This enum describes the default action for the view when pressing and dragging the mouse over the viewport.

See also

dragMode, QGraphicsScene::setSelectionArea()

This enums describe the possible anchors that QGraphicsView can use when the user resizes the view or when the view is transformed.

See also

resizeAnchor, transformationAnchor

This enum describes how QGraphicsView updates its viewport when the scene contents change or are exposed.

See also

viewportUpdateMode

Constructs a QGraphicsView. The parent is passed to QWidget's constructor.

Constructs a QGraphicsView and sets the visualized scene to scene. The parent is passed to QWidget's constructor.

Destructs the QGraphicsView object.

Property documentation pending.

Property documentation pending.

Property documentation pending.

Scrolls the contents of the viewport to ensure that item is centered in the view.

See also

ensureVisible()

Scrolls the contents of the viewport to ensure that the scene coordinate pos, is centered in the view. Because pos> is a floating point coordinate, and the scroll bars operate on integer coordinates, the centering is only an approximation.

Note

If the item is close to or outside the border, it will be visible in the view, but not centered.

See also

ensureVisible()

This method is provided for convenience. It is equivalent to calling centerOn(QPointF(x, y)).

Reimplemented from QWidget::contextMenuEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::dragEnterEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::dragLeaveEvent().

Reimplemented from QWidget.

Property documentation pending.

Reimplemented from QWidget::dragMoveEvent().

Reimplemented from QWidget.

Draws the background of the scene using painter, before any items and the foreground are drawn. Reimplement this function to provide a custom background for this view.

If all you want is to define a color, texture or gradient for the background, you can call setBackgroundBrush() instead.

All painting is done in scene coordinates. rect is the exposed rectangle.

The default implementation fills rect using the view's backgroundBrush. If no such brush is defined (the default), the scene's drawBackground() function is called instead.

See also

drawForeground(), QGraphicsScene::drawBackground()

Draws the foreground of the scene using painter, after the background and all items are drawn. Reimplement this function to provide a custom foreground for this view.

If all you want is to define a color, texture or gradient for the foreground, you can call setForegroundBrush() instead.

All painting is done in scene coordinates. rect is the exposed rectangle.

The default implementation fills rect using the view's foregroundBrush. If no such brush is defined (the default), the scene's drawForeground() function is called instead.

See also

drawBackground(), QGraphicsScene::drawForeground()

Deprecated:

Draws the items items in the scene using painter, after the background and before the foreground are drawn. numItems is the number of items in items and options in options. options is a list of styleoptions; one for each item. Reimplement this function to provide custom item drawing for this view.

The default implementation calls the scene's drawItems() function.

This function is not called unless the QGraphicsView::IndirectPainting flag is given as an Optimization flag.

See also

drawForeground(), drawBackground(), QGraphicsScene::drawItems()

Reimplemented from QWidget::dropEvent().

Reimplemented from QWidget.

Scrolls the contents of the viewport so that the center of item item is visible, with margins specified in pixels by xmargin and ymargin. If the specified point can not be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

See also

centerOn()

Scrolls the contents of the viewport so that the scene rectangle rect is visible, with margins specified in pixels by xmargin and ymargin. If the specified rect can not be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

See also

centerOn()

This method is provided for convenience. It is equivalent to calling ensureVisible(QRectF(x, y, w, h), xmargin, ymargin).

Reimplemented from QObject::event().

Ensures item fits tightly inside the view, scaling the view according to mode.

See also

ensureVisible(), centerOn()

Scales the view matrix and scrolls the scroll bars to ensure that the scene rectangle rect fits inside the viewport. The rect must be inside the scene rect, otherwise fitInView() can not guarantee that the whole rect is visible.

This function keeps the view's rotation, translation, or shear. The view is scaled according to mode. The rect will be centered in the view if it does not fit tightly.

It's common to call fitInView() from inside a reimplementation of resizeEvent(), to ensure that the whole scene, or parts of the scene, scales automatically to fit the new size of the viewport as the view is resized. Note though, that calling fitInView() from inside resizeEvent() can lead to unwanted resize recursion, if the new transformation toggles the automatic state of the scrollbars. You can toggle the scrollbar policies to always on or always off to prevent this (see horizontalScrollBarPolicy() and verticalScrollBarPolicy()).

If rect is empty, or if the viewport is too small, this function will do nothing.

See also

setTransform(), ensureVisible(), centerOn()

Equivalent to calling fitInView(QRectF(x, y, w, h), mode).

See also

ensureVisible(), centerOn()

Reimplemented from QWidget::focusInEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::focusNextPrevChild().

Reimplemented from QWidget.

Reimplemented from QWidget::focusOutEvent().

Reimplemented from QWidget.

Property documentation pending.

Reimplemented from QWidget::inputMethodEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::inputMethodQuery().

Reimplemented from QWidget.

Invalidates and schedules a redraw of layers inside rect. The rect is in scene coordinates. Any cached content for layers inside rect is unconditionally invalidated and redrawn.

You can call this function to notify QGraphicsView of changes to the background or the foreground of the scene. It is commonly used for scenes with tile-based backgrounds to notify changes when QGraphicsView has enabled background caching.

QGraphicsView currently supports background caching only (see QGraphicsView::CacheBackground). This function is equivalent to calling update() if any layer but QGraphicsScene::BackgroundLayer is passed.

See also

QGraphicsScene::invalidate(), update()

Property documentation pending.

Returns true if the view is transformed (i.e., a non-identity transform has been assigned, or the scrollbars are adjusted).

See also

setTransform(), horizontalScrollBar(), verticalScrollBar()

Returns the item at position pos, which is in viewport coordinates. If there are several items at this position, this function returns the topmost item.

Example:

See also

items(), Sorting

This method is provided for convenience. It is equivalent to calling itemAt(QPoint(x, y)).

Returns a list of all the items in the associated scene, in descending stacking order (i.e., the first item in the returned list is the uppermost item).

See also

QGraphicsScene::items(), Sorting

Returns a list of all the items that, depending on mode, are either contained by or intersect with path. The value for path is in viewport coordinates.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with or is contained by path are returned.

See also

itemAt(), items(), mapToScene(), Sorting

Returns a list of all the items at the position pos in the view. The items are listed in descending stacking order (i.e., the first item in the list is the uppermost item, and the last item is the lowermost item). pos is in viewport coordinates.

This function is most commonly called from within mouse event handlers in a subclass in QGraphicsView. pos is in untransformed viewport coordinates, just like QMouseEvent::pos().

See also

QGraphicsScene::items(), Sorting

Returns a list of all the items that, depending on mode, are either contained by or intersect with polygon. The value for polygon is in viewport coordinates.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with or is contained by polygon are returned. The items are sorted by descending stacking order (i.e., the first item in the returned list is the uppermost item).

See also

itemAt(), items(), mapToScene(), Sorting

Returns a list of all the items that, depending on mode, are either contained by or intersect with rect. The value for rect is in viewport coordinates.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with or is contained by rect are returned. The items are sorted in descending stacking order (i.e., the first item in the returned list is the uppermost item).

See also

itemAt(), items(), mapToScene(), Sorting

This function is provided for convenience. It's equivalent to calling items(QPoint(x, y)).

This convenience function is equivalent to calling items(QRectF(x, y, w, h), mode).

Reimplemented from QWidget::keyPressEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::keyReleaseEvent().

Reimplemented from QWidget.

Returns the scene coordinate painter path path to a viewport coordinate painter path.

See also

mapToScene()

Returns the scene coordinate point to viewport coordinates.

See also

mapToScene()

Returns the scene coordinate polygon polygon to a viewport coordinate polygon.

See also

mapToScene()

Returns the scene rectangle rect to a viewport coordinate polygon.

See also

mapToScene()

This function is provided for convenience. It's equivalent to calling mapFromScene(QPointF(x, y)).

This function is provided for convenience. It's equivalent to calling mapFromScene(QRectF(x, y, w, h)).

Returns the viewport painter path path mapped to a scene coordinate painter path.

See also

mapFromScene()

Returns the viewport coordinate point mapped to scene coordinates.

Note: It can be useful to map the whole rectangle covered by the pixel at point instead of the point itself. To do this, you can call mapToScene(QRect(point, QSize(2, 2))).

See also

mapFromScene()

Returns the viewport polygon polygon mapped to a scene coordinate polygon.

See also

mapFromScene()

Returns the viewport rectangle rect mapped to a scene coordinate polygon.

See also

mapFromScene()

This function is provided for convenience. It's equivalent to calling mapToScene(QPoint(x, y)).

This function is provided for convenience. It's equivalent to calling mapToScene(QRect(x, y, w, h)).

Returns the current transformation matrix for the view. If no current transformation is set, the identity matrix is returned.

See also

setMatrix(), transform(), rotate(), scale(), shear(), translate()

Reimplemented from QWidget::mouseDoubleClickEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::mouseMoveEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::mousePressEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::mouseReleaseEvent().

Reimplemented from QWidget.

Property documentation pending.

Reimplemented from QWidget::paintEvent().

Reimplemented from QWidget.

Renders the source rect, which is in view coordinates, from the scene into target, which is in paint device coordinates, using painter. This function is useful for capturing the contents of the view onto a paint device, such as a QImage (e.g., to take a screenshot), or for printing to QPrinter.

If source is a null rect, this function will use viewport()->rect() to determine what to draw. If target is a null rect, the full dimensions of painter's paint device (e.g., for a QPrinter, the page size) will be used.

The source rect contents will be transformed according to mode to fit into the target rect. By default, the aspect ratio is kept, and source is scaled to fit in target.

See also

QGraphicsScene::render()

Property documentation pending.

Resets any cached content. Calling this function will clear QGraphicsView's cache. If the current cache mode is CacheNone, this function does nothing.

This function is called automatically for you when the backgroundBrush or QGraphicsScene::backgroundBrush properties change; you only need to call this function if you have reimplemented QGraphicsScene::drawBackground() or QGraphicsView::drawBackground() to draw a custom background, and need to trigger a full redraw.

See also

cacheMode()

Resets the view transformation matrix to the identity matrix.

See also

resetTransform()

Resets the view transformation to the identity matrix.

See also

transform(), setTransform()

Property documentation pending.

Reimplemented from QWidget::resizeEvent().

Reimplemented from QWidget.

Rotates the current view transformation angle degrees clockwise.

See also

setTransform(), transform(), scale(), shear(), translate()

This signal is emitted when the rubber band rect is changed. The viewport Rect is specified by rubberBandRect. The drag start position and drag end position are provided in scene points with fromScenePoint and toScenePoint.

When rubberband selection ends this signal will be emitted with null vales.

See also

rubberBandRect()

This method returns the current rubber band area (in viewport coordinates) if the user is currently doing an item selection with the rubber band. When the user is not using the rubber band this method returns a null QRectF.

Part of this QRect can be outside the visual viewport or contain negative values.

See also

rubberBandSelectionMode, rubberBandChanged()

Property documentation pending.

Scales the current view transformation by (sx, sy).

See also

setTransform(), transform(), rotate(), shear(), translate()

Returns a pointer to the scene that is currently visualized in the view. If no scene is currently visualized, 0 is returned.

See also

setScene()

Property documentation pending.

Reimplemented from QAbstractScrollArea::scrollContentsBy().

Reimplemented from QAbstractScrollArea.

Property documentation pending.

Property documentation pending.

Property documentation pending.

Property documentation pending.

Property documentation pending.

Property documentation pending.

Sets the view's current transformation matrix to matrix.

If combine is true, then matrix is combined with the current matrix, otherwise matrix replaces the current matrix. combine is false by default.

The transformation matrix transforms the scene into view coordinates. Using the default transformation, provided by the identity matrix, one pixel in the view represents one unit in the scene (e.g., a 10x10 rectangular item is drawn using 10x10 pixels in the view). If a 2x2 scaling matrix is applied, the scene will be drawn in 1:2 (e.g., a 10x10 rectangular item is then drawn using 20x20 pixels in the view).

Example:

To simplify interaction with items using a transformed view, QGraphicsView provides mapTo... and mapFrom... functions that can translate between scene and view coordinates. For example, you can call mapToScene() to map a view coordinate to a floating point scene coordinate, or mapFromScene() to map from floating point scene coordinates to view coordinates.

See also

matrix(), setTransform(), rotate(), scale(), shear(), translate()

Enables flag if enabled is true, otherwise disables flag.

See also

optimizationFlags

Property documentation pending.

If enabled is true, the render hint hint is enabled, otherwise it is disabled.

See also

renderHints

Property documentation pending.

Property documentation pending.

Property documentation pending.

Sets the current scene to scene. If scene is already being viewed, this function does nothing.

When a scene is set on a view, the QGraphicsScene::changed() signal is automatically connected to this view's updateScene() slot, and the view's scroll bars are adjusted to fit the size of the scene.

See also

scene()

Property documentation pending.

Property documentation pending.

Sets the view's current transformation matrix to matrix.

If combine is true, then matrix is combined with the current matrix, otherwise matrix replaces the current matrix. combine is false by default.

The transformation matrix transforms the scene into view coordinates. Using the default transformation, provided by the identity matrix, one pixel in the view represents one unit in the scene (e.g., a 10x10 rectangular item is drawn using 10x10 pixels in the view). If a 2x2 scaling matrix is applied, the scene will be drawn in 1:2 (e.g., a 10x10 rectangular item is then drawn using 20x20 pixels in the view).

Example:

To simplify interaction with items using a transformed view, QGraphicsView provides mapTo... and mapFrom... functions that can translate between scene and view coordinates. For example, you can call mapToScene() to map a view coordinate to a floating point scene coordinate, or mapFromScene() to map from floating point scene coordinates to view coordinates.

See also

transform(), rotate(), scale(), shear(), translate()

Property documentation pending.

This slot is called by QAbstractScrollArea after setViewport() has been called. Reimplement this function in a subclass of QGraphicsView to initialize the new viewport widget before it is used.

See also

setViewport()

Property documentation pending.

Shears the current view transformation by (sh, sv).

See also

setTransform(), transform(), rotate(), scale(), translate()

Reimplemented from QWidget::showEvent().

Reimplemented from QWidget.

Reimplemented from QWidget::sizeHint().

Reimplemented from QWidget.

Returns the current transformation matrix for the view. If no current transformation is set, the identity matrix is returned.

See also

setTransform(), rotate(), scale(), shear(), translate()

Property documentation pending.

Translates the current view transformation by (dx, dy).

See also

setTransform(), transform(), rotate(), shear()

Schedules an update of the scene rectangles rects.

See also

QGraphicsScene::changed()

Notifies QGraphicsView that the scene's scene rect has changed. rect is the new scene rect. If the view already has an explicitly set scene rect, this function does nothing.

See also

sceneRect, QGraphicsScene::sceneRectChanged()

Reimplemented from QAbstractScrollArea::viewportEvent().

Reimplemented from QAbstractScrollArea.

Returns a matrix that maps viewport coordinates to scene coordinates.

See also

mapToScene(), mapFromScene()

Property documentation pending.

Reimplemented from QWidget::wheelEvent().

Reimplemented from QWidget.

This property holds the alignment of the scene in the view when the whole scene is visible.

If the whole scene is visible in the view, (i.e., there are no visible scroll bars,) the view's alignment will decide where the scene will be rendered in the view. For example, if the alignment is Qt::AlignCenter, which is default, the scene will be centered in the view, and if the alignment is (Qt::AlignLeft | Qt::AlignTop), the scene will be rendered in the top-left corner of the view.

This property holds the background brush of the scene.

This property sets the background brush for the scene in this view. It is used to override the scene's own background, and defines the behavior of drawBackground(). To provide custom background drawing for this view, you can reimplement drawBackground() instead.

By default, this property contains a brush with the Qt::NoBrush pattern.

See also

QGraphicsScene::backgroundBrush, foregroundBrush

This property holds which parts of the view are cached.

QGraphicsView can cache pre-rendered content in a QPixmap, which is then drawn onto the viewport. The purpose of such caching is to speed up the total rendering time for areas that are slow to render. Texture, gradient and alpha blended backgrounds, for example, can be notably slow to render; especially with a transformed view. The CacheBackground flag enables caching of the view's background. For example:

The cache is invalidated every time the view is transformed. However, when scrolling, only partial invalidation is required.

By default, nothing is cached.

See also

resetCachedContent(), QPixmapCache

This property holds the behavior for dragging the mouse over the scene while the left mouse button is pressed.

This property defines what should happen when the user clicks on the scene background and drags the mouse (e.g., scrolling the viewport contents using a pointing hand cursor, or selecting multiple items with a rubber band). The default value, NoDrag, does nothing.

This behavior only affects mouse clicks that are not handled by any item. You can define a custom behavior by creating a subclass of QGraphicsView and reimplementing mouseMoveEvent().

This property holds the foreground brush of the scene.

This property sets the foreground brush for the scene in this view. It is used to override the scene's own foreground, and defines the behavior of drawForeground(). To provide custom foreground drawing for this view, you can reimplement drawForeground() instead.

By default, this property contains a brush with the Qt::NoBrush pattern.

See also

QGraphicsScene::foregroundBrush, backgroundBrush

This property holds whether the view allowed scene interaction.

If enabled, this view is set to allow scene interaction. Otherwise, this view will not allow interaction, and any mouse or key events are ignored (i.e., it will act as a read-only view).

By default, this property is true.

This property holds flags that can be used to tune QGraphicsView's performance.

QGraphicsView uses clipping, extra bounding rect adjustments, and certain other aids to improve rendering quality and performance for the common case graphics scene. However, depending on the target platform, the scene, and the viewport in use, some of these operations can degrade performance.

The effect varies from flag to flag; see the OptimizationFlags documentation for details.

By default, no optimization flags are enabled.

See also

setOptimizationFlag()

This property holds the default render hints for the view.

These hints are used to initialize QPainter before each visible item is drawn. QPainter uses render hints to toggle rendering features such as antialiasing and smooth pixmap transformation.

QPainter::TextAntialiasing is enabled by default.

Example:

This property holds how the view should position the scene when the view is resized.

QGraphicsView uses this property to decide how to position the scene in the viewport when the viewport widget's size changes. The default behavior, NoAnchor, leaves the scene's position unchanged during a resize; the top-left corner of the view will appear to be anchored while resizing.

Note that the effect of this property is noticeable when only a part of the scene is visible (i.e., when there are scroll bars). Otherwise, if the whole scene fits in the view, QGraphicsScene uses the view alignment to position the scene in the view.

See also

alignment, transformationAnchor, Qt::WNorthWestGravity