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.Simulation
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.Simulation
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The abstract base class for all items in a plot. More...
Signals | |
| void | selectionChanged (bool selected) |
| This signal is emitted when the selection state of this item has changed, either by user interaction or by a direct call to setSelected. | |
Public Member Functions | |
| QCPAbstractItem (QCustomPlot *parentPlot) | |
| Base class constructor which initializes base class members. | |
| bool | clipToAxisRect () const |
| QCPAxis * | clipKeyAxis () const |
| QCPAxis * | clipValueAxis () const |
| bool | selectable () const |
| bool | selected () const |
| void | setClipToAxisRect (bool clip) |
| Sets whether the item shall be clipped to the axis rect or whether it shall be visible on the entire QCustomPlot. More... | |
| void | setClipAxes (QCPAxis *keyAxis, QCPAxis *valueAxis) |
| Sets both clip axes. More... | |
| void | setClipKeyAxis (QCPAxis *axis) |
| Sets the clip key axis. More... | |
| void | setClipValueAxis (QCPAxis *axis) |
| Sets the clip value axis. More... | |
| void | setSelectable (bool selectable) |
| Sets whether the user can (de-)select this item by clicking on the QCustomPlot surface. More... | |
| void | setSelected (bool selected) |
| Sets whether this item is selected or not. More... | |
| virtual double | selectTest (const QPointF &pos) const =0 |
| This function is used to decide whether a click hits an item or not. More... | |
| QList< QCPItemPosition * > | positions () const |
| Returns all positions of the item in a list. More... | |
| QList< QCPItemAnchor * > | anchors () const |
| Returns all anchors of the item in a list. More... | |
| QCPItemPosition * | position (const QString &name) const |
| Returns the QCPItemPosition with the specified name. More... | |
| QCPItemAnchor * | anchor (const QString &name) const |
| Returns the QCPItemAnchor with the specified name. More... | |
| bool | hasAnchor (const QString &name) const |
| Returns whether this item has an anchor with the specified name. More... | |
 Public Member Functions inherited from QCPlot::QCPLayerable | |
| QCPLayerable (QCustomPlot *parentPlot) | |
| Creates a new QCPLayerable instance. More... | |
| bool | visible () const |
| QCustomPlot * | parentPlot () const |
| QCPLayer * | layer () const |
| bool | antialiased () const |
| void | setVisible (bool on) |
| Sets the visibility of this layerable object. More... | |
| bool | setLayer (QCPLayer *layer) |
| Sets the layer of this layerable object. More... | |
| bool | setLayer (const QString &layerName) |
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Sets the layer of this layerable object by name. More... | |
| void | setAntialiased (bool enabled) |
| Sets whether this object will be drawn antialiased or not. More... | |
Protected Member Functions | |
| virtual QRect | clipRect () const |
| virtual void | applyDefaultAntialiasingHint (QCPPainter *painter) const |
| virtual void | draw (QCPPainter *painter)=0 |
| 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 |
| QCPItemPosition * | createPosition (const QString &name) |
| QCPItemAnchor * | createAnchor (const QString &name, int anchorId) |
| Protected Member Functions inherited from QCPlot::QCPLayerable | |
| bool | moveToLayer (QCPLayer *layer, bool prepend) |
| void | applyAntialiasingHint (QCPPainter *painter, bool localAntialiased, QCP::AntialiasedElement overrideElement) const |
Protected Attributes | |
| bool | mClipToAxisRect |
| QCPAxis * | mClipKeyAxis |
| QCPAxis * | mClipValueAxis |
| bool | mSelectable |
| bool | mSelected |
| QList< QCPItemPosition * > | mPositions |
| QList< QCPItemAnchor * > | mAnchors |
| Protected Attributes inherited from QCPlot::QCPLayerable | |
| bool | mVisible |
| QCustomPlot * | mParentPlot |
| QCPLayer * | mLayer |
| bool | mAntialiased |
Friends | |
| class | QCustomPlot |
| class | QCPItemAnchor |
The abstract base class for all items in a plot.
In QCustomPlot, items are supplemental graphical elements that are neither plottables (QCPAbstractPlottable) nor axes (QCPAxis). While plottables are always tied to two axes and thus plot coordinates, items can also be placed in absolute coordinates independent of any axes. Each specific item has at least one QCPItemPosition member which controls the positioning. Some items are defined by more than one coordinate and thus have two or more QCPItemPosition members (For example, QCPItemRect has topLeft and bottomRight).
This abstract base class defines a very basic interface like visibility and clipping. Since this class is abstract, it can't be instantiated. Use one of the subclasses or create a subclass yourself to create new items.
The built-in items are:
| QCPItemLine | A line defined by a start and an end point. May have different ending styles on each side (e.g. arrows). |
| QCPItemStraightLine | A straight line defined by a start and a direction point. Unlike QCPItemLine, the straight line is infinitely long and has no endings. |
| QCPItemCurve | A curve defined by start, end and two intermediate control points. May have different ending styles on each side (e.g. arrows). |
| QCPItemRect | A rectangle |
| QCPItemEllipse | An ellipse |
| QCPItemPixmap | An arbitrary pixmap |
| QCPItemText | A text label |
| QCPItemBracket | A bracket which may be used to reference/highlight certain parts in the plot. |
| QCPItemTracer | An item that can be attached to a QCPGraph and sticks to its data points, given a key coordinate. |
First you instantiate the item you want to use and add it to the plot:
by default, the positions of the item are bound to the x- and y-Axis of the plot. So we can just set the plot coordinates where the line should start/end:
If we wanted the line to be positioned not in plot coordinates but a different coordinate system, e.g. absolute pixel positions on the QCustomPlot surface, we would have changed the position type like this:
Then we can set the coordinates, this time in pixels:
To create an own item, you implement a subclass of QCPAbstractItem. These are the pure virtual functions, you must implement:
See the documentation of those functions for what they need to do.
As mentioned, item positions are represented by QCPItemPosition members. Let's assume the new item shall have only one coordinate as its position (as opposed to two like a rect or multiple like a polygon). You then add a public member of type QCPItemPosition like so:
the const makes sure the pointer itself can't be modified from the user of your new item (the QCPItemPosition instance it points to, can be modified, of course). The initialization of this pointer is made easy with the createPosition function. Just assign the return value of this function to each QCPItemPosition in the constructor of your item. createPosition takes a string which is the name of the position, typically this is identical to the variable name. For example, the constructor of QCPItemExample could look like this:
Your implementation of the draw function should check whether the item is visible (mVisible) and then draw the item. You can retrieve its position in pixel coordinates from the position member(s) via QCPItemPosition::pixelPoint.
To optimize performance you should calculate a bounding rect first (don't forget to take the pen width into account), check whether it intersects the clipRect, and only draw the item at all if this is the case.
Your implementation of the selectTest function may use the helpers distSqrToLine and rectSelectTest. With these, the implementation of the selection test becomes significantly simpler for most items.
Providing anchors (QCPItemAnchor) starts off like adding a position. First you create a public member, e.g.
and create it in the constructor with the createAnchor function, assigning it a name and an anchor id (an integer enumerating all anchors on the item, you may create an own enum for this). Since anchors can be placed anywhere, relative to the item's position(s), your item needs to provide the position of every anchor with the reimplementation of the anchorPixelPoint(int anchorId) function.
In essence the QCPItemAnchor is merely an intermediary that itself asks your item for the pixel position when anything attached to the anchor needs to know the coordinates.
| QCPItemAnchor * QCPlot::QCPAbstractItem::anchor | ( | const QString & | name | ) | const |
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).
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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.
| bool QCPlot::QCPAbstractItem::hasAnchor | ( | const QString & | name | ) | const |
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).
| QCPItemPosition * QCPlot::QCPAbstractItem::position | ( | const QString & | name | ) | const |
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).
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pure 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.
Implemented in QCPlot::QCPItemTracer, QCPlot::QCPItemBracket, QCPlot::QCPItemCurve, QCPlot::QCPItemText, QCPlot::QCPItemPixmap, QCPlot::QCPItemRect, QCPlot::QCPItemEllipse, QCPlot::QCPItemLine, and QCPlot::QCPItemStraightLine.
Sets both clip axes.
Together they define the axis rect that will be used to clip the item when setClipToAxisRect is set to true.
| void QCPlot::QCPAbstractItem::setClipKeyAxis | ( | QCPAxis * | axis | ) |
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.
| void QCPlot::QCPAbstractItem::setClipToAxisRect | ( | bool | clip | ) |
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 QCPlot::QCPAbstractItem::setClipValueAxis | ( | QCPAxis * | axis | ) |
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.
| void QCPlot::QCPAbstractItem::setSelectable | ( | bool | selectable | ) |
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.
| void QCPlot::QCPAbstractItem::setSelected | ( | bool | selected | ) |
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.
1.8.5
