////  ViewController.m//  12-图片的拉伸问题////  Created by xiaomage on 15/12/30.//  Copyright © 2015年 小码哥. All rights reserved.//#import "ViewController.h"#import "UIImage+XMGExtention.h"@interface ViewController ()@property (weak, nonatomic) IBOutlet UIButton *button;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // 1.1 创建UIImage对象    UIImage *image = [UIImage resizableImageWithLocalImageName:@"car"];//扩展了系统类的方法        //UIImage *image = [UIImage imageNamed:@"car"];        // 1.2 拿到image的尺寸    /*    CGFloat imageWidth = image.size.width;    CGFloat imageHeight = image.size.height;    */        // 1.3 返回一张受保护而且拉伸的图片 --->CapInsets:哪些地方要保护:上面保护图片高度一半，左边保护图片宽度一半，右边保护宽度一半减一，下面保护高度一半减一。只有中间1*1的区域拉伸。        // 方式一    /*    UIImage *resizableImage = [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageHeight * 0.5, imageWidth * 0.5, imageHeight * 0.5 -1, imageWidth * 0.5 - 1)];    UIImageResizingModeTile, 平铺    UIImageResizingModeStretch, 拉伸(伸缩)        UIImage *resizableImage = [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageHeight * 0.5, imageWidth * 0.5, imageHeight * 0.5 -1, imageWidth * 0.5 - 1) resizingMode:UIImageResizingModeTile];    */        // 方式二    /*    // 右边需要保护的区域 = 图片的width - leftCapWidth - 1    // bottom cap =  height - topCapHeight - 1    UIImage *resizableImage = [image stretchableImageWithLeftCapWidth:imageWidth * 0.5 topCapHeight:imageHeight * 0.5];    */        //2.把图片设置到按钮上    [self.button setBackgroundImage:image forState:UIControlStateNormal];     }@end

////  UIImage+XMGExtention.h//  12-图片的拉伸问题//#import 
     
      @interface UIImage (XMGExtention)  //分类/** * 返回一张受保护的图片(被拉伸的) */+ (instancetype)resizableImageWithLocalImageName: (NSString *)localImageName;@end
     

////  UIImage+XMGExtention.m//#import "UIImage+XMGExtention.h"@implementation UIImage (XMGExtention)+ (instancetype)resizableImageWithLocalImageName:(NSString *)localImageName{   // 创建图片对象    UIImage *image = [UIImage imageNamed:localImageName];        // 获取图片的尺寸    CGFloat imageWidth = image.size.width;    CGFloat imageHeiht = image.size.height;        // 返回一张拉伸且受保护的图片    return [image stretchableImageWithLeftCapWidth:imageWidth * 0.5 topCapHeight:imageHeiht * 0.5 ];}@end