add image support

[richardanaya]

Adding basic image support.

I'm feeling like Frame should be called Surface.

[nbrr]

I'm feeling like Frame should be called Surface.

How about Canvas?

I think we'd want to advance on #9 before we start drawing actual stuff.

[richardanaya]

Canvas sounds good to m, one thing I observed is that pixel drawing is slow. I'm wondering how we'll be able to address that in layers.

[nbrr]

Canvas sounds good to m, one thing I observed is that pixel drawing is slow. I'm wondering how we'll be able to address that in layers.

How slow? At what point did it become slow? I am working on layers and the drag example and it is indeed very slow, it wasn't the case before.

[richardanaya]

I was actually referring to drawing canvases on canvas in particular with draw_canvas

at one point I was just for looping over each pixel and copying the pixel from the image to the canvas' pixels and it was slow

I switched over to using copy_from_slice to copy pixels and it became an order of magnitude faster.

hmm, i'm not exactly how drag could have changed .. i'll check it the example on my phone!

[nbrr]

It didn't affect drag, my attempt at layers did, so I wanted to know whether we might have ran into the same issue. And we did, I run into troubles when I try to for loop on the pixels to clear the screen. I'm not sure how to get rid of the issue though.