Still confused about iPhone 4 new resolution

Question

I've been reading as much as I can about the new iPhone 4 high resolution (640x960), but am still confused.

Is it basically just a bigger screen like the iPad? If so, does it automatically translate touches, ie touch in the middle of the screen becomes (320, 480), or do I have to check the device and translate the touches myself?

Or, is it essentially size 320x480, but images can be twice as big and look better?

Sorry, I'm just really confused by what the new high resolution means for us :(

Answer 1

Rather than using a pixel coordinate system, iOS now uses a point (pt) coordinate system. This means that when developing for the iPhone, you are still developing on a screen that is 320 pts by 480 pts. Right now, that just means that on the iPhone 4, 1 pt is equal to 2 px. However, Apple has made it clear that they are reserving the ability to change the pt to px conversion ratio on future devices.

Unless you are doing complex drawing, the only thing you will need to worry about is providing higher resolution versions of your images. Essentially, by doubling the resolution of your images, your application will look extremely crisp and sharp on the iPhone 4.

Answer 2

The iPhone 4 has the same/similar physical display size, but a much higher resolution. This means that you get much higher quality image and video viewing on the same size screen. The hardware/HAL should automatically translate the touches.