | } |
| 28 | |
| 29 | void MyScrollArea::setWidget(QWidget *w) |
| 30 | { |
| 31 | widget = w; |
| 32 | widget->setParent(viewport()); |
| 33 | if (!widget->testAttribute(attribute: Qt::WA_Resized)) |
| 34 | widget->resize(widget->sizeHint()); |
| 35 | |
| 36 | verticalScrollBar()->setValue(0); |
| 37 | verticalScrollBar()->setValue(0); |
| 38 | |
| 39 | updateArea(); |
| 40 | } |
| 41 | |
| 42 | void MyScrollArea::updateWidgetPosition() |
| 43 | { |
| 44 | //! [0] |
| 45 | int hvalue = horizontalScrollBar()->value(); |
| 46 | int vvalue = verticalScrollBar()->value(); |
| 47 | QPoint topLeft = viewport()->rect().topLeft(); |
| 48 | |
| 49 | widget->move(ax: topLeft.x() - hvalue, ay: topLeft.y() - vvalue); |
| 50 | //! [0] |
| 51 | } |
| 52 | |
| 53 | void MyScrollArea::scrollContentsBy(int dx, int dy) |
| 54 | { |
| 55 | Q_UNUSED(dx); |
| 56 | Q_UNUSED(dy); |
| 57 | updateWidgetPosition(); |
| 58 | } |
| 59 | |
| 60 | void MyScrollArea::updateArea() |
| 61 | { |
| 62 | //! [1] |
| 63 | QSize areaSize = viewport()->size(); |
| 64 | QSize widgetSize = widget->size(); |
| 65 | |
| 66 | verticalScrollBar()->setPageStep(areaSize.height()); |
| 67 | horizontalScrollBar()->setPageStep(areaSize.width()); |
| 68 | verticalScrollBar()->setRange(min: 0, max: widgetSize.height() - areaSize.height()); |
| 69 | horizontalScrollBar()->setRange(min: 0, max: widgetSize.width() - areaSize.width()); |
| 70 | updateWidgetPosition(); |
| 71 | //! [1] |
| 72 | } |
| 73 | |
| 74 | void MyScrollArea::resizeEvent(QResizeEvent *event) |
| 75 | { |
| 76 | Q_UNUSED(event); |
| 77 | updateArea(); |
| 78 | } |
| 79 |