iOS自定义相机截取图片旋转90°的问题

来源：互联网发布：linux enca 编辑：程序博客网时间：2024/05/16 05:42

前段时间做了个小项目，让完全自定义一个相机，并且实现各种功能，好在有官方的API文档和各个资料啊，最后是写出来了，使用的是AVFoundation的框架，但是后来发现拍照的照片是旋转了90°的，另外截屏框里面的截取之后的图片位置也是不对的，研究了大半天，发现系统API的AVCaptureStillImageOutput生成的图片fixOrientation没有设置，所以需要各位手动旋转了！

因为今年一开始就一直在用swift开发项目，所以博主就不贴OC的代码了，写出来的是swift2.3的，假如有使用3.0的请自行更改部分错误提示，话说3.0变动确实挺大的。

下面是封装的方法：

 //MARK: -旋转图片    func fixOrientation(aImage:UIImage)->UIImage {        if (aImage.imageOrientation == UIImageOrientation.Up) {            return aImage        }        var transform:CGAffineTransform = CGAffineTransformIdentity;        switch (aImage.imageOrientation) {        case UIImageOrientation.Down,UIImageOrientation.DownMirrored:            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);            transform = CGAffineTransformRotate(transform, CGFloat(M_PI));            break;        case UIImageOrientation.Left,UIImageOrientation.LeftMirrored:            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);            transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2));            break;        case UIImageOrientation.Right,UIImageOrientation.RightMirrored:            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);            transform = CGAffineTransformRotate(transform, CGFloat(-M_PI_2));            break;        default:            break;        }        switch (aImage.imageOrientation) {        case UIImageOrientation.UpMirrored,UIImageOrientation.DownMirrored:            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);            transform = CGAffineTransformScale(transform, -1, 1);            break;        case UIImageOrientation.LeftMirrored,UIImageOrientation.RightMirrored:            transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);            transform = CGAffineTransformScale(transform, -1, 1);            break;        default:            break;        }                let ctx:CGContextRef = CGBitmapContextCreate(nil, Int(aImage.size.width), Int(aImage.size.height),CGImageGetBitsPerComponent(aImage.CGImage), 0,CGImageGetColorSpace(aImage.CGImage),CGImageGetBitmapInfo(aImage.CGImage).rawValue)!;        CGContextConcatCTM(ctx, transform);        switch (aImage.imageOrientation) {        case UIImageOrientation.Left,UIImageOrientation.LeftMirrored,UIImageOrientation.Right,UIImageOrientation.RightMirrored:            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);            break;        default:            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);            break;        }        let cgimg:CGImageRef = CGBitmapContextCreateImage(ctx)!;        let img:UIImage = UIImage.init(CGImage: cgimg)        return img    }

当你需要一个裁剪框裁剪图片的时候，其实就是你给一个区域然后自己drawImage重新绘制生成一张图片，经测试，我感觉这是实现裁剪的一个比较简单的方法：

//MARK: -裁剪图片    func cutImageFromAlbum(cutImage:UIImage)->UIImage {        let subImageSize:CGSize = CGSizeMake(SCREENWIDTH, SCREENHEIGHT);        //定义裁剪的区域相对于原图片的位置        let subImageRect:CGRect = CGRectMake((SCREENWIDTH/6) * kDeviceScale,(SCREENHEIGHT/6) * kDeviceScale, quJingWidth * kDeviceScale, quJingHeight * kDeviceScale)        let imageRef:CGImageRef = cutImage.CGImage!;        let subImageRef:CGImageRef = CGImageCreateWithImageInRect(imageRef, subImageRect)!        UIGraphicsBeginImageContextWithOptions(subImageSize,false,kDeviceScale);        let context:CGContextRef = UIGraphicsGetCurrentContext()!        CGContextDrawImage(context, subImageRect, subImageRef)        let subImage:UIImage = UIImage.init(CGImage: subImageRef)        UIGraphicsEndImageContext()        //返回裁剪的部分图像        return subImage    }

注意:

kDeviceScale其实就是UIScreen.mainScreen().scale，也就是判断当前屏幕分辨率的，当屏幕分辨率为640x940时UIScreen.mainScreen().scale = 2，当屏幕分辨率为320x480时UIScreen.mainScreen().scale = 1。上面在计算裁剪区域位置的时候，一定要 * kDeviceScale，不然你裁剪的位置根本就不是你想要裁剪的位置，这个坑切记，亲身试验找出的问题，多么痛的领悟啊！

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