A J2ME and MIDP 2 question

Question

2 Questions
1. If I have a sprite on a layer but the layer manager is only showing a part of the layer and the sprite is not on that part of the screen are any resources being taken up by the sprite? If so what would be a good way to manage sprites (in this case enemies) that have a predetermined position on the much larger layer that need to be added to the layer when the screen is visible?
2. What is the largest size I can use for a image that I am going to be using as my game area?

Answer 1

1: yes, the sprite is using resources. it uses space from the offscreen buffer.
i suppose that you are a game buff. there are two types of having bbiigg maps. one is zelda type (gbc). and the other is pokemon type(gbc). in zelda type, each screen is one layer, and you move from screen to screen by moving from layer to layer, with a 2d matrix of layers coming together to make a map.
in pokemon type, there is one bbbbbbbbbbiiiiiiiiiigggggggggg layer through which you scroll smoothly. this is tougher. best is to have a condition for each sprite like isVisible. if it is false, suspend all animations for that sprite. if it is on the screen, start it's animation.
You can divide this into smaller layers by using tricks like 'doors' through which you pass through to go to other layers. never have a layer too big because it will kill performance.
for an image the largest size can be indeterminate, as long as you have the space for it on the heap. also only a part of it as large as the screen size can be displayed at once.
hope this helps
Arjun