我正在iOS 3.1.3 iPhone上测试我的iPhone应用程序。我正在使用UIImagePickerController选择/捕获图像:
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
[imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
[imagePicker setDelegate:self];
[self.navigationController presentModalViewController:imagePicker animated:YES];
[imagePicker release];
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
self.image = [info objectForKey:UIImagePickerControllerOriginalImage];
imageView.image = self.image;
[self.navigationController dismissModalViewControllerAnimated:YES];
submitButton.enabled = YES;
}
然后在某个时候，我使用ASI类将它发送到我的web服务器:
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://example.com/myscript.php"]];
[request setDelegate:self];
[request setStringEncoding:NSUTF8StringEncoding];
[request setShouldContinueWhenAppEntersBackground:YES];
//other post keys/values
[request setFile:UIImageJPEGRepresentation(self.image, 100.0f) withFileName:[NSString stringWithFormat:@"%d.jpg", [[NSDate date] timeIntervalSinceNow]] andContentType:@"image/jpg" forKey:@"imageFile"];
[request startAsynchronous];
存在的问题:
当我拿着iPhone拍照时，照片会被上传到服务器，就像你期望的那样。手持竖屏拍照时，上传的照片是旋转90度后观看的。
我的应用程序被设置为只在纵向模式(倒置和常规)下工作。
我怎样才能使图像始终显示正确的方向后上传?
在UIImageView中显示的图像是正确的(直接在拍照后)，但在服务器上查看则不然。
基于Sourabh Sharma的回答更新了Swift 3.1，并清理了代码。
extension UIImage {
func fixedOrientation() -> UIImage {
if imageOrientation == .up { return self }
var transform:CGAffineTransform = .identity
switch imageOrientation {
case .down, .downMirrored:
transform = transform.translatedBy(x: size.width, y: size.height).rotated(by: .pi)
case .left, .leftMirrored:
transform = transform.translatedBy(x: size.width, y: 0).rotated(by: .pi/2)
case .right, .rightMirrored:
transform = transform.translatedBy(x: 0, y: size.height).rotated(by: -.pi/2)
default: break
}
switch imageOrientation {
case .upMirrored, .downMirrored:
transform = transform.translatedBy(x: size.width, y: 0).scaledBy(x: -1, y: 1)
case .leftMirrored, .rightMirrored:
transform = transform.translatedBy(x: size.height, y: 0).scaledBy(x: -1, y: 1)
default: break
}
let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height),
bitsPerComponent: cgImage!.bitsPerComponent, bytesPerRow: 0,
space: cgImage!.colorSpace!, bitmapInfo: cgImage!.bitmapInfo.rawValue)!
ctx.concatenate(transform)
switch imageOrientation {
case .left, .leftMirrored, .right, .rightMirrored:
ctx.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.height,height: size.width))
default:
ctx.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.width,height: size.height))
}
return UIImage(cgImage: ctx.makeImage()!)
}
}
选取器委托方法示例:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
guard let originalImage = info[UIImagePickerControllerOriginalImage] as? UIImage else { return }
let fixedImage = originalImage.fixedOrientation()
// do your work
}
这是一个不改变原始图像颜色空间的解决方案。如果你想规范化一个灰度图像的方向，你不会幸运地使用所有基于UIGraphicsBeginImageContextWithOptions的解决方案，因为它在RGB颜色空间中创建了一个上下文。相反，你必须创建一个具有与原始图像相同属性的上下文并绘制:
extension UIImage {
static let rotatedOrentations: [UIImage.Orientation] = [.left, .leftMirrored, .right, .rightMirrored]
func normalizedImage() -> UIImage {
if imageOrientation == .up {
return self
}
let image = self.cgImage!
let swapOrientation = UIImage.rotatedOrentations.contains(imageOrientation)
let width = swapOrientation ? image.height : image.width
let height = swapOrientation ? image.width : image.height
let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: image.bitsPerComponent, bytesPerRow: image.bytesPerRow, space: image.colorSpace!, bitmapInfo: image.bitmapInfo.rawValue)!
let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: CGFloat(height));
context.concatenate(flipVertical)
UIGraphicsPushContext(context)
self.draw(at: .zero)
UIGraphicsPopContext()
return UIImage(cgImage: context.makeImage()!)
}
}
