API Docs for: 0.99.4
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# PSEUDO

Extends Sector
Module: JXG

A circumcircle sector is different from a Sector mostly in the way the parent elements are interpreted. At first, the circum centre is determined from the three given points. Then the sector is drawn from p1 through p2 to p3.

## Constructor

### CircumcircleSector

(
• p1,p2,p1
)

#### Parameters:

• p1,p2,p1 JXG.Point_JXG.Point_JXG.Point

A circumcircle sector is defined by the circumcircle which is determined by these three given points. The circumcircle sector is always drawn from p1 through p2 to p3.

#### Throws:

Error:

If the element cannot be constructed with the given parent objects an exception is thrown.

#### Example:

// Create an arc out of three free points
var p1 = board.create('point', [1.5, 5.0]),
p2 = board.create('point', [1.0, 0.5]),
p3 = board.create('point', [5.0, 3.0]),

a = board.create('circumcirclesector', [p1, p2, p3]);

## Methods

### hideElement

() chainable

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

()

Inherited from Sector but overwritten in src/element/sector.js:367

Returns the radius of the sector.

#### Returns:

Number:

The distance between {@link Sector#point1} and {@link Sector#point2}.

### maxX

()

Gives the default value of the right bound for the curve. May be overwritten in JXG.Curve#generateTerm.

#### Returns:

Number:

Right bound for the curve.

### Z

(
• t
)

Treat the curve as curve with homogeneous coordinates.

#### Parameters:

• t Number

A number between 0.0 and 1.0.

Number:

Always 1.0

### hasPoint

(
• x
• y
• start
)

Inherited from JXG.GeometryElement but overwritten in src/base/curve.js:194

Checks whether (x,y) is near the curve.

#### Parameters:

• x Number

Coordinate in x direction, screen coordinates.

• y Number

Coordinate in y direction, screen coordinates.

• start Number

Optional start index for search on data plots.

#### Returns:

Boolean:

True if (x,y) is near the curve, False otherwise.

### allocatePoints

() private chainable

Allocate points in the Coords array this.points

### update

() chainable

Inherited from JXG.GeometryElement but overwritten in src/base/curve.js:327

Computes for equidistant points on the x-axis the values of the function

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateDataArray

()

For dynamic dat aplots, updateDataArray can be used to compute new entries for the arrays JXG.Curve#dataX and JXG.Curve#dataY. It is used in JXG.Curve#updateCurve. Default is an empty method, can be overwritten by the user.

#### Example:

In this example the filled curve which shows the intersection of two polygons is plotted. The curve is defined by the coordinates in dataX and dataY.

var i,
board = JXG.JSXGraph.initBoard('box', {boundingbox: [-8,8,8,-8], axis: true}),
pts1 = [[-2, 3], [-4, -3], [2, 0], [4, 4]],
pts2 = [[-2, -3], [-4, 1], [0, 4], [5, 1]];

// Clipping polygon
var pol = board.create('polygon', pts1,
{hasInnerPoints: true,
borders: {names: ['', '', '', '']},
name:'Polygon1', withLabel: true, visible: true,
fillColor: 'yellow'});

// Polygon to be clipped
var pol2 = board.create('polygon', pts2,
{hasInnerPoints: false,
borders: {names: ['', '', '', '']},
name:'Polygon2', withLabel: true, visible: true
});

var curve = board.create('curve', [[],[]], {fillColor: 'blue', fillOpacity: 0.4});
curve.updateDataArray = function() {
var mat = JXG.Math.transpose(pol.intersect(pol2));

if (mat.length == 3) {
this.dataX = mat[1];
this.dataY = mat[2];
} else {
this.dataX = [];
this.dataY = [];
}

};

board.update();

### updateCurve

() chainable

Computes the path of coordinates defining the curve. For this various methods are used, depending whether the curve is defined by a data array of by function terms. If the mousemove event triggers this update, we use only few points. Otherwise, e.g. on mouseup, many points are used.

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateTransformMatrix

() private chainable

Update the transfomration matrices bound to this curve.

#### Returns:

JXG.Curve:

Reference to the curve object.

### checkReal

() private chainable

Check if at least one point on the curve is finite and real and sets the property isReal.

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateParametricCurveNaive

(
• mi
• ma
• len
)
chainable

Updates the data points of a parametric curve using a fixed set of equidistant points. This version is used if undefined is false.

#### Parameters:

• mi Number

Left bound of curve

• ma Number

Right bound of curve

• len Number

Number of data points

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateParametricCurveOld

(
• mi
• ma
)
deprecated chainable

Updates the data points of a parametric curve. This version is used if undefined is true. Since 0.99 this algorithm is deprecated. It still can be used if undefined is true.

#### Parameters:

• mi Number

Left bound of curve

• ma Number

Right bound of curve

#### Returns:

JXG.Curve:

Reference to the curve object.

### isSegmentOutside

(
• x0
• y0
• x1
• y1
)
private

Crude and cheap test if the segment defined by the two points (x0, y0) and (x1, y1) is outside the viewport of the board. All parameters have to be given in screen coordinates.

#### Returns:

Boolean:

true if the given segment is outside the visible area.

### isDistOK

(
• dx
• dy
• MAXX
• MAXY
)
private

Compares the absolute value of dx with MAXX and the absolute value of dy with MAXY.

#### Returns:

Boolean:

true, if |dx| < MAXX and |dy| < MAXY.

() private

### _insertPoint

(
• pnt
)
private

Add a point to the curve plot. If the new point is too close to the previously inserted point, it is skipped. Used in undefined.

#### Parameters:

• pnt JXG.Coords

Coords to add to the list of points

### _borderCase

(
• a
• b
• c
• ta
• tb
• tc
• depth
)
JXG.Boolean private

Investigate a function term at the bounds of intervals where the function is not defined, e.g. log(x) at x = 0.

c is between a and b

#### Parameters:

• a Array

Screen coordinates of the left interval bound

• b Array

Screen coordinates of the right interval bound

• c Array

Screen coordinates of the bisection point at (ta + tb) / 2

• ta Number

Parameter which evaluates to a, i.e. [1, X(ta), Y(ta)] = a in screen coordinates

• tb Number

Parameter which evaluates to b, i.e. [1, X(tb), Y(tb)] = b in screen coordinates

• tc Number

(ta + tb) / 2 = tc. Parameter which evaluates to b, i.e. [1, X(tc), Y(tc)] = c in screen coordinates

• depth Number

Actual recursion depth. The recursion stops if depth is equal to 0.

#### Returns:

JXG.Boolean:

true if the point is inserted and the recursion should stop, false otherwise.

### _triangleDists

(
• a
• b
• c
)
private

Compute distances in screen coordinates between the points ab, ac, cb, and cd, where d = (a + b)/2. cd is used for the smoothness test, ab, ac, cb are used to detect jumps, cusps and poles.

#### Parameters:

• a Array

Screen coordinates of the left interval bound

• b Array

Screen coordinates of the right interval bound

• c Array

Screen coordinates of the bisection point at (ta + tb) / 2

#### Returns:

Array:

array of distances in screen coordinates between: ab, ac, cb, and cd.

### _isUndefined

(
• a
• ta
• b
• tb
)
private

Test if the function is undefined on an interval: If the interval borders a and b are undefined, 20 random values are tested if they are undefined, too. Only if all values are undefined, we declare the function to be undefined in this interval.

#### Parameters:

• a Array

Screen coordinates of the left interval bound

• ta Number

Parameter which evaluates to a, i.e. [1, X(ta), Y(ta)] = a in screen coordinates

• b Array

Screen coordinates of the right interval bound

• tb Number

Parameter which evaluates to b, i.e. [1, X(tb), Y(tb)] = b in screen coordinates

### _isOutside

(
• a
• ta
• b
• tb
)
private

Determines if a segment is outside of the visible canvas (plus a certain border).

#### Parameters:

• a Number

First point of the segement

• ta Number

Parameter of the curve for first point

• b Number

Second point of the segment

• tb Number

Parameter of the curve for second point

#### Returns:

Boolean:

True if segment is visible.

### _plotRecursive

(
• a
• ta
• b
• tb
• depth
• delta
)
private chainable

Recursive interval bisection algorithm for curve plotting. Used in undefined.

#### Parameters:

• a Array

Screen coordinates of the left interval bound

• ta Number

Parameter which evaluates to a, i.e. [1, X(ta), Y(ta)] = a in screen coordinates

• b Array

Screen coordinates of the right interval bound

• tb Number

Parameter which evaluates to b, i.e. [1, X(tb), Y(tb)] = b in screen coordinates

• depth Number

Actual recursion depth. The recursion stops if depth is equal to 0.

• delta Number

If the distance of the bisection point at (ta + tb) / 2 from the point (a + b) / 2 is less then delta, the segment [a,b] is regarded as straight line.

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateParametricCurve

(
• mi
• ma
)
chainable

Updates the data points of a parametric curve. This version is used if undefined is true.

#### Parameters:

• mi Number

Left bound of curve

• ma Number

Right bound of curve

#### Returns:

JXG.Curve:

Reference to the curve object.

### updateTransform

(
• p
)

Applies the transformations of the curve to the given point p. Before using it, JXG.Curve#updateTransformMatrix has to be called.

JXG.Point:

The given point.

### addTransform

(
• transform
)
chainable

Inherited from JXG.GeometryElement but overwritten in src/base/curve.js:1172

Add transformations to this curve.

#### Parameters:

• transform

Either one {@link JXG.Transformation} or an array of {@link JXG.Transformation}s.

#### Returns:

JXG.Curve:

Reference to the curve object.

### interpolationFunctionFromArray

(
• which
)
private

Generate the method curve.X() in case curve.dataX is an array and generate the method curve.Y() in case curve.dataY is an array.

#### Parameters:

• which String

Either 'X' or 'Y'

### generateTerm

(
• varname
• xterm
• yterm
• mi
• ma
)
chainable

Converts the GEONExT syntax of the defining function term into JavaScript. New methods X() and Y() for the Curve object are generated, further new methods for minX() and maxX().

#### Parameters:

• varname String

Name of the parameter, e.g. 't' or 'x'

• xterm

[description]

• yterm

[description]

• mi

[description]

• ma

[description]

#### Returns:

JXG.Curve:

Reference to the curve object.

#### See also:

• JXG.Curve#JXG.GeonextParser.geonext2JS.

### notifyParents

(
• contentStr
)
chainable

Finds dependencies in a given term and notifies the parents by adding the dependent object to the found objects child elements.

#### Parameters:

• contentStr String

String containing dependencies for the given object.

#### Returns:

JXG.Curve:

Reference to the curve object.

### addChild

(
• obj
)
chainable

Add an element as a child to the current element. Can be used to model dependencies between geometry elements.

### addDescendants

(
• obj
)
private chainable

Adds the given object to the descendants list of this object and all its child objects.

### addParents

(
• parents
)
JXG.Object chainable

Adds ids of elements to the array this.parents. This method needs to be called if some dependencies can not be detected automatically by JSXGraph. For example if a function graph is given by a function which referes to coordinates of a point, calling addParents() is necessary.

#### Parameters:

• parents Array

Array of elements or ids of elements. Alternatively, one can give a list of objects as parameters.

#### Returns:

JXG.Object:

reference to the object itself.

#### Example:

// Movable function graph
var A = board.create('point', [1, 0], {name:'A'}),
B = board.create('point', [3, 1], {name:'B'}),
f = board.create('functiongraph', function(x) {
var ax = A.X(),
ay = A.Y(),
bx = B.X(),
by = B.Y(),
a = (by - ay) / ( (bx - ax) * (bx - ax) );
return a * (x - ax) * (x - ax) + ay;
}, {fixed: false});
f.addParents([A, B]);

### setParents

(
• parents
)
JXG.Object chainable

Sets ids of elements to the array this.parents. First, this.parents is cleared. See undefined.

#### Parameters:

• parents Array

Array of elements or ids of elements. Alternatively, one can give a list of objects as parameters.

#### Returns:

JXG.Object:

reference to the object itself.

### removeChild

(
• obj
)
chainable

Remove an element as a child from the current element.

### removeDescendants

(
• obj
)
private chainable

Removes the given object from the descendants list of this object and all its child objects.

### countChildren

() private

Counts the direct children of an object without counting labels.

#### Returns:

Number:

Number of children

### getName

()

Returns the elements name, used in JessieCode.

### draggable

() private

Decides whether an element can be dragged. This is used in JXG.GeometryElement#setPositionDirectly methods where all parent elements are checked if they may be dragged, too.

### setPosition

(
• method
• coords
)
chainable

Translates the object by (x, y). In case the element is defined by points, the defining points are translated, e.g. a circle constructed by a center point and a point on the circle line.

#### Parameters:

• method Number

The type of coordinates used here. Possible values are {@link JXG.COORDS_BY_USER} and {@link JXG.COORDS_BY_SCREEN}.

• coords Array

array of translation vector.

#### Returns:

JXG.GeometryElement:

Reference to the element object.

### setPositionDirectly

(
• method
• coords
• oldcoords
)
chainable

Moves an by the difference of two coordinates.

#### Parameters:

• method Number

The type of coordinates used here. Possible values are {@link JXG.COORDS_BY_USER} and {@link JXG.COORDS_BY_SCREEN}.

• coords Array

coordinates in screen/user units

• oldcoords Array

previous coordinates in screen/user units

#### Returns:

JXG.GeometryElement:

this element

### 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.

### animate

(
• hash
• time
• [options]
)
chainable

Animates properties for that object like stroke or fill color, opacity and maybe even more later.

#### Parameters:

• hash Object

Object containing properties with target values for the animation.

• time Number

Number of milliseconds to complete the animation.

• [options] Object 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

### updateRenderer

() private chainable

Provide updateRenderer method.

### minX

()

Gives the default value of the left bound for the curve. May be overwritten in JXG.Curve#generateTerm.

#### Returns:

Number:

Left bound for the curve.

### showElement

() chainable

Make the element visible.

### _set

(
• property
• value
)
private chainable

Sets the value of property property to value.

#### Parameters:

• property String

The property's name.

• value Object

The new value

### resolveShortcuts

(
• properties
)

Resolves property shortcuts like color and expands them, e.g. strokeColor and fillColor. Writes the expanded properties back to the given properties.

#### Returns:

Object:

The given parameter with shortcuts expanded.

### setLabel

(
• str
)
chainable

Sets a label and it's text If label doesn't exist, it creates one

### setLabelText

(
• str
)
chainable

Updates the element's label text, strips all html.

### setName

(
• str
)
chainable

Updates the element's label text and the element's attribute "name", strips all html.

### setProperty

() deprecated

Inherited from JXG.GeometryElement: src/base/element.js:1030

Deprecated: Use {@link JXG.GeometryElement#setAttribute}.

Deprecated alias for JXG.GeometryElement#setAttribute.

### setAttribute

(
• attributes
)
chainable

Sets an arbitrary number of attributes.

#### Parameters:

• attributes Object

An object with attributes.

#### Example:

// 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
});

### getProperty

() deprecated

Inherited from JXG.GeometryElement: src/base/element.js:1237

Deprecated: Use {@link JXG.GeometryElement#getAttribute}.

Deprecated alias for JXG.GeometryElement#getAttribute.

### getAttribute

(
• key
)

Get the value of the property key.

#### Parameters:

• key String

The name of the property you are looking for

#### Returns:

The value of the property

### setDash

(
• dash
)
private chainable

Set the dash style of an object. See undefined for a list of available dash styles. You should use undefined instead of this method.

#### Parameters:

• dash Number

Indicates the new dash style

### prepareUpdate

() private chainable

Notify all child elements for updates.

### remove

() chainable

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.

### 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.

### 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.

### setArrow

(
• firstArrow
• lastArrow
)
chainable

Determines whether the element has arrows at start or end of the arc.

#### Parameters:

• firstArrow Boolean

True if there is an arrow at the start of the arc, false otherwise.

• lastArrow Boolean

True if there is an arrow at the end of the arc, false otherwise.

### createGradient

() private chainable

Creates a gradient nodes in the renderer.

#### See also:

• JXG.SVGRenderer#setGradient

### createLabel

() chainable

Creates a label element for this geometry element.

#### See also:

• #addLabelToElement

### highlight

(
• [force=false]
)
chainable

Highlights the element.

#### Parameters:

• [force=false] Boolean optional

Force the highlighting

### noHighlight

() chainable

Uses the "normal" properties of the element.

### clearTrace

() chainable

Removes all objects generated by the trace function.

### cloneToBackground

() chainable

Copy the element to background. This is used for tracing elements.

### 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 {@link JXG.Board#setBoundingBox}.

### normalize

() private chainable

Normalize the element's standard form.

### toJSON

() private

EXPERIMENTAL. Generate JSON object code of visProp and other properties.

#### Returns:

JSON string containing element's properties.

### addRotation

(
• angle
)
chainable

Rotate texts or images by a given degree. Works only for texts where JXG.Text#display equal to "internal".

#### Parameters:

• angle Number

The degree of the rotation (90 means vertical text).

#### See also:

• JXG.GeometryElement#rotate

### highlightStrokeColor

(
• sColor
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1611

Deprecated: Use {@link #setAttribute}

Set the highlightStrokeColor of an element

#### Parameters:

• sColor String

String which determines the stroke color of an object when its highlighted.

### strokeColor

(
• sColor
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1626

Deprecated: Use {@link #setAttribute}

Set the strokeColor of an element

#### Parameters:

• sColor String

String which determines the stroke color of an object.

### strokeWidth

(
• width
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1641

Deprecated: Use {@link #setAttribute}

Set the strokeWidth of an element

#### Parameters:

• width Number

Integer which determines the stroke width of an outline.

### fillColor

(
• fColor
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1657

Deprecated: Use {@link #setAttribute}

Set the fillColor of an element

#### Parameters:

• fColor String

String which determines the fill color of an object.

### highlightFillColor

(
• fColor
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1673

Deprecated: Use {@link #setAttribute}

Set the highlightFillColor of an element

#### Parameters:

• fColor String

String which determines the fill color of an object when its highlighted.

### labelColor

(
• lColor
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1688

Deprecated: Use {@link #setAttribute}

Set the labelColor of an element

#### Parameters:

• lColor String

String which determines the text color of an object's label.

### dash

(
• d
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1703

Deprecated: Use {@link #setAttribute}

Set the dash type of an element

#### Parameters:

• d Number

Integer which determines the way of dashing an element's outline.

### visible

(
• v
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1718

Deprecated: Use {@link #setAttribute}

Set the visibility of an element

#### Parameters:

• v Boolean

Boolean which determines whether the element is drawn.

### shadow

(
• s
)
deprecated chainable

Inherited from JXG.GeometryElement: src/base/element.js:1733

Deprecated: Use {@link #setAttribute}

Set the shadow of an element

#### Parameters:

• s Boolean

Boolean which determines whether the element has a shadow or not.

### getTpye

()

The type of the element as used in JXG.Board#create.

### getParents

()

List of the element ids resp. values used as parents in JXG.Board#create.

### snapToGrid

() chainable

Snaps the element to the grid. Only works for points, lines and circles. Points will snap to the grid as defined in their properties undefined and undefined. Lines and circles will snap their parent points to the grid, if they have undefined set to true.

#### Returns:

JXG.GeometryElement:

Reference to the element.

### snapToPoints

() chainable

Snaps the element to points. Only works for points. Points will snap to the next point as defined in their properties undefined and undefined. Lines and circles will snap their parent points to points.

#### Returns:

JXG.GeometryElement:

Reference to the element.

### getAttributes

()

Retrieve a copy of the current visProp.

### handleSnapToGrid

(
• force
)
chainable

Move an element to its nearest grid point. The function uses the coords object of the element as its actual position. If there is no coords object, nothing is done.

#### Parameters:

• force Boolean

force snapping independent from what the snaptogrid attribute says

#### Returns:

JXG.GeometryElement:

Reference to this element

## Properties

### _org_type

Number final

Original type of the element at construction time. Used for removing glider property.

### _pos

Number private

The position of this element inside the undefined.

Default: -1

### ancestors

Object

Elements on which this element depends on are stored here.

### baseElement

JXG.GeometryElement private

Default: null

### board

JXG.Board

Reference to the board associated with the element.

### center

Circumcenter

Center of the circumcirclesector

### childElements

Object

Stores all dependent objects to be updated when this point is moved.

### descendants

Object

Elements depending on this element are stored here.

### dump

Boolean

The element is saved with an explicit entry in the file (true) or implicitly via a composition.

Default: true

### elementClass

Number final

The element's class.

### elType

String

The string used with JXG.Board#create

### hasLabel

Boolean

If element has a label subelement then this property will be set to true.

Default: false

### highlighted

Boolean

True, if the element is currently highlighted.

Default: false

### id

String

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

### isDraggable

Boolean

Controls if this element can be dragged. In GEONExT only free points and gliders can be dragged.

Default: false

### isReal

Boolean

If element is in two dimensional real space this is true, else false.

Default: true

### lastDragTime

Date

Time stamp containing the last time this element has been dragged.

Default: creation time

### methodMap

Object

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.

### mouseover

Boolean

Is the mouse over this element?

Default: false

### name

String

Not necessarily unique name for the element.

Default: Name generated by {@link JXG.Board#generateName}.

### needsUpdate

Boolean

Controls if updates are necessary

Default: true

### notExistingParents

Object

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

### numberPoints

Number

Number of points on curves when plotted with updateParametricCurveNaive. This value changes between the attribute values numberPointsLow and numberPointsHigh. The first value is taken during drag events, the latter one is taken in the up event. It is set in JXG.Curve#updateCurve.

### numTraces

Number

Counts the number of objects drawn as part of the trace of the element.

### parents

Object

Ids of elements on which this element depends directly are stored here.

### point1

JXG.Point

Midpoint of the sector.

### point2

JXG.Point

This point together with Sector#point1 defines the radius..

### point3

JXG.Point

Defines the sector's angle.

### point4

JXG.Point

Defines the sectors orientation in case of circumCircleSectors.

### qdt

JXG.Math.Quadtree

Stores a quad tree if it is required. The quad tree is generated in the curve updates and can be used to speed up the hasPoint method.

### quadraticform

Array

Quadratic form representation of circles (and conics)

Default: [[1,0,0],[0,1,0],[0,0,1]]

### rendNode

Object

Stores the rendering node for the element.

### stdform

Array

[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: [1, 0, 0, 0, 1, 1, 0, 0]

### subs

Object

Subs contains the subelements, created during the create method.

### symbolic

Object

Stores variables for symbolic computations

### traces

Object

Keeps track of all objects drawn as part of the trace of the element.

### transformations

Array

Stores the transformations which are applied during update in an array

### type

Number final

Type of the element.

### visProp

Object

An associative array containing all visual properties.

Default: empty object

## Events

### attribute

Notify everytime an attribute is changed.

#### Event Payload:

• o Object

A list of changed attributes and their new value.

• el Object

Reference to the element

### attribute:<attribute>

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.

### down

Whenever the user starts to touch or click an element.

#### Event Payload:

• e Event

The browser's event object.

### drag

This event is fired whenever the user drags an element.

#### Event Payload:

• e Event

The browser's event object.

### mousedown

Whenever the user starts to click an element.

#### Event Payload:

• e Event

The browser's event object.

### mousedrag

This event is fired whenever the user drags the element with a mouse.

#### Event Payload:

• e Event

The browser's event object.

### mousemove

This event is fired whenever the user is moving the mouse over an element.

#### Event Payload:

• e Event

The browser's event object.

### mouseout

This event is fired whenever the user puts the mouse away from an element.

#### Event Payload:

• e Event

The browser's event object.

### mouseover

This event is fired whenever the user puts the mouse over an element.

#### Event Payload:

• e Event

The browser's event object.

### mouseup

Whenever the user releases the mousebutton over an element.

#### Event Payload:

• e Event

The browser's event object.

### move

This event is fired whenever the user is moving over an element.

#### Event Payload:

• e Event

The browser's event object.

### out

This event is fired whenever the user is leaving an element.

#### Event Payload:

• e Event

The browser's event object.

### over

This event is fired whenever the user is hovering over an element.

#### Event Payload:

• e Event

The browser's event object.

### touchdown

Whenever the user starts to touch an element.

#### Event Payload:

• e Event

The browser's event object.

### touchdrag

This event is fired whenever the user drags the element on a touch device.

#### Event Payload:

• e Event

The browser's event object.

### touchup

Whenever the user stops touching an element.

#### Event Payload:

• e Event

The browser's event object.

### up

Whenever the user stops to touch or click an element.

#### Event Payload:

• e Event

The browser's event object.