# comp.graphics.algorithms

## Subject: Plotting non overlapping rectangles

Hello all,

I'm not really sure what to call my objective apart from rectangle
avoidance. Anyway I'll do my best to describe the task at hand.

I have one fixed rectangle of known coordinates with its baseline
horizontal.

Within this rectangle (not necessarily center) I have a point of known
coordinates, which I'll call A.

Outside the rectangle I have another point also of known coordinates, which
I'll call B.

Point A is fixed, but Point B is moveable.

Points A and B describe the center line of another rectangle. To generate
the coordinates for the 4 corners of this rectangle I add or subtract
predetermined offsets (xoff & yoff) to Ax, Ay and Bx, By. xoff and yoff
being calculated from the known width of this rectangle.

If you can understand what I've tried to describe you'll see that you have 2
overlapping rectangles.

What I need to do is calculate the coordinates of a point C, along the line
AB and just outside the fixed rectangle. When I construct a rectangle around
the line CB using the same offsets as before, I want the resulting rectangle
to touch but not overlap the fixed rectangle.

If I were to replace the fixed rectangle with a polygon which has all sides
either vertical or horizontal, how would I go about finding a similar
solution.

Many thanks.

Steve