Difference between revisions of "Even simpler function plotter"

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Line 3: Line 3:
 
<input type="button" value="plot" onClick="plotter()">
 
<input type="button" value="plot" onClick="plotter()">
 
<input type="button" value="add tangent" onClick="addTangent()">
 
<input type="button" value="add tangent" onClick="addTangent()">
 +
<input type="button" value="add tangent" onClick="addDerivative()">
 
<input type="button" value="clear all" onClick="clearAll()">  
 
<input type="button" value="clear all" onClick="clearAll()">  
 
</form>
 
</form>
Line 35: Line 36:
 
     if (JXG.isFunction(f)) {
 
     if (JXG.isFunction(f)) {
 
         board.suspendUpdate();
 
         board.suspendUpdate();
         var p = board.create('glider',[0,0,curve], {name:'drag me'});
+
         var p = board.create('glider',[1,0,curve], {name:'drag me'});
 
         board.create('tangent',[p], {name:'drag me'});
 
         board.create('tangent',[p], {name:'drag me'});
 
         board.unsuspendUpdate();
 
         board.unsuspendUpdate();
 
     }
 
     }
 
}
 
}
 +
 +
function addDerivative() {
 +
    if (JXG.isFunction(f)) {
 +
        board.create('functiongraph',[JXG.Math.D(f),
 +
                function(){
 +
                  var c = new JXG.Coords(JXG.COORDS_BY_SCREEN,[0,0],board);
 +
                  return c.usrCoords[1];
 +
                },
 +
                function(){
 +
                  var c = new JXG.Coords(JXG.COORDS_BY_SCREEN,[board.canvasWidth,0],board);
 +
                  return c.usrCoords[1];
 +
                }
 +
], {dash:2});
 +
    }
 +
}
 +
  
 
</jsxgraph>
 
</jsxgraph>

Revision as of 15:08, 15 July 2010

The underlying JavaScript code

<input type="text" id="input" value="sin(x)*x">
<input type="button" value="plot" onClick="plotter()">
<input type="button" value="clear all" onClick="clearAll()">
var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-5,8,8,-5], axis:true});

function plotter() {
  var t = JXG.GeonextParser.geonext2JS(document.getElementById('input').value);
  var f = new Function('x','var y = '+t+'; return y;');
  board.create('functiongraph',[f,
                function(){ 
                  var c = new JXG.Coords(JXG.COORDS_BY_SCREEN,[0,0],board);
                  return c.usrCoords[1];
                },
                function(){ 
                  var c = new JXG.Coords(JXG.COORDS_BY_SCREEN,[board.canvasWidth,0],board);
                  return c.usrCoords[1];
                }
              ]);
}
function clearAll() {
    JXG.JSXGraph.freeBoard(board);
    board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-5,8,8,-5], axis:true});
}