Divide 3d line into segments

Hello,

I've got an object in an image which is positioned at an angle. I can draw a line across each side of the object, forming a sheared bounding box for the object.

I need to split the top and bottom lines (the horizontal lines) into a number of parts. For straight lines this would be fairly easy, something like this:

point1 = [664, 10];
point2 = [1556, 10];

length = point2(2) - point1(2);
numberOfSegments = 30;

segmentSize = length / numberOfSegments;

(664 and 1556 are X-axis positions, 10 is the Y-axis position)

This creates 30 segments of 30 pixels wide each. My line represents a 3D-plane in the image though, so the segments should not be the same width as the line planes towards the camera.

Imagine the following points that I've found in my image:

point1 = [644 220];
point2 = [1556 5];

(664 and 1556 are X-axis positions, 220 and 5 are Y-axis positions)

The segments closer to point 1 should be small in width and the width should increase for segments closer to point 2.

How can I calculate the width of each segment on the angled line?

Thanks!