Rotating an image, windows mobile, vb.net

[yehoshua]

So I have been messing around with windows mobile development (in vb, don't hate me, i have grown accustomed to vb because of work). Anyways I come to a point where i would like to use the graphics object to draw an image and rotate it on occasion based on the state of the program. My instincts told me to use System.Drawing.Drawing2D.Matrix object to create that rotation but as it turns out it appears .net compact framework doesn't support that object.

So my question then is, is there any other method for rotating an image as i draw it. I can program in other languages as well if that is what is required, I was really only using vb because it was easy.

Any ideas?
Thanks

[Rudegar]

don't know about vb but
in c# i would look for an event to subscribe to
which would be fired when the orientation changed
or the resolution changed or some control resized

[yehoshua]

Sorry the question isn't related to orientation or resolution. I know when I want to rotate the image.

I will give more information, the image is a compass and I want to rotate the compass image based on GPS data received (Calculating the angles is not the problem either). Once I know that say I am 10 degrees off of north, i want to rotate the image of the compass so that north is still pointing north.

In my desktop development this would be done in vb or c# using the System.Drawing.Drawing2D.Matrix class, using Matrix.Rotate and them applying that matrix to the graphics object before i draw the image using graphics.drawImage().

Now the problem comes when I move to the mobile platform where System.Drawing.Drawing2D.Matrix does not exist and is appariently unimplemented. So then my question is, are there any other API's on the Windows Mobile Platform that support Rotation of an image by an arbitrary angle, and if not does any one have any good ideas where to start looking for implementing the rotation manually myself.

Thanks in advance

[stephj]

That's one of the annoyances with the .NET compact framework, not all of the PC .NET framework is implemented, and sometimes it's the bit you really want.

Time for a different angle on the problem. Create 36 compass images 10 degrees apart and store them all in an ImageList object. Pull the one you require out of it when the heading changes. Not quite as elegant as the Matrix class, but it may have to do.

The other approach would be to use DirectX drawing. The coding to do it, would probably involve a very steep learning curve, but not having dabbled in this arena yet, I can't offer much help.

[stephj]

The ImageList object in the .NET compact framework does not support ImageList.Draw(), (darn!, see previous post), so you would have to create a PictureBox object or similar and use :-

PictureBox1.Image = ImageList1.Images[i];

Where i is the index of the image you want to use. (0 to 35)

[yehoshua]

Thanks for the suggestions, I did end up predrawing the images of the compass. At the moment I went ahead and made 360 images but I am surely going to cut that down quite a bit. The question then becomes smoothness vs space. But either way you shake it it is working.