I'm trying to show an image taken through the camera in Portrait mode but I always get it shown on my UIImageView in Landascape mode. The image is scaled before being added to the UIImageView but it seems this is not the problem as I tried many different solutions found on the web (even some quite smart ones like the one coming from Trevor's Bike Shed).
Here is my code:
UIImage *image = [UIImage imageWithContentsOfFile:imgPath];
CGRect newFrame = [scrollView frame];
UIImage *resizedImage = [ImageViewController imageFromImage:image scaledToSize:newFrame.size];
imageView = [[UIImageView alloc] initWithFrame:newFrame];
[imageView setImage:resizedImage];
[scrollView setContentSize:imageView.frame.size];
[scrollView addSubview:imageView];
[imageView release];
imgPath is the path of the image coming as a parameter and scrollView is an IBOutlet linked to a UIScrollView.
Is there something I'm missing about the UIImageView?
As I wrote above, it seems that the problem is not related to the scaling...
Are you certain that imageOrientation is set as you expect on resizedImage? Incorrect scaling can absolutely mess up imageOrientation.
There is an imageOrientation property for a UIImage. Check out the docs. It can be set through the initializer:
UIImage *rotatedImage = [UIImage imageWithCGImage:[resizedImage CGImage] scale:1 orientation:UIImageOrientationUp]
Creates and returns an image object with the specified scale and
orientation factors.
+ (UIImage *)imageWithCGImage:(CGImageRef)imageRef scale:(CGFloat)scale orientation:(UIImageOrientation)orientation
Parameters:
imageRef The Quartz image object.
scale The scale factor to use when interpreting the image data.
Specifying a scale factor of 1.0 results in an image whose size
matches the pixel-based dimensions of the image. Applying a different
scale factor changes the size of the image as reported by the size
(page 12) property.
orientation The orientation of the image data. You can use this
parameter to specify any rotation factors applied to the image.
Return Value A new image object for the specified Quartz image, or
nil if the method could not initialize the image from the specified
image reference.
UIImage* image=[UIImage imageNamed:#"abc.jpg"];
UIImageOrientation orientation=image.imageOrientation;
Use image in imageView or where ever you want to use,
UIImageView* imageView=[[UIImageView alloc] initWithImage:image];
After that reset the image to orientation it was before usage
UIImage* image1=[UIImage imageWithCGImage:[image CGImage] scale:1.0 orientation:orientation];
image1 is your image in the orientation it was before
Related
I am using a UITableViewCellStyleSubTitle. I am trying to add thumbnails to my table cells.
UIViewContentModeScaleAspectFit does not seem to work for reasons unknown. I have seen a lot of answers in stack overflow for similar kind of questions. If i crop the image using drawInRect it works, like this
[thumbnail drawInRect:thumbnailRect];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
But what i am trying to achieve should not need me to do this. I am only trying to scale the image and not crop it.
So setting the content mode to "UIViewContentModeScaleAspectFit" for the imageview of the default cell should work.. but it does not.
cell.imageView.contentMode = UIViewContentModeScaleAspectFit;
Complete logic for setting thumbnails.. fPath is the path to image
UIImage *thumbnail = [UIImage imageWithContentsOfFile:fPath];
[cell.imageView setImage:thumbnail];
cell.imageView.contentMode = UIViewContentModeScaleAspectFit;
cell.imageView.clipsToBounds = YES;
I found out that drawInRect stretches the original image if the size is lower or croppes it if it is bigger.
This article will help you to prepare a thumbnail of your image
http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/
It has several useful UIImage classes extentions:
* UIImage+Resize
* UIImage+Alpha
* UIImage+RoundedCorner
Example Usage:
UIImage *imageThumb = [YourImage thumbnailImage:70 transparentBorder:0 cornerRadius:10 interpolationQuality:kCGInterpolationHigh];
and then you can use drawInRect method. If the image is not rectangle - the image will crop the bigger side and take the middle of the image
Hope this answer will guide you.
I load a image and create a mirror in this way:
originalImg = [UIImage imageNamed:#"ms06.png"];
mirrorImg = [UIImage imageWithCGImage:[originalImg CGImage] scale:1.0 orientation:UIImageOrientationUpMirrored];
Then I set the above UIImage object to a subclass of UIView, and override the drawRect:
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGAffineTransform t0 = CGContextGetCTM(context);
CGContextConcatCTM(context, t0);
CGContextDrawImage(context, self.bounds, [image CGImage]);
CGContextRestoreGState(context);
}
No matter which image I draw, the displayed image always be the original one, mirrored image was never displayed when set to the UIView subclass.
I'm sure that the mirrored image was set to the UIView correctly because the debug info showed that the orientation member variable equals to 4, which means "UIImageOrientationUpMirrored", while the original image equals to 0.
Does anyone could help me with this problem, thanks.
I also tried to display the mirrored image in UIImageView with setImage: and it works correctly. By the way I found that the breakpoint in drawRect was never hit when call the setImage of UIImageView, how can we define the drawing behavior(such as draw a line above the image) when loading image to the UIImageView?
You mirrow the image on UI-Level. This returns a new UIImage, but the CGImage stays the same. If you do some NSLogs, you will notice this.
You can also do transformations on UI-Level. If you use this approach, I would suggest to use originalImg.scale instead of 1.0. Then the code would work for retina and non-retina displays.
[UIImage imageWithCGImage:[originalImg CGImage] scale:originalImg.scale orientation:UIImageOrientationUpMirrored];
If you really need to mirror the CGImage, take a look at NYXImagesKit on GitHub (see UIImage+Rotating.m)
I have scenario, in which I am getting images using Web Service and all images are in different resolution. Now my requirement is that I want resolution of each Images and using that I want to define size of UIImageView so I can prevent my Images from getting blurred
For example image resolution if 326 pixel/inch the imageview should be as size of that image can represent fully without any blur.
UIImage *img = [UIImage imageNamed:#"foo.png"];
CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);
UIImageView *imgView = [[UIImageView alloc] initWithFrame:rect];
[imgView setImage:img];
Image size IS it's resolution.
Your problem might be - retina display!
Check for Retina display and thus - make UIImageView width/height twice smaller (so that each UIImageView pixel would consist of four smaller UIImage pixels for retina display).
How to check for retina display:
https://stackoverflow.com/a/7607087/894671
How to check image size (without actually loading image in memory):
NSString *mFullPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]
stringByAppendingPathComponent:#"imageName.png"];
NSURL *imageFileURL = [NSURL fileURLWithPath:mFullPath];
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, NULL);
if (imageSource == NULL)
{
// Error loading image ...
}
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:NO], (NSString *)kCGImageSourceShouldCache, nil];
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, (CFDictionaryRef)options);
NSNumber *mImgWidth;
NSNumber *mImgHeight;
if (imageProperties)
{
//loaded image width
mImgWidth = (NSNumber *)CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelWidth);
//loaded image height
mImgHeight = (NSNumber *)CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelHeight);
CFRelease(imageProperties);
}
if (imageSource != NULL)
{
CFRelease(imageSource);
}
So - for example:
UIImageView *mImgView = [[UIImageView alloc] init];
[mImgView setImage:[UIImage imageNamed:#"imageName.png"]];
[[self view] addSubview:mImgView];
if ([UIScreen instancesRespondToSelector:#selector(scale)])
{
CGFloat scale = [[UIScreen mainScreen] scale];
if (scale > 1.0)
{
//iphone retina screen
[mImgView setFrame:CGRectMake(0,0,[mImgWidth intValue]/2,[mImgHeight intValue]/2)];
}
else
{
//iphone screen
[mImgView setFrame:CGRectMake(0,0,[mImgWidth intValue],[mImgHeight intValue])];
}
}
Hope that helps!
You can get image size using following code. So, first calculate downloaded image size and than make image view according to that.
UIImage *Yourimage = [UIImage imageNamed:#"image.png"];
CGFloat width = Yourimage.size.width;
CGFloat height = Yourimage.size.height;
Hope, this will help you..
UIImage *oldimage = [UIImage imageWithContentsOfFile:imagePath]; // or you can set from url with NSURL
CGSize imgSize = [oldimage size];
imgview.frame = CGRectMake(10, 10, imgSize.width,imgSize.height);
[imgview setImage:oldimage];
100% working ....
To solve this problem, we need to take care of the device's display resolution..
For example you have an image of resolution 326ppi which is same as of iPhone4, iPhone4S and iPod 4th Gen. So you can simply use solutions suggested by #Nit and #Peko. But for other devices(or for image with different resolution on these devices) you will need to apply maths to calculate size for better display.
Now suppose you have 260ppi(with dimensions W x H) image and you wish to display it on iPhone4S, so as the information contained in it per inches is less than the display resolution of iPhone so we will need to resize it by reducing image size by 326/260 factor. so now the size for imageView that you will use is
imageViewWidth = W*(260/326);
imageViewHeight = H*(260/326);
In general:
resizeFactor = imageResolution/deviceDisplayResolution;
imageViewWidth = W*resizeFactor;
imageViewHeight = H*resizeFactor;
Here I am considering when we set an image in imageView and resize it, it does not removes or adds pixels from image,
Let the UIImageView do the work by utilizing the contentMode property to do your image resizing for you.
You probably want to be displaying your UIImageView with a static sizing (the "frame" property) that represents the maximum size of the image you want to display, and allowing the images to resize within that frame relative to their own particular size requirements (overall size, aspect ratio, etc.). You can let the UIImageView do the heavy lifting for you of dealing with different sized images by mastering the contentMode property. It has many different settings, one of which is UIViewContentModeScaleAspectFit, which will downsize your image as necessary to fit within the UIImageView, which if the image is smaller, it will simply display centered. You can play with the setting to get the results you want.
Note that with this approach, there is nothing special you need to do to deal with scaling issues associated with a Retina display.
As per the requirement you stated in the question body, I believe you need not change UIImageView size.
Image can represent fully without any blur using this line of code:
imageView.contentMode = UIViewContentModeScaleAspectFit;
I'm trying to merge two UIImageViews. The first UIImageView (theimageView) is the background, and the second UIImageView (Birdie) is an image overlaying the first UIImageView. You can load the first UIImageView from a map or take a picture. After this you can drag, rotate and scale the second UIImageView over the first one. I want the output (saved image) to look the same as what I see on the screen.
I got that working, but I get borders and the quality and size are bad. I want the size to be the same as that of the image which is chosen, and the quality to be good. Also I get a crash if I save it a second time, right after the first time.
Here is my current code:
//save actual design in photo library
- (void)captureScreen {
UIImage *myImage = [self addImage:theImageView ToImage:Birdie];
[myImage retain];
UIImageWriteToSavedPhotosAlbum(myImage, self, #selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), self);
}
- (UIImage*) addImage:(UIImage*)theimageView toImage:(UIImage*)Birdie{
CGSize size = CGSizeMake(theimageView.size.height, theimageView.size.width);
UIGraphicsBeginImageContext(size);
CGPoint pointImg1 = CGPointMake(0,0);
[theimageView drawAtPoint:pointImg1 ];
CGPoint pointImage2 = CGPointMake(0, 0);
[Birdie drawAtPoint:pointImage2 ];
UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}
But I only get errors with this code!
Thanks in advanced!
Take a look at Drawing a PNG Image Into a Graphics Context for Blending Mode Manipulation
I have an image inside an UIImageView which is within a UIScrollView. What I want to do is rotate this image 90 degrees so that it is in landscape by default, and set the initial zoom of the image so that the entire image fits into the scrollview and then allow it to be zoomed up to 100% and back down to minimum zoom again.
This is what I have so far:
self.imageView.transform = CGAffineTransformMakeRotation(-M_PI/2);
float minimumScale = scrollView.frame.size.width / self.imageView.frame.size.width;
scrollView.minimumZoomScale = minimumScale;
scrollView.zoomScale = minimumScale;
scrollView.contentSize = CGSizeMake(self.imageView.frame.size.height,self.imageView.frame.size.width);
The problem is that if I set the transform, nothing shows up in the scrollview. However if I commented out the transform, everything works except the image is not in the landscape orientation that I want it to be!
If I apply the transform and remove the code that sets the minimumZoomScale and zoomScale properties, then the image shows up in the correct orientation, however with the incorrect zoomScale and seems like the contentSize property isn't set correctly either - since the doesn't scroll to the edge of the image in the left/right direction, however does top and bottom but much over the edge.
NB: image is being loaded from a URL
Maybe rotating the image itself fits your needs:
UIImage* rotateUIImage(const UIImage* src, float angleDegrees) {
UIView* rotatedViewBox = [[UIView alloc] initWithFrame: CGRectMake(0, 0, src.size.width, src.size.height)];
float angleRadians = angleDegrees * ((float)M_PI / 180.0f);
CGAffineTransform t = CGAffineTransformMakeRotation(angleRadians);
rotatedViewBox.transform = t;
CGSize rotatedSize = rotatedViewBox.frame.size;
[rotatedViewBox release];
UIGraphicsBeginImageContext(rotatedSize);
CGContextRef bitmap = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);
CGContextRotateCTM(bitmap, angleRadians);
CGContextScaleCTM(bitmap, 1.0, -1.0);
CGContextDrawImage(bitmap, CGRectMake(-src.size.width / 2, -src.size.height / 2, src.size.width, src.size.height), [src CGImage]);
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
I believe the easiest way (and thread safe too) is to do:
//assume that the image is loaded in landscape mode from disk
UIImage * LandscapeImage = [UIImage imageNamed: imgname];
UIImage * PortraitImage = [[UIImage alloc] initWithCGImage: LandscapeImage.CGImage
scale: 1.0
orientation: UIImageOrientationLeft];
Any calculations that you do based on the imageView's frame should probably be done before you apply any transformations to it. But I would actually suggest doing those calculations based on the size of the UIImage, not the UIImageView. Then set both the UIImageView's frame and the UIScrollView's contentSize based on that.
Max's suggestion is a good one, although with a larger image it could be a performance killer. Are you displaying this image from your app's resources? If so, why not just rotate the images before you even build the app?
There's a much easier solution that is also faster, just do this:
- (void) imageRotateTapped:(id)sender
{
[UIView animateWithDuration:0.33f animations:^()
{
self.imageView.transform = CGAffineTransformMakeRotation(RADIANS(self.rotateDegrees += 90.0f));
self.imageView.frame = self.imageView.superview.bounds; // change this to whatever rect you want
}];
}
When the user is done, you will need to actually create a new rotated image, but that is very easy to do.
I was using the accepted answer for a while until we noticed that non-square rotations based on images taken directly from the camera seemed stretched (they were rotated as desired, just the frame width/height wasn't adjusted).
Great explanation/post here from Trevor: http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/
In the end, it was a very simple import of Trevor's code which uses categories to add a resizedImage:interpoationQuality method to UIImage. So yeah, user beware, if it still works for you, great. But if it doesn't, I'd take a look at the library instead.