UIImage resizableImageWithCapInsets example ios

resizableImageWithCapInsets:

Creates and returns a new image object with the specified cap insets.

- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets

Parameters

capInsets

The values to use for the cap insets.

Return Value

A new image object with the specified cap insets.

Discussion of [UIImage resizableImageWithCapInsets]

You use this method to add cap insets to an image or to change the existing cap insets of an image. In both cases, you get back a new image and the original image remains untouched.

During scaling or resizing of the image, areas covered by a cap are not scaled or resized. Instead, the pixel area not covered by the cap in each direction is tiled, left-to-right and top-to-bottom, to resize the image. This technique is often used to create variable-width buttons, which retain the same rounded corners but whose center region grows or shrinks as needed. For best performance, use a tiled area that is a 1x1 pixel area in size.

Example of [UIImage resizableImageWithCapInsets]

-(UIImage *) resizableImageWithCapInsets2: (UIEdgeInsets) inset
    {
        if ([self respondsToSelector:@selector(resizableImageWithCapInsets:resizingMode:)])
        {
            return [self resizableImageWithCapInsets:inset resizingMode:UIImageResizingModeStretch];
        }
        else
        {
            float left = (self.size.width-2)/2;//The middle points rarely vary anyway
            float top = (self.size.height-2)/2;
            return [self stretchableImageWithLeftCapWidth:left topCapHeight:top];
        }
    }