项目中出现一个问题，苹果原相机拍的照片个别会出现图片被逆旋转90度，也就是说明明是竖着的照片，上传服务器后，就变成横着的了。
经过一系列排查发现，被逆旋转的照片是在选中照片后就被旋转了，在回调里有一个UIImageOrientation图片属性
[[PHImageManagerdefaultManager]requestImageDataForAsset:self.assetoptions:optionsresultHandler:^(NSData*_Nullable imageData,NSString* _Nullable dataUTI, UIImageOrientation orientation, NSDictionary*_Nullable info)
UIImageOrientation属性
在实际开发中，如果图片是正常的，UIImageOrientation 属性返回0，也就是UIImageOrientationUp；那同理，如果图片被逆旋转90度，UIImageOrientation 属性返回3即UIImageOrientationLeft。
知道了原因就有解决的方向了，写一个UIImage的工具类，将被旋转的图片再旋转回来就好了。
//防止图片被旋转90度
- (UIImage*)fixOrientation:(UIImage*)aImage {
if (aImage.imageOrientation == UIImageOrientationUp)
returnaImage;
CGAffineTransform transform = CGAffineTransformIdentity;
switch(aImage.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform =CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
transform =CGAffineTransformRotate(transform,M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform =CGAffineTransformTranslate(transform, aImage.size.width,0);
transform =CGAffineTransformRotate(transform,M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform =CGAffineTransformTranslate(transform,0, aImage.size.height);
transform =CGAffineTransformRotate(transform, -M_PI_2);
break;
default:
break;
}
switch(aImage.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform =CGAffineTransformTranslate(transform, aImage.size.width,0);
transform =CGAffineTransformScale(transform, -1,1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform =CGAffineTransformTranslate(transform, aImage.size.height,0);
transform =CGAffineTransformScale(transform, -1,1);
break;
default:
break;
}
CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
CGImageGetBitsPerComponent(aImage.CGImage),0,
CGImageGetColorSpace(aImage.CGImage),
CGImageGetBitmapInfo(aImage.CGImage));
CGContextConcatCTM(ctx, transform);
switch(aImage.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
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;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage*img = [UIImageimageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
returnimg;
}
以上即可解决。