qt5base-lts/examples/widgets/scroller/graphicsview/main.cpp
Christian Ehrlicher 4af00753fa Cleanup QtWidgets examples
Cleanup QtWidgets examples:
 - use nullptr (clang-tidy)
 - use member-initialization
 - adjust the style
 - fix includes

Change-Id: Ic5448606aacc525ea60b615a69227017aa2b821a
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
2019-10-11 06:32:30 +02:00

303 lines
9.6 KiB
C++

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtCore>
#include <QtWidgets>
#define NUM_ITEMS 100
#define NUM_LISTS 10
/*!
\class RectObject
Note that it needs to be a QGraphicsObject or else the gestures will not work correctly.
*/
class RectObject : public QGraphicsObject
{
Q_OBJECT
public:
RectObject(const QString &text, qreal x, qreal y, qreal width, qreal height, QBrush brush, QGraphicsItem *parent = nullptr)
: QGraphicsObject(parent)
, m_text(text)
, m_rect(x, y, width, height)
, m_pen(brush.color().lighter(), 3.0)
, m_brush(brush)
{
setFlag(QGraphicsItem::ItemClipsToShape, true);
}
QRectF boundingRect() const override
{
// here we only want the size of the children and not the size of the children of the children...
qreal halfpw = m_pen.widthF() / 2;
QRectF rect = m_rect;
if (halfpw > 0.0)
rect.adjust(-halfpw, -halfpw, halfpw, halfpw);
return rect;
}
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override
{
Q_UNUSED(option);
Q_UNUSED(widget);
painter->setPen(m_pen);
painter->setBrush(m_brush);
painter->drawRect(m_rect);
painter->setPen(Qt::black);
QFont f;
f.setPixelSize(m_rect.height());
painter->setFont(f);
painter->drawText(m_rect, Qt::AlignCenter, m_text);
}
QString m_text;
QRectF m_rect;
QPen m_pen;
QBrush m_brush;
};
class ViewObject : public QGraphicsObject
{
Q_OBJECT
public:
ViewObject(QGraphicsObject *parent)
: QGraphicsObject(parent)
{ }
QRectF boundingRect() const override
{
QRectF rect;
const auto items = childItems();
for (const QGraphicsItem *item : items)
rect |= item->boundingRect().translated(item->pos());
return rect;
}
void paint(QPainter *, const QStyleOptionGraphicsItem *, QWidget *) override
{ }
};
class ListObject : public QGraphicsObject
{
Q_OBJECT
public:
ListObject(const QSizeF &size, bool useTouch)
{
m_size = size;
setFlag(QGraphicsItem::ItemClipsChildrenToShape, true);
// grab gesture via Touch or Mouse events
QScroller::grabGesture(this, useTouch ? QScroller::TouchGesture : QScroller::LeftMouseButtonGesture);
// this needs to be QGraphicsOBJECT - otherwise gesture recognition
// will not work for the parent of the viewport (in this case the
// list)
m_viewport = new ViewObject(this);
}
QGraphicsObject *viewport() const
{
return m_viewport;
}
bool event(QEvent *e) override
{
switch (e->type()) {
// ![2]
case QEvent::ScrollPrepare: {
QScrollPrepareEvent *se = static_cast<QScrollPrepareEvent *>(e);
se->setViewportSize(m_size);
QRectF br = m_viewport->boundingRect();
se->setContentPosRange(QRectF(0, 0,
qMax(qreal(0), br.width() - m_size.width()),
qMax(qreal(0), br.height() - m_size.height())));
se->setContentPos(-m_viewport->pos());
se->accept();
return true;
}
// ![1]
// ![2]
case QEvent::Scroll: {
QScrollEvent *se = static_cast<QScrollEvent *>(e);
m_viewport->setPos(-se->contentPos() - se->overshootDistance());
return true;
}
// ![2]
default:
break;
}
return QGraphicsObject::event(e);
}
bool sceneEvent(QEvent *e) override
{
switch (e->type()) {
case QEvent::TouchBegin: {
// We need to return true for the TouchBegin here in the
// top-most graphics object - otherwise gestures in our parent
// objects will NOT work at all (the accept() flag is already
// set due to our setAcceptTouchEvents(true) call in the c'tor
return true;
}
case QEvent::GraphicsSceneMousePress: {
// We need to return true for the MousePress here in the
// top-most graphics object - otherwise gestures in our parent
// objects will NOT work at all (the accept() flag is already
// set to true by Qt)
return true;
}
default:
break;
}
return QGraphicsObject::sceneEvent(e);
}
QRectF boundingRect() const override
{
return QRectF(0, 0, m_size.width() + 3, m_size.height());
}
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override
{
Q_UNUSED(option);
Q_UNUSED(widget);
painter->setPen(QPen(QColor(100, 100, 100), 3.0));
painter->drawRect(QRectF(1.5, 1.5, m_size.width() - 3, m_size.height() - 3));
}
QSizeF m_size;
ViewObject *m_viewport;
};
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(bool useTouch)
{
m_scene = new QGraphicsScene();
// -- make the main list
ListObject *mainList = new ListObject(QSizeF(780, 400), useTouch);
mainList->setObjectName(QLatin1String("MainList"));
m_scene->addItem(mainList);
// ![3]
for (int i=0; i<NUM_LISTS; i++) {
ListObject *childList = new ListObject(QSizeF(mainList->m_size.width()/3, mainList->m_size.height()), useTouch);
childList->setObjectName(QString("ChildList %1").arg(i));
fillList(childList);
childList->setParentItem(mainList->viewport());
childList->setPos(i*mainList->m_size.width()/3, 0);
}
mainList->viewport()->setPos(0, 0);
/*
list1->setTransformOriginPoint(200, 200);
list1->setRotation(135);
list1->setPos(20 + 200 * .41, 20 + 200 * .41);
*/
// ![3]
m_view = new QGraphicsView(m_scene);
setCentralWidget(m_view);
setWindowTitle(tr("Gesture example"));
m_scene->setSceneRect(0, 0, m_view->viewport()->width(), m_view->viewport()->height());
}
/**
* Fills the list object \a list with RectObjects.
*/
void fillList(ListObject *list)
{
qreal h = list->m_size.height() / 10;
for (int i=0; i<NUM_ITEMS; i++) {
QColor color = QColor(255*i/NUM_ITEMS, 255*(NUM_ITEMS-i)/NUM_ITEMS, 127*(i%2)+64*(i/2%2));
QString text = QLatin1String("Item #") + QString::number(i);
QGraphicsItem *rect = new RectObject(text, 0, 0, list->m_size.width() - 6, h - 3, QBrush(color), list->viewport());
rect->setPos(3, h*i+3);
}
list->viewport()->setPos(0, 0);
}
protected:
void resizeEvent(QResizeEvent *e) override
{
// resize the scene according to our own size to prevent scrolling
m_scene->setSceneRect(0, 0, m_view->viewport()->width(), m_view->viewport()->height());
QMainWindow::resizeEvent(e);
}
QGraphicsScene *m_scene;
QGraphicsView *m_view;
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
bool touch = (a.arguments().contains(QLatin1String("--touch")));
MainWindow mw(touch);
mw.show();
#ifdef Q_OS_MAC
mw.raise();
#endif
return a.exec();
}
#include "main.moc"