我在这里遇到一个非常奇怪的问题.当我以纵向模式单击图像并上传它然后再次获取它时,显示逆时针旋转90度.但是当我在相机胶卷中看到它时,它会以正确的方向显示.我已经尝试了几乎所有可能的链接/代码来解决这个问题,但似乎没有任何帮助.我以JPEG格式保存图像.请帮助这个人.
提前致谢！！
提前致谢！！
解决方法
解决方法是在UI
Image上创建一个类别,并根据其元数据EXIF缩放和旋转图像.
这是一段神奇的代码：
- (UIImage *)scaleAndRotateImage:(UIImage *)image {
int kMaxResolution = 640; // Or whatever
CGImageRef imgRef = image.CGImage;
CGFloat width = CGImageGetWidth(imgRef);
CGFloat height = CGImageGetHeight(imgRef);
CGAffineTransform transform = CGAffineTransformIdentity;
CGRect bounds = CGRectMake(0,width,height);
if (width > kMaxResolution || height > kMaxResolution) {
CGFloat ratio = width/height;
if (ratio > 1) {
bounds.size.width = kMaxResolution;
bounds.size.height = roundf(bounds.size.width / ratio);
}
else {
bounds.size.height = kMaxResolution;
bounds.size.width = roundf(bounds.size.height * ratio);
}
}
CGFloat scaleRatio = bounds.size.width / width;
CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef),CGImageGetHeight(imgRef));
CGFloat boundHeight;
UIImageOrientation orient = image.imageOrientation;
switch(orient) {
case UIImageOrientationUp: //EXIF = 1
transform = CGAffineTransformIdentity;
break;
case UIImageOrientationUpMirrored: //EXIF = 2
transform = CGAffineTransformMakeTranslation(imageSize.width,0.0);
transform = CGAffineTransformScale(transform,-1.0,1.0);
break;
case UIImageOrientationDown: //EXIF = 3
transform = CGAffineTransformMakeTranslation(imageSize.width,imageSize.height);
transform = CGAffineTransformRotate(transform,M_PI);
break;
case UIImageOrientationDownMirrored: //EXIF = 4
transform = CGAffineTransformMakeTranslation(0.0,imageSize.height);
transform = CGAffineTransformScale(transform,1.0,-1.0);
break;
case UIImageOrientationLeftMirrored: //EXIF = 5
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(imageSize.height,imageSize.width);
transform = CGAffineTransformScale(transform,1.0);
transform = CGAffineTransformRotate(transform,3.0 * M_PI / 2.0);
break;
case UIImageOrientationLeft: //EXIF = 6
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(0.0,imageSize.width);
transform = CGAffineTransformRotate(transform,3.0 * M_PI / 2.0);
break;
case UIImageOrientationRightMirrored: //EXIF = 7
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeScale(-1.0,M_PI / 2.0);
break;
case UIImageOrientationRight: //EXIF = 8
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(imageSize.height,0.0);
transform = CGAffineTransformRotate(transform,M_PI / 2.0);
break;
default:
[NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];
}
UIGraphicsBeginImageContext(bounds.size);
CGContextRef context = UIGraphicsGetCurrentContext();
if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
CGContextScaleCTM(context,-scaleRatio,scaleRatio);
CGContextTranslateCTM(context,-height,0);
}
else {
CGContextScaleCTM(context,scaleRatio,-scaleRatio);
CGContextTranslateCTM(context,-height);
}
CGContextConcatCTM(context,transform);
CGContextDrawImage(UIGraphicsGetCurrentContext(),CGRectMake(0,height),imgRef);
UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return imageCopy;
}
