DisplayWidget Class Reference

#include <displaywidget.h>

Inheritance diagram for DisplayWidget:

[legend]Collaboration diagram for DisplayWidget:

[legend]List of all members.

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Detailed Description

Definition at line 32 of file displaywidget.h.

Signals
void	actionRequested (const QString &name)
void	displayEmpty ()
void	categoryRequested (const QString &name)
void	documentationRequested (const QString &name)
void	exampleRequested (const QString &name)
void	launchRequested (const QString &name)
Public Member Functions
	DisplayWidget (QWidget *parent=0)
QSize	minimumSizeHint () const
DisplayShape *	shape (int index) const
int	shapesCount () const
void	appendShape (DisplayShape *shape)
void	enableUpdates ()
void	insertShape (int position, DisplayShape *shape)
void	reset ()
Protected Member Functions
void	mouseMoveEvent (QMouseEvent *event)
void	mousePressEvent (QMouseEvent *event)
void	paintEvent (QPaintEvent *event)
void	timerEvent (QTimerEvent *event)
Private Attributes
bool	empty
bool	emptying
bool	updatesEnabled
QList< DisplayShape * >	shapes
QBasicTimer	timer

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Constructor & Destructor Documentation

DisplayWidget::DisplayWidget

(

QWidget *

parent = 0

)

Definition at line 34 of file displaywidget.cpp.

References QPalette::Base, empty, emptying, enableUpdates(), QWidget::setBackgroundRole(), and QWidget::setMouseTracking().

    : QWidget(parent)
{
#if defined(Q_WS_X11)
    frameTime = 0;
    avgRate = 0;
    numFrames = 0;
    testDrawSpeed = true;
#endif
    empty = true;
    emptying = false;

    enableUpdates();

    setBackgroundRole(QPalette::Base);
    setMouseTracking(true);
}

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Member Function Documentation

QSize DisplayWidget::minimumSizeHint

(

)

const [virtual]

Reimplemented from QWidget.

Definition at line 66 of file displaywidget.cpp.

{
    return QSize(800, 600);
}

DisplayShape * DisplayWidget::shape

(

int

index

)

const

Definition at line 194 of file displaywidget.cpp.

References shapes, and QList< T >::value().

Referenced by appendShape(), Launcher::enableLaunching(), Launcher::fadeShapes(), insertShape(), mouseMoveEvent(), mousePressEvent(), paintEvent(), reset(), and timerEvent().

{
    return shapes.value(index);
}

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int DisplayWidget::shapesCount

(

)

const

Definition at line 199 of file displaywidget.cpp.

References shapes, and QList< T >::size().

Referenced by Launcher::enableLaunching(), and Launcher::fadeShapes().

{
    return shapes.size();
}

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void DisplayWidget::appendShape

(

DisplayShape *

shape

)

Definition at line 52 of file displaywidget.cpp.

References QList< T >::append(), empty, enableUpdates(), shape(), and shapes.

Referenced by Launcher::addTitle(), Launcher::addVersionAndCopyright(), Launcher::showCategories(), Launcher::showExamples(), Launcher::showExampleSummary(), and Launcher::updateExampleSummary().

{
    shapes.append(shape);
    empty = false;
    enableUpdates();
}

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void DisplayWidget::enableUpdates

(

)

Definition at line 204 of file displaywidget.cpp.

References QBasicTimer::isActive(), QBasicTimer::start(), and timer.

Referenced by appendShape(), DisplayWidget(), Launcher::enableLaunching(), insertShape(), mouseMoveEvent(), mousePressEvent(), and reset().

{
    if (!timer.isActive())
        timer.start(25, this);
}

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void DisplayWidget::insertShape	(	int	position,
		DisplayShape *	shape
	)

Definition at line 59 of file displaywidget.cpp.

References empty, enableUpdates(), QList< T >::insert(), shape(), and shapes.

Referenced by Launcher::addTitleBackground(), Launcher::showCategories(), Launcher::showExamples(), and Launcher::showExampleSummary().

{
    shapes.insert(position, shape);
    empty = false;
    enableUpdates();
}

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void DisplayWidget::reset

(

)

Definition at line 174 of file displaywidget.cpp.

References displayEmpty(), emit, empty, emptying, enableUpdates(), DisplayShape::setMetaData(), shape(), shapes, QList< T >::size(), QBasicTimer::stop(), and timer.

Referenced by Launcher::executeAction(), and Launcher::toggleFullScreen().

{
    if (emptying)
        return;

    if (shapes.size() == 0) {
        empty = true;
        timer.stop();
        emit displayEmpty();    // Note: synchronous signal
    } else {
        enableUpdates();
        emptying = true;
        empty = false;
        foreach (DisplayShape *shape, shapes) {
            shape->setMetaData("fade", -15);
            shape->setMetaData("fade minimum", 0);
        }
    }
}

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void DisplayWidget::mouseMoveEvent

(

QMouseEvent *

event

)

[protected, virtual]

This event handler, for event event, can be reimplemented in a subclass to receive mouse move events for the widget.

If mouse tracking is switched off, mouse move events only occur if a mouse button is pressed while the mouse is being moved. If mouse tracking is switched on, mouse move events occur even if no mouse button is pressed.

QMouseEvent::pos() reports the position of the mouse cursor, relative to this widget. For press and release events, the position is usually the same as the position of the last mouse move event, but it might be different if the user's hand shakes. This is a feature of the underlying window system, not Qt.

See also:

setMouseTracking(), mousePressEvent(), mouseReleaseEvent(), mouseDoubleClickEvent(), event(), QMouseEvent, {Scribble Example}

Reimplemented from QWidget.

Definition at line 71 of file displaywidget.cpp.

References QRectF::contains(), DisplayShape::contains(), emptying, enableUpdates(), QWidget::event(), DisplayShape::isInteractive(), DisplayShape::metaData(), DisplayShape::rect(), DisplayShape::setMetaData(), shape(), shapes, and QVariant::toBool().

{
    if (emptying)
        return;

    bool updated = false;

    foreach (DisplayShape *shape, shapes) {
        if (shape->rect().contains(event->pos())) {
            if (shape->isInteractive() && !shape->contains("fade")
                && !shape->contains("highlight")) {
                shape->setMetaData("highlight", true);
                updated = true;
            }
        } else if (shape->isInteractive() && shape->contains("highlight")
                   && shape->metaData("highlight").toBool()) {
            shape->setMetaData("highlight", false);
            updated = true;
        }
    }

    if (updated)
        enableUpdates();
}

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void DisplayWidget::mousePressEvent

(

QMouseEvent *

event

)

[protected, virtual]

This event handler, for event event, can be reimplemented in a subclass to receive mouse press events for the widget.

If you create new widgets in the mousePressEvent() the mouseReleaseEvent() may not end up where you expect, depending on the underlying window system (or X11 window manager), the widgets' location and maybe more.

The default implementation implements the closing of popup widgets when you click outside the window. For other widget types it does nothing.

See also:

mouseReleaseEvent(), mouseDoubleClickEvent(), mouseMoveEvent(), event(), QMouseEvent, {Scribble Example}

Reimplemented from QWidget.

Definition at line 96 of file displaywidget.cpp.

References actionRequested(), categoryRequested(), QRectF::contains(), DisplayShape::contains(), documentationRequested(), emit, emptying, enableUpdates(), QWidget::event(), exampleRequested(), launchRequested(), Qt::LeftButton, DisplayShape::metaData(), DisplayShape::rect(), DisplayShape::setMetaData(), shape(), shapes, and QVariant::toString().

{
    if (event->button() != Qt::LeftButton)
        return;

    if (emptying)
        return;

    foreach (DisplayShape *shape, shapes) {
        if (shape->rect().contains(event->pos()) && !shape->contains("fade")) {
            if (shape->contains("action"))
                emit actionRequested(shape->metaData("action").toString());
            else if (shape->contains("category"))
                emit categoryRequested(shape->metaData("category").toString());
            else if (shape->contains("example"))
                emit exampleRequested(shape->metaData("example").toString());
            else if (shape->contains("documentation")) {
                emit documentationRequested(
                    shape->metaData("documentation").toString());
                shape->setMetaData("highlight", false);
                enableUpdates();
            } else if (shape->contains("launch")) {
                emit launchRequested(shape->metaData("launch").toString());
                shape->setMetaData("fade", -5);
                enableUpdates();
            }
        }
    }
}

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void DisplayWidget::paintEvent

(

QPaintEvent *

event

)

[protected, virtual]

This event handler can be reimplemented in a subclass to receive paint events which are passed in the event parameter.

A paint event is a request to repaint all or part of the widget. It can happen as a result of repaint() or update(), or because the widget was obscured and has now been uncovered, or for many other reasons.

Many widgets can simply repaint their entire surface when asked to, but some slow widgets need to optimize by painting only the requested region: QPaintEvent::region(). This speed optimization does not change the result, as painting is clipped to that region during event processing. QListView and QTableView do this, for example.

Qt also tries to speed up painting by merging multiple paint events into one. When update() is called several times or the window system sends several paint events, Qt merges these events into one event with a larger region (see QRegion::united()). repaint() does not permit this optimization, so we suggest using update() whenever possible.

When the paint event occurs, the update region has normally been erased, so that you're painting on the widget's background.

The background can be set using setBackgroundRole() and setPalette().

From Qt 4.0, QWidget automatically double-buffers its painting, so there's no need to write double-buffering code in paintEvent() to avoid flicker.

Note: Under X11 it is possible to toggle the global double buffering by calling qt_x11_set_global_double_buffer(). Example usage:

    ...
    extern void qt_x11_set_global_double_buffer(bool);
    qt_x11_set_global_double_buffer(false);
    ...

See also:

event(), repaint(), update(), QPainter, QPixmap, QPaintEvent, {Analog Clock Example}

Reimplemented from QWidget.

Definition at line 126 of file displaywidget.cpp.

References QPainter::begin(), QTime::elapsed(), QPainter::end(), QWidget::event(), QPainter::fillRect(), QRectF::intersects(), DisplayShape::paint(), DisplayShape::rect(), QTime::restart(), shape(), shapes, QTimer::singleShot(), SLOT, Qt::white, and X11.

{
#if defined(Q_WS_X11)
    QTime renderTime;
    if (testDrawSpeed)
        renderTime.restart();
#endif

    QPainter painter;
    painter.begin(this);
    painter.fillRect(event->rect(), Qt::white);
    foreach (DisplayShape *shape, shapes) {
        if (shape->rect().intersects(event->rect()))
            shape->paint(&painter);
    }
    painter.end();

#if defined(Q_WS_X11)
    if (testDrawSpeed) {
        numFrames++;
        frameTime += renderTime.elapsed();
        avgRate = frameTime/numFrames;
        if (numFrames > 20) {
            testDrawSpeed = false;
            if (avgRate > 50 && X11->use_xrender)
                QTimer::singleShot(0, this, SLOT(toggleXRender()));
        }
    }
#endif
}

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void DisplayWidget::timerEvent

(

QTimerEvent *

event

)

[protected, virtual]

This event handler can be reimplemented in a subclass to receive timer events for the object.

QTimer provides a higher-level interface to the timer functionality, and also more general information about timers. The timer event is passed in the event parameter.

See also:

startTimer(), killTimer(), event()

Reimplemented from QObject.

Definition at line 210 of file displaywidget.cpp.

References QRect::adjusted(), DisplayShape::animate(), DisplayShape::contains(), displayEmpty(), emit, empty, emptying, QWidget::event(), DisplayShape::rect(), QList< T >::removeAll(), shape(), shapes, QList< T >::size(), QBasicTimer::stop(), timer, QObject::timerEvent(), QBasicTimer::timerId(), QRectF::toRect(), and QWidget::update().

{
    if (event->timerId() == timer.timerId()) {
        QVector<DisplayShape*> discard;

        int updated = 0;

        foreach (DisplayShape *shape, shapes) {
            QRect oldRect = shape->rect().toRect().adjusted(-1,-1,1,1);
            if (shape->animate()) {

                update(oldRect);
                QRect newRect = shape->rect().toRect().adjusted(-1,-1,1,1);
                ++updated;

                if (shape->contains("destroy")) {
                    discard.append(shape);
                } else {
                    update(newRect);
                }
            }
        }

        if (updated == 0)
            timer.stop();

        foreach (DisplayShape *shape, discard) {
            shapes.removeAll(shape);
            delete shape;
        }

        if (shapes.size() == 0 && !empty) {
            empty = true;
            emptying = false;
            timer.stop();
            emit displayEmpty();    // Note: synchronous signal
        }
    } else {
  QWidget::timerEvent(event);
    }
}

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void DisplayWidget::actionRequested

(

const QString &

name

)

[signal]

Referenced by mousePressEvent().

void DisplayWidget::displayEmpty

(

)

[signal]

Referenced by reset(), and timerEvent().

void DisplayWidget::categoryRequested

(

const QString &

name

)

[signal]

Referenced by mousePressEvent().

void DisplayWidget::documentationRequested

(

const QString &

name

)

[signal]

Referenced by mousePressEvent().

void DisplayWidget::exampleRequested

(

const QString &

name

)

[signal]

Referenced by mousePressEvent().

void DisplayWidget::launchRequested

(

const QString &

name

)

[signal]

Referenced by mousePressEvent().

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Member Data Documentation

bool DisplayWidget::empty [private]

Definition at line 61 of file displaywidget.h.

Referenced by appendShape(), DisplayWidget(), insertShape(), reset(), and timerEvent().

bool DisplayWidget::emptying [private]

Definition at line 62 of file displaywidget.h.

Referenced by DisplayWidget(), mouseMoveEvent(), mousePressEvent(), reset(), and timerEvent().

bool DisplayWidget::updatesEnabled [private]

Definition at line 63 of file displaywidget.h.

QList<DisplayShape*> DisplayWidget::shapes [private]

Definition at line 64 of file displaywidget.h.

Referenced by appendShape(), insertShape(), mouseMoveEvent(), mousePressEvent(), paintEvent(), reset(), shape(), shapesCount(), and timerEvent().

QBasicTimer DisplayWidget::timer [private]

Definition at line 65 of file displaywidget.h.

Referenced by enableUpdates(), reset(), and timerEvent().

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The documentation for this class was generated from the following files:

• examples/tools/qtdemo/displaywidget.h
• examples/tools/qtdemo/displaywidget.cpp

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