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Fix Ellipse#containsPoint #44

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Merged
merged 2 commits into from
Jul 24, 2017
Merged

Fix Ellipse#containsPoint #44

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c54cc9a
Fix Ellipse#containsPoint
Jul 9, 2017
cfd6494
Write unit tests around Ellipse#containsPoint
Jul 9, 2017
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28 changes: 20 additions & 8 deletions lib/toxi/geom/Ellipse.js
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,11 @@ Ellipse = function(a,b,c,d) {
extend(Ellipse,Vec2D);

Ellipse.prototype.containsPoint = function(p) {
// Immediately reject points outside the containing rectangle
if (mathUtils.abs(p.x - this.x) > this.radius.x ||
mathUtils.abs(p.y - this.y) > this.radius.y) {
return false;
}
var foci = this.getFoci();
return p.distanceTo(foci[0]) + p.distanceTo(foci[1]) < 2 * mathUtils.max(this.radius.x, this.radius.y);
};
Expand Down Expand Up @@ -90,15 +95,16 @@ Ellipse.prototype.getCircumference = function() {
* @return the focus
*/
Ellipse.prototype.getFoci = function() {
var foci = [];
if (this.radius.x > this.radius.y) {
foci[0] = this.sub(this.focus, 0);
foci[1] = this.add(this.focus, 0);
} else {
foci[0] = this.sub(0, this.focus);
foci[1] = this.add(0, this.focus);
return [
this.sub(this.focus, 0),
this.add(this.focus, 0)
];
}
return foci;
return [
this.sub(0, this.focus),
this.add(0, this.focus)
];
};

/**
Expand All @@ -122,7 +128,13 @@ Ellipse.prototype.setRadii = function(rx,ry) {
rx = rx.x;
}
this.radius.set(rx, ry);
this.focus = this.radius.magnitude();

if (this.radius.x > this.radius.y) {
this.focus = Math.sqrt(this.radius.x * this.radius.x - this.radius.y * this.radius.y);
} else {
this.focus = Math.sqrt(this.radius.y * this.radius.y - this.radius.x * this.radius.x);
}

return this;
};

Expand Down
56 changes: 56 additions & 0 deletions test/geom.Ellipse.js
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Expand Up @@ -14,4 +14,60 @@ describe('toxi.geom.Ellipse', function(){
});
});
});
describe('#containsPoint', function(){
describe('tall ellipse', function(){
var ellipse = new toxi.geom.Ellipse(100, 100, 20, 50);
it('should return true for the center', function(){
var p = new toxi.geom.Vec2D(100, 100);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for an internal point', function(){
var p = new toxi.geom.Vec2D(110, 110);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for a point inside the top edge', function(){
var p = new toxi.geom.Vec2D(100, 149.9);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for a point inside the right edge', function(){
var p = new toxi.geom.Vec2D(119.9, 100);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return false for a point outside the ellipse', function(){
var p = new toxi.geom.Vec2D(119, 149);
assert.equal(ellipse.containsPoint(p), false);
});
it('should return false for a point outside the containing rectangle of the ellipse', function(){
var p = new toxi.geom.Vec2D(125, 155);
assert.equal(ellipse.containsPoint(p), false);
});
});
describe('wide ellipse', function(){
var ellipse = new toxi.geom.Ellipse(100, 100, 50, 20);
it('should return true for the center', function(){
var p = new toxi.geom.Vec2D(100, 100);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for an internal point', function(){
var p = new toxi.geom.Vec2D(110, 110);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for a point inside the top edge', function(){
var p = new toxi.geom.Vec2D(100, 119.9);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return true for a point inside the right edge', function(){
var p = new toxi.geom.Vec2D(149.9, 100);
assert.equal(ellipse.containsPoint(p), true);
});
it('should return false for a point outside the ellipse', function(){
var p = new toxi.geom.Vec2D(149, 119);
assert.equal(ellipse.containsPoint(p), false);
});
it('should return false for a point outside the containing rectangle of the ellipse', function(){
var p = new toxi.geom.Vec2D(155, 125);
assert.equal(ellipse.containsPoint(p), false);
});
});
});
});