How to extend line until end of image

Lets say, i have a line and i want to extend the line until the end of the image.

The line is displayed in the first photo with the green is my basic line, i want to extend it like the second image, until the end of the image.

I want to do this for all the lines that i have detected.

Does anyone knows how to do this?

[pasta pontikaki]

I think i found it

X= [x1, x2]

Y=[y1, y2]

c = [[1; 1] X(:)]\Y(:);

slope_m = c(2)

intercept_b = c(1)

aLine = [slope_m,-1,intercept_b];

points = lineToBorderPoints(aLine,size(negfillHoles))

line(points([1 ,3]),points([2 ,4]),'LineWidth',1.5,'Color','r');

plot(x1,y1,'*','LineWidth',2,'Color','g');