iOS 视频图片添加文字水印

最近项目中遇到在拍视频和图片(类似微信发朋友圈那种)之后添加水印的需求，此处记录相关代码

//self.fileNameString    //类似这种20190522175147-部门-姓名-地址,需求是把地址作为水印内容

#define degreesToRadians( degrees ) ( ( degrees ) / 180.0 * M_PI )
#define textLabelHeight 300
#define textLabelFontSize 40

- (void)addWaterTextWithVideoPath:(NSString*)path complete:(void (^)(NSString *compressStr))complete{
    //1 创建AVAsset实例
    AVURLAsset*videoAsset = [AVURLAsset assetWithURL:[NSURL fileURLWithPath:path]];
    
    AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];
    
    //3 视频通道
    AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
                                                                        preferredTrackID:kCMPersistentTrackID_Invalid];
    [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                        ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject]
                         atTime:kCMTimeZero error:nil];
    
    //2 音频通道
    AVMutableCompositionTrack *audioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio
                                                                        preferredTrackID:kCMPersistentTrackID_Invalid];
    [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                        ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeAudio] firstObject]
                         atTime:kCMTimeZero error:nil];
    
    //3.1 AVMutableVideoCompositionInstruction 视频轨道中的一个视频，可以缩放、旋转等
    AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration);
    
    // 3.2 AVMutableVideoCompositionLayerInstruction 一个视频轨道，包含了这个轨道上的所有视频素材
    AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
    
    [videolayerInstruction setOpacity:0.0 atTime:videoAsset.duration];
    //AVMutableVideoComposition：管理所有视频轨道，水印添加就在这上面
    AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
    
    //视频旋转处理
    CGAffineTransform t1 = CGAffineTransformMakeTranslation(videoTrack.naturalSize.height, 0.0);
    // Rotate transformation
    CGAffineTransform  t2 = CGAffineTransformRotate(t1, degreesToRadians(90.0));
    [videolayerInstruction setTransform:t2 atTime:kCMTimeZero];
    
    // 3.3 - Add instructions
    mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];
    
    
    AVAssetTrack *videoAssetTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject];
//    CGSize naturalSize = videoAssetTrack.naturalSize;
    CGSize naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
    
    float renderWidth, renderHeight;
    renderWidth = naturalSize.width;
    renderHeight = naturalSize.height;
    mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);
    mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
    mainCompositionInst.frameDuration = CMTimeMake(1, 30);
    [self applyVideoEffectsToComposition:mainCompositionInst size:naturalSize];
    
    //    // 4 - 输出路径
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:
                             [NSString stringWithFormat:@"%@.mp4",self.fileNameString]];
    //判断文件是否存在，如果已经存在删除
    [[NSFileManager defaultManager] removeItemAtPath:myPathDocs error:nil];
    NSURL* videoUrl = [NSURL fileURLWithPath:myPathDocs];
    
    // 5 - 视频文件输出
    AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition
                                                                      presetName:AVAssetExportPresetHighestQuality];
    exporter.outputURL = videoUrl;
    exporter.outputFileType = AVFileTypeMPEG4;
    exporter.shouldOptimizeForNetworkUse = YES;
    exporter.videoComposition = mainCompositionInst;
    [exporter exportAsynchronouslyWithCompletionHandler:^{
        dispatch_async(dispatch_get_main_queue(), ^{
            if( exporter.status == AVAssetExportSessionStatusCompleted ){
                NSLog(@"导出完成");
                NSURL *compressURL = exporter.outputURL;
                NSLog(@"导出完毕,导出后大小 %f MB",[self ytfileSize:compressURL]);
                NSString *compressUrlStr = compressURL.absoluteString;
                if ([compressUrlStr containsString:@"file://"]) {
                    compressUrlStr = [compressUrlStr substringFromIndex:7];
                }
                complete(compressUrlStr);
            }else if( exporter.status == AVAssetExportSessionStatusFailed ){
                NSLog(@"导出failed");
                complete(nil);
            }
        });
    }];
}

- (void)applyVideoEffectsToComposition:(AVMutableVideoComposition *)composition size:(CGSize)size
{
    // 文字
    CATextLayer *subtitle1Text = [[CATextLayer alloc] init];
//    [subtitle1Text setFont:@"Helvetica-Bold"];
    [subtitle1Text setFontSize:textLabelFontSize];
    subtitle1Text.wrapped = YES;//自动换行
    [subtitle1Text setFrame:CGRectMake(10, size.height-10-textLabelHeight, size.width-20, textLabelHeight)];
    [subtitle1Text setString:[self cutAddressFromFileName]];
//    [subtitle1Text setAlignmentMode:kCAAlignmentCenter];
    [subtitle1Text setForegroundColor:[[UIColor whiteColor] CGColor]];
    
    //图片
//    CALayer*picLayer = [CALayer layer];
//    picLayer.contents = (id)[UIImage imageNamed:@"videoWater2"].CGImage;
//    picLayer.frame = CGRectMake(size.width-15-87, 15, 87, 26);
    
    // 2 - The usual overlay
    CALayer *overlayLayer = [CALayer layer];
//    [overlayLayer addSublayer:picLayer];
    [overlayLayer addSublayer:subtitle1Text];
    overlayLayer.frame = CGRectMake(0, 0, size.width, size.height);
    [overlayLayer setMasksToBounds:YES];
    
    CALayer *parentLayer = [CALayer layer];
    CALayer *videoLayer = [CALayer layer];
    parentLayer.frame = CGRectMake(0, 0, size.width, size.height);
    videoLayer.frame = CGRectMake(0, 0, size.width, size.height);
    [parentLayer addSublayer:videoLayer];
    [parentLayer addSublayer:overlayLayer];
    
    composition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
}

-(NSString *)cutAddressFromFileName{
    NSString *addressStr = @"test";
    if ([self.fileNameString containsString:@"-"]) {
        NSArray *infoArr = [self.fileNameString componentsSeparatedByString:@"-"];
        addressStr = (NSString *)infoArr.lastObject;
    }
    return addressStr;
}

//计算文件大小
-(CGFloat)ytfileSize:(NSURL *)path{
    return [[NSData dataWithContentsOfURL:path] length]/1024.00 /1024.00;
}

//给图片添加文字水印
-(UIImage *)imageWithimage:(UIImage *)image content:(NSString *)content frame:(CGRect)frame {
    // 开启图形'上下文'
    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);
    // 绘制原生图片
    [image drawAtPoint:CGPointZero];
    // 在原生图上绘制文字
    NSString *str = content;
    // 创建文字属性字典
    NSDictionary *dictionary = @{NSForegroundColorAttributeName: [UIColor whiteColor], NSFontAttributeName: [UIFont systemFontOfSize:textLabelFontSize]};
    // 绘制文字属性
    [str drawInRect:frame withAttributes:dictionary];
    // 从当前上下文获取修改后的图片
    UIImage *imageNew = UIGraphicsGetImageFromCurrentImageContext();
    // 结束图形上下文
    UIGraphicsEndImageContext();
    return imageNew;
}

后续有时间再记录微信发朋友圈拍摄页面代码

补充：2020.7.3
最近同事出现一个问题，文字水印有的时候不显示，后来还是他自己找到了解决方法：
在CATextLayer属性设置都OK后调用display方法

[subtitle1Text display];

测试有效，感谢我牛逼的同事