Borland C++ arc/circle drawing function

Using Borland C++ Builder 5, I would like to have a function (or functions) written that will draw an arc and or circle onto a TCanvas object. Here is the signature of the function I would like to have. void __fastcall DrawArc( TCanvas *Canvas, int StartX, int StartY, int EndX, int EndY, int Radius ); Here is the tricky part. All of the arc drawing routines I've found online require a starting angle and ending angle for drawing. What I have is the starting point and ending point in cartesian coordinates. the radius will be positive or negative to determine the direction of drawing. i.e. a positive radius will draw counter clockwise and a negative radius will draw clockwise. this is important as this determines which portion of the circle to draw. I want this routine to be fast, but I am willing to work on optimization myself as long as I can figure out what you're doing. I would like to have the code commented where necessary, if the code you write is "self documenting" then that is enough, but where you think you would need to explain a portion to someone, that's the part that I would want documented. If you can supply additional information regarding the math behind your solution that would be wonderful. Thanks for taking the time to bid. Tim Gallagher -------------- comment added: Here's what I'm trying to do... There is a file format called DDES that has an arc entity that only defines the starting and ending points plus a radius. I need to read that info and draw the arc on the screen. I used to use a cad program that would allow a command like this: radius 1 from 1,1 fin 270 (this is an angle) radius 1 center 0,0 start 90 fin 270 (both angles) One thing I just remembered is that the function will have the center coordinates available to it. new signature: void __fastcall DrawArc( TCanvas *Canvas, int CenterX, int CenterY, int StartX, int StartY, int EndX, int EndY, int Radius ); ## Deliverables 1) Complete, tested, and fully-functional working function(s) in source code form. 2) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). I am open to opensource/freeware options, but would prefer to have all rights to the code. * * *This broadcast message was sent to all bidders on Sunday Jun 26, 2005 8:53:01 AM: Here's what I'm trying to do... There is a file format called DDES that has an arc entity that only defines the starting and ending points plus a radius. I need to read that info and draw the arc on the screen. I used to use a cad program that would allow a command like this: radius 1 from 1,1 fin 270 (this is an angle) radius 1 center 0,0 start 90 fin 270 (both angles) The radius is negative if we are drawing clockwise (always starting from the start coords) the radius is positive if we are drawing counter-clockwise (always starting from the start coords) One thing I just remembered is that the function will have the center coordinates available to it. ## Platform Borland C++ Builder 5.0