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QCPItemLine Class Reference

A line from one point to another. More...

Inheritance diagram for QCPItemLine:
Inheritance graph

Public Functions

 QCPItemLine (QCustomPlot *parentPlot)
QPen pen () const
QPen selectedPen () const
QCPLineEnding head () const
QCPLineEnding tail () const
void setPen (const QPen &pen)
void setSelectedPen (const QPen &pen)
void setHead (const QCPLineEnding &head)
void setTail (const QCPLineEnding &tail)
virtual double selectTest (const QPointF &pos) const
bool clipToAxisRect () const
QCPAxisclipKeyAxis () const
QCPAxisclipValueAxis () const
bool selectable () const
bool selected () const
void setClipToAxisRect (bool clip)
void setClipAxes (QCPAxis *keyAxis, QCPAxis *valueAxis)
void setClipKeyAxis (QCPAxis *axis)
void setClipValueAxis (QCPAxis *axis)
void setSelectable (bool selectable)
void setSelected (bool selected)
QList< QCPItemPosition * > positions () const
QList< QCPItemAnchor * > anchors () const
QCPItemPositionposition (const QString &name) const
QCPItemAnchoranchor (const QString &name) const
bool hasAnchor (const QString &name) const
bool visible () const
QCustomPlotparentPlot () const
QCPLayerlayer () const
bool antialiased () const
void setVisible (bool on)
bool setLayer (QCPLayer *layer)
bool setLayer (const QString &layerName)
void setAntialiased (bool enabled)

Public Members

QCPItemPosition *const start
QCPItemPosition *const end

Signals

void selectionChanged (bool selected)

Protected Functions

virtual void draw (QCPPainter *painter)
QLineF getRectClippedLine (const QVector2D &start, const QVector2D &end, const QRect &rect) const
QPen mainPen () const
virtual QRect clipRect () const
virtual void applyDefaultAntialiasingHint (QCPPainter *painter) const
double distSqrToLine (const QPointF &start, const QPointF &end, const QPointF &point) const
double rectSelectTest (const QRectF &rect, const QPointF &pos, bool filledRect) const
virtual QPointF anchorPixelPoint (int anchorId) const
QCPItemPositioncreatePosition (const QString &name)
QCPItemAnchorcreateAnchor (const QString &name, int anchorId)
bool moveToLayer (QCPLayer *layer, bool prepend)
void applyAntialiasingHint (QCPPainter *painter, bool localAntialiased, QCP::AntialiasedElement overrideElement) const

Detailed Description

A line from one point to another.

QCPItemLine.png
Line example. Blue dotted circles are anchors, solid blue discs are positions.

It has two positions, start and end, which define the end points of the line.

With setHead and setTail you may set different line ending styles, e.g. to create an arrow.


Constructor & Destructor Documentation

Creates a line item and sets default values.

The constructed item can be added to the plot with QCustomPlot::addItem.


Member Function Documentation

void QCPItemLine::setPen ( const QPen &  pen)

Sets the pen that will be used to draw the line

See also:
setSelectedPen
void QCPItemLine::setSelectedPen ( const QPen &  pen)

Sets the pen that will be used to draw the line when selected

See also:
setPen, setSelected
void QCPItemLine::setHead ( const QCPLineEnding head)

Sets the line ending style of the head. The head corresponds to the end position.

Note that due to the overloaded QCPLineEnding constructor, you may directly specify a QCPLineEnding::EndingStyle here, e.g.

See also:
setTail
void QCPItemLine::setTail ( const QCPLineEnding tail)

Sets the line ending style of the tail. The tail corresponds to the start position.

Note that due to the overloaded QCPLineEnding constructor, you may directly specify a QCPLineEnding::EndingStyle here, e.g.

See also:
setHead
double QCPItemLine::selectTest ( const QPointF &  pos) const [virtual]

This function is used to decide whether a click hits an item or not.

pos is a point in pixel coordinates on the QCustomPlot surface. This function returns the shortest pixel distance of this point to the item. If the item is either invisible or the distance couldn't be determined, -1.0 is returned. setSelectable has no influence on the return value of this function.

If the item is represented not by single lines but by an area like QCPItemRect or QCPItemText, a click inside the area returns a constant value greater zero (typically 99% of the selectionTolerance of the parent QCustomPlot). If the click lies outside the area, this function returns -1.0.

Providing a constant value for area objects allows selecting line objects even when they are obscured by such area objects, by clicking close to the lines (i.e. closer than 0.99*selectionTolerance).

The actual setting of the selection state is not done by this function. This is handled by the parent QCustomPlot when the mouseReleaseEvent occurs.

See also:
setSelected, QCustomPlot::setInteractions

Implements QCPAbstractItem.

void QCPItemLine::draw ( QCPPainter painter) [protected, virtual]

Draws this item with the provided painter. Called by QCustomPlot::draw on all its visible items.

The cliprect of the provided painter is set to the rect returned by clipRect before this function is called. For items this depends on the clipping settings defined by setClipToAxisRect, setClipKeyAxis and setClipValueAxis.

Implements QCPAbstractItem.

QLineF QCPItemLine::getRectClippedLine ( const QVector2D &  start,
const QVector2D &  end,
const QRect &  rect 
) const [protected]

Returns the section of the line defined by start and end, that is visible in the specified rect.

This is a helper function for draw.

QPen QCPItemLine::mainPen ( ) const [protected]

Returns the pen that should be used for drawing lines. Returns mPen when the item is not selected and mSelectedPen when it is.

void QCPAbstractItem::setClipToAxisRect ( bool  clip) [inherited]

Sets whether the item shall be clipped to the axis rect or whether it shall be visible on the entire QCustomPlot. The axis rect is defined by the clip axes which can be set via setClipAxes or individually with setClipKeyAxis and setClipValueAxis.

void QCPAbstractItem::setClipAxes ( QCPAxis keyAxis,
QCPAxis valueAxis 
) [inherited]

Sets both clip axes. Together they define the axis rect that will be used to clip the item when setClipToAxisRect is set to true.

See also:
setClipToAxisRect, setClipKeyAxis, setClipValueAxis
void QCPAbstractItem::setClipKeyAxis ( QCPAxis axis) [inherited]

Sets the clip key axis. Together with the clip value axis it defines the axis rect that will be used to clip the item when setClipToAxisRect is set to true.

See also:
setClipToAxisRect, setClipAxes, setClipValueAxis
void QCPAbstractItem::setClipValueAxis ( QCPAxis axis) [inherited]

Sets the clip value axis. Together with the clip key axis it defines the axis rect that will be used to clip the item when setClipToAxisRect is set to true.

See also:
setClipToAxisRect, setClipAxes, setClipKeyAxis
void QCPAbstractItem::setSelectable ( bool  selectable) [inherited]

Sets whether the user can (de-)select this item by clicking on the QCustomPlot surface. (When QCustomPlot::setInteractions contains QCustomPlot::iSelectItems.)

However, even when selectable was set to false, it is possible to set the selection manually, by calling setSelected directly.

See also:
QCustomPlot::setInteractions, setSelected
void QCPAbstractItem::setSelected ( bool  selected) [inherited]

Sets whether this item is selected or not. When selected, it might use a different visual appearance (e.g. pen and brush), this depends on the specific item, though.

The entire selection mechanism for items is handled automatically when QCustomPlot::setInteractions contains QCustomPlot::iSelectItems. You only need to call this function when you wish to change the selection state manually.

This function can change the selection state even when setSelectable was set to false.

emits the selectionChanged signal when selected is different from the previous selection state.

See also:
selectTest
QList< QCPItemPosition * > QCPAbstractItem::positions ( ) const [inline, inherited]

Returns all positions of the item in a list.

See also:
anchors, position
QList< QCPItemAnchor * > QCPAbstractItem::anchors ( ) const [inline, inherited]

Returns all anchors of the item in a list. Note that since a position (QCPItemPosition) is always also an anchor, the list will also contain the positions of this item.

See also:
positions, anchor
QCPItemPosition * QCPAbstractItem::position ( const QString &  name) const [inherited]

Returns the QCPItemPosition with the specified name. If this item doesn't have a position by that name, returns 0.

This function provides an alternative way to access item positions. Normally, you access positions direcly by their member pointers (which typically have the same variable name as name).

See also:
positions, anchor
QCPItemAnchor * QCPAbstractItem::anchor ( const QString &  name) const [inherited]

Returns the QCPItemAnchor with the specified name. If this item doesn't have an anchor by that name, returns 0.

This function provides an alternative way to access item anchors. Normally, you access anchors direcly by their member pointers (which typically have the same variable name as name).

See also:
anchors, position
bool QCPAbstractItem::hasAnchor ( const QString &  name) const [inherited]

Returns whether this item has an anchor with the specified name.

Note that you can check for positions with this function, too, because every position is also an anchor (QCPItemPosition inherits from QCPItemAnchor).

See also:
anchor, position
QRect QCPAbstractItem::clipRect ( ) const [protected, virtual, inherited]

Returns the rect the visual representation of this item is clipped to. This depends on the current setting of setClipToAxisRect aswell as the clip axes set with setClipAxes.

If the item is not clipped to an axis rect, the QCustomPlot::viewport rect is returned.

See also:
draw

Reimplemented from QCPLayerable.

void QCPAbstractItem::applyDefaultAntialiasingHint ( QCPPainter painter) const [protected, virtual, inherited]

A convenience function to easily set the QPainter::Antialiased hint on the provided painter before drawing item lines.

This is the antialiasing state the painter passed to the draw method is in by default.

This function takes into account the local setting of the antialiasing flag as well as the overrides set e.g. with QCustomPlot::setNotAntialiasedElements.

See also:
setAntialiased

Implements QCPLayerable.

double QCPAbstractItem::distSqrToLine ( const QPointF &  start,
const QPointF &  end,
const QPointF &  point 
) const [protected, inherited]

Finds the shortest squared distance of point to the line segment defined by start and end.

This function may be used to help with the implementation of the selectTest function for specific items.

Note:
This function is identical to QCPAbstractPlottable::distSqrToLine
See also:
rectSelectTest
double QCPAbstractItem::rectSelectTest ( const QRectF &  rect,
const QPointF &  pos,
bool  filledRect 
) const [protected, inherited]

A convenience function which returns the selectTest value for a specified rect and a specified click position pos. filledRect defines whether a click inside the rect should also be considered a hit or whether only the rect border is sensitive to hits.

This function may be used to help with the implementation of the selectTest function for specific items.

For example, if your item consists of four rects, call this function four times, once for each rect, in your selectTest reimplementation. Finally, return the minimum of all four returned values which were greater or equal to zero. (Because this function may return -1.0 when pos doesn't hit rect at all). If all calls returned -1.0, return -1.0, too, because your item wasn't hit.

See also:
distSqrToLine
QPointF QCPAbstractItem::anchorPixelPoint ( int  anchorId) const [protected, virtual, inherited]

Returns the pixel position of the anchor with Id anchorId. This function must be reimplemented in item subclasses if they want to provide anchors (QCPItemAnchor).

For example, if the item has two anchors with id 0 and 1, this function takes one of these anchor ids and returns the respective pixel points of the specified anchor.

See also:
createAnchor

Reimplemented in QCPItemBracket, QCPItemText, QCPItemPixmap, QCPItemRect, and QCPItemEllipse.

QCPItemPosition * QCPAbstractItem::createPosition ( const QString &  name) [protected, inherited]

Creates a QCPItemPosition, registers it with this item and returns a pointer to it. The specified name must be a unique string that is usually identical to the variable name of the position member (This is needed to provide the name based position access to positions).

Don't delete positions created by this function manually, as the item will take care of it.

Use this function in the constructor (initialization list) of the specific item subclass to create each position member. Don't create QCPItemPositions with new yourself, because they won't be registered with the item properly.

See also:
createAnchor
QCPItemAnchor * QCPAbstractItem::createAnchor ( const QString &  name,
int  anchorId 
) [protected, inherited]

Creates a QCPItemAnchor, registers it with this item and returns a pointer to it. The specified name must be a unique string that is usually identical to the variable name of the anchor member (This is needed to provide the name based anchor access to anchors).

The anchorId must be a number identifying the created anchor. It is recommended to create an enum (e.g. "AnchorIndex") for this on each item that uses anchors. This id is used by the anchor to identify itself when it calls QCPAbstractItem::anchorPixelPoint. That function then returns the correct pixel coordinates for the passed anchor id.

Don't delete anchors created by this function manually, as the item will take care of it.

Use this function in the constructor (initialization list) of the specific item subclass to create each anchor member. Don't create QCPItemAnchors with new yourself, because then they won't be registered with the item properly.

See also:
createPosition
void QCPAbstractItem::selectionChanged ( bool  selected) [signal, inherited]

This signal is emitted when the selection state of this item has changed, either by user interaction or by a direct call to setSelected.

void QCPLayerable::setVisible ( bool  on) [inherited]

Sets the visibility of this layerable object. If an object is not visible, it will not be drawn on the QCustomPlot surface, and user interaction with it (e.g. click/selection) is not possible.

bool QCPLayerable::setLayer ( QCPLayer layer) [inherited]

Sets the layer of this layerable object. The object will be placed on top of the other objects already on layer.

Returns true on success, i.e. if layer is a valid layer.

bool QCPLayerable::setLayer ( const QString &  layerName) [inherited]

This is an overloaded function.

Sets the layer of this layerable object by name

Returns true on success, i.e. if layerName is a valid layer name.

void QCPLayerable::setAntialiased ( bool  enabled) [inherited]

Sets whether this object will be drawn antialiased or not.

Note that antialiasing settings may be overridden by QCustomPlot::setAntialiasedElements and QCustomPlot::setNotAntialiasedElements.

bool QCPLayerable::moveToLayer ( QCPLayer layer,
bool  prepend 
) [protected, inherited]

Moves this layerable object to layer. If prepend is true, this object will be prepended to the new layer's list, i.e. it will be drawn below the objects already on the layer. If it is false, the object will be appended.

Returns true on success, i.e. if layer is a valid layer.

void QCPLayerable::applyAntialiasingHint ( QCPPainter painter,
bool  localAntialiased,
QCP::AntialiasedElement  overrideElement 
) const [protected, inherited]

Sets the QPainter::Antialiasing render hint on the provided painter, depending on the localAntialiased value as well as the overrides QCustomPlot::setAntialiasedElements and QCustomPlot::setNotAntialiasedElements. Which override enum this function takes into account is controlled via overrideElement.


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