PaintArea Class Reference

#include <paintarea.h>

Inheritance diagram for PaintArea:

[legend]Collaboration diagram for PaintArea:

[legend]List of all members.

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Detailed Description

Definition at line 34 of file paintarea.h.

Public Member Functions
	PaintArea (QWidget *parent=0)
bool	openImage (const QString &fileName)
bool	saveImage (const QString &fileName, const char *fileFormat)
void	setImage (const QImage &image)
void	insertShape (const QPainterPath &path)
void	setBrushColor (const QColor &color)
void	setBrushWidth (int width)
void	setBrush (BrushInterface *brushInterface, const QString &brush)
QImage	image () const
QColor	brushColor () const
int	brushWidth () const
QSize	sizeHint () const
Protected Member Functions
void	paintEvent (QPaintEvent *event)
void	mousePressEvent (QMouseEvent *event)
void	mouseMoveEvent (QMouseEvent *event)
void	mouseReleaseEvent (QMouseEvent *event)
Private Member Functions
void	setupPainter (QPainter &painter)
Private Attributes
QImage	theImage
QColor	color
int	thickness
BrushInterface *	brushInterface
QString	brush
QPoint	lastPos
QPainterPath	pendingPath

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Constructor & Destructor Documentation

PaintArea::PaintArea

(

QWidget *

parent = 0

)

Definition at line 29 of file paintarea.cpp.

References Qt::blue, brushInterface, color, QImage::fill(), QImage::Format_RGB32, lastPos, qRgb(), QWidget::setAttribute(), theImage, thickness, Qt::WA_NoBackground, and Qt::WA_StaticContents.

    : QWidget(parent)
{
    setAttribute(Qt::WA_StaticContents);
    setAttribute(Qt::WA_NoBackground);

    theImage = QImage(500, 400, QImage::Format_RGB32);
    theImage.fill(qRgb(255, 255, 255));
    color = Qt::blue;
    thickness = 3;
    brushInterface = 0;
    lastPos = QPoint(-1, -1);
}

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Member Function Documentation

bool PaintArea::openImage

(

const QString &

fileName

)

Definition at line 43 of file paintarea.cpp.

References image(), QImage::load(), and setImage().

{
    QImage image;
    if (!image.load(fileName))
        return false;

    setImage(image);
    return true;
}

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bool PaintArea::saveImage	(	const QString &	fileName,
		const char *	fileFormat
	)

Definition at line 53 of file paintarea.cpp.

References QImage::save(), and theImage.

{
    return theImage.save(fileName, fileFormat);
}

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void PaintArea::setImage

(

const QImage &

image

)

Definition at line 58 of file paintarea.cpp.

References QImage::convertToFormat(), QImage::Format_RGB32, image(), theImage, QWidget::update(), and QWidget::updateGeometry().

Referenced by MainWindow::applyFilter(), and openImage().

{
    theImage = image.convertToFormat(QImage::Format_RGB32);
    update();
    updateGeometry();
}

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void PaintArea::insertShape

(

const QPainterPath &

path

)

Definition at line 65 of file paintarea.cpp.

References Qt::CrossCursor, path, pendingPath, and QWidget::setCursor().

Referenced by MainWindow::insertShape().

{
    pendingPath = path;
    setCursor(Qt::CrossCursor);
}

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void PaintArea::setBrushColor

(

const QColor &

color

)

Definition at line 71 of file paintarea.cpp.

References color.

Referenced by MainWindow::brushColor().

{
    this->color = color;
}

void PaintArea::setBrushWidth

(

int

width

)

Definition at line 76 of file paintarea.cpp.

References thickness.

Referenced by MainWindow::brushWidth().

{
    thickness = width;
}

void PaintArea::setBrush	(	BrushInterface *	brushInterface,
		const QString &	brush
	)

Definition at line 81 of file paintarea.cpp.

References brush, and brushInterface.

Referenced by MainWindow::changeBrush().

{
    this->brushInterface = brushInterface;
    this->brush = brush;
}

QImage PaintArea::image

(

)

const [inline]

Definition at line 49 of file paintarea.h.

References theImage.

Referenced by MainWindow::applyFilter(), openImage(), and setImage().

{ return theImage; }

QColor PaintArea::brushColor

(

)

const [inline]

Definition at line 50 of file paintarea.h.

References color.

Referenced by MainWindow::brushColor().

{ return color; }

int PaintArea::brushWidth

(

)

const [inline]

Definition at line 51 of file paintarea.h.

References thickness.

Referenced by MainWindow::brushWidth().

{ return thickness; }

QSize PaintArea::sizeHint

(

)

const [virtual]

Reimplemented from QWidget.

Definition at line 87 of file paintarea.cpp.

References QImage::size(), and theImage.

{
    return theImage.size();
}

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void PaintArea::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 92 of file paintarea.cpp.

References QPainter::drawImage(), and theImage.

{
    QPainter painter(this);
    painter.drawImage(QPoint(0, 0), theImage);
}

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void PaintArea::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 98 of file paintarea.cpp.

References QColor::blue, QRectF::bottomLeft(), QPainterPath::boundingRect(), brush, brushInterface, QRectF::center(), color, QWidget::event(), QColor::green, QPainterPath::isEmpty(), lastPos, Qt::LeftButton, BrushInterface::mousePress(), pendingPath, QWidget::rect(), QColor::red, setupPainter(), theImage, QRectF::topRight(), QRectF::translate(), QWidget::unsetCursor(), and QWidget::update().

{
    if (event->button() == Qt::LeftButton) {
        if (!pendingPath.isEmpty()) {
            QPainter painter(&theImage);
            setupPainter(painter);

            QRectF boundingRect = pendingPath.boundingRect();
            QLinearGradient gradient(boundingRect.topRight(),
                                     boundingRect.bottomLeft());
            gradient.setColorAt(0.0, QColor(color.red(), color.green(),
                                            color.blue(), 63));
            gradient.setColorAt(1.0, QColor(color.red(), color.green(),
                                            color.blue(), 191));
            painter.setBrush(gradient);
            painter.translate(event->pos() - boundingRect.center());
            painter.drawPath(pendingPath);

            pendingPath = QPainterPath();
            unsetCursor();
            update();
        } else {
            if (brushInterface) {
                QPainter painter(&theImage);
                setupPainter(painter);
                QRect rect = brushInterface->mousePress(brush, painter,
                                                        event->pos());
                update(rect);
            }

            lastPos = event->pos();
        }
    }
}

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void PaintArea::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 133 of file paintarea.cpp.

References brush, brushInterface, QWidget::event(), lastPos, Qt::LeftButton, QWidget::rect(), setupPainter(), theImage, and QWidget::update().

{
    if ((event->buttons() & Qt::LeftButton) && lastPos != QPoint(-1, -1)) {
        if (brushInterface) {
            QPainter painter(&theImage);
            setupPainter(painter);
            QRect rect = brushInterface->mouseMove(brush, painter, lastPos,
                                                   event->pos());
            update(rect);
        }

        lastPos = event->pos();
    }
}

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void PaintArea::mouseReleaseEvent

(

QMouseEvent *

event

)

[protected, virtual]

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

See also:

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

Reimplemented from QWidget.

Definition at line 148 of file paintarea.cpp.

References brush, brushInterface, QWidget::event(), lastPos, Qt::LeftButton, QWidget::rect(), setupPainter(), theImage, and QWidget::update().

{
    if (event->button() == Qt::LeftButton && lastPos != QPoint(-1, -1)) {
        if (brushInterface) {
            QPainter painter(&theImage);
            setupPainter(painter);
            QRect rect = brushInterface->mouseRelease(brush, painter,
                                                      event->pos());
            update(rect);
        }

        lastPos = QPoint(-1, -1);
    }
}

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void PaintArea::setupPainter

(

QPainter &

painter

)

[private]

Definition at line 163 of file paintarea.cpp.

References QPainter::Antialiasing, color, Qt::RoundCap, Qt::RoundJoin, QPainter::setPen(), QPainter::setRenderHint(), Qt::SolidLine, and thickness.

Referenced by mouseMoveEvent(), mousePressEvent(), and mouseReleaseEvent().

{
    painter.setRenderHint(QPainter::Antialiasing, true);
    painter.setPen(QPen(color, thickness, Qt::SolidLine, Qt::RoundCap,
                   Qt::RoundJoin));
}

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Member Data Documentation

QImage PaintArea::theImage [private]

Definition at line 63 of file paintarea.h.

Referenced by image(), mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), PaintArea(), paintEvent(), saveImage(), setImage(), and sizeHint().

QColor PaintArea::color [private]

Definition at line 64 of file paintarea.h.

Referenced by brushColor(), mousePressEvent(), PaintArea(), setBrushColor(), and setupPainter().

int PaintArea::thickness [private]

Definition at line 65 of file paintarea.h.

Referenced by brushWidth(), PaintArea(), setBrushWidth(), and setupPainter().

BrushInterface* PaintArea::brushInterface [private]

Definition at line 67 of file paintarea.h.

Referenced by mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), PaintArea(), and setBrush().

QString PaintArea::brush [private]

Definition at line 68 of file paintarea.h.

Referenced by mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), and setBrush().

QPoint PaintArea::lastPos [private]

Definition at line 69 of file paintarea.h.

Referenced by mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), and PaintArea().

QPainterPath PaintArea::pendingPath [private]

Definition at line 71 of file paintarea.h.

Referenced by insertShape(), and mousePressEvent().

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

• examples/tools/plugandpaint/paintarea.h
• examples/tools/plugandpaint/paintarea.cpp

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