I've borrowed from Eric Bainville's answer:
0 <= dot(AB,AM) <= dot(AB,AB) && 0 <= dot(BC,BM) <= dot(BC,BC)
Which in javascript looks like this:
function pointInRectangle(m, r) {
var AB = vector(r.A, r.B);
var AM = vector(r.A, m);
var BC = vector(r.B, r.C);
var BM = vector(r.B, m);
var dotABAM = dot(AB, AM);
var dotABAB = dot(AB, AB);
var dotBCBM = dot(BC, BM);
var dotBCBC = dot(BC, BC);
return 0 <= dotABAM && dotABAM <= dotABAB && 0 <= dotBCBM && dotBCBM <= dotBCBC;
}
function vector(p1, p2) {
return {
x: (p2.x - p1.x),
y: (p2.y - p1.y)
};
}
function dot(u, v) {
return u.x * v.x + u.y * v.y;
}
eg:
var r = {
A: {x: 50, y: 0},
B: {x: 0, y: 20},
C: {x: 10, y: 50},
D: {x: 60, y: 30}
};
var m = {x: 40, y: 20};
then:
pointInRectangle(m, r); // returns true.
Here's a codepen to draw the output as a visual test :) http://codepen.io/mattburns/pen/jrrprN
