Create/Rotate/Move objects with Graphics and GDI+

Question

I'm working on a project wich kinda involves making some kind of improved "MsPaint" allowing the user to create a few types of figures, using GDI+ in C#. But since that kind of figures and the way to make them (drawLine, drawLines, drawRectangle) just make lines on a bitmap, I can't completely understand how to make a solid object from, for example, a triangle I made using 'drawlines' method.

For now I just simplified the sourcecode from an Addisson Wesley book "Addison Wesley - Graphics Programming With C Sharp And Gdi+" and I'm using it to learn the basics. Thing is, I'm not even sure if this starting point is the correct to ultimately make the program I wanna make, which as I said before, it should let the user to create "figures" or "objects from figures" and rotate, transform, move them around.

The source code is from this actual site:
http://www.c-sharpcorner.com/Store/Books/0-321-16077-0.asp
I only used Chapter 03 "GDI+ Painter" as I think it could help.

Thank you very much in advanced. I attached the simplified version wich only allows to draw simple lines ellipses and rectangles based on the mentioned GDI+ Painter.

Adrian Z · Answer

Well I spend a few minutes glancing and what Felipe recommended and I probably stick with it although I find it reeeeally hard to understand due my lack of .NET skills :P Thing is can present this mini-project on December 2010 or February 2011 and I'm still concerned about learning or at least taking good advantage of what Duncan made since it requires a bit of knowledge about the subject.

Mahesh Chand · Answer

Did you try link given by Felipe? It that helps you probably stick with Windows Forms/GDI+. WPF is a learning curve and has lot of new things. IF you do want to learn WPF check out WPF section of C# Corner.

Felipe Ramos · Answer

Adrian I second Mahesh WPF (Windows Presentation Foundation) would be the next evolutionary step. The learning curve will be that you will have to learn XAML but once you know XAML you will be able to jump to other technologies like Silverlight. Maybe Mahesh can shine some light on this but I believe all the rendering is done using DirectX for WPF so you get the extra benefits of having a tested API for hardware integration.

Adrian Z · Answer

Well I have no idea what exactly WPF is or how to use it so it's gonna be like starting all over again for me haha. Any resource will be appreciated although I'm already looking for links and examples to see if I can get to know this whole thing and have a fresh start from scratch. Again thanks Mahesh for the advice since the main thing I was concerned about was to know whether I was on the right track to accomplish what I ultimately wanted for the project or not. Although I didn't mind learning all the stuff from your book since I'm always at the look of learning new things anyway. Thanks again for all the trouble.

Mahesh Chand · Answer

Adrian Thank you! I am glad you liked my book. However If you have a choice use WPF instead. Drawing support is much much better in WPF than GDI+/Windows Forms. Plus GDI+ has many resource leaks and performance is not good either. Go for WPF.

Adrian Z · Answer

Again many thanks. I'm going to take a look at it. Thanks again and I'll probably be back with more questions later haha.

Felipe Ramos · Answer

You can build the application you want using GDI+ but I am not sure how well it will scale and you will also need to write a lot of support code. I would suggest also reading the MSDN article Creating a Design Surface Using Windows Forms and GDI+ . Download the code and you should be able to start extending the functionality to fit your needs. -They included rotating dragging objects and many more.

Adrian Z · Answer

Well first of all thanks and that's the thing about this whole project. I'm concerned about finally being able to transform each figure the user may draw (rectangles or whatever) into movable objects as if you were for example drawing in Word those default shapes. So I'm not even absolutely sure if using GDI+ and C# is a good starting point to even getting to the final simple product of making a program with the features I mentioned early actually haha. EDIT:BTW your book is awesome although I'm having troubles with this whole make movable objects thing I learned a lot with your work.

Mahesh Chand · Answer

GDI+ does not have built-in API for creating triangle and other objects. You must create a triangle using the DrawLines method. You can create a Triangle class inherited from Shape object and have three points as public properties. Internally this class may have a method called Draw and on this method you draw three lines inside the class. So 1. Triangle class 2. Three public Point properties - P1 P2 P3 3. Draw method 4. Surface or Canvas property (handle of control that you want this triangle to be drawn on such as a Form or a Panel) I hope this gives you some starting clues. Good luck!