SetPixel and GetPixel extensions to WritableBitmap?

[Shadowblitz16]

Are there SetPixel and GetPixel extensions to WritableBitmap?
Specifically ones that use a 1d index and a color struct?
Also preferably with pixelFormat support

[maxkatz6]

No, and not planned for two reasons:

1. It's slow requiring Lock on each method call. Users will misuse this API in for-loops just like they do with System.Drawing.Bitmap SetPixel.
2. Implementation is not so trivial with more complex pixel formats.

[Shadowblitz16]

Also how exactly do I assign a value to a writable bitmap?

public class Palette(uint colorCount, uint swapCount) : WriteableBitmap(new((int)colorCount, (int)swapCount+1), Vector.One, PixelFormat.Rgba8888, Avalonia.Platform.AlphaFormat.Premul)\
{
    private ILockedFramebuffer _locked = Lock();
    
    public void SetPixel(uint index, Color color)
    {
        unsafe
        {
            &((_locked.Address + index+0) % (Size.Width * Size.Height)) = color.R;
            &((_locked.Address + index+1) % (Size.Width * Size.Height)) = color.G;
            &((_locked.Address + index+2) % (Size.Width * Size.Height)) = color.B;
            &((_locked.Address + index+3) % (Size.Width * Size.Height)) = color.A;
        }
    }
    public Color GetPixel(uint index)
    {
        unsafe
        {
            var r = &((_locked.Address + index+0) % (Size.Width * Size.Height));
            var g = &((_locked.Address + index+1) % (Size.Width * Size.Height));
            var b = &((_locked.Address + index+2) % (Size.Width * Size.Height));
            var a = &((_locked.Address + index+3) % (Size.Width * Size.Height));
            return new Color(a, r, g, b);
        }
    }
}

[maxkatz6]

What do you mean "assign a value"?

private ILockedFramebuffer _locked = Lock();

You should NOT keep bitmap locked all the time. It will cause all sorts of problems and it likely won't be usable in the rendering. You need to lock it only when you need to write or read anything.

[Gillibald]

https://github.com/Gillibald/Avalonia/blob/fdffe1b1242798cbac96cfec41794b160c1805fc/src/Avalonia.Visuals/Platform/LockedFramebufferExtensions.cs

[Shadowblitz16]

https://github.com/Gillibald/Avalonia/blob/fdffe1b1242798cbac96cfec41794b160c1805fc/src/Avalonia.Visuals/Platform/LockedFramebufferExtensions.cs

This uses two different formats for getting and setting pixels.

[Shadowblitz16]

What do you mean "assign a value"?

private ILockedFramebuffer _locked = Lock();

You should NOT keep bitmap locked all the time. It will cause all sorts of problems and it likely won't be usable in the rendering. You need to lock it only when you need to write or read anything.

Ok idk then.

[TobisLee]

Hey @Shadowblitz16 . Sorry to bother you after such a long time. I'd like to know how you solved this problem? Did you use the SetPixel in the link?

[Shadowblitz16]

Hey @Shadowblitz16 . Sorry to bother you after such a long time. I'd like to know how you solved this problem? Did you use the SetPixel in the link?

I kinda just gave up

[TobisLee]

LOL. Thanks bro.