If you go for that style of solution there's plenty you could do to improve the safety of the solution I outlined - private destructor, cleanup function a friend of the interface so it can be deleted, quick typedef for shared_ptr and a helper to create them. If you need some more help with the details please ask another question and I can bore you further! Cheers, Ash

You are right. maps do it.

What you want is a 2D coordinate system in the plane of intersection, then you can use your equation for area. Assume that your original points are represented as vectors {Vk} from some origin O (this is your original 3D coordinate system). As you have the equation of the plane, choose one point on it as the new origin Op, and choose two orthogonal unit vectors (U1, U2) that lie in the plane as the new axes. (i.e. choose two orthogonal vectors orthogonal to the normal of the plane) Then in your new coordinate system, the 2D coordinates of the point Vk are: ( (Vk-Op).U1, (Vk-Op).U2 ) i.e. you simply project the 3D vector from your new origin onto your new axes. Note - this includes Alan's solution, the vectors U1 and U2 would be rows of his rotation matrix. It's just a different way of looking at things. Peter "Until the invention of the computer, the machine gun was the device that enabled humans to make the most mistakes in the smallest amount of time."

See 'Checking Existence of Keys and Values' in this[^] article. There is sufficient light for those who desire to see, and there is sufficient darkness for those of a contrary disposition. Blaise Pascal

i found what i want to do in here, lots of digging :). http://www.codeguru.com/cpp/controls/menu/bitmappedmenus/article.php/c3725/[^] Best Regards. Bekir.

Thank you for the all answers, I will have a look at it. Best Regards.

Hello, I have seen your article about using RT_RCDATA, thanks for the pointer. I will give a try. Thanks.

i didn't look at the Crpyto API,however i have done encrpytion of a file before. That was not a problem, it was a license file and i was encrypting and writing to a file and reading as binary, checking the date etc. (i searched in google and codeproject about encryption before doing this) now i am going to look at Crypto API, i have seen two articles on codeproject. Thanks for the pointer.

Thank you for the links and for your time John. I went to the Doc/View after reading your first post (out of mere curiosity) but obviously missed these two articles. I got stuck on such articles:http://www.codeproject.com/docview/nodoc_views.asp[^] which are a bit more elaborated. John Simmons / outlaw programmer wrote: The actual point of my original response was to show the person that if he just took the time to search instead of being lazy, he'd find the answer and be on his way a lot faster. I was perfectly aware of that and I totally agree with you. No offense meant in my post, it is only that I have been looking for a really simple tutorial and did not expect to have to look that closer to the article list to find that. ~RaGE();

Great! It's a lot easier to use the brute force approach and get the computer to work hard, rather than to have to learn how to implement complicated edge-detection algorithms. Of course, if the map changes frequently, my suggestion would not be useful.