Question

I have this code, which should repeat the same UIImage:

UIView *paperMiddle = [[UIView alloc] initWithFrame:CGRectMake(0, 34, 320, rect.size.height - 34)];
UIImage *paperPattern = paperBackgroundPattern(context);
paperMiddle.backgroundColor = [UIColor colorWithPatternImage:paperPattern];
[self addSubview:paperMiddle];

And this is the paperBackgroundPattern method:

UIImage *paperBackgroundPattern(CGContextRef context) {
    CGRect paper3 = CGRectMake(10, -15, 300, 16);
    CGRect paper2 = CGRectMake(13, -15, 294, 16);
    CGRect paper1 = CGRectMake(16, -15, 288, 16);

    //Shadow
    CGContextSetShadowWithColor(context, CGSizeMake(0,0), 10, [[UIColor colorWithWhite:0 alpha:0.5]CGColor]);
    CGPathRef path = createRoundedRectForRect(paper3, 0);
    CGContextSetFillColorWithColor(context, [[UIColor blackColor] CGColor]);
    CGContextAddPath(context, path);
    CGContextFillPath(context);

    //Layers of paper
    CGContextSaveGState(context);
    drawPaper(context, paper3);
    drawPaper(context, paper2);
    drawPaper(context, paper1);

    CGContextRestoreGState(context);
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(320, 1), NO, 0);
    UIImage *paperImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return paperImage;
}

It isn’t repeating the image. A result of having the image there though is that it shows as the top pixel of the screen (which isn’t the frame i’ve given it).

Any ideas why?

Answer 1

I don’t know what the context is that you’re passing in, but whatever it is, you shouldn’t be drawing into it. And you aren’t drawing anything into the context that you made with UIGraphicsBeginImageContextWithOptions.

If you want to generate an image, you don’t need to pass in a context, just use the one that UIGraphicsBeginImageContextWithOptions makes for you.

UIImage *paperBackgroundPattern() {
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(320, 1), NO, 0);
    CGContextRef context = UIGraphicsGetCurrentContext();

    // draw into context, then...

    UIImage *paperImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return paperImage;
}

Also — are you really trying to make an image that’s 320 pt wide and 1 high? It seems odd that you are drawing such elaborate stuff into such a tiny image.