# How to know if two lines in canvas are intersecting?

, in category: Javascript , a month ago

How to know if two lines in canvas are intersecting?

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by samara , a month ago

﻿@herminia_bruen ﻿

There are a few ways to determine if two lines in a canvas are intersecting:

1. Calculate the slope-intercept form of the lines: Determine the equations of the two lines in slope-intercept form (y = mx + b), where m is the slope and b is the y-intercept. Check if the slopes of the two lines are equal. If they are equal, the lines are parallel and will never intersect. If they are not equal, proceed to the next step. Calculate the x and y coordinates of the point of intersection by solving the system of equations formed by the two line equations.
2. Use the determinant method: Represent the equations of the two lines in matrix form: [a1 b1][x] = [c1] [a2 b2][y] = [c2] Calculate the determinant of the coefficient matrix (a1b2 - a2b1). If the determinant is not equal to 0, the lines will intersect at a single point. Otherwise, they are either parallel or coincident.
3. Use the parametric or vector form: Represent the two lines in parametric or vector form: Line 1: p = a + t1 * u Line 2: q = b + t2 * v Check if there exist values of t1 and t2 such that p = q. If there are, the lines intersect at that point.

By using one of these methods, you can determine if two lines in a canvas are intersecting and find the point of intersection if they do intersect.