Rendering Scale Question (RSQ)

Image A

<img src="https://dl.dropbox.com/u/1024727/scirra/1.png" border="0" />

Image B

<img src="https://dl.dropbox.com/u/1024727/scirra/3.png" border="0" />

Image C

<img src="https://dl.dropbox.com/u/1024727/scirra/2.png" border="0" />

1. I'm pretty sure that when scale with "Letterbox scale" it doesn't stretch the image, but instead changes the "resolution" and scales all the assets up? (For instance from image A to B, notice how in image A there is an enemy which is 50% smaller but when the game is scaled up it looks out of place because it is sharper)

2. I've noticed that when changing the scale of the game (or making it fullscreen) the game runs slower for some computers, if the game just stretched the image (like from image A to C, instead of A to B) would it run faster than the current rendering speed? (This would be a great option as it would allow for a more cohesive looking game)

1. That's right, it increases the canvas size and compensates by zooming.

2. Any desktop computer using hardware acceleration should be able to draw at any resolution without any big performance difference. Are you sure these computers are using hardware acceleration? Which browsers did you try and do they have up to date graphics drivers?

Yeah I've noticed on multiple computers that scaling the game larger/smaller increases/decreases performance. With hardware acceleration/WebGL and latest graphic drivers, on my brothers computer he gets 35/37 FPS fullscreen and 60 FPS when it is normal size (latest Firefox/chrome).

What kind of hardware setup is their computer? Is it very old? Also, what does the chrome://gpu page say? (Assuming you're using Chrome - if not, give it a shot and see if it's any faster.)

I could change this, but it could be quite complicated, and even modern phones can handle this kind of drawing so I would prefer to leave it as it is. 30fps+ should also be perfectly playable.