iOS拍照后图片自动旋转90度的完美解决方法
今天开发一个拍照获取照片的功能的时候,发现上传之后图片会自动旋转90.
测试发现,只要是图片大于2M,系统就会自动翻转照片
相机拍照后直接取出来的UIimage（用UIImagePickerControllerOriginalImage取出），它本身的imageOrientation属性是3，即UIImageOrientationRight。如果这个图片直接使用则没事，但是如果对它进行裁剪、缩放等操作后，它的这个imageOrientation属性会变成0。此时这张图片用在别的地方就会发生旋转。imageOrientation是只读的，不能直接修改其值。
解决方法如下:
1.设置相机的一个属性allowsEditing为YES，设了这个值，你拍完照片后会在照片上出现一个框框，这就是对照片的裁剪编辑。在相机的代理方法中取照片的时候就别用UIImagePickerControllerOriginalImage来取了，要用UIImagePickerControllerEditedImage。用这个key取出来的照片，它的imageOrientation是0，所以之后的任何裁剪、缩放操作都不会造成旋转。这是第一种方法。
2.第一种解决方法基本没用,开发中基本都会对图片进行裁剪和压缩.这里有一个专门针对这个事的很好的category
+(UIImage*)fixOrientation:(UIImage*)aImage{
//No-opiftheorientationisalreadycorrect
if(aImage.imageOrientation==UIImageOrientationUp)
returnaImage;
//Weneedtocalculatethepropertransformationtomaketheimageupright.
//Wedoitin2steps:RotateifLeft/Right/Down,andthenflipifMirrored.
CGAffineTransformtransform=CGAffineTransformIdentity;
switch(aImage.imageOrientation){
caseUIImageOrientationDown:
caseUIImageOrientationDownMirrored:
transform=CGAffineTransformTranslate(transform,aImage.size.width,aImage.size.height);
transform=CGAffineTransformRotate(transform,M_PI);
break;
caseUIImageOrientationLeft:
caseUIImageOrientationLeftMirrored:
transform=CGAffineTransformTranslate(transform,aImage.size.width,0);
transform=CGAffineTransformRotate(transform,M_PI_2);
break;
caseUIImageOrientationRight:
caseUIImageOrientationRightMirrored:
transform=CGAffineTransformTranslate(transform,0,aImage.size.height);
transform=CGAffineTransformRotate(transform,-M_PI_2);
break;
default:
break;
}
switch(aImage.imageOrientation){
caseUIImageOrientationUpMirrored:
caseUIImageOrientationDownMirrored:
transform=CGAffineTransformTranslate(transform,aImage.size.width,0);
transform=CGAffineTransformScale(transform,-1,1);
break;
caseUIImageOrientationLeftMirrored:
caseUIImageOrientationRightMirrored:
transform=CGAffineTransformTranslate(transform,aImage.size.height,0);
transform=CGAffineTransformScale(transform,-1,1);
break;
default:
break;
}
//NowwedrawtheunderlyingCGImageintoanewcontext,applyingthetransform
//calculatedabove.
CGContextRefctx=CGBitmapContextCreate(NULL,aImage.size.width,aImage.size.height,
CGImageGetBitsPerComponent(aImage.CGImage),0,
CGImageGetColorSpace(aImage.CGImage),
CGImageGetBitmapInfo(aImage.CGImage));
CGContextConcatCTM(ctx,transform);
switch(aImage.imageOrientation){
caseUIImageOrientationLeft:
caseUIImageOrientationLeftMirrored:
caseUIImageOrientationRight:
caseUIImageOrientationRightMirrored:
//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;
}
//AndnowwejustcreateanewUIImagefromthedrawingcontext
CGImageRefcgimg=CGBitmapContextCreateImage(ctx);
UIImage*img=[UIImageimageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
returnimg;
}
以上所述是小编给大家介绍的iOS拍照后图片自动旋转90度的完美解决方法，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对毛票票网站的支持！