iOS 使用系统的UITabBarController 修改展示的图片大小

1. 设置TabBarItem图片的大小

 1 - (void)configurationAppTabBarAndNavigationBar
 2 {
 3     // 选中的item普通状态图片的大小
 4     UIImage *normalImage = self.navigationController.tabBarController.tabBar.selectedItem.image;
 5     UIImage *tabNormalImage = [ToolObject createNewImageWithColor:normalImage multiple:1.1];
 6     tabNormalImage = [tabNormalImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
 7     [self.navigationController.tabBarController.tabBar.selectedItem setImage:tabNormalImage];
 8     // 选中的item选中撞他图片的大小
 9     UIImage *selectImage = self.navigationController.tabBarController.tabBar.selectedItem.selectedImage;
10     UIImage *tabSelectImage = [self createNewImageWithColor:selectImage multiple:1.1];
11     tabSelectImage = [tabSelectImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
12     [self.navigationController.tabBarController.tabBar.selectedItem setSelectedImage:tabSelectImage];
13     self.navigationController.tabBarController.tabBar.tintColor = [UIColor colorWithRed:0.11f green:0.61f blue:0.97f alpha:1.00f];
14     self.navigationController.tabBarController.tabBar.barTintColor = [UIColor colorWithRed:0.85f green:0.85f blue:0.85f alpha:1.00f];
15 }

2.图片放大或压缩处理 ，图片放大倍数 0 ~ 2 之间 ，0~1 缩小图片，1~2 放大图片 

 1 /**
 2  *  根据image 返回放大或缩小之后的图片
 3  *
 4  *  @param image    原始图片
 5  *  @param multiple 放大倍数 0 ~ 2 之间
 6  *
 7  *  @return 新的image
 8  */
 9 + (UIImage *) createNewImageWithColor:(UIImage *)image multiple:(CGFloat)multiple
10 {
11     CGFloat newMultiple = multiple;
12     if (multiple == 0) {
13         newMultiple = 1;
14     }
15     else if((fabs(multiple) > 0 && fabs(multiple) < 1) || (fabs(multiple)>1 && fabs(multiple)<2))
16     {
17         newMultiple = multiple;
18     }
19     else
20     {
21         newMultiple = 1;
22     }
23     CGFloat w = image.size.width*newMultiple;
24     CGFloat h = image.size.height*newMultiple;
25     CGFloat scale = [UIScreen mainScreen].scale;
26     UIImage *tempImage = nil;
27     CGRect imageFrame = CGRectMake(0, 0, w, h);
28     UIGraphicsBeginImageContextWithOptions(image.size, NO, scale);
29     [[UIBezierPath bezierPathWithRoundedRect:imageFrame cornerRadius:0] addClip];
30     [image drawInRect:imageFrame];
31     tempImage = UIGraphicsGetImageFromCurrentImageContext();
32     UIGraphicsEndImageContext();
33     return tempImage;
34 }