Stretch background image for UIButton

Question

I got texture, which really shorter, than my UIButton.

I got this texture:

Answer 1

From the example images you provided I'm pretty sure you're looking for UIImage's resizableImageWithCapInsets:

UIImage *originalImage = [UIImage imageNamed:@"myImage.png"];
UIEdgeInsets insets = UIEdgeInsetsMake(top, left, bottom, right);
UIImage *stretchableImage = [originalImage resizableImageWithCapInsets:insets];
[myButton setBackgroundImage:stretchableImage forState:UIControlStateNormal];
// the image will be stretched to fill the button, if you resize it.

The values in the UIEdgeInsets struct determine the margins you don't want to be stretched. Your left and right values could be about this wide:

The top and bottom values can be either 0 (if you don't want to resize the button vertically), or probably half of the total height.

Answer 2

By not tiling, I assume you can thus not use

- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets

The way to do what you want is to use:

UIGraphicsBeginImageContextWithOptions(newSize, NO, 0); // should be proportionally larger
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, (CGRect){{0,0}, newSize}, [yourImage CGImage]);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;

Answer 3

Use stretchableImageWithLeftCapWidth:topCapHeight: method.

Refer: https://github.com/boctor/idev-recipes/tree/master/StretchableImages

Answer 4

With Xcode 6 (and iOS7+ target) you can use slicing editor when working with images assets. Toggle slicing mode with Editor -> Show Slicing menu or press Show Slicing button when select specific image with editor (showed below).

Then you can select image for specific display scale and drag rules or edit insets values manually.

After that you can select this image in Interface Builder for UIButton Background Image (IB button's representation could look bad, but it should be OK when running).

My buttons look well (running iOS 7.1 simulator and iOS 8 device).

This Apple doc link could be helpful.

Answer 5

Or using Stretchable Images:

UIImage* imgbkg =[[UIImage imageNamed: @"my_bkg_image.png"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];

[_button setBackgroundImage: imgbkg forState: UIControlStateNormal];

Use 0 if you don't want to stretch certain side.