I have a UIImage and I want to adjust what is shown on the device based on a UIImageView.
The UIImage is:
UIImage *image = // a PNG I have
// width = 1200
CGFloat width = image.size.width;
// height = 900
CGFloat height = image.size.height;
And I have an UIImageView
UIImageView *iview = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, 675.0, 900.0)];
How do I get my UIImage into the UIImageView without adjust the aspect ratio? I want the UIImage to be cropped off the edges?
hope this helps
-(UIImage*)crop:(CGRect)frame
{
// Find the scalefactors UIImageView's widht and height / UIImage width and height
CGFloat widthScale = self.bounds.size.width / self.image.size.width;
CGFloat heightScale = self.bounds.size.height / self.image.size.height;
// Calculate the right crop rectangle
frame.origin.x = frame.origin.x * (1 / widthScale);
frame.origin.y = frame.origin.y * (1 / heightScale);
frame.size.width = frame.size.width * (1 / widthScale);
frame.size.height = frame.size.height * (1 / heightScale);
// Create a new UIImage
CGImageRef imageRef = CGImageCreateWithImageInRect(self.image.CGImage, frame);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return croppedImage;//(return value is uiimage)
}
and then add it to uiimageview
If u want to crop off the edges and center the position of ur image then
Set the Imageview properties to AspectFill
myImageView.contentMode = UIViewContentModeScaleAspectFill;
myImageView.clipsToBounds = YES;
Hope this helps
Try setting the contentMode property of your UIImageView to UIViewContentModeScaleAspectFill, which according to the documentation is:
The option to scale the content to fill the size of the view. Some portion of the
content may be clipped to fill the view’s bounds.
You can see the other options in the UIView documentation.
Related
I am using the code below first to create an image thumb (using a category) and then tailor the thumb to the VC in question, for example, make it round.
Somehow, the aspect ratio of images is not getting preserved with some getting squashed vertically...so a face looks like a sideways oval while others get squashed horizontally, so a round ball looks like an upright football. In the code for individual VCs, I am using UIViewContentModeScaleAspectFill and setting clip to bounds to yes but to no avail. Also tried checking these in Storybord but still no luck.
Can anyone see what might be wrong with code below?
//code in viewDidLoad
UIImage *thumbnail = [selectedImage createThumbnailToFillSize:CGSizeMake(side, side)];
//see createThumbNail method below
self.contactImage.image = thumbnail;
//image has been selected and trimmed to thumb. Now format it
CGSize itemSize = CGSizeMake(64, 64);
UIGraphicsBeginImageContextWithOptions(itemSize, NO, UIScreen.mainScreen.scale);
CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);
self.contactImage.contentMode = UIViewContentModeScaleAspectFill;
self.contactImage.clipsToBounds = YES;
[self.contactImage.image drawInRect:imageRect];
self.contactImage.image = UIGraphicsGetImageFromCurrentImageContext();
self.contactImage.layer.cornerRadius=60.0;
UIGraphicsEndImageContext();
//Generic category to create thumb
-(UIImage *) createThumbnailToFillSize:(CGSize)size
{
CGSize mainImageSize = size;
UIImage *thumb;
CGFloat widthScaler = size.width / mainImageSize.width;
CGFloat heightScaler = size.height / mainImageSize.height;
CGSize repositionedMainImageSize = mainImageSize;
CGFloat scaleFactor;
// Determine if we should shrink based on width or hight
if(widthScaler > heightScaler)
{
// calculate based on width scaler
scaleFactor = widthScaler;
repositionedMainImageSize.height = ceil(size.height / scaleFactor);
}
else {
// calculate based on height scaler
scaleFactor = heightScaler;
repositionedMainImageSize.width = ceil(size.width / heightScaler);
}
UIGraphicsBeginImageContext(size);
CGFloat xInc = ((repositionedMainImageSize.width-mainImageSize.width) / 2.f) *scaleFactor;
CGFloat yInc = ((repositionedMainImageSize.height-mainImageSize.height) / 2.f) *scaleFactor;
[self drawInRect:CGRectMake(xInc, yInc, mainImageSize.width * scaleFactor, mainImageSize.height * scaleFactor)];
thumb = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return thumb;
}
I need to set the UIImageView size aspectfit according to height .
means my requirement is that my height of image should be fix but the width of image should be change according to height i know that in UIViewContentModeScaleAspectFit it will take width and hieght automatically but what if i need fix height and dynamic width like aspectfit according to height.
UIImage *originalImage = [UIImage imageNamed:#"image.png"];
double width = originalImage.size.width;
double height = originalImage.size.height;
double apect = width/height;
double nWidth = 320.f/ apect;
self.img.frame = CGRectMake(0, 0, nWidth, 320.f);
self.img.center = self.view.center;
self.img.image = originalImage;
-(CGSize)resizeImage:(CGSize)imageSize toTargetedHeight:(float)height {
NSLog(#"actualImageSize : %#", NSStringFromCGSize(imageSize));
float scaleFactor = height / imageSize.height;
float newHeight = imageSize.height * scaleFactor;
float newWidth = imageSize.width * scaleFactor;
CGSize newSize = CGSizeMake(newWidth, newHeight);
NSLog(#"convertedImageSize : %#", NSStringFromCGSize(newSize));
return newSize;
}
This will create your image with specific height with maintaining its aspect ratio.
I have an UIImageView (red squares) that will display a UIImage that must be scaled (I can receive images greater or smaller that the UIImageView). After scaling it, the showed part of the UIImage is the center of it.
What I need is to show the part of the image in the blue squares, how can I archive it?
I'm only able to get the image size (height and width), but it display the original size, when it's supposed to be the scaled one.
self.viewIm = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 120, 80)];
self.viewIm.backgroundColor = [UIColor greenColor];
self.viewIm.layer.borderColor = [UIColor redColor].CGColor;
self.viewIm.layer.borderWidth = 5.0;
UIImage *im = [UIImage imageNamed:#"benjen"];
self.viewIm.image = im;
self.viewIm.contentMode = UIViewContentModeScaleAspectFill;
// self.viewim.clipsToBounds = YES;
[self.view addSubview:self.viewIm];
To do what you're trying to do, I'd recommend looking into CALayer's contentsRect property.
Since seeing your answer, I've been trying to work out the proper solution for a while, but the mathematics escapes me because contentsRect:'s x and y parameters seem sort of mysterious... But here's some code that may point you in the right direction...
float imageAspect = self.imageView.image.size.width/self.imageView.image.size.height;
float imageViewAspect = self.imageView.frame.size.width/self.imageView.frame.size.height;
if (imageAspect > imageViewAspect) {
float scaledImageWidth = self.imageView.frame.size.height * imageAspect;
float offsetWidth = -((scaledImageWidth-self.imageView.frame.size.width)/2);
self.imageView.layer.contentsRect = CGRectMake(offsetWidth/self.imageView.frame.size.width, 0.0, 1.0, 1.0);
} else if (imageAspect < imageViewAspect) {
float scaledImageHeight = self.imageView.frame.size.width * imageAspect;
float offsetHeight = ((scaledImageHeight-self.imageView.frame.size.height)/2);
self.imageView.layer.contentsRect = CGRectMake(0.0, offsetHeight/self.imageView.frame.size.height, 1.0, 1.0);
}
Try something like this:
CGRect cropRect = CGRectMake(0,0,200,200);
CGImageRef imageRef = CGImageCreateWithImageInRect([ImageToCrop CGImage],cropRect);
UIImage *image = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
I found a very good approximation on this answer. In that, the category resize the image, and use the center point to crop after that. I adapt it to crop using (0,0) as origin point. As I don't really need a category, I use it as a single method.
- (UIImage *)imageByScalingAndCropping:(UIImage *)image forSize:(CGSize)targetSize {
UIImage *sourceImage = image;
UIImage *newImage = nil;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetSize.width;
CGFloat scaledHeight = targetSize.height;
if (CGSizeEqualToSize(image.size, targetSize) == NO) {
if ((targetSize.width / image.size.width) > (targetSize.height / image.size.height)) {
scaleFactor = targetSize.width / image.size.width; // scale to fit height
} else {
scaleFactor = targetSize.height / image.size.height; // scale to fit width
}
scaledWidth = image.size.width * scaleFactor;
scaledHeight = image.size.height * scaleFactor;
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = CGPointZero;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil) {
NSLog(#"could not scale image");
}
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}
And my call is something like this:
self.viewIm = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 120, 80)];
self.viewIm.image = [self imageByScalingAndCropping:[UIImage imageNamed:#"benjen"] forSize:CGSizeMake(120, 80)];
[self.view addSubview:self.viewIm];
I've spent some time on this and finally created a Swift 3.2 solution (based on one of my answers on another thread, as well as one of the answers above). This code only allows for Y translation of the image, but with some tweaks anyone should be able to add horizontal translation as well ;)
let yOffset: CGFloat = 20
myImageView.contentMode = .scaleAspectFill
//scale image to fit the imageView's width (maintaining aspect ratio), but allow control over the image's Y position
UIGraphicsBeginImageContextWithOptions(myImageView.frame.size, myImageView.isOpaque, 0.0)
let ratio = myImage.size.width / myImage.size.height
let newHeight = myImageView.frame.width / ratio
let rect = CGRect(x: 0, y: -yOffset, width: myImageView.frame.width, height: newHeight)
myImage.draw(in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext() ?? myImage
UIGraphicsEndImageContext()
//set the new image
myImageView.image = newImage
Now you can adjust how far down or up you need the image to be by changing the yOffset.
How do I resize UIImageView after setting its contentmode to UIViewContentModeScaleAspectFit so that i can remove the white spaces from top & below.
Please see the attached image
Thanks in advance:)
Hope this will help some others as well ,please do comment if it will break in some condition :)
- (CGRect)frameForImageattribute:(CGSize)image inImageViewAspectFit:(UIImageView *)imageView {
float imageRatio = image.width / image.height;
float viewRatio = imageView.frame.size.width / imageView.frame.size.height;
if (imageRatio < viewRatio) {
float scale = imageView.frame.size.height / image.height;
float width = scale * image.width;
return CGRectMake(kLeftPading, kTopPading, width, imageView.frame.size.height);
}
else {
float scale = imageView.frame.size.width / image.width;
float height = scale * image.height;
return CGRectMake(kLeftPading, kTopPading, imageView.frame.size.width, height);
}
}
You need to get the scale factor of the image view. it can be obtained by
float scaleFactor = MAX(image.size.width/imageView.bounds.size.width, image.size.height/imageView.bounds.size.height);
Then do
CGRect ivFrame = imageView.frame;
ivframe.size.height = image.size.height/scalefactor;
ivFrame.size.width = image.size.width/scalefactor;
imageView.frame = ivFrame;
theres probably a category out there that does this automagically.
EDIT: Heres one for the scalefactor calculation, and it even respects the content mode of the mageView:
how can I get the scale factor of a UIImageView who's mode is AspectFit?
If you know only the width of the imageview and when the height of the image is dynamic then you need to scale the image's height according to the given width to remove the white spaces above and below your image in UIViewContentModeScaleAspectFit mode. Use the following method from here to scale the height of the image according to the standard width of your screen.
-(UIImage*)imageWithImage: (UIImage*) sourceImage scaledToWidth: (float) i_width
{
float oldWidth = sourceImage.size.width;
float scaleFactor = i_width / oldWidth;
float newHeight = sourceImage.size.height * scaleFactor;
float newWidth = oldWidth * scaleFactor;
UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight));
[sourceImage drawInRect:CGRectMake(0, 0, newWidth, newHeight)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
And call it from your cellForRowAtIndexPath: method like this:
UIImage *img = [dictImages objectForKey:yourImageKey]; // loaded the image
cell.imgView.image = [self imageWithImage:img scaledToWidth:self.view.frame.size.width];
I am creating an iPhone app which has image cropping feature. In this, I am getting the photos from the UIImagePickerController and passing it for cropping. There it has a scrollview and the selected image will be added as a subview to the scrollview. And I am using a UIButton for selecting the area for cropping. User can move the button over the imageview and place it anywhere, and when click on CROP button, the area similar to the frame size of the button should be cropped from the imageview.
I used the following code, but it is not returning the actual image.
CGRect clippedRect = CGRectMake(self.scrollView.frame.origin.x+90, self.scrollView.frame.origin.y, self.scrollView.frame.size.width-180, self.scrollView.frame.size.height-220);
CGImageRef imageRef = CGImageCreateWithImageInRect([self.myPhoto CGImage], clippedRect);
UIImage *newImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
self.imageView.image = newImage;
also used
- (UIImage *)cropImage:(UIImage *)oldImage {
CGSize imageSize = self.cropFrame.frame.size;
UIGraphicsBeginImageContextWithOptions( CGSizeMake( imageSize.width, imageSize.height), NO, 0.);
[oldImage drawAtPoint:CGPointMake( xPosition, yPosition)
blendMode:kCGBlendModeCopy
alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
but the result image is not the exact image as per the button frame. I am getting the image from another area.
Updated code
- (void)loadPhoto{
CGFloat w = self.myPhoto.size.width;
CGFloat h = self.myPhoto.size.height;
CGRect imageViewFrame = CGRectMake(0.0f, 0.0f, roundf(w / 2.0f), roundf(h / 2.0f));
self.scrollView.contentSize = imageViewFrame.size;
UIImageView *iv = [[UIImageView alloc] initWithFrame:imageViewFrame];
iv.contentMode = UIViewContentModeScaleAspectFit;
iv.image = self.myPhoto;
[self.view addSubview:iv];
self.imageView = iv;
[iv release];
}
CGRect crop;//= CGRectMake(10, 10, 360, 360);
crop.origin.x = self.cropFrame.frame.origin.x;
crop.origin.y = self.cropFrame.frame.origin.y;
crop.size.width = roundf(self.cropFrame.frame.size.width * 2.0f); //self.cropFrame.frame.size.width * 2;
crop.size.height = roundf(self.cropFrame.frame.size.height * 2.0f); //self.cropFrame.frame.size.height * 2;
NSLog(#"Rect: %#", NSStringFromCGRect(crop));
self.imageView.image = [self croppedImage:crop];
- (UIImage *)croppedImage:(CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect([self.imageView.image CGImage], bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:self.myPhoto.imageOrientation];
CGImageRelease(imageRef);
return croppedImage;
}
Please help to find a solution.
The iOS has a default feature for cropping images.Try this code.
picker.allowsEditing = YES;
and also check this controller for cropping..this is exactly the one you are looking for I think https://github.com/barrettj/BJImageCropper .Hope this helps you..
Since you are using a scrollView that allows the image to be scrolled, you need to adjust your crop rect to the scrollView's position:
float zoomScale = self.scrollView.zoomScale;
int cropX = (self.scrollView.contentOffset.x-imageView.frame.origin.x)/zoomScale;
int cropY = (self.scrollView.contentOffset.y-imageView.frame.origin.y)/zoomScale;
You could use this crop tool that I made. It essentially gives you an interface to allow the user to select the crop area. I think it is in line with that you are looking for.
https://github.com/nicholjs/BFCropInterface
Believing you have solve this problem. Me too had this when tried cropping functionality
Set image.size as the imageView.size & scrollView.contentSize. Below code will give the rect to crop
cropRect.origin = scrollView.contentOffset;
cropRect.size = scrollView.bounds.size;
cropRect.origin.x /= scrollView.zoomScale;
cropRect.origin.y /= scrollView.zoomScale;
cropRect.size.width /= scrollView.zoomScale;
cropRect.size.height /= scrollView.zoomScale;
If planning to show the full image first on visible rect. Setting the imageView.size & scrollView.contentSize to visible view size will give crop image of some other area. Instead try finding the zoom scale by
CGFloat dxWidth = viewCrop.frame.size.width / imageView.image.size.width;
CGFloat dxHeight = viewCrop.frame.size.height / imageView.image.size.height;
CGFloat zoomScale = fmaxf(dWidth, dHeight)
and apply (if by adding subView then after addSubView)
scrollView.minimumZoomScale = zoomScale; // to disable further zoom-out
[scrollView setZoomScale: zoomScale];