QSvgRenderer Class | Qt SVG 5.6

Qt 5.6 | Qt SVG | C++ Classes | QSvgRenderer

Qt 5.6.2 Reference Documentation

# QSvgRenderer Class

The QSvgRenderer class is used to draw the contents of SVG files onto paint devices. More...

Header: | #include <QSvgRenderer>
qmake: | QT += svg
Since: | Qt 4.1
Inherits: | QObject

- List of all members, including inherited members

Note: All functions in this class are reentrant.

## Properties

- framesPerSecond : int
- viewBox : QRectF

- 1 property inherited from QObject

## Public Functions

| QSvgRenderer(QObject *parent = Q_NULLPTR)
| QSvgRenderer(const QString &filename, QObject *parent = Q_NULLPTR)
| QSvgRenderer(const QByteArray &contents, QObject *parent = Q_NULLPTR)
| QSvgRenderer(QXmlStreamReader *contents, QObject *parent = Q_NULLPTR)
| ~QSvgRenderer()
bool | animated() const
QRectF | boundsOnElement(const QString &id) const
QSize | defaultSize() const
bool | elementExists(const QString &id) const
int | framesPerSecond() const
bool | isValid() const
QMatrix | matrixForElement(const QString &id) const
void | setFramesPerSecond(int num)
void | setViewBox(const QRect &viewbox)
void | setViewBox(const QRectF &viewbox)
QRect | viewBox() const
QRectF | viewBoxF() const

- 31 public functions inherited from QObject

## Public Slots

bool | load(const QString &filename)
bool | load(const QByteArray &contents)
bool | load(QXmlStreamReader *contents)
void | render(QPainter *painter)
void | render(QPainter *painter, const QRectF &bounds)
void | render(QPainter *painter, const QString &elementId, const QRectF &bounds = QRectF())

- 1 public slot inherited from QObject

## Signals

void | repaintNeeded()

- 2 signals inherited from QObject

### Additional Inherited Members

- 1 public variable inherited from QObject
- 10 static public members inherited from QObject
- 9 protected functions inherited from QObject
- 2 protected variables inherited from QObject

## Detailed Description

The QSvgRenderer class is used to draw the contents of SVG files onto paint devices.

Using QSvgRenderer, Scalable Vector Graphics (SVG) can be rendered onto any QPaintDevice subclass, including QWidget, QImage, and QGLWidget.

QSvgRenderer provides an API that supports basic features of SVG rendering, such as loading and rendering of static drawings, and more interactive features like animation. Since the rendering is performed using QPainter, SVG drawings can be rendered on any subclass of QPaintDevice.

SVG drawings are either loaded when an QSvgRenderer is constructed, or loaded later using the load() functions. Data is either supplied directly as serialized XML, or indirectly using a file name. If a valid file has been loaded, either when the renderer is constructed or at some later time, isValid() returns true; otherwise it returns false. QSvgRenderer provides the render() slot to render the current document, or the current frame of an animated document, using a given painter.

The defaultSize() function provides information about the amount of space that is required to render the currently loaded SVG file. This is useful for paint devices, such as QWidget, that often need to supply a size hint to their parent layout. The default size of a drawing may differ from its visible area, found using the viewBox property.

Animated SVG drawings are supported, and can be controlled with a simple collection of functions and properties:

- The animated() function indicates whether a drawing contains animation information.
- The framesPerSecond property contains the rate at which the animation plays.

Finally, the QSvgRenderer class provides the repaintNeeded() signal which is emitted whenever the rendering of the document needs to be updated.

See also QSvgWidget, Qt SVG C++ Classes, SVG Viewer Example, and QPicture.

## Property Documentation

### framesPerSecond : int

This property holds the number of frames per second to be shown.

The number of frames per second is 0 if the current document is not animated.

Access functions:

int | framesPerSecond() const
void | setFramesPerSecond(int num)

See also animated().

### viewBox : QRectF

This property holds the rectangle specifying the visible area of the document in logical coordinates.

This property was introduced in Qt 4.2.

Access functions:

QRectF | viewBoxF() const
void | setViewBox(const QRect &viewbox)
void | setViewBox(const QRectF &viewbox)

## Member Function Documentation

### QSvgRenderer::QSvgRenderer(QObject *parent = Q_NULLPTR)

Constructs a new renderer with the given parent.

### QSvgRenderer::QSvgRenderer(const QString &filename, QObject *parent = Q_NULLPTR)

Constructs a new renderer with the given parent and loads the contents of the SVG file with the specified filename.

### QSvgRenderer::QSvgRenderer(const QByteArray &contents, QObject *parent = Q_NULLPTR)

Constructs a new renderer with the given parent and loads the SVG data from the byte array specified by contents.

### QSvgRenderer::QSvgRenderer(QXmlStreamReader *contents, QObject *parent = Q_NULLPTR)

Constructs a new renderer with the given parent and loads the SVG data using the stream reader specified by contents.

This function was introduced in Qt 4.5.

### QSvgRenderer::~QSvgRenderer()

Destroys the renderer.

### bool QSvgRenderer::animated() const

Returns true if the current document contains animated elements; otherwise returns false.

See also framesPerSecond().

### QRectF QSvgRenderer::boundsOnElement(const QString &id) const

Returns bounding rectangle of the item with the given id. The transformation matrix of parent elements is not affecting the bounds of the element.

This function was introduced in Qt 4.2.

See also matrixForElement().

### QSize QSvgRenderer::defaultSize() const

Returns the default size of the document contents.

### bool QSvgRenderer::elementExists(const QString &id) const

Returns true if the element with the given id exists in the currently parsed SVG file and is a renderable element.

Note: this method returns true only for elements that can be rendered. Which implies that elements that are considered part of the fill/stroke style properties, e.g. radialGradients even tough marked with "id" attributes will not be found by this method.

This function was introduced in Qt 4.2.

### bool QSvgRenderer::isValid() const

Returns true if there is a valid current document; otherwise returns false.

### `[slot]` bool QSvgRenderer::load(const QString &filename)

Loads the SVG file specified by filename, returning true if the content was successfully parsed; otherwise returns false.

### `[slot]` bool QSvgRenderer::load(const QByteArray &contents)

Loads the specified SVG format contents, returning true if the content was successfully parsed; otherwise returns false.

### `[slot]` bool QSvgRenderer::load(QXmlStreamReader *contents)

Loads the specified SVG in contents, returning true if the content was successfully parsed; otherwise returns false.

The reader will be used from where it currently is positioned. If contents is `null`, behavior is undefined.

This function was introduced in Qt 4.5.

### QMatrix QSvgRenderer::matrixForElement(const QString &id) const

Returns the transformation matrix for the element with the given id. The matrix is a product of the transformation of the element's parents. The transformation of the element itself is not included.

To find the bounding rectangle of the element in logical coordinates, you can apply the matrix on the rectangle returned from boundsOnElement().

This function was introduced in Qt 4.2.

See also boundsOnElement().

### `[slot]` void QSvgRenderer::render(QPainter *painter)

Renders the current document, or the current frame of an animated document, using the given painter.

### `[slot]` void QSvgRenderer::render(QPainter *painter, const QRectF &bounds)

Renders the current document, or the current frame of an animated document, using the given painter on the specified bounds within the painter. If the bounding rectangle is not specified the SVG file is mapped to the whole paint device.

### `[slot]` void QSvgRenderer::render(QPainter *painter, const QString &elementId, const QRectF &bounds = QRectF())

Renders the given element with elementId using the given painter on the specified bounds. If the bounding rectangle is not specified the SVG element is mapped to the whole paint device.

### `[signal]` void QSvgRenderer::repaintNeeded()

This signal is emitted whenever the rendering of the document needs to be updated, usually for the purposes of animation.

### QRect QSvgRenderer::viewBox() const

Returns viewBoxF().toRect().

See also setViewBox() and viewBoxF().