IOS第17天(2,Quartz2D图片剪裁变圆行图，和截屏图片）

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#import "HMViewController.h"

#import "UIImage+Tool.h"

@interface HMViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation HMViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

//    _imageView.image = [UIImage imageWithName:@"阿狸头像" border:10 borderColor:[UIColor redColor]];

    [self clipCircle];

}

- (void)clipCircle
{
    // 圆环的宽度
    CGFloat borderW = ;

    // 加载旧的图片
    UIImage *oldImage =  [UIImage imageNamed:@"阿狸头像"];

    // 新的图片尺寸
    CGFloat imageW = oldImage.size.width +  * borderW;
    CGFloat imageH = oldImage.size.height +  * borderW;

    // 设置新的图片尺寸
    CGFloat circirW = imageW > imageH ? imageH : imageW;

    // 开启上下文
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(circirW, circirW), NO, 0.0);

    // 画大圆
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(, , circirW, circirW)];

    // 获取当前上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();

    // 添加到上下文
    CGContextAddPath(ctx, path.CGPath);

    [[UIColor whiteColor] set];      //边框颜色

    // 渲染
    CGContextFillPath(ctx);

    CGRect clipR = CGRectMake(borderW, borderW, oldImage.size.width, oldImage.size.height);

    // 画圆：正切于旧图片的圆
    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:clipR];

    // 设置裁剪区域
    [clipPath addClip];

    // 画图片
    [oldImage drawAtPoint:CGPointMake(borderW, borderW)];

    // 获取新的图片
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // 关闭上下文
    UIGraphicsEndImageContext();

    _imageView.image = newImage;
}

- (void)clip
{
    // 1.加载旧的图片
    UIImage *oldImage = [UIImage imageNamed:@"阿狸头像"];

    // 2.开启上下文
    UIGraphicsBeginImageContextWithOptions(oldImage.size, NO, 0.0);

    // 3.画圆：正切于上下文
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(, , oldImage.size.width, oldImage.size.height)];

    // 4.设为裁剪区域
    [path addClip];

    // 5.画图片
    [oldImage drawAtPoint:CGPointZero];

    // 6.生成一个新的图片
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // 7.关闭上下文
    UIGraphicsEndImageContext();
}
@end

*********************工具类

#import "UIImage+Tool.h"

@implementation UIImage (Tool)

+ (instancetype)imageWithCaptureView:(UIView *)view
{
    // 开启上下文
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, 0.0);

    // 获取上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();

    // 渲染控制器view的图层到上下文
    // 图层只能用渲染不能用draw
    [view.layer renderInContext:ctx];

    // 获取截屏图片
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // 关闭上下文
    UIGraphicsEndImageContext();

    return newImage;
}

+ (instancetype)imageWithName:(NSString *)name border:(CGFloat)border borderColor:(UIColor *)color
{
    // 圆环的宽度
    CGFloat borderW = border;

    // 加载旧的图片
    UIImage *oldImage =  [UIImage imageNamed:name];

    // 新的图片尺寸
    CGFloat imageW = oldImage.size.width +  * borderW;
    CGFloat imageH = oldImage.size.height +  * borderW;

    // 设置新的图片尺寸
    CGFloat circirW = imageW > imageH ? imageH : imageW;

    // 开启上下文
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(circirW, circirW), NO, 0.0);

    // 画大圆
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(, , circirW, circirW)];

    // 获取当前上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();

    // 添加到上下文
    CGContextAddPath(ctx, path.CGPath);

    // 设置颜色
    [color set];

    // 渲染
    CGContextFillPath(ctx);

    CGRect clipR = CGRectMake(borderW, borderW, oldImage.size.width, oldImage.size.height);

    // 画圆：正切于旧图片的圆
    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:clipR];

    // 设置裁剪区域
    [clipPath addClip];

    // 画图片
    [oldImage drawAtPoint:CGPointMake(borderW, borderW)];

    // 获取新的图片
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // 关闭上下文
    UIGraphicsEndImageContext();

    return newImage;
}

@end