126 lines
4.0 KiB
C++
126 lines
4.0 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include <QtWidgets>
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class MyScrollArea : public QAbstractScrollArea
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{
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public:
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MyScrollArea(QWidget *w);
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void setWidget(QWidget *w);
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protected:
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void scrollContentsBy(int dx, int dy) override;
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void resizeEvent(QResizeEvent *event) override;
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private:
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void updateWidgetPosition();
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void updateArea();
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QWidget *widget;
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};
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MyScrollArea::MyScrollArea(QWidget *widget)
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: QAbstractScrollArea()
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{
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setWidget(widget);
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}
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void MyScrollArea::setWidget(QWidget *w)
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{
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widget = w;
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widget->setParent(viewport());
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if (!widget->testAttribute(Qt::WA_Resized))
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widget->resize(widget->sizeHint());
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verticalScrollBar()->setValue(0);
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verticalScrollBar()->setValue(0);
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updateArea();
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}
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void MyScrollArea::updateWidgetPosition()
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{
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//! [0]
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int hvalue = horizontalScrollBar()->value();
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int vvalue = verticalScrollBar()->value();
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QPoint topLeft = viewport()->rect().topLeft();
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widget->move(topLeft.x() - hvalue, topLeft.y() - vvalue);
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//! [0]
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}
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void MyScrollArea::scrollContentsBy(int dx, int dy)
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{
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Q_UNUSED(dx);
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Q_UNUSED(dy);
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updateWidgetPosition();
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}
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void MyScrollArea::updateArea()
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{
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//! [1]
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QSize areaSize = viewport()->size();
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QSize widgetSize = widget->size();
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verticalScrollBar()->setPageStep(areaSize.height());
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horizontalScrollBar()->setPageStep(areaSize.width());
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verticalScrollBar()->setRange(0, widgetSize.height() - areaSize.height());
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horizontalScrollBar()->setRange(0, widgetSize.width() - areaSize.width());
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updateWidgetPosition();
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//! [1]
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}
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void MyScrollArea::resizeEvent(QResizeEvent *event)
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{
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Q_UNUSED(event);
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updateArea();
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}
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