Android: Canvas.DrawBitmap VS Drawable.Draw - Huge performance boost

Question

I just found out something and I was wondering about how and why. I'm developing a small arcade game for Android. I decided to ignore OpenGL and use the standard SurfaceView and Drawables to do it, since it's suppose to be light (10 sprites or so). I have drawables that I load, and I use the method Draw and passing them my canvas. This how every sprite is drawn to the screen. Well it turns out that drawing 4-5 big sprites (200X400 or so) takes a long time on less-than-brand-new phone models. Long enough to make my game unplayable. We're talking about 50-60 milliseconds to draw a single frame using this method. And I really don't do anything there apart from drawing, nowhere I can cut costs. So I decided to try and use Bitmaps instead. Here, however, I need to pre-set the size, since there's no 'setBounds' method in a bitmap. No prob, I resize them to fit my current screen on load, problem solved.

OK. So I got bitmaps. I use Canvas.DrawBitmap now to draw. I bench the new draw method.. and I get a whooping 400% performance boost! Instead of 50-60ms, the entire draw loop now takes 8-12ms. What the hell?? To rule it out, I timed the setBounds too, it takes <1ms so it's not to blame. It's the actual Drawable.Draw that slows things down.

For me this is great news, since I really didn't want to learn OpenGL to make my game playable, but I can't stop wondering about it - Is it fine? are there problems with my method? Why isn't it mentioned anywhere?

Answer 1

The SurfaceView of your Canvas is meant to be used when you should iterate constantly and Drawable is not for that purpose.