使用 resizableImageWithCapInsets 方法实现可伸缩图片

之前介绍过通过 stretchableImageWithLeftCapWidth:topCapHeight: 方法来实现可伸缩图片；

可看这篇随笔：使用 stretchableImageWithLeftCapWidth 方法实现可伸缩图片

iOS5 中提供了一个新的 UIImage 对象实例方法：resizableImageWithCapInsets:，可以将图片转换为以某一偏移值为偏移的可伸缩图片（偏移值内的图片内容将不被拉伸或压缩）。

stretchableImageWithLeftCapWidth:topCapHeight: 模式（此方法已经过期，推荐用下面的resizableImageWithCapInsets: 方法）；

resizableImageWithCapInsets: 模式还能实现类似图片渐变的效果，更灵活控制。

效果如下：

ViewController.h

 #import <UIKit/UIKit.h>

 @interface ViewController : UIViewController
 @end

ViewController.m

 #import "ViewController.h"

 @interface ViewController ()
 - (void)layoutUI;
 @end

 @implementation ViewController
 #define kWidthOfButton 160.0
 #define kHeightOfButton 49.0

 - (void)viewDidLoad {
     [super viewDidLoad];

     [self layoutUI];
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 - (void)layoutUI {
     //普通模式
     UIImage *img = [UIImage imageNamed:@"blueButton"]; //size: 39*39
     UIButton *btnNormal = [[UIButton alloc] initWithFrame:CGRectMake(20.0, 40.0, kWidthOfButton, kHeightOfButton)];
     [btnNormal setTitle:@"btnNormal" forState:UIControlStateNormal];
     [btnNormal setBackgroundImage:img forState:UIControlStateNormal];
     [self.view addSubview:btnNormal];

     //stretchableImageWithLeftCapWidth:topCapHeight:模式（此方法已经过期，推荐用下面的resizableImageWithCapInsets:方法）
     UIImage *imgStretchable = [img stretchableImageWithLeftCapWidth:16.0 topCapHeight:16.0];
     UIButton *btnStretchable = [[UIButton alloc] initWithFrame:CGRectMake(20.0, 50.0+kHeightOfButton, kWidthOfButton, kHeightOfButton)];
     [btnStretchable setTitle:@"btnStretchable" forState:UIControlStateNormal];
     [btnStretchable setBackgroundImage:imgStretchable forState:UIControlStateNormal];
     [self.view addSubview:btnStretchable];

     //resizableImageWithCapInsets:模式；相比stretchableImageWithLeftCapWidth:topCapHeight:模式来说，resizableImageWithCapInsets:模式还能实现类似图片渐变的效果，更灵活控制
     UIImage *imgResizable = [img resizableImageWithCapInsets:UIEdgeInsetsMake(30.0, 16.0, 9.0, 16.0)];
     UIButton *btnResizable = [[UIButton alloc] initWithFrame:CGRectMake(20.0, 60.0+(kHeightOfButton*), kWidthOfButton, kHeightOfButton)];
     [btnResizable setTitle:@"btnResizable" forState:UIControlStateNormal];
     [btnResizable setBackgroundImage:imgResizable forState:UIControlStateNormal];
     [self.view addSubview:btnResizable];
 }

 @end