最近开发一个app,需要大量用到这方面的知识,于是写了这一个文档,希望能帮上一些需要查阅的小伙伴,基本上都是代码片段,没有什么概念知识。
截取图片的一部分
-(UIImage *)getPartOfImage:(UIImage *)img rect:(CGRect)partRect { CGImageRef imageRef = img.CGImage; CGImageRef imagePartRef = CGImageCreateWithImageInRect(imageRef, partRect); UIImage *retImg = [UIImage imageWithCGImage:imagePartRef]; CGImageRelease(imagePartRef); return retImg; }
ios屏幕截图
普通截图不能截取通过openGl渲染的视频,所以截取视频是不能使用下面的方法的,需要小伙伴自己去寻找其他openGL的截图方法了
UIGraphicsBeginImageContextWithOptions(_videoRect.size, YES, 0); //设置截屏大小 [[_moviePlayerController.view layer] renderInContext:UIGraphicsGetCurrentContext()]; UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRef imageRef = viewImage.CGImage; // CGRect rect = CGRectMake(166, 211, 426, 320);//这里可以设置想要截图的区域 CGRect rect = _videoRect;//这里可以设置想要截图的区域 CGImageRef imageRefRect =CGImageCreateWithImageInRect(imageRef, rect); UIImage *sendImage = [[UIImage alloc] initWithCGImage:imageRefRect]; UIImageWriteToSavedPhotosAlbum(sendImage, nil, nil, nil);//保存图片到照片库 NSData *imageViewData = UIImagePNGRepresentation(sendImage); NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *pictureName= [NSString stringWithFormat:@"screenShow_%d.png",2]; NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:pictureName]; NSLog(@"截屏路径打印: %@", savedImagePath); [imageViewData writeToFile:savedImagePath atomically:YES];//保存照片到沙盒目录 CGImageRelease(imageRefRect);
视频截图一
ASSet中有两个方法可以截图,下面的方法就是其中一个,相比于(视频截图二)那个方法,这一个要快得多
但是我不能把控他得很多细节,所以推荐使用(视频截图三)
NSURL *url = [[NSURL alloc] initWithString:[NSString stringWithFormat:@"%@",urlstring]];//initFileURLWithPath:videoURL] autorelease]; AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:url options:nil]; AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset]; generator.appliesPreferredTrackTransform = NO; generator.maximumSize = _videoRect.size; NSError *error = nil; for (float i = 0; i < second ; i += 0.1) { //不会CMTime就去了解一下 CGImageRef img = [generator copyCGImageAtTime:CMTimeMake(i, 10) actualTime:NULL error:&error]; UIImage *image = [UIImage imageWithCGImage: img]; [imageArray addObject:image]; } NSLog(@"iamgeArray = %@",imageArray); return imageArray;
视频截图二
iOS 9.0之后就不使用下面的方法了,如果大量截图的话建议不要使用这种方法,很慢,但是有点就是MPMovie中的时间就是我们平时的时间 1 秒对应视频中得 第1秒、两秒对应视频中得第2秒 ...,而且几句代码就搞定了
NSMutableArray *imageArray = [NSMutableArray array]; MPMoviePlayerViewController * mpviemController =[[MPMoviePlayerViewController alloc] initWithContentURL:urlstring]; MPMoviePlayerController *mp=[mpviemController moviePlayer]; for (float i = 0; i < second; i += 0.1) { UIImage *thumbImage=[mp thumbnailImageAtTime:i timeOption:MPMovieTimeOptionExact]; //MPMovieTimeOptionExact截取每一帧的图片,MPMovieTimeOptionNearestKeyFrame关键帧 NSData *imagedata =UIImagePNGRepresentation(thumbImage); UIImage *image = [UIImage imageWithData:imagedata]; [imageArray addObject:image]; } return imageArray;
视频截图三
这是最快捷视频切图片的方法,Asset中的最快的方法,使用块来进行截图,速度就比其他快上贼多
//pragma mark --- 视频截取 -(void)cutVideoGetImageArrayWithURl:(NSURL *)urlstring Second:(float)second{ _imageArray = [NSMutableArray array]; AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:urlstring options:nil];// //获取视频时长,单位:秒 AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset]; generator.appliesPreferredTrackTransform = YES; generator.maximumSize = _videoRect.size; //下面两句是截取每一帧的关键 generator.requestedTimeToleranceBefore = kCMTimeZero; generator.requestedTimeToleranceAfter = kCMTimeZero; NSMutableArray *timeArray = [NSMutableArray array]; for (int i = 1; i < second * 10 + 1 ; i++) { [timeArray addObject:[NSValue valueWithCMTime:CMTimeMake(i * 6, 60)]]; } //开始截图 [generator generateCGImagesAsynchronouslyForTimes:timeArray completionHandler:^(CMTime requestedTime, CGImageRef _Nullable image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError * _Nullable error) { UIImage *imageSen = [UIImage imageWithCGImage:image]; [_imageArray addObject:imageSen]; }]; }
以上。