Correctly implement the blocks in the drawing view

问题

How to correctly implement the blocks in the drawing view, so that when they could cut the line in two parts. Using UIImageView or UIImage?

After the cut blocks should fall under the influence of physics.

回答1:

First, how many cuts could happen in total? How many independent pieces of block could result? 10? 100? Before implementing any of these, test moving that number of objects around on an iPhone or iPod touch. Just because it works on the simulator does not mean it will be fast enough on the actual device.

Second, as already noted, there are libraries for game graphics and physics that may do a lot of the work for you. Cocos2D appears to be a popular option, combining OpenGL drawing with relatively easy access to physics libraries.

Anyway, to do your own drawing, here are the choices:

1. Move all the graphics into OpenGL. This should not be undertaken lightly - you lose a lot of the ease of working in Cocoa Touch. You also have maximum control over your graphics and animation, and can achieve the smoothest performance if you take the time to optimise it.

2. Have a single UIView, adding CALayer sublayers to its main layer for every independent block. CALayers are designed for rapid moving and compositing. However, if you're running a physics simulation, your first step will be to remove their animation behavior. This tutorial series may be useful.

3. Have a separate UIView for each block. This will have similar performance to using CALayers, as UIViews are actually drawn with CALayer. This option will use up more memory, (you have at least as many layers and more views than before), but you have all of the power of CALayers plus a few drawing options that are easier on views.

4. Have a single UIView, and draw every block during its drawRect method. This may look easy to implement, but it will almost certainly be too slow.

If at all possible, test each of these. Before you continue with the cutting and physics parts, how many blocks can you animate across the screen before it slows down too far? Can you make a game with that Remember that your physics system will slow the game down when it does work.

来源：https://stackoverflow.com/questions/10137289/correctly-implement-the-blocks-in-the-drawing-view