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。
我把这个换成了Xamarin:
private static UIImage FixImageOrientation(UIImage image)
{
if (image.Orientation == UIImageOrientation.Up)
{
return image;
}
var transform = CGAffineTransform.MakeIdentity();
float pi = (float)Math.PI;
switch (image.Orientation)
{
case UIImageOrientation.Down:
case UIImageOrientation.DownMirrored:
transform = CGAffineTransform.Translate(transform, image.Size.Width, image.Size.Height);
transform = CGAffineTransform.Rotate(transform, pi);
break;
case UIImageOrientation.Left:
case UIImageOrientation.LeftMirrored:
transform = CGAffineTransform.Translate(transform, image.Size.Width, 0);
transform = CGAffineTransform.Rotate(transform, pi / 2);
break;
case UIImageOrientation.Right:
case UIImageOrientation.RightMirrored:
transform = CGAffineTransform.Translate(transform, 0, image.Size.Height);
transform = CGAffineTransform.Rotate(transform, -(pi / 2));
break;
}
switch (image.Orientation)
{
case UIImageOrientation.UpMirrored:
case UIImageOrientation.DownMirrored:
transform = CGAffineTransform.Translate(transform, image.Size.Width, 0);
transform = CGAffineTransform.Scale(transform, -1, 1);
break;
case UIImageOrientation.LeftMirrored:
case UIImageOrientation.RightMirrored:
transform = CGAffineTransform.Translate(transform, image.Size.Height, 0);
transform = CGAffineTransform.Scale(transform, -1, 1);
break;
}
var ctx = new CGBitmapContext(null, (nint)image.Size.Width, (nint)image.Size.Height, image.CGImage.BitsPerComponent,
image.CGImage.BytesPerRow, image.CGImage.ColorSpace, image.CGImage.BitmapInfo);
ctx.ConcatCTM(transform);
switch (image.Orientation)
{
case UIImageOrientation.Left:
case UIImageOrientation.LeftMirrored:
case UIImageOrientation.Right:
case UIImageOrientation.RightMirrored:
ctx.DrawImage(new CGRect(0, 0, image.Size.Height, image.Size.Width), image.CGImage);
break;
default:
ctx.DrawImage(new CGRect(0, 0, image.Size.Width, image.Size.Height), image.CGImage);
break;
}
var cgimg = ctx.ToImage();
var img = new UIImage(cgimg);
ctx.Dispose();
ctx = null;
cgimg.Dispose();
cgimg = null;
return img;
}
一个UIImage有一个imageOrientation属性，它指示UIImageView和其他UIImage消费者旋转原始图像数据。在上传的jpeg图像中，这个标志很有可能被保存到exif数据中，但是用于查看它的程序没有执行该标志。
为了在上传时旋转UIImage以正确显示，你可以使用这样的类别:
UIImage+fixOrientation.h
@interface UIImage (fixOrientation)
- (UIImage *)fixOrientation;
@end
UIImage+fixOrientation.m
@implementation UIImage (fixOrientation)
- (UIImage *)fixOrientation {
// No-op if the orientation is already correct
if (self.imageOrientation == UIImageOrientationUp) return self;
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
CGAffineTransform transform = CGAffineTransformIdentity;
switch (self.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, self.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, self.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationUp:
case UIImageOrientationUpMirrored:
break;
}
switch (self.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, self.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, self.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationUp:
case UIImageOrientationDown:
case UIImageOrientationLeft:
case UIImageOrientationRight:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
CGImageGetBitsPerComponent(self.CGImage), 0,
CGImageGetColorSpace(self.CGImage),
CGImageGetBitmapInfo(self.CGImage));
CGContextConcatCTM(ctx, transform);
switch (self.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
break;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage *img = [UIImage imageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
return img;
}
@end
迅捷;)
更新swift 3.0: d
func sFunc_imageFixOrientation(img:UIImage) -> UIImage {
// No-op if the orientation is already correct
if (img.imageOrientation == UIImageOrientation.up) {
return img;
}
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
var transform:CGAffineTransform = CGAffineTransform.identity
if (img.imageOrientation == UIImageOrientation.down
|| img.imageOrientation == UIImageOrientation.downMirrored) {
transform = transform.translatedBy(x: img.size.width, y: img.size.height)
transform = transform.rotated(by: CGFloat(M_PI))
}
if (img.imageOrientation == UIImageOrientation.left
|| img.imageOrientation == UIImageOrientation.leftMirrored) {
transform = transform.translatedBy(x: img.size.width, y: 0)
transform = transform.rotated(by: CGFloat(M_PI_2))
}
if (img.imageOrientation == UIImageOrientation.right
|| img.imageOrientation == UIImageOrientation.rightMirrored) {
transform = transform.translatedBy(x: 0, y: img.size.height);
transform = transform.rotated(by: CGFloat(-M_PI_2));
}
if (img.imageOrientation == UIImageOrientation.upMirrored
|| img.imageOrientation == UIImageOrientation.downMirrored) {
transform = transform.translatedBy(x: img.size.width, y: 0)
transform = transform.scaledBy(x: -1, y: 1)
}
if (img.imageOrientation == UIImageOrientation.leftMirrored
|| img.imageOrientation == UIImageOrientation.rightMirrored) {
transform = transform.translatedBy(x: img.size.height, y: 0);
transform = transform.scaledBy(x: -1, y: 1);
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
let ctx:CGContext = CGContext(data: nil, width: Int(img.size.width), height: Int(img.size.height),
bitsPerComponent: img.cgImage!.bitsPerComponent, bytesPerRow: 0,
space: img.cgImage!.colorSpace!,
bitmapInfo: img.cgImage!.bitmapInfo.rawValue)!
ctx.concatenate(transform)
if (img.imageOrientation == UIImageOrientation.left
|| img.imageOrientation == UIImageOrientation.leftMirrored
|| img.imageOrientation == UIImageOrientation.right
|| img.imageOrientation == UIImageOrientation.rightMirrored
) {
ctx.draw(img.cgImage!, in: CGRect(x:0,y:0,width:img.size.height,height:img.size.width))
} else {
ctx.draw(img.cgImage!, in: CGRect(x:0,y:0,width:img.size.width,height:img.size.height))
}
// And now we just create a new UIImage from the drawing context
let cgimg:CGImage = ctx.makeImage()!
let imgEnd:UIImage = UIImage(cgImage: cgimg)
return imgEnd
}
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()!)
}
}
Swift 3版本基于@jake1981，他从@MetalHeart2003中获得了它
extension UIImage {
func fixOrientation() -> UIImage {
// No-op if the orientation is already correct
if ( self.imageOrientation == UIImageOrientation.up ) {
return self;
}
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
var transform: CGAffineTransform = CGAffineTransform.identity
if ( self.imageOrientation == UIImageOrientation.down || self.imageOrientation == UIImageOrientation.downMirrored ) {
transform = transform.translatedBy(x: self.size.width, y: self.size.height)
transform = transform.rotated(by: CGFloat(M_PI))
}
if ( self.imageOrientation == UIImageOrientation.left || self.imageOrientation == UIImageOrientation.leftMirrored ) {
transform = transform.translatedBy(x: self.size.width, y: 0)
transform = transform.rotated(by: CGFloat(M_PI_2))
}
if ( self.imageOrientation == UIImageOrientation.right || self.imageOrientation == UIImageOrientation.rightMirrored ) {
transform = transform.translatedBy(x: 0, y: self.size.height);
transform = transform.rotated(by: CGFloat(-M_PI_2));
}
if ( self.imageOrientation == UIImageOrientation.upMirrored || self.imageOrientation == UIImageOrientation.downMirrored ) {
transform = transform.translatedBy(x: self.size.width, y: 0)
transform = transform.scaledBy(x: -1, y: 1)
}
if ( self.imageOrientation == UIImageOrientation.leftMirrored || self.imageOrientation == UIImageOrientation.rightMirrored ) {
transform = transform.translatedBy(x: self.size.height, y: 0);
transform = transform.scaledBy(x: -1, y: 1);
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
let ctx: CGContext = CGContext(data: nil, width: Int(self.size.width), height: Int(self.size.height),
bitsPerComponent: self.cgImage!.bitsPerComponent, bytesPerRow: 0,
space: self.cgImage!.colorSpace!,
bitmapInfo: self.cgImage!.bitmapInfo.rawValue)!
ctx.concatenate(transform)
if ( self.imageOrientation == UIImageOrientation.left ||
self.imageOrientation == UIImageOrientation.leftMirrored ||
self.imageOrientation == UIImageOrientation.right ||
self.imageOrientation == UIImageOrientation.rightMirrored ) {
ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: self.size.height, height: self.size.width))
} else {
ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
}
// And now we just create a new UIImage from the drawing context and return it
return UIImage(cgImage: ctx.makeImage()!)
}
}
