C++ functions for patterns drawing

For a very simple program that draws AutoCAD patterns (.pat files) I need new drawing functions, in C++. What i need is a C++ function that do all the work of drawing a set of parallel lines, given a point and an angle. The lines must be hatched (with segments/points of different length) as in DWG patterns. For sample, i want to call: DrawParallesLines(DRAWING_CANVAS, double x, double y, double angle, double hatches[], double deltax, double deltay); This function should draw a line passing for (x,y), with angle provided and using segment lengths in the hatches array (negative length are for invisible segments); first segment should start from the point given and a distance along the line defined by deltax. The function must draw all lines parallel to those given that are contained in DRAWING_CANVAS, each line have a distance of deltay from the base one. Even if base point is outside DRAWING_CANVAS, this must be filled with the parallel hatched lines. Hatches segments must also fill any line in both directions. I need a robust and fast function, that draw exactly the segments contained in DRAWING_CANVAS. I consider the project completed only if i can see a correct preview of any normal pattern (.pat files), with various hatches styles, various angle and so on. DRAWING_CANVAS could be any object you're confortable to use, for drawing. On windows, you can use an handle of a GDI canvas, for sample, or a TCanvas of C++ Builder or any surface you like (OpenGL and so on). What's important is that i get a set of line() commands, inside your function, that draw the hatched lines that i need, it's my problem to convert your code to me needings. If you like just to compute a give me back an array of segments (x,y)-(x',y') without any drawing function, for me is ok. All rights to source code must be given to me. Don't use any free/open source code.