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@lobodin
Created October 22, 2010 17:17
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function Point(x, y) {
this.x = x;
this.y = y;
}
function Figure(position) {
this.position = position;
}
function Line(position, endPosition) {
Figure.call(this, position);
this.endPosition = endPosition;
this.name = "Line";
this.square = function() {
return 0;
}
}
Line.prototype = new Figure;
function Rectangle(position, endPosition) {
Line.call(this, position, endPosition);
this.name = "Rectangle"
this.square = function() {
return (this.endPosition.x - this.position.x) *
(this.endPosition.y - this.position.y);
}
}
Rectangle.prototype = new Line;
function Circle(position, radius) {
Figure.call(this, position);
this.radius = radius;
this.name = "Circle";
this.square = function() {
return Math.PI * this.radius * this.radius;
}
}
Circle.prototype = new Figure;
var Intersection = (function() {
function LineAndLine(a, b) {
var x1 = a.position.x, y1 = a.position.y,
x2 = a.endPosition.x, y2 = a.endPosition.y,
x3 = b.position.x, y3 = b.position.y,
x4 = b.endPosition.x, y4 = b.endPosition.y;
var result = new Point;
result.x = ((x1*y2 - y1*x2)*(x3 - x4) - (x1 - x2)*(x3*y4 - y3*x4)) /
((x1 - x2)*(y3 - y4) - (y1 - y2)*(x3 - x4));
result.y = ((x1*y2 - y1*x2)*(y3 - y4) - (y1 - y2)*(x3*y4 - y3*x4)) /
((x1 - x2)*(y3 - y4) - (y1 - y2)*(x3 - x4));
return isNaN(result.x) ||
Math.abs(result.x) != Infinity &&
Math.abs(result.y) != Infinity &&
result.x >= Math.min(x1, x2) &&
result.x >= Math.min(x3, x4) &&
result.y >= Math.min(y1, y2) &&
result.y >= Math.min(y3, y4) &&
result.x <= Math.max(x1, x2) &&
result.x <= Math.max(x3, x4) &&
result.y <= Math.max(y1, y2) &&
result.y <= Math.max(y3, y4);
}
function convertRectangleToLines(rect) {
var topLeft = new Point(rect.position.x, rect.endPosition.y),
bottomRight = new Point(rect.endPosition.x, rect.position.y);
return [new Line(rect.position, topLeft),
new Line(topLeft, rect.endPosition),
new Line(rect.endPosition, bottomRight),
new Line(bottomRight, rect.position)];
}
function LineAndRectangle(a, b) {
var lines = convertRectangleToLines(b);
for (var i in lines) if (LineAndLine(a, lines[i])) return true;
return false;
}
function RectangleAndRectangle(a, b) {
var linesA = convertRectangleToLines(a),
linesB = convertRectangleToLines(b);
for (var i in linesA) for (var j in linesB) if (LineAndLine(linesA[i], linesB[j])) return true;
return false;
}
function LineAndCircle(a, b) {
var x1 = a.position.x + b.position.x,
y1 = a.position.y + b.position.y;
x2 = a.endPosition.x + b.position.x;
y2 = a.endPosition.y + b.position.y;
var dr = Math.sqrt(Math.abs((x2 - x1)*(x2 - x1)) + Math.abs((y2 - y1)*(y2 - y1))),
D = x1*y2 - x2*y1;
return b.radius*b.radius*dr*dr - D*D >= 0;
}
function CircleAndRectangle(a, b) {
var lines = convertRectangleToLines(b);
for (var i in lines) if (LineAndCircle(lines[i], a)) return true;
return false;
}
function CircleAndCircle(a, b) {
var d = Math.sqrt(Math.pow(a.position.x - b.position.x, 2) +
Math.pow(a.position.y - b.position.y, 2));
return d <= a.radius + b.radius && d >= Math.abs(a.radius - b.radius);
}
return {
doIntersect: function(a, b) {
if (!(a instanceof Figure && b instanceof Figure)) {
return false;
}
return a.name.length < b.name.length ?
eval(composeFunction(a, b, "(a, b)")) :
eval(composeFunction(b, a, "(b, a)"));
}
}
function composeFunction(a, b, args) {
return a.name + "And" + b.name + args;
}
})();
<!DOCTYPE HTML>
<html>
<head>
<meta charset="UTF-8">
<title>Figures</title>
<script type="text/javascript" src="figures.js"></script>
<script type="text/javascript">
var line = new Line(new Point(0, 0), new Point(2, 2));
var line1 = new Line(new Point(2, 0), new Point(1, 10));
var rectangle = new Rectangle(new Point(1, 1), new Point(4, 3));
var rectangle1 = new Rectangle(new Point(10, 10), new Point(20, 20));
var circle = new Circle(new Point(2, 2), 3);
var circle1 = new Circle(new Point(0, 0), 1);
document.write(Intersection.doIntersect(line, line1));
</script>
</head>
<body>
</body>
</html>
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