一 . 视频封面中间原图,背景模糊效果实现方法( 用到的方法在文章最后)
- (void)portraitBtnClick:(id)sender {
// 0.获取竖屏视频
NSString *vedioPath = [[NSBundle mainBundle] pathForResource:@"portrait" ofType:@"mp4"];
NSURL *url = [NSURL fileURLWithPath:vedioPath];
dispatch_async(dispatch_get_global_queue(0, 0), ^{
// 1.获取视频第一帧图片
UIImage *cover = [self getVideoPreViewImage:url];
//2.按照比例截取封面图片
//获取coverImg（视频封面的UI控件）的宽高比例用于截取图片（竖屏这里截取的图片保持宽不变，以图片中心为基准，按照coverImg的比例裁剪的高，得到图片）
CGFloat scale = self.coverImg.frame.size.width/self.coverImg.frame.size.height;
//获取第一帧图片的大小（可以根据这个判断出来是横屏视频还是竖屏视频）
CGSize size = cover.size;
CGFloat clipH = size.width/scale;
//获取按比例裁剪后的图片
UIImage *clipImage = [self getImageByCuttingImage:cover Rect:CGRectMake(0, size.height/2-clipH/2, size.width,clipH)];
//3.获取模糊图片
UIImage *dimImg = [self coreBlurImage:clipImage withBlurNumber:30.0f];
//获取模糊图大小
UIImage *bottom = dimImg;
CGImageRef imgRef1 = bottom.CGImage;
CGFloat w1 = CGImageGetWidth(imgRef1);
CGFloat h1 = CGImageGetHeight(imgRef1);
//4. 获取放在封面中间的清晰图片
UIImage *clearImg = [self thumbnailWithImageWithoutScale:cover size:CGSizeMake((size.height/h1)*w1, h1)];
//获取清晰图片大小
CGImageRef imgRef = clearImg.CGImage;
CGFloat w = CGImageGetWidth(imgRef);
CGFloat h = CGImageGetHeight(imgRef);
//5.合成图片以模糊图片大小为画布创建上下文（以模糊图片为底图将清晰图放到模糊图中心）
UIGraphicsBeginImageContext(CGSizeMake(w1, h1));
[bottom drawInRect:CGRectMake(0, 0, w1, h1)];
//把清晰图画到上下文中
[clearImg drawInRect:CGRectMake(w1/2 - w/2, 0, w, h)];
//6.获取合成图片
UIImage *resultImg = UIGraphicsGetImageFromCurrentImageContext();//从当前上下文中获得最终图片
//关闭上下文
UIGraphicsEndImageContext();
dispatch_async(dispatch_get_main_queue(), ^{
// 7. 改变UI
self.coverImg.image = resultImg;
});
});
}
二. 横屏视频封面处理(用到的方法在文章最后)
- (void)landscapeBtnClick:(id)sender {
NSString *path = [[NSBundle mainBundle] pathForResource:@"landscape" ofType:@"mp4"];
NSURL *url = [NSURL fileURLWithPath:path];
dispatch_async(dispatch_get_global_queue(0, 0), ^{
// 1.获取视频第一帧图片
UIImage *cover = [self getVideoPreViewImage:url];
//2.按照比例截取封面图片
//获取coverImg（视频封面的UI控件）的宽高比例用于截取图片（横屏这里截取的图片保持高不变，以图片中心为基准，按照coverImg的比例裁剪的宽，得到图片）
CGFloat scale = self.coverImg.frame.size.width/self.coverImg.frame.size.height;
CGSize size = cover.size;
CGFloat clipW = size.height*scale;
UIImage *resultImg = [self getImageByCuttingImage:cover Rect:CGRectMake(size.width/2 - clipW/2 , 0, clipW, size.height)];
dispatch_async(dispatch_get_main_queue(), ^{
//3.修改UI
self.coverImg.image = resultImg;
});
});
}
三. 共用代码部分
//截取视频第一针
-(UIImage*)getVideoPreViewImage:(NSURL *)path
{
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:path options:nil];
AVAssetImageGenerator *assetGen = [[AVAssetImageGenerator alloc] initWithAsset:asset];
assetGen.appliesPreferredTrackTransform = YES;
CMTime time = CMTimeMakeWithSeconds(0.0, 600);
NSError *error = nil;
CMTime actualTime;
CGImageRef image = [assetGen copyCGImageAtTime:time actualTime:&actualTime error:&error];
UIImage *videoImage = [[UIImage alloc] initWithCGImage:image];
CGImageRelease(image);
return videoImage;
}
///裁剪正方形展示
-(UIImage *)getImageByCuttingImage:(UIImage *)image Rect:(CGRect)rect{
//大图bigImage
//定义myImageRect，截图的区域
CGRect myImageRect = rect;
UIImage* bigImage= image;
CGImageRef imageRef = bigImage.CGImage;
CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);
CGSize size;
size.width = rect.size.width;
size.height = rect.size.height;
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, myImageRect, subImageRef);
UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
return smallImage;
}
//保持原来的长宽比，生成一个缩略图
-(UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize
{
UIImage *newimage;
if (nil == image) {
newimage = nil;
}
else{
CGSize oldsize = image.size;
CGRect rect;
if (asize.width/asize.height > oldsize.width/oldsize.height) {
rect.size.width = asize.height*oldsize.width/oldsize.height;
rect.size.height = asize.height;
rect.origin.x = (asize.width - rect.size.width)/2;
rect.origin.y = 0;
}
else{
rect.size.width = asize.width;
rect.size.height = asize.width*oldsize.height/oldsize.width;
rect.origin.x = 0;
rect.origin.y = (asize.height - rect.size.height)/2;
}
UIGraphicsBeginImageContext(asize);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
UIRectFill(CGRectMake(0, 0, asize.width, asize.height));//clear background
[image drawInRect:rect];
newimage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
return newimage;
}
//返回模糊图效果
- (UIImage *)coreBlurImage:(UIImage *)image withBlurNumber:(CGFloat)blur{
CIContext *context = [CIContext contextWithOptions:nil];
CIImage *inputImage = [CIImage imageWithCGImage:image.CGImage];
//设置filter
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
[filter setValue:inputImage forKey:kCIInputImageKey];
[filter setValue:@(blur) forKey:@"inputRadius"];
//模糊图片
CIImage *result = [filter valueForKey:kCIOutputImageKey];
//CGImageRef outImage = [context createCGImage:result fromRect:[result extent]];
CIImage *im = [CIImage imageWithCGImage:image.CGImage];
CGImageRef outImage = [context createCGImage: result fromRect:[im extent]];
UIImage *blurImage = [UIImage imageWithCGImage:outImage];
CGImageRelease(outImage);
return blurImage;
}
四 . 项目下载地址：https://github.com/Bobo168/vedioCover
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