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Class JXG.GeometryElement


      ↳ JXG.GeometryElement

This is the basic class for geometry elements like points, circles and lines.

Defined in: element.js.

Class Summary
Constructor Attributes Constructor Name and Description
 
JXG.GeometryElement(board, attributes, type, oclass)
Constructs a new GeometryElement object.
Attributes Summary
Field Attributes Field Name and Description
 
Determines the elements border-style.
 
If true the element will be drawn in grey scale colors to visualize that it's only a draft.
 
The fill color of this geometry element.
 
Opacity for fill color.
 
If true the element is fixed and can not be dragged around.
 
If true the element is fixed and can not be dragged around.
 
 
The fill color of the given geometry element when the mouse is pointed over it.
 
Opacity for fill color when the object is highlighted.
 
The stroke color of the given geometry element when the user moves the mouse over it.
 
Opacity for stroke color when the object is highlighted.
 
Width of the element's stroke when the mouse is pointed over it.
 
If this is set to true, the element is updated in every update call of the board.
 
Determines whether two-finger manipulation of this object may change its size.
 
If true the element will get a shadow.
 
Snaps the element or its parents to the grid.
 
The stroke color of the given geometry element.
 
Opacity for element's stroke color.
 
Width of the element's stroke.
 
If true the element will be traced, i.e.
 
Extra visual properties for traces of an element
 
If false the element won't be visible on the board, otherwise it is shown.
 
If true a label will display the element's name.
Field Summary
Field Attributes Field Name and Description
<private>  
The position of this element inside the JXG.Board#objectsList.
 
 
Elements on which this elements depends on are stored here.
<private>  
 
Reference to the board associated with the element.
 
Stores all dependent objects to be updated when this point is moved.
 
Elements depending on this element are stored here.
 
The element is saved with an explicit entry in the file (true) or implicitly via a composition.
<constant>  
The element's class.
 
The string used with JXG.Board#create
 
Holds the registered event handlers.
<deprecated>  
Deprecated alias for JXG.GeometryElement#getAttribute.
 
If element has a label subelement then this property will be set to true.
 
True, if the element is currently highlighted.
 
id
Unique identifier for the element.
 
Controls if this element can be dragged.
 
If element is in two dimensional real space this is true, else false.
 
Time stamp containing the last time this element has been dragged.
 
The methodMap determines which methods can be called from within JessieCode and under which name it can be used.
 
Is the mouse over this element?
 
Not necessarily unique name for the element.
 
Controls if updates are necessary
 
Stores all Intersection Objects which in this moment are not real and so hide this element.
 
Counts the number of objects drawn as part of the trace of the element.
 
Quadratic form representation of circles (and conics)
 
 
Stores the rendering node for the element.
<deprecated>  
Deprecated alias for JXG.GeometryElement#setAttribute.
 
[c,b0,b1,a,k,r,q0,q1] See A.E.
 
Subs contains the subelements, created during the create method.
 
Stores variables for symbolic computations
 
Keeps track of all objects drawn as part of the trace of the element.
 
Stores the transformations which are applied during update in an array
<constant>  
Type of the element.
 
An associative array containing all visual properties.
Method Summary
Method Attributes Method Name and Description
<private>  
_set(property, value)
Sets the value of property property to value.
 
addChild(obj)
Add an element as a child to the current element.
<private>  
Adds the given object to the descendants list of this object and all its child objects.
 
addRotation(angle)
Rotate texts or images by a given degree.
 
addTransform(transform)
Add transformations to this element.
 
animate(hash, time, options)
Animates properties for that object like stroke or fill color, opacity and maybe even more later.
 
Dimensions of the smallest rectangle enclosing the element.
 
Removes all objects generated by the trace function.
 
Copy the element to background.
<private>  
Counts the direct children of an object without counting labels.
<private>  
Creates a gradient nodes in the renderer.
 
Creates a label element for this geometry element.
<private>  
Decides whether an element can be dragged.
 
Array of strings containing the polynomials defining the element.
 
Get the value of the property key.
 
Retrieve a copy of the current visProp.
 
Returns the coords object where the label of the element shall be drawn.
 
Returns the elements name, Used in JessieCode.
 
List of the element ids resp.
 
Returns the coords object where a text that is bound to the element shall be drawn.
 
The type of the element as used in JXG.Board#create.
 
hasPoint(x, y)
Checks whether (x,y) is near the element.
 
Hide the element.
<deprecated>  
labelColor(lColor)
Set the labelColor of an element
 
Uses the "normal" properties of the element.
<private>  
Normalize the element's standard form.
 
off(event, handler)
Unregister an event handler.
 
on(event, handler, context)
Register a new event handler.
<private>  
Notify all child elements for updates.
 
Removes the element from the construction.
 
Remove an element as a child from the current element.
<private>  
Removes the given object from the descendants list of this object and all its child objects.
 
resolveShortcuts(properties)
Resolves property shortcuts like color and expands them, e.g.
 
setArrow(firstArrow, lastArrow)
Determines whether the element has arrows at start or end of the arc.
 
setAttribute(attributes)
Sets an arbitrary number of attributes.
<private>  
setDash(dash)
Set the dash style of an object.
 
Updates the element's label text, strips all html.
 
Make the element visible.
 
triggerEventHandlers(event, args)
Triggers all event handlers of this element for a given event.
 
General update method.
<private>  
Provide updateRenderer method.
Event Summary
Event Attributes Event Name and Description
 
attribute(o, el)
Notify everytime an attribute is changed.
 
attribute:<attribute><attribute>(val, nval, el)
This is a generic event handler.
 
down(e)
Whenever the user starts to touch or click an element.
 
drag(e)
This event is fired whenever the user drags an element.
 
Whenever the user starts to click an element.
 
This event is fired whenever the user drags the element with a mouse.
 
This event is fired whenever the user is moving the mouse over an element.
 
This event is fired whenever the user puts the mouse away from an element.
 
This event is fired whenever the user puts the mouse over an element.
 
Whenever the user releases the mousebutton over an element.
 
move(e)
This event is fired whenever the user is moving over an element.
 
out(e)
This event is fired whenever the user is leaving an element.
 
over(e)
This event is fired whenever the user is hovering over an element.
 
Whenever the user starts to touch an element.
 
This event is fired whenever the user drags the element on a touch device.
 
Whenever the user stops touching an element.
 
up(e)
Whenever the user stops to touch or click an element.
Class Detail
JXG.GeometryElement(board, attributes, type, oclass)
Constructs a new GeometryElement object.
Parameters:
{JXG.Board} board
Reference to the board the element is constructed on.


{Object} attributes
Hash of attributes and their values.


{Number} type
Element type (a JXG.OBJECT_TYPE_ value).


{Number} oclass
The element's class (a JXG.OBJECT_CLASS_ value).


Attribute Detail
{Number} dash
Determines the elements border-style. Possible values are:
Defined in: options.js.
Default Value:
0

{boolean} draft
If true the element will be drawn in grey scale colors to visualize that it's only a draft.
Defined in: options.js.

{String} fillColor
The fill color of this geometry element.
Defined in: options.js.
See:
JXG.GeometryElement#highlightFillColor
JXG.GeometryElement#fillOpacity
JXG.GeometryElement#highlightFillOpacity

{number} fillOpacity
Opacity for fill color.
Defined in: options.js.
See:
JXG.GeometryElement#fillColor
JXG.GeometryElement#highlightFillColor
JXG.GeometryElement#highlightFillOpacity

{Boolean} fixed
If true the element is fixed and can not be dragged around. The element will be repositioned on zoom and moveOrigin events.
Defined in: options.js.
Default Value:
false

{Boolean} frozen
If true the element is fixed and can not be dragged around. The element will even stay at its position on zoom and moveOrigin events. Only free elements like points, texts, curves can be frozen.
Defined in: options.js.
Default Value:
false

{Boolean} highlight

Defined in: options.js.
Default Value:
true

{String} highlightFillColor
The fill color of the given geometry element when the mouse is pointed over it.
Defined in: options.js.
See:
JXG.GeometryElement#fillColor
JXG.GeometryElement#fillOpacity
JXG.GeometryElement#highlightFillOpacity

{number} highlightFillOpacity
Opacity for fill color when the object is highlighted.
Defined in: options.js.
See:
JXG.GeometryElement#fillColor
JXG.GeometryElement#highlightFillColor
JXG.GeometryElement#fillOpacity

{String} highlightStrokeColor
The stroke color of the given geometry element when the user moves the mouse over it.
Defined in: options.js.
See:
JXG.GeometryElement#strokeColor
JXG.GeometryElement#strokeWidth
JXG.GeometryElement#strokeOpacity
JXG.GeometryElement#highlightStrokeOpacity

{number} highlightStrokeOpacity
Opacity for stroke color when the object is highlighted.
Defined in: options.js.
See:
JXG.GeometryElement#strokeColor
JXG.GeometryElement#highlightStrokeColor
JXG.GeometryElement#strokeWidth
JXG.GeometryElement#strokeOpacity

{number} highlightStrokeWidth
Width of the element's stroke when the mouse is pointed over it.
Defined in: options.js.
See:
JXG.GeometryElement#strokeColor
JXG.GeometryElement#highlightStrokeColor
JXG.GeometryElement#strokeOpacity
JXG.GeometryElement#highlightStrokeOpacity
JXG.GeometryElement#highlightFillColor

{Boolean} needsRegularUpdate
If this is set to true, the element is updated in every update call of the board. If set to false, the element is updated only after zoom events or more generally, when the bounding box has been changed. Examples for the latter behaviour should be axes.
Defined in: options.js.
See:
JXG.GeometryElement#needsRegularUpdate
Default Value:
true

{Boolean} scalable
Determines whether two-finger manipulation of this object may change its size. If set to false, the object is only rotated and translated.
Defined in: options.js.
Default Value:
true

{boolean} shadow
If true the element will get a shadow.
Defined in: options.js.
Default Value:
false

{Boolean} snapToGrid
Snaps the element or its parents to the grid. Currently only relevant for points, circles, and lines. Points are snapped to grid directly, on circles and lines it's only the parent points that are snapped
Defined in: options.js.
Default Value:
false

{String} strokeColor
The stroke color of the given geometry element.
Defined in: options.js.
See:
JXG.GeometryElement#highlightStrokeColor
JXG.GeometryElement#strokeWidth
JXG.GeometryElement#strokeOpacity
JXG.GeometryElement#highlightStrokeOpacity

{number} strokeOpacity
Opacity for element's stroke color.
Defined in: options.js.
See:
JXG.GeometryElement#strokeColor
JXG.GeometryElement#highlightStrokeColor
JXG.GeometryElement#strokeWidth
JXG.GeometryElement#highlightStrokeOpacity

{number} strokeWidth
Width of the element's stroke.
Defined in: options.js.
See:
JXG.GeometryElement#strokeColor
JXG.GeometryElement#highlightStrokeColor
JXG.GeometryElement#strokeOpacity
JXG.GeometryElement#highlightStrokeOpacity

{Boolean} trace
If true the element will be traced, i.e. on every movement the element will be copied to the background. Use JXG.GeometryElement#clearTrace to delete the trace elements.
Defined in: options.js.
See:
JXG.GeometryElement#clearTrace
JXG.GeometryElement#traces
JXG.GeometryElement#numTraces
Default Value:
false

{Object} traceAttributes
Extra visual properties for traces of an element
Defined in: options.js.
See:
JXG.GeometryElement#trace

{boolean} visible
If false the element won't be visible on the board, otherwise it is shown.
Defined in: options.js.
See:
JXG.GeometryElement#hideElement
JXG.GeometryElement#showElement
Default Value:
true

{Boolean} withLabel
If true a label will display the element's name.
Defined in: options.js.
Default Value:
false
Field Detail
<private> _pos
The position of this element inside the JXG.Board#objectsList.
Default Value:
-1

addEvent
Alias of JXG.GeometryElement#on.

{Object} ancestors
Elements on which this elements depends on are stored here.

<private> {JXG.GeometryElement} baseElement
Default Value:
null

{JXG.Board} board
Reference to the board associated with the element.

{Object} childElements
Stores all dependent objects to be updated when this point is moved.

{Object} descendants
Elements depending on this element are stored here.

{Boolean} dump
The element is saved with an explicit entry in the file (true) or implicitly via a composition.
Default Value:
true

<constant> {number} elementClass
The element's class.

{String} elType
The string used with JXG.Board#create

{Object} eventHandlers
Holds the registered event handlers.
Defined in: event.js.

getProperty
Deprecated alias for JXG.GeometryElement#getAttribute.
Deprecated:
Use JXG.GeometryElement#getAttribute.

{Boolean} hasLabel
If element has a label subelement then this property will be set to true.
Default Value:
false

{Boolean} highlighted
True, if the element is currently highlighted.
Default Value:
false

{String} id
Unique identifier for the element. Equivalent to id-attribute of renderer element.

{Boolean} isDraggable
Controls if this element can be dragged. In GEONExT only free points and gliders can be dragged.
Default Value:
false

{Boolean} isReal
If element is in two dimensional real space this is true, else false.
Default Value:
true

{Date} lastDragTime
Time stamp containing the last time this element has been dragged.
Default Value:
creation time

{Object} methodMap
The methodMap determines which methods can be called from within JessieCode and under which name it can be used. The map is saved in an object, the name of a property is the name of the method used in JessieCode, the value of a property is the name of the method in JavaScript.

{Boolean} mouseover
Is the mouse over this element?
Default Value:
false

{String} name
Not necessarily unique name for the element.
See:
JXG.Board#generateName
Default Value:
Name generated by JXG.Board#generateName.

{Boolean} needsUpdate
Controls if updates are necessary
Default Value:
true

{Object} notExistingParents
Stores all Intersection Objects which in this moment are not real and so hide this element.

{Number} numTraces
Counts the number of objects drawn as part of the trace of the element.
See:
JXG.GeometryElement#traced
JXG.GeometryElement#clearTrace
JXG.GeometryElement#traces

{Array} quadraticform
Quadratic form representation of circles (and conics)
Default Value:
[[1,0,0],[0,1,0],[0,0,1]]

removeEvent
Alias of JXG.GeometryElement#off.

{Object} rendNode
Stores the rendering node for the element.

setProperty
Deprecated alias for JXG.GeometryElement#setAttribute.
Deprecated:
Use JXG.GeometryElement#setAttribute.

{Array} stdform
[c,b0,b1,a,k,r,q0,q1] See A.E. Middleditch, T.W. Stacey, and S.B. Tor: "Intersection Algorithms for Lines and Circles", ACM Transactions on Graphics, Vol. 8, 1, 1989, pp 25-40. The meaning of the parameters is: Circle: points p=[p0,p1] on the circle fulfill a<p,p> + <b,p> + c = 0 For convenience we also store r: radius k: discriminant = sqrt(<b,b>-4ac) q=[q0,q1] center Points have radius = 0. Lines have radius = infinity. b: normalized vector, representing the direction of the line. Should be put into Coords, when all elements possess Coords.
Default Value:
[1, 0, 0, 0, 1, 1, 0, 0]

{Object} subs
Subs contains the subelements, created during the create method.

{Object} symbolic
Stores variables for symbolic computations

{Object} traces
Keeps track of all objects drawn as part of the trace of the element.
See:
JXG.GeometryElement#traced
JXG.GeometryElement#clearTrace
JXG.GeometryElement#numTraces

{Array} transformations
Stores the transformations which are applied during update in an array
See:
JXG.Transformation

<constant> {number} type
Type of the element.

{Object} visProp
An associative array containing all visual properties.
Default Value:
empty object
Method Detail
<private> _set(property, value)
Sets the value of property property to value.
Parameters:
{String} property
The property's name.
value
The new value

addChild(obj)
Add an element as a child to the current element. Can be used to model dependencies between geometry elements.
Parameters:
{JXG.GeometryElement} obj
The dependent object.

<private> addDescendants(obj)
Adds the given object to the descendants list of this object and all its child objects.
Parameters:
{JXG.GeometryElement} obj
The element that is to be added to the descendants list.
Returns:

addRotation(angle)
Rotate texts or images by a given degree. Works only for texts where JXG.Text#display equal to "internal".
Parameters:
{number} angle
The degree of the rotation (90 means vertical text).
See:
JXG.GeometryElement#rotate

{JXG.GeometryElement} addTransform(transform)
Add transformations to this element.
Parameters:
{JXG.Transformation|Array} transform
Either one JXG.Transformation or an array of JXG.Transformations.
Returns:
{JXG.GeometryElement} Reference to the element.

{JXG.GeometryElement} animate(hash, time, options)
Animates properties for that object like stroke or fill color, opacity and maybe even more later.
Parameters:
{Object} hash
Object containing propiertes with target values for the animation.
{number} time
Number of milliseconds to complete the animation.
{Object} options Optional
Optional settings for the animation:
  • callback: A function that is called as soon as the animation is finished.
Returns:
{JXG.GeometryElement} A reference to the object

{Array} bounds()
Dimensions of the smallest rectangle enclosing the element.
Returns:
{Array} The coordinates of the enclosing rectangle in a format like the bounding box in JXG.Board#setBoundingBox.

clearTrace()
Removes all objects generated by the trace function.

{JXG.GeometryElement} cloneToBackground()
Copy the element to background. This is used for tracing elements.
Returns:
{JXG.GeometryElement} A reference to the element

<private> {number} countChildren()
Counts the direct children of an object without counting labels.
Returns:
{number} Number of children

<private> createGradient()
Creates a gradient nodes in the renderer.
See:
JXG.SVGRenderer#setGradient

createLabel()
Creates a label element for this geometry element.
See:
#addLabelToElement

<private> {boolean} draggable()
Decides whether an element can be dragged. This is used in setPositionDirectly methods where all parent elements are checked if they may be dragged, too.
Returns:
{boolean}

{Array} generatePolynomial()
Array of strings containing the polynomials defining the element. Used for determining geometric loci the groebner way.
Returns:
{Array} An array containing polynomials describing the locus of the current object.

getAttribute(key)
Get the value of the property key.
Parameters:
{String} key
The name of the property you are looking for
Returns:
The value of the property

{Object} getAttributes()
Retrieve a copy of the current visProp.
Returns:
{Object}

{JXG.Coords} getLabelAnchor()
Returns the coords object where the label of the element shall be drawn. Differs in some cases from the values that getTextAnchor returns.
Returns:
{JXG.Coords} JXG.Coords Place where the text shall be drawn.
See:
JXG.GeometryElement#getTextAnchor

{String} getName()
Returns the elements name, Used in JessieCode.
Returns:
{String}

{Array} getParents()
List of the element ids resp. values used as parents in JXG.Board#create.
Returns:
{Array}

{JXG.Coords} getTextAnchor()
Returns the coords object where a text that is bound to the element shall be drawn. Differs in some cases from the values that getLabelAnchor returns.
Returns:
{JXG.Coords} JXG.Coords Place where the text shall be drawn.
See:
JXG.GeometryElement#getLabelAnchor

{String} getType()
The type of the element as used in JXG.Board#create.
Returns:
{String}

{Boolean} hasPoint(x, y)
Checks whether (x,y) is near the element.
Parameters:
{Number} x
Coordinate in x direction, screen coordinates.
{Number} y
Coordinate in y direction, screen coordinates.
Returns:
{Boolean} True if (x,y) is near the element, False otherwise.

hideElement()
Hide the element. It will still exist but not visible on the board.

labelColor(lColor)
Set the labelColor of an element
Parameters:
{String} lColor
String which determines the text color of an object's label.
Deprecated:
Use #setAttribute
See:
JXG.GeometryElement#labelColor

{JXG.Board} noHighlight()
Uses the "normal" properties of the element.
Returns:
{JXG.Board}

<private> normalize()
Normalize the element's standard form.

off(event, handler)
Unregister an event handler.
Defined in: event.js.
Parameters:
{String} event
{Function} handler Optional
Returns:
Reference to the object.

on(event, handler, context)
Register a new event handler. For a list of possible events see documentation of the elements and objects implementing the EventEmitter interface.
Defined in: event.js.
Parameters:
{String} event
{Function} handler
{Object} context Optional
The context the handler will be called in, default is the element itself.
Returns:
Reference to the object.

<private> prepareUpdate()
Notify all child elements for updates.

remove()
Removes the element from the construction. This only removes the SVG or VML node of the element and its label (if available) from the renderer, to remove the element completely you should use JXG.Board#removeObject.

removeChild(obj)
Remove an element as a child from the current element.
Parameters:
{JXG.GeometryElement} obj
The dependent object.

<private> removeDescendants(obj)
Removes the given object from the descendants list of this object and all its child objects.
Parameters:
{JXG.GeometryElement} obj
The element that is to be removed from the descendants list.
Returns:

{Object} resolveShortcuts(properties)
Resolves property shortcuts like color and expands them, e.g. strokeColor and fillColor. Writes the expanded properties back to the given properties.
Parameters:
{Object} properties
Returns:
{Object} The given parameter with shortcuts expanded.

setArrow(firstArrow, lastArrow)
Determines whether the element has arrows at start or end of the arc.
Parameters:
{Boolean} firstArrow
True if there is an arrow at the start of the arc, false otherwise.
{Boolean} lastArrow
True if there is an arrow at the end of the arc, false otherwise.

setAttribute(attributes)
Sets an arbitrary number of attributes.
Parameters:
{Object} attributes
An object with attributes.
Examples:
// Set property directly on creation of an element using the attributes object parameter
var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-1, 5, 5, 1]};
var p = board.create('point', [2, 2], {visible: false});

// Now make this point visible and fixed:
p.setAttribute({
    fixed: true,
    visible: true
});

<private> setDash(dash)
Set the dash style of an object. See #dash for a list of available dash styles. You should use #setAttribute instead of this method.
Parameters:
{number} dash
Indicates the new dash style

setLabelText(str)
Updates the element's label text, strips all html.
Parameters:
{String} str

showElement()
Make the element visible.

triggerEventHandlers(event, args)
Triggers all event handlers of this element for a given event.
Defined in: event.js.
Parameters:
{Array} event
{Array} args
The arguments passed onto the event handler
Returns:
Reference to the object.

update()
General update method. Should be overwritten by the element itself. Can be used sometimes to commit changes to the object.

<private> updateRenderer()
Provide updateRenderer method.
Event Detail
attribute(o, el)
Notify everytime an attribute is changed.
Parameters:
{Object} o
A list of changed attributes and their new value.
{Object} el
Reference to the element

attribute:<attribute>(val, nval, el)
This is a generic event handler. It exists for every possible attribute that can be set for any element, e.g. if you want to be notified everytime an element's strokecolor is changed, is the event attribute:strokecolor.
Parameters:
val
The old value.
nval
The new value
{Object} el
Reference to the element

down(e)
Whenever the user starts to touch or click an element.
Parameters:
{Event} e
The browser's event object.

drag(e)
This event is fired whenever the user drags an element.
Parameters:
{Event} e
The browser's event object.

mousedown(e)
Whenever the user starts to click an element.
Parameters:
{Event} e
The browser's event object.

mousedrag(e)
This event is fired whenever the user drags the element with a mouse.
Parameters:
{Event} e
The browser's event object.

mousemove(e)
This event is fired whenever the user is moving the mouse over an element.
Parameters:
{Event} e
The browser's event object.

mouseout(e)
This event is fired whenever the user puts the mouse away from an element.
Parameters:
{Event} e
The browser's event object.

mouseover(e)
This event is fired whenever the user puts the mouse over an element.
Parameters:
{Event} e
The browser's event object.

mouseup(e)
Whenever the user releases the mousebutton over an element.
Parameters:
{Event} e
The browser's event object.

move(e)
This event is fired whenever the user is moving over an element.
Parameters:
{Event} e
The browser's event object.

out(e)
This event is fired whenever the user is leaving an element.
Parameters:
{Event} e
The browser's event object.

over(e)
This event is fired whenever the user is hovering over an element.
Parameters:
{Event} e
The browser's event object.

touchdown(e)
Whenever the user starts to touch an element.
Parameters:
{Event} e
The browser's event object.

touchdrag(e)
This event is fired whenever the user drags the element on a touch device.
Parameters:
{Event} e
The browser's event object.

touchup(e)
Whenever the user stops touching an element.
Parameters:
{Event} e
The browser's event object.

up(e)
Whenever the user stops to touch or click an element.
Parameters:
{Event} e
The browser's event object.

Documentation generated by JsDoc Toolkit 2.4.0 on Fri Sep 27 2013 11:32:43 GMT+0200 (CEST)