联系人:石虎QQ: 1224614774 昵称:嗡嘛呢叭咪哄
//GCD 图片合成效果:
#import"SHViewController.h"
@interfaceViewController()
@property(weak,nonatomic)IBOutletUIImageView*imageView;//视图 imageView
@property(nonatomic,strong)UIImage*image1;
@property(nonatomic,strong)UIImage*image2;
@end
@implementationSHViewController
- (void)viewDidLoad {
[superviewDidLoad];
[selfsyntheticImages];//合成图片
}
-(void)syntheticImages//合成图片
{
//创建队列组
dispatch_group_tgroup =dispatch_group_create();
//1.开子线程下载图片
//创建队列(并发)
dispatch_queue_tqueue =dispatch_get_global_queue(0,0);
//异步执行并发队列
dispatch_group_async(group, queue, ^{
//1.获取url地址
NSURL*url = [NSURLURLWithString:@"https://imgsa.baidu.com/baike/c0=baike180,5,5,180,60/sign=b531c24482025aafc73f76999a84c001/b21c8701a18b87d6435d2f9b070828381f30fd13.jpg"];
//2.下载图片
NSData*data = [NSDatadataWithContentsOfURL:url];
//3.把二进制数据转换成图片
self.image1= [UIImageimageWithData:data];
});
//下载图片2
dispatch_group_async(group, queue, ^{
//1.获取url地址
NSURL*url = [NSURLURLWithString:@"https://imgsa.baidu.com/baike/c0=baike220,5,5,220,73/sign=62c273b38a13632701e0ca61f0e6cb89/8644ebf81a4c510faae40d756059252dd42aa5b9.jpg"];
//2.下载图片
NSData*data = [NSDatadataWithContentsOfURL:url];
//3.把二进制数据转换成图片
self.image2= [UIImageimageWithData:data];
});
//合成
dispatch_group_notify(group, queue, ^{
//开启图形上下文
UIGraphicsBeginImageContext(CGSizeMake(200,200));
//画1
[self.image1drawInRect:CGRectMake(0,0,200,100)];
//画2[self.image2drawInRect:CGRectMake(0,100,200,100)];
//根据图形上下文拿到图片
UIImage*image =UIGraphicsGetImageFromCurrentImageContext();
//关闭上下文
UIGraphicsEndImageContext();
dispatch_async(dispatch_get_main_queue(), ^{
self.imageView.image= image;});});
}
@end
