Creating geometric elements

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Revision as of 14:34, 17 September 2008 by (talk)
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Through the variable board new geometry elements can be added to the board. All elements are added with the method createElement():

board.createElement('point', [1,3], {name:'A', strokecolor:'red'});

Another example:

board.createElement('point', [function(){return s.X();},function(){return t.X()}], {trace:true});

The parameters of createElement() are:

board.createElement(elementType, parentElements, attributes);


  • elementType is a string containing the type of the element which is constructed. At the moment, possible types are:
    • primitive elements
    • composite elements:
      • arrowparallel
      • bisector
      • circumcircle
      • circumcirclemidpoint
      • integral
      • midpoint
      • mirrorpoint
      • normal
      • parallel
      • parallelpoint
      • perpendicular
      • perpendicularpoint
      • reflection
  • parentElements is an array containing the parameters which define the element. This can be parent elements like two points which define a line. It can also consist of JavaScript functions, numbers, and strings containing GEONExT syntax. The possible array elements depend on the element type.
  • attributes is a JavaScript object. Usually it is given in the "literal object" form
{key1:value1, key2:value2, ...}
  • Properties of a point:
    • style
    • strokeColor
    • strokeWidth
    • fillColor
    • highlightStrokeColor
    • highlightFillColor
    • labelColor
    • visible
    • fixed
    • draft
    • trace
  • Additional properties of a line:
    • straightFirst
    • straightLast

There are no additional properties of a circle

  • Additional properties for an element:
    • needsRegularUpdate = [true]/false (eg axis are set to needsRegularUpdate=false) These elements are updated only, if the origin of the board is moved or after zooming
  • Possible parameters:
el.setProperty({key1:value1, key2:value2},...);