Difference between revisions of "Desargues's theorem"

From JSXGraph Wiki
Jump to navigationJump to search
 
(14 intermediate revisions by the same user not shown)
Line 3: Line 3:
 
JXG.Options.text.fontSize = 24;
 
JXG.Options.text.fontSize = 24;
  
var board = JXG.JSXGraph.initBoard("jxgbox", {boundingbox: [-5,5,5,-5], axis:true, showCopyright:false, showNavigation:false});
+
var board = JXG.JSXGraph.initBoard("jxgbox", {boundingbox: [-5,5,5,-5], axis:false, showCopyright:false, showNavigation:false});
  
 
var r = board.create('point', [-4, -2], {name:'r'});
 
var r = board.create('point', [-4, -2], {name:'r'});
Line 10: Line 10:
 
var r3 = board.create('point', [-1.5, -0.5], {name:'', color: 'blue'});
 
var r3 = board.create('point', [-1.5, -0.5], {name:'', color: 'blue'});
  
var l1 = board.create('line', [r, r1], {straightFirst: false});
+
var l1 = board.create('line', [r, r1], {straightFirst: false, name: 'g_1', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});
var l2 = board.create('line', [r, r2], {straightFirst: false});
+
var l2 = board.create('line', [r, r2], {straightFirst: false, name: 'g_2', withLabel: true, label: {position: 'rt', offset: [-10, 10]}});
var l3 = board.create('line', [r, r3], {straightFirst: false});
+
var l3 = board.create('line', [r, r3], {straightFirst: false, name: 'g_3', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});
  
 
var p1 = board.create('glider', [-1, -2, l1], {name:'p_1'});
 
var p1 = board.create('glider', [-1, -2, l1], {name:'p_1'});
Line 18: Line 18:
 
var p3 = board.create('glider', [-0.5, 0, l3], {name:'p_3'});
 
var p3 = board.create('glider', [-0.5, 0, l3], {name:'p_3'});
  
var q1 = board.create('glider', [1.5, -2, l1], {name:'q_1'});
+
var q1 = board.create('glider', [0.75, -2, l1], {name:'q_1'});
  
 
var s1 = board.create('segment', [p1, p2], {color: 'black'});
 
var s1 = board.create('segment', [p1, p2], {color: 'black'});
Line 24: Line 24:
 
var s3 = board.create('segment', [p2, p3], {color: 'red'});
 
var s3 = board.create('segment', [p2, p3], {color: 'red'});
  
var par1 = board.create('parallel', [s1, q1], {color: 'black'});
+
var par1 = board.create('parallel', [s1, q1], {visible: false});
var par2 = board.create('parallel', [s2, q1], {color: 'black'});
+
var par2 = board.create('parallel', [s2, q1], {visible: false});
 
 
  
 +
var q2 = board.create('intersection', [par1, l2], {name:'q_2', color: 'black'});
 +
var q3 = board.create('intersection', [par2, l3], {name:'q_3', color: 'black'});
  
 +
var s4 = board.create('segment', [q1, q2], {color: 'black'});
 +
var s5 = board.create('segment', [q1, q3], {color: 'black'});
 +
var s6 = board.create('segment', [q2, q3], {color: 'red'});
 
</jsxgraph>
 
</jsxgraph>
  
Line 34: Line 38:
  
 
<source lang="javascript">
 
<source lang="javascript">
 +
JXG.Options.label.autoPosition = true;
 +
JXG.Options.text.fontSize = 24;
 +
 +
var board = JXG.JSXGraph.initBoard("jxgbox", {boundingbox: [-5,5,5,-5], axis:false, showCopyright:false, showNavigation:false});
 +
 +
var r = board.create('point', [-4, -2], {name:'r'});
 +
var r1 = board.create('point', [-1.5, -2.5], {name:'', color: 'blue'});
 +
var r2 = board.create('point', [-1.5, -1.7], {name:'', color: 'blue'});
 +
var r3 = board.create('point', [-1.5, -0.5], {name:'', color: 'blue'});
 +
 +
var l1 = board.create('line', [r, r1], {straightFirst: false, name: 'g_1', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});
 +
var l2 = board.create('line', [r, r2], {straightFirst: false, name: 'g_2', withLabel: true, label: {position: 'rt', offset: [-10, 10]}});
 +
var l3 = board.create('line', [r, r3], {straightFirst: false, name: 'g_3', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});
 +
 +
var p1 = board.create('glider', [-1, -2, l1], {name:'p_1'});
 +
var p2 = board.create('glider', [0.5, -2, l2], {name:'p_2'});
 +
var p3 = board.create('glider', [-0.5, 0, l3], {name:'p_3'});
 +
 +
var q1 = board.create('glider', [0.75, -2, l1], {name:'q_1'});
 +
 +
var s1 = board.create('segment', [p1, p2], {color: 'black'});
 +
var s2 = board.create('segment', [p1, p3], {color: 'black'});
 +
var s3 = board.create('segment', [p2, p3], {color: 'red'});
 +
 +
var par1 = board.create('parallel', [s1, q1], {visible: false});
 +
var par2 = board.create('parallel', [s2, q1], {visible: false});
 +
 +
var q2 = board.create('intersection', [par1, l2], {name:'q_2', color: 'black'});
 +
var q3 = board.create('intersection', [par2, l3], {name:'q_3', color: 'black'});
 +
 +
var s4 = board.create('segment', [q1, q2], {color: 'black'});
 +
var s5 = board.create('segment', [q1, q3], {color: 'black'});
 +
var s6 = board.create('segment', [q2, q3], {color: 'red'});
 
</source>
 
</source>
  
 
[[Category:Examples]]
 
[[Category:Examples]]
 
[[Category:Geometry]]
 
[[Category:Geometry]]

Latest revision as of 09:16, 3 May 2021

The underlying JavaScript code

JXG.Options.label.autoPosition = true;
JXG.Options.text.fontSize = 24;

var board = JXG.JSXGraph.initBoard("jxgbox", {boundingbox: [-5,5,5,-5], axis:false, showCopyright:false, showNavigation:false});

var r = board.create('point', [-4, -2], {name:'r'});
var r1 = board.create('point', [-1.5, -2.5], {name:'', color: 'blue'});
var r2 = board.create('point', [-1.5, -1.7], {name:'', color: 'blue'});
var r3 = board.create('point', [-1.5, -0.5], {name:'', color: 'blue'});

var l1 = board.create('line', [r, r1], {straightFirst: false, name: 'g_1', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});
var l2 = board.create('line', [r, r2], {straightFirst: false, name: 'g_2', withLabel: true, label: {position: 'rt', offset: [-10, 10]}});
var l3 = board.create('line', [r, r3], {straightFirst: false, name: 'g_3', withLabel: true, label: {position: 'rt', offset: [-10, 0]}});

var p1 = board.create('glider', [-1, -2, l1], {name:'p_1'});
var p2 = board.create('glider', [0.5, -2, l2], {name:'p_2'});
var p3 = board.create('glider', [-0.5, 0, l3], {name:'p_3'});

var q1 = board.create('glider', [0.75, -2, l1], {name:'q_1'});

var s1 = board.create('segment', [p1, p2], {color: 'black'});
var s2 = board.create('segment', [p1, p3], {color: 'black'});
var s3 = board.create('segment', [p2, p3], {color: 'red'});

var par1 = board.create('parallel', [s1, q1], {visible: false});
var par2 = board.create('parallel', [s2, q1], {visible: false});

var q2 = board.create('intersection', [par1, l2], {name:'q_2', color: 'black'});
var q3 = board.create('intersection', [par2, l3], {name:'q_3', color: 'black'});

var s4 = board.create('segment', [q1, q2], {color: 'black'});
var s5 = board.create('segment', [q1, q3], {color: 'black'});
var s6 = board.create('segment', [q2, q3], {color: 'red'});