Graphics and Unmanaged buffer

TinyCLR OS
1

In examples of user interface, we can see these lines:

        var ptr = Memory.UnmanagedMemory.Allocate(640 * 480 * 2);
        var data = Memory.UnmanagedMemory.ToBytes(ptr, 640 * 480 * 2);

I suppose it is to use unmanaged memory to display application, but how application can know data is buffer to display ? It isn’t used after. Is Something missing in example ?

2

Unmanaged Memroy serves 2 things:

  1. For graphics: It is automatic. There is nothing for you to do!
  2. For your application if you need very large buffers and that is what you show in your example.
3

So in code (in user-interface.md):

        var screen = Graphics.FromHdc(display.Hdc);
        var controller = I2cController.GetDefault();
        var ptr = Memory.UnmanagedMemory.Allocate(640 * 480 * 2);
        var data = Memory.UnmanagedMemory.ToBytes(ptr, 640 * 480 * 2);

ptr and data are unused ? (As screen Which use graphics use already unmanaged)
As data is never used again.

4

We were probably testing it but those lines should not be there! We will fix the docs.

1 Like
5

you dont need those lines.

2 Likes
6

I understand better ! :wink: