QPixmapConvolutionFilter Class Reference

The QPixmapConvolutionFilter class provides convolution filtering for pixmaps. More...

#include <qpixmapfilter_p.h>

Inheritance diagram for QPixmapConvolutionFilter:

Public Functions
QRectF	boundingRectFor (const QRectF &rect) const
void	draw (QPainter *painter, const QPointF &dest, const QPixmap &src, const QRectF &srcRect=QRectF()) const
	QPixmapConvolutionFilter (QObject *parent=0)
	Constructs a pixmap convolution filter. More...
void	setConvolutionKernel (const qreal *matrix, int rows, int columns)
	Sets convolution kernel with the given number of rows and columns. More...
	~QPixmapConvolutionFilter ()
	Destructor of pixmap convolution filter. More...
Public Functions inherited from QPixmapFilter
FilterType	type () const
	Returns the type of the filter. More...
virtual	~QPixmapFilter ()=0
	Destroys the pixmap filter. More...
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
virtual bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Private Functions
int	columns () const
	Gets the number of columns in the convolution kernel. More...
const qreal *	convolutionKernel () const
	Gets the convolution kernel data. More...
int	rows () const
	Gets the number of rows in the convolution kernel. More...

Friends
class	QGLPixmapConvolutionFilter
class	QVGPixmapConvolutionFilter

Additional Inherited Members
Public Types inherited from QPixmapFilter
enum	FilterType {   ConvolutionFilter, ColorizeFilter, DropShadowFilter, BlurFilter,   UserFilter = 1024 }
	This enum describes the types of filter that can be applied to pixmaps. More...
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...
Protected Functions inherited from QPixmapFilter
	QPixmapFilter (QPixmapFilterPrivate &d, FilterType type, QObject *parent)
	QPixmapFilter (FilterType type, QObject *parent)
	Constructs a default QPixmapFilter with the given type. More...
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const
virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

The QPixmapConvolutionFilter class provides convolution filtering for pixmaps.

Since

4.5

QPixmapConvolutionFilter implements a convolution pixmap filter, which is applied when QPixmapFilter::draw() is called. A convolution filter lets you distort an image by setting the values of a matrix of qreal values called its kernel. The matrix's values are usually between -1.0 and 1.0.

Warning

This function is not part of the public interface. In convolution filtering, the pixel value is calculated from the neighboring pixels based on the weighting convolution kernel. This needs explaining to be useful.

Example:

QPixmapConvolutionFilter *myFilter = new QPixmapConvolutionFilter;
qreal kernel[] = {
     0.0,-1.0, 0.0,
    -1.0, 5.0,-1.0,
     0.0,-1.0, 0.0
    };
myFilter->setConvolutionKernel(kernel, 3, 3);
myFilter->draw(painter, QPoint(0, 0), originalPixmap);

See also

{Pixmap Filters Example}, QPixmapColorizeFilter, QPixmapDropShadowFilter

Warning

This function is not part of the public interface.

Definition at line 101 of file qpixmapfilter_p.h.

Constructors and Destructors

QPixmapConvolutionFilter()

QPixmapConvolutionFilter::QPixmapConvolutionFilter

(

QObject *

parent = 0

)

Constructs a pixmap convolution filter.

By default there is no convolution kernel.

Warning

This function is not part of the public interface.

Definition at line 241 of file qpixmapfilter.cpp.

    : QPixmapFilter(*new QPixmapConvolutionFilterPrivate, ConvolutionFilter, parent)
{
    Q_D(QPixmapConvolutionFilter);
    d->convoluteAlpha = true;
}

~QPixmapConvolutionFilter()

QPixmapConvolutionFilter::~QPixmapConvolutionFilter

(

)

Destructor of pixmap convolution filter.

Warning

This function is not part of the public interface.

Definition at line 253 of file qpixmapfilter.cpp.

{
}

Functions

boundingRectFor()

QRectF QPixmapConvolutionFilter::boundingRectFor ( const QRectF &  rect ) const

virtual

Warning

This function is not part of the public interface.

Reimplemented from QPixmapFilter.

Definition at line 315 of file qpixmapfilter.cpp.

Referenced by draw().

{
    Q_D(const QPixmapConvolutionFilter);
    return rect.adjusted(-d->kernelWidth / 2, -d->kernelHeight / 2, (d->kernelWidth - 1) / 2, (d->kernelHeight - 1) / 2);
}

columns()

int QPixmapConvolutionFilter::columns ( ) const

private

Gets the number of columns in the convolution kernel.

Warning

This function is not part of the public interface.

Definition at line 305 of file qpixmapfilter.cpp.

Referenced by QVGPixmapConvolutionFilter::draw(), QGLPixmapConvolutionFilter::processGL(), and setConvolutionKernel().

{
    Q_D(const QPixmapConvolutionFilter);
    return d->kernelWidth;
}

convolutionKernel()

const qreal * QPixmapConvolutionFilter::convolutionKernel ( ) const

private

Gets the convolution kernel data.

Warning

This function is not part of the public interface.

Definition at line 283 of file qpixmapfilter.cpp.

Referenced by QVGPixmapConvolutionFilter::draw().

{
    Q_D(const QPixmapConvolutionFilter);
    return d->convolutionKernel;
}

draw()

void QPixmapConvolutionFilter::draw ( QPainter *  painter, const QPointF &  p, const QPixmap &  src, const QRectF &  srcRect = QRectF()  ) const

virtual

Warning

This function is not part of the public interface.

Implements QPixmapFilter.

Reimplemented in QGLPixmapFilter< QPixmapConvolutionFilter >, and QVGPixmapConvolutionFilter.

Definition at line 425 of file qpixmapfilter.cpp.

Referenced by QVGPixmapConvolutionFilter::draw(), and draw().

{
    Q_D(const QPixmapConvolutionFilter);
    if (!painter->isActive())
        return;

    if(d->kernelWidth<=0 || d->kernelHeight <= 0)
        return;

    if (src.isNull())
        return;

    QPixmapFilter *filter = painter->paintEngine() && painter->paintEngine()->isExtended() ?
        static_cast<QPaintEngineEx *>(painter->paintEngine())->pixmapFilter(type(), this) : 0;
    QPixmapConvolutionFilter *convolutionFilter = static_cast<QPixmapConvolutionFilter*>(filter);
    if (convolutionFilter) {
        convolutionFilter->setConvolutionKernel(d->convolutionKernel, d->kernelWidth, d->kernelHeight);
        convolutionFilter->d_func()->convoluteAlpha = d->convoluteAlpha;
        convolutionFilter->draw(painter, p, src, srcRect);
        return;
    }

    // falling back to raster implementation

    QImage *target = 0;
    if (painter->paintEngine()->paintDevice()->devType() == QInternal::Image) {
        target = static_cast<QImage *>(painter->paintEngine()->paintDevice());

        QTransform mat = painter->combinedTransform();

        if (mat.type() > QTransform::TxTranslate) {
            // Disabled because of transformation...
            target = 0;
        } else {
            QRasterPaintEngine *pe = static_cast<QRasterPaintEngine *>(painter->paintEngine());
            if (pe->clipType() == QRasterPaintEngine::ComplexClip)
                // disabled because of complex clipping...
                target = 0;
            else {
                QRectF clip = pe->clipBoundingRect();
                QRectF rect = boundingRectFor(srcRect.isEmpty() ? src.rect() : srcRect);
                QTransform x = painter->deviceTransform();
                if (!clip.contains(rect.translated(x.dx() + p.x(), x.dy() + p.y()))) {
                    target = 0;
                }

            }
        }
    }

    if (target) {
        QTransform x = painter->deviceTransform();
        QPointF offset(x.dx(), x.dy());

        convolute(target, p+offset, src.toImage(), srcRect, QPainter::CompositionMode_SourceOver, d->convolutionKernel, d->kernelWidth, d->kernelHeight);
    } else {
        QRect srect = srcRect.isNull() ? src.rect() : srcRect.toRect();
        QRect rect = boundingRectFor(srect).toRect();
        QImage result = QImage(rect.size(), QImage::Format_ARGB32_Premultiplied);
        QPoint offset = srect.topLeft() - rect.topLeft();
        convolute(&result,
                  offset,
                  src.toImage(),
                  srect,
                  QPainter::CompositionMode_Source,
                  d->convolutionKernel,
                  d->kernelWidth,
                  d->kernelHeight);
        painter->drawImage(p - offset, result);
    }
}

rows()

int QPixmapConvolutionFilter::rows ( ) const

private

Gets the number of rows in the convolution kernel.

Warning

This function is not part of the public interface.

Definition at line 294 of file qpixmapfilter.cpp.

Referenced by QVGPixmapConvolutionFilter::draw(), QGLPixmapConvolutionFilter::processGL(), and setConvolutionKernel().

{
    Q_D(const QPixmapConvolutionFilter);
    return d->kernelHeight;
}

setConvolutionKernel()

void QPixmapConvolutionFilter::setConvolutionKernel	(	const qreal *	kernel,
		int	rows,
		int	columns
	)

Sets convolution kernel with the given number of rows and columns.

Values from kernel are copied to internal data structure.

To preserve the intensity of the pixmap, the sum of all the values in the convolution kernel should add up to 1.0. A sum greater than 1.0 produces a lighter result and a sum less than 1.0 produces a darker and transparent result.

Warning

This function is not part of the public interface.

Definition at line 268 of file qpixmapfilter.cpp.

Referenced by draw().

{
    Q_D(QPixmapConvolutionFilter);
    delete [] d->convolutionKernel;
    d->convolutionKernel = new qreal[rows * columns];
    memcpy(d->convolutionKernel, kernel, sizeof(qreal) * rows * columns);
    d->kernelWidth = columns;
    d->kernelHeight = rows;
}

Friends and Related Functions

QGLPixmapConvolutionFilter

friend class QGLPixmapConvolutionFilter

friend

Definition at line 116 of file qpixmapfilter_p.h.

QVGPixmapConvolutionFilter

friend class QVGPixmapConvolutionFilter

friend

Definition at line 117 of file qpixmapfilter_p.h.

---

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

• /src/gui/image/qpixmapfilter_p.h
• /src/gui/image/qpixmapfilter.cpp