ios4 - I need to scroll a background image larger than the screen size and make it loop endlessly -

i writing ipad app have locked orientation landscape mode for. want have png file 100 pixels high 4 times width of ipad screen.

what want background image shown on screen automatically begin scrolling on timer. have made sure start , end parts of image match up. once end of image reached, start bit show again. image should scroll along either @ 1 pixel movements or larger jumps if slow.

i stuck looking example code show how show this.

it not game writing not want use opengl or fancy.

the examples have looked @ far not after.

can simplify , state stuck on..

lets load image memory 1000 pixels wide 100 in height.

can show me few lines of code let me cut out rectangle begins 200 pixels across x axis larger image , rectangle 100 100 pixels.

how cut rectangle out , show on screen - speed not important stated before.

i can work out scrolling part myself (i hope) , post here later..

i thinking along lines of cgcontext type commands despite looking @ examples , @ docs still against brick wall. 'cutting rectangular section out' stumbling at.

thanks.

any appreciated.

disclosure - i'm not iphone dev @ all.

but, break image chunks. (maybe 8) so, end having 8 chunks each 100px tall, , 1/2 width of screen.

then, image scrolls, can load each image before turn displayed. so, images flow off screen, can replace them next image displayed on other side of screen.