How can I make my pattern view extend without stretching? - iphone

Question

EDIT - I've worked out what I was originally doing wrong. I was changing the size of the UIScrollView, instead of the pattern subview. I have fixed that, but amended my question with the new problem this has thrown up.
I am making a notes section in my app with a lined-paper effect. The lines are on a separate UIScrollView which responds to scrollViewDidScroll: so the lines and text always move together. My lines are set up like this in viewWillAppear:
CGRect noteLinesRect = CGRectMake(self.view.bounds.origin.x,
self.view.bounds.origin.y,
self.view.bounds.size.width,
noteTextView.contentSize.height+self.view.bounds.size.height);
UIScrollView *anoteXLinesView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
self.noteXLinesView = anoteXLinesView;
[anoteXLinesView release];
LinePatternView *linesPattern = [[LinePatternView alloc] initWithFrame:noteLinesRect];
self.linesPatternView = linesPattern; [linesPattern release];
[self.noteXLinesView addSubview:self.linesPatternView];
[linesPattern release];
CGPoint newOffset = CGPointMake(self.noteTextView.contentOffset.x, noteTextView.contentOffset.y - NOTE_LINES_OFFSET);
self.noteXLinesView.contentOffset = newOffset;
[self.view insertSubview:self.noteXLinesView atIndex:0];
This works fine when the user first looks at a stored note - all the text is nicely underlined. But when they write more text, eventually they get to the bottom of the lines I created in viewWillAppear and are writing on 'blank paper'. So I need my lined-paper pattern to dynamically get bigger and smaller so it is always a bit bigger than the contentSize of my textView. I am trying to do that like this:
-(void)textViewDidChange:(UITextView *)textView
{
self.linesPatternView.frame = CGRectMake( self.linesPatternView.frame.origin.x, //-self.noteTextView.contentOffset.y+NOTE_LINES_OFFSET,
self.linesPatternView.frame.origin.y,
self.linesPatternView.frame.size.width,
noteTextView.contentSize.height+self.view.bounds.size.height );
}
The problem is, although the lined-paper pattern does increase in size, it doesn't add new lines at the bottom. Instead, the pattern stretches out and gets bigger as the view gets bigger. What am I doing wrong?

Answer 1

One of the solutions is to make 3 views, each containing the lines of the size of your scrollview frame on screen. You position the three one underneath the other in the scrollview and monitor the scrollview through its delegate.
When scrolling down you check:
As soon as the topmost one goes offscreen for more than Y pixels you remove it from the scrollview and insert it underneath the bottom one.
When scrolling up you check:
As soon as the bottommost one goes offscreen for more than Y pixels you remove it from the scrollview and insert it above the top one.

Answer 2

Is there a reason you’re not simply using a tiled pattern as your background view’s backgroundColor? UIColor’s +colorWithPatternImage: will let you set a background that’ll tile indefinitely and won’t stretch as your view resizes. If part of the background has to be different—like the top of your paper, for instance—you can just place an image view containing that at the top of your background view.

Answer 3

Fixed! In addition to the changes outlined in my edit to the question above, I just needed to call [self.linesPatternView setNeedsDisplay]; after the resize.