Hi everyone,
I'm having an issue rotating a portrait UIImage (i.e. WIDTH < HEIGHT) that somehow has an orientation equal to UIImageOrientationRight. I'm not sure how this comes to be but it happens with a few images in my library captured with an iPhone 4.
This is my code (that does work but only if the orientation is equal to UIImageOrientationUp):
UIGraphicsBeginImageContextWithOptions(rotatedScaledRect.size, NO, 0.0);
CGContextRef myContext = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(myContext, kCGInterpolationHigh);
CGContextTranslateCTM(myContext,
(rotatedScaledRect.size.width/2),
(rotatedScaledRect.size.height/2));
CGContextConcatCTM(myContext, transformation);
CGContextScaleCTM(myContext, 1.0, -1.0);
CGContextDrawImage(myContext, CGRectMake(-roundf(newImage.size.width / 2), -roundf(newImage.size.height / 2), newImage.size.width, newImage.size.height), [newImage CGImage]);
newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I need to apply CGContextConcatCTM because I have several concatenated transformations to the image.
I've tried several different approaches to no avail.
Thanks in advance for your help.
First of all, excuse me for my english, because it's not my native language. I hope it's not so late to give this answer!
I had a similar problem loading photos from library taken with iPhone or iPod cammera because of this. If that's your case, you can found some info here: https://discussions.apple.com/thread/2495567?start=30&tstart=0, specifically from an answer that says "Apple chose to use the Orientation flag in the EXIF data to inform the program displaying the image as to how to rotate it so the image is presented correctly."
So, for load a photo from library taken with iPhone Cammera, you have to do this:
ALAssetRepresentation *assetRep = [photo defaultRepresentation];
CGImageRef imageRef = [assetRep fullResolutionImage];
UIImage *image = [UIImage imageWithCGImage:imageRef scale:[assetRep scale] orientation:[assetRep orientation]];
where photo is an ALAsset object taken from library.
Well, i hope this helps!
Related
I make ios7 apps.
And this app can capture. but it's white noise in addsubview images.
Please help me.
iOS6 and iOS5 is Not has white noise.
This is my code.
CGRect rect = [[UIScreen mainScreen] bounds];
UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextFillRect(ctx, rect);
[self.view.layer renderInContext:ctx];
NSdate pngData = UIImagePNGRepresentation (UIGraphicsGetImageFromCurrentImageContext ());
I use alpha png image in UIimage. And addSubview on view.
white noise imase here
iOS 7 has a different way of making screen shots
UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, self.window.screen.scale);
[self drawViewHierarchyInRect:self.frame afterScreenUpdates:NO];
UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
You are using CGContextFillRect to fill the rectangle with what? You don't seem to have defined the fill color or pattern. Although iOS7 has a new method as described in the previous answer, the previous methods should still work if coded properly.
My guess is that in previous OS, the fill color is defaulting to 0, or you have coded it properly there, and in iOS7, it must be using whatever happens to be in memory or something. Try calling CGContextSetFillColorWithColor before CGContextFillRect.
I current have an app that uses ALAsssetsLibrary to fetch the photos. I have placed the photo to an image view and I am able to upload to the server. When I tested on the real device after taking some photos, I found out the photos that supposed to be taken in Portrait become a landscape.
Therefore, I called different function to get the CGImage like this:
UIImage *image = [UIImage imageWithCGImage:[representation fullResolutionImage] scale:1.0 orientation:(UIImageOrientation)[representation orientation]];
The first tried out, I used this :
UIImage *image = [UIImage imageWithCGImage:[representation fullResolutionImage]]
I thought the one with scale and orientation could give me the right orientation that the photo was taken. But it didn't give me the right solution.
Do I miss anything that is necessary to generate a correct orientation of photo?
The correct orientation handling depends on the iOS version you are using.
On iOS4 and iOS 5 the thumbnail is already correctly rotated, so you can initialize your UIImage without specifying any rotation parameters.
However for the fullScreenImage, the behavior is different for each iOS version. On iOS 5 the image is already rotated on iOS 4 not.
So on iOS4 you should use:
ALAssetRepresentation *defaultRep = [asset defaultRepresentation];
UIImage *_image = [UIImage imageWithCGImage:[defaultRep fullScreenImage]
scale:[defaultRep scale] orientation:(UIImageOrientation)[defaultRep orientation]];
On iOS5 the following code should work correctly:
ALAssetRepresentation *defaultRep = [asset defaultRepresentation];
UIImage *_image = [UIImage imageWithCGImage:[defaultRep fullScreenImage] scale:[defaultRep scale] orientation:0];
Cheers,
Hendrik
Try this code:-
UIImage* img = [UIImage imageWithCGImage:asset.thumbnail];
img = [UIImage imageWithCGImage:img.CGImage scale:1.0 orientation:UIImageOrientationUp];
This may help you.
My experience is limited to IOS 5.x but I can tell you that the thumbnail and fullscreen images are oriented properly. It's the fullresolutionimage that's horizontal when shot vertically. My solution is to use a category on uiimage that I got from here:
http://www.catamount.com/forums/viewtopic.php?f=21&t=967&start=0
It provides a nice rotating method on a UIImage like this:
UIImage *tmp = [UIImage imageWithCGImage:startingFullResolutionImage];
startingFullResolutionImage = [[tmp imageRotatedByDegrees:-90.0f] CGImage];
For fullResolutionImage, I'd like to provide a solution as follows,
ALAssetRepresentation *rep = [asset defaultRepresentation];
// First, write orientation to UIImage, i.e., EXIF message.
UIImage *image = [UIImage imageWithCGImage:[rep fullResolutionImage] scale:rep.scale orientation:(UIImageOrientation)rep.orientation];
// Second, fix orientation, and drop out EXIF
if (image.imageOrientation != UIImageOrientationUp) {
UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
[image drawInRect:(CGRect){0, 0, image.size}];
UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
image = normalizedImage;
}
// Third, compression
NSData *imageData = UIImageJPEGRepresentation(image, 1.0);
imageData is what you want, and just upload it to your photo server.
By the way, if you think EXIF is useful, you can complement it to normalizedImage as you wish.
I built an app for 4.x which should be deployed for all iPhones 3.0-4.x. I realized that the imageWithCGImage:scale:orientation method is only available in 4.0 and later. Any alternative for 3.x? For reference:
Creates and returns an image object with the specified scale and orientation factors.
+ (UIImage *)imageWithCGImage:(CGImageRef)imageRef scale:(CGFloat)scale orientation:(UIImageOrientation)orientation
My current usage:
UIImage *inputImage = [UIImage imageWithCGImage:[[UIImage imageNamed: #"arrow.png"] CGImage] scale:1.2 orientation:UIImageOrientationUp];
The scale is static (i.e. I never change it) so I might scale the image through photoshop instead but the orientation remains a necessity in my application.
Thanks!
You can do the scale, rotate (translate) with CGContext functions. Then you can use...
CGImageRef CGBitmapContextCreateImage (
CGContextRef c
);
and
+ (UIImage *)imageWithCGImage:(CGImageRef)cgImage
i want to take screenshots in landscape mode.
currently my below code takes screenshots in PORTRAIT mode.
also i want to store the images into the given location not in photo library..
how can i attain this...
thanks for any help
below is my code
UIGraphicsBeginImageContext(self.view.bounds.size) ;
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, self, nil, nil);
As far as I know there is no way to take screenshots in landscape mode. Images taken with the iPhone contain an information called imageOrientation which is then used to rotate an UIImageView displaying that image.
But you should be able to take an image in portrait mode and rotate it by 90 degree before saving it. I can't try it right now but the following should work:
Create a method for rotation and pass the UIImage as an argument.
CGSize size = sizeOfImage;
UIGraphicsBeginImageContext(size);
CGContextRotateCTM(ctx, angleInRadians); // (M_PI/2) or (3M_PI/2) depending on left/right rotation
CGContextDrawImage(UIGraphicsGetCurrentContext(),
CGRectMake(0,0,size.width, size.height),
image);
UIImage *copy = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return copy;
To store into a given location you can use NSData as I have answered on your other question ( Saving images to a given location )
I'm having problems with drawing rotated images on PDF, my output is worse.
My case is, we don't know have any fixed co-ordinates. X,Y, rotation, etc. depends on ImageView itself. I select the ImageView and rotate it through Sliders.
Check on ZOSH application. I need to implement functionalities like that app. I want to make PDF by adding images one by one.
Please send me link for any example that can help me out, I'm stuck here. I'm drawing the image on PDF based on center of the imageview.
Please help me, Thank You.
Was having the same problem,after a fair amount of time i was able to find a solution....might be helpful to you
-(UIImage*)RotateImage:(UIImage*)Image :(float)Angle
{
CGFloat angleInRadians =-1*Angle* (M_PI / 180.0);
CGAffineTransform transform=CGAffineTransformIdentity;
transform = CGAffineTransformMakeRotation(angleInRadians);
//transform = CGAffineTransformMakeScale(1, -1);
//transform =CGAffineTransformMakeTranslation(0,80);
CGRect rotatedRect = CGRectApplyAffineTransform(CGRectMake(0,0,Image.size.width,Image.size.height), transform);
UIGraphicsBeginImageContext(rotatedRect.size);
//[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), 0,rotatedRect.size.height);
CGContextScaleCTM(UIGraphicsGetCurrentContext(),1, -1);
//CGContextTranslateCTM(UIGraphicsGetCurrentContext(), +(rotatedRect.size.width/2),+(rotatedRect.size.height/2));
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), (rotatedRect.origin.x)*-1,(rotatedRect.origin.y)*-1);
CGContextRotateCTM(UIGraphicsGetCurrentContext(), angleInRadians);
//CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -(rotatedRect.size.width/2),-(rotatedRect.size.height/2));
CGImageRef temp = [Image CGImage];
CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, Image.size.width,Image.size.height), temp);
//CGContextRotateCTM(UIGraphicsGetCurrentContext(), -angleInRadians);
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//[viewImage autorelease];
return viewImage;
}
for Zooming issues....i suggest you try to make a subclass for the application window
I found this web page that shows how to subclass the application window so as to observe taps and forward those taps to the view controller.
http://mithin.in/2009/08/26/detecting-taps-and-events-on-uiwebview-the-right-way/
Hope that helps you...
The answer is in Apple's documentation. Listings 13-3 and 13-4 seems like what you are after.