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Editorial Team
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Asked: 2026-05-16T22:14:58+00:00

I’m coding a map app for iPhone , like Google Maps but with my

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I’m coding a map app for iPhone, like Google Maps but with my own maps.

What I have so far is working, but sadly, slower than I would like.

I’m basically drawing the correct map tiles in each drawRect:
[image drawAtPoint:CGPointMake(x, y)];

X and Y are being calculated in each call to drawRect
( these calcs are not very expensive ).

The maximum number of images being drawn at a time is 4.
Each image is 512 x 512.

I feel that some kind of optimization is lacking here.

Can anyone help with something?
Thanks you all.

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1 Answer

  1. Editorial Team

    Why not create UIImageView objects for each tile?

    INstead of drawing each image in drawRect, just move the UIIMageView to the correct position in layoutSubviews

    The UIImageView will handle drawing when it needs to and will cache it’s drawn rect. You’re re-rendering each image every time drawRect is called.

    The trade-off will probably be more memory consumption as you’re making UIImageView objects but you can find a scheme to release ones that aren’t being displayed if you need to.

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