# JSXGraph Reference

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Class Index | File Index

## Elements

## Classes

- _global_
- Angle
- Arc
- Arrow
- Arrowparallel
- Axis
- Bisector
- Bisectorlines
- Button
- Cardinalspline
- Checkbox
- Circle
- Circumcenter
- Circumcircle
- CircumcircleArc
- CircumcircleSector
- Conic
- Curve
- Derivative
- Ellipse
- Functiongraph
- Glider
- Grid
- Group
- Hatch
- Hyperbola
- Image
- Incenter
- Incircle
- Inequality
- Input
- Integral
- Intersection
- JXG
- JXG.AbstractRenderer
- JXG.Board
- JXG.C
- JXG.CA
- JXG.CanvasRenderer
- JXG.Circle
- JXG.Complex
- JXG.Composition
- JXG.Coords
- JXG.CoordsElement
- JXG.Curve
- JXG.Dump
- JXG.EventEmitter
- JXG.GeometryElement
- JXG.GeonextParser
- JXG.Group
- JXG.Image
- JXG.JessieCode
- JXG.JSXGraph
- JXG.Line
- JXG.Math
- JXG.Math.Geometry
- JXG.Math.Numerics
- JXG.Math.Poly
- JXG.Math.Poly.Monomial
- JXG.Math.Poly.Polynomial
- JXG.Math.Poly.Ring
- JXG.Math.Statistics
- JXG.Math.Symbolic
- JXG.NoRenderer
- JXG.Options
- JXG.Point
- JXG.Polygon
- JXG.Server
- JXG.Server.modules
- JXG.SVGRenderer
- JXG.Text
- JXG.Ticks
- JXG.Transformation
- JXG.Turtle
- JXG.Util
- JXG.Util.Base64
- JXG.Util.Unzip
- JXG.Util.UTF8
- JXG.VMLRenderer
- JXG.XML
- Label
- Line
- Locus
- MajorArc
- MajorSector
- Midpoint
- MinorArc
- MinorSector
- Mirrorelement
- Mirrorpoint
- NonReflexAngle
- Normal
- Orthogonalprojection
- OtherIntersection
- Parabola
- Parallel
- Parallelpoint
- Perpendicular
- PerpendicularPoint
- PerpendicularSegment
- Point
- PolarLine
- PolePoint
- Polygon
- Quadtree
- RadicalAxis
- Reflection
- ReflexAngle
- RegularPolygon
- Riemannsum
- Sector
- Segment
- Semicircle
- Slider
- Slopetriangle
- Spline
- Stepfunction
- Tangent
- Tapemeasure
- Text
- Ticks
- Tracecurve
- Transformation
- Turtle

# Class PolePoint

JXG.CoordsElement,JXG.GeometryElement
↳ JXG.Point
↳ PolePoint

This element is used to provide a constructor for the pole point of a line with respect to a conic or a circle.
Defined in: point.js.
Extends JXG.Point.

Class Summary
Constructor Attributes | Constructor Name and Description
--- | ---
| PolePoint(el1,el2, el1,el2) The pole point is the unique reciprocal relationship of a line with respect to a conic.

Fields borrowed from class JXG.GeometryElement:
  _org_type, _pos, ancestors, baseElement, board, childElements, dash, descendants, draft, dump, elementClass, elType, fillColor, fillOpacity, fixed, frozen, hasLabel, highlight, highlighted, highlightFillColor, highlightFillOpacity, highlightStrokeColor, highlightStrokeOpacity, highlightStrokeWidth, id, inherits, isDraggable, isReal, lastDragTime, methodMap, mouseover, name, needsRegularUpdate, needsUpdate, notExistingParents, numTraces, parents, quadraticform, rendNode, scalable, shadow, snapToGrid, stdform, strokeColor, strokeOpacity, strokeWidth, subs, symbolic, trace, traceAttributes, traces, transformations, transitionDuration, type, visible, visProp, visPropCalc, withLabel
Fields borrowed from class JXG.CoordsElement:
  coords, groups, needsUpdateFromParent, onPolygon, position, slideObject, slideObjects

Fields borrowed from class JXG.GeometryElement:
  _org_type, _pos, ancestors, baseElement, board, childElements, dash, descendants, draft, dump, elementClass, elType, fillColor, fillOpacity, fixed, frozen, hasLabel, highlight, highlighted, highlightFillColor, highlightFillOpacity, highlightStrokeColor, highlightStrokeOpacity, highlightStrokeWidth, id, inherits, isDraggable, isReal, lastDragTime, methodMap, mouseover, name, needsRegularUpdate, needsUpdate, notExistingParents, numTraces, parents, quadraticform, rendNode, scalable, shadow, snapToGrid, stdform, strokeColor, strokeOpacity, strokeWidth, subs, symbolic, trace, traceAttributes, traces, transformations, transitionDuration, type, visible, visProp, visPropCalc, withLabel
Fields borrowed from class JXG.CoordsElement:
  coords, groups, needsUpdateFromParent, onPolygon, position, slideObject, slideObjects

Methods borrowed from class JXG.Point:
  face, hasPoint, makeIntersection, normalizeFace, setStyle, size, update, updateRenderer, updateTransform
Methods borrowed from class JXG.GeometryElement:
  _set, addChild, addDescendants, addParents, addRotation, addTransform, animate, bounds, clearTrace, cloneToBackground, countChildren, createGradient, createLabel, draggable, fullUpdate, generatePolynomial, getAttribute, getAttributes, getLabelAnchor, getName, getParents, getProperty, getTextAnchor, getType, handleSnapToGrid, hideElement, labelColor, noHighlight, normalize, prepareUpdate, remove, removeChild, removeDescendants, resolveShortcuts, setArrow, setAttribute, setDash, setDisplayRendNode, setLabel, setLabelText, setName, setParents, setPosition, setPositionDirectly, setProperty, showElement, snapToPoints, updateVisibility
Methods borrowed from class JXG.CoordsElement:
  _anim, addAnchor, addConstraint, Dist, free, handleAttractors, handleSnapToPoints, makeGlider, moveAlong, moveTo, popSlideObject, setGliderPosition, setPositionByTransform, updateConstraint, updateCoords, updateGlider, updateGliderFromParent, visit, X, XEval, Y, YEval, Z, ZEval

Events borrowed from class JXG.GeometryElement:
  attribute, attribute:<attribute><attribute>, down, drag, mousedown, mousedrag, mousemove, mouseout, mouseover, mouseup, move, out, over, touchdown, touchdrag, touchup, up

Class Detail
PolePoint(el1,el2, el1,el2)
The pole point is the unique reciprocal relationship of a line with respect to a conic. The lines tangent to the intersections of a conic and a line intersect at the pole point of that line with respect to that conic. A line tangent to a conic has the pole point of that line with respect to that conic as the tangent point. See http://en.wikipedia.org/wiki/Pole_and_polar for more information on pole and polar.

Parameters:
{JXG.Conic|JXG.Circle_JXG.Point} el1,el2
  or
{JXG.Point_JXG.Conic|JXG.Circle} el1,el2
  The result will be the pole point of the line with respect to the conic or the circle.

Throws:
{Exception}
  If the element cannot be constructed with the given parent objects an exception is thrown.

Examples:

    // Create the pole point of a line with respect to a conic
    var p1 = board.create('point', [-1, 2]);
    var p2 = board.create('point', [ 1, 4]);
    var p3 = board.create('point', [-1,-2]);
    var p4 = board.create('point', [ 0, 0]);
    var p5 = board.create('point', [ 4,-2]);
    var c1 = board.create('conic',[p1,p2,p3,p4,p5]);
    var p6 = board.create('point', [-1, 4]);
    var p7 = board.create('point', [2, -2]);
    var l1 = board.create('line', [p6, p7]);
    var p8 = board.create('polepoint', [c1, l1]);

    // Create the pole point of a line with respect to a circle
    var p1 = board.create('point', [1, 1]);
    var p2 = board.create('point', [2, 3]);
    var c1 = board.create('circle',[p1,p2]);
    var p3 = board.create('point', [-1, 4]);
    var p4 = board.create('point', [4, -1]);
    var l1 = board.create('line', [p3, p4]);
    var p5 = board.create('polepoint', [c1, l1]);