Difference between revisions of "Point 'fixed' in one direction"

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`A` and `B` are free points. Whenever the board is updated, e.g.
+
''A'' and ''B'' are free points. Whenever the board is updated, e.g.
after a drag event, the x-coordinate of `A` is set to 1 and
+
after a drag event, the x-coordinate of ''A'' is set to 1 and
the y-coordinate of `B` is set to 1. Therefore, `A` moves  
+
the y-coordinate of ''B'' is set to 1. Therefore, ''A'' moves  
on a vertical line, `B` moves on a horizontal line.
+
on the vertical line through x=1, ''B'' moves on the horizontal line through y=1.
 
<jsxgraph width="600" height="600">
 
<jsxgraph width="600" height="600">
 
var brd = JXG.JSXGraph.initBoard('jxgbox',{axis:true,boundingbox:[-1,2,2,-1]});
 
var brd = JXG.JSXGraph.initBoard('jxgbox',{axis:true,boundingbox:[-1,2,2,-1]});

Revision as of 14:09, 8 October 2012

A and B are free points. Whenever the board is updated, e.g. after a drag event, the x-coordinate of A is set to 1 and the y-coordinate of B is set to 1. Therefore, A moves on the vertical line through x=1, B moves on the horizontal line through y=1.

The JavaScript code

var brd = JXG.JSXGraph.initBoard('jxgbox',{axis:true,boundingbox:[-1,2,2,-1]});

var A = brd.create('point', [1,0]);
var B = brd.create('point', [0,1]);

brd.on('update', function(){
        A.moveTo([1, A.Y()]);
        B.moveTo([B.X(), 1]);
});