I am trying to save an image coming from the iPhone camera to a file. I use the following code:
try UIImageJPEGRepresentation(toWrite, 0.8)?.write(to: tempURL, options: NSData.WritingOptions.atomicWrite)
This results in a file double the resolution of the toWrite UIImage. I confirmed in the watch expressions that creating a new UIImage from UIImageJPEGRepresentation doubles its resolution
-> toWrite.size CGSize (width = 3264, height = 2448)
-> UIImage(data: UIImageJPEGRepresentation(toWrite, 0.8)).size CGSize? (width = 6528, height = 4896)
Any idea why this would happen, and how to avoid it?
Thanks
Your initial image has scale factor = 2, but when you init your image from data you will get image with scale factor = 1. Your way to solve it is to control the scale and init the image with scale property:
#available(iOS 6.0, *)
public init?(data: Data, scale: CGFloat)
Playground code that represents the way you can set scale
extension UIImage {
class func with(color: UIColor, size: CGSize) -> UIImage? {
let rect = CGRect(origin: .zero, size: size)
UIGraphicsBeginImageContextWithOptions(size, true, 2.0)
guard let context = UIGraphicsGetCurrentContext() else { return nil }
context.setFillColor(color.cgColor)
context.fill(rect)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
let image = UIImage.with(color: UIColor.orange, size: CGSize(width: 100, height: 100))
if let image = image {
let scale = image.scale
if let data = UIImageJPEGRepresentation(image, 0.8) {
if let newImage = UIImage(data: data, scale: scale) {
debugPrint(newImage?.size)
}
}
}
I want to convert a UIView to an image and save it in my app. Can someone please tell me how to take screenshot of a view or convert it to an image and what is the best way to save it in an app (Not camera roll)? Here is the code for the view:
var overView = UIView(frame: CGRectMake(0, 0, self.view.frame.width/1.3, self.view.frame.height/1.3))
overView.center = CGPointMake(CGRectGetMidX(self.view.bounds),
CGRectGetMidY(self.view.bounds)-self.view.frame.height/16);
overView.backgroundColor = UIColor.whiteColor()
self.view.addSubview(overView)
self.view.bringSubviewToFront(overView)
An extension on UIView should do the trick.
extension UIView {
// Using a function since `var image` might conflict with an existing variable
// (like on `UIImageView`)
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
}
}
Apple discourages using UIGraphicsBeginImageContext starting iOS 10 with the introduction of the P3 color gamut. UIGraphicsBeginImageContext is sRGB and 32-bit only. They introduced the new UIGraphicsImageRenderer API that is fully color managed, block-based, has subclasses for PDFs and images, and automatically manages the context lifetime. Check out WWDC16 session 205 for more details (image rendering begins around the 11:50 mark)
To be sure that it works on every device, use #available with a fallback to earlier versions of iOS:
extension UIView {
// Using a function since `var image` might conflict with an existing variable
// (like on `UIImageView`)
func asImage() -> UIImage {
if #available(iOS 10.0, *) {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
} else {
UIGraphicsBeginImageContext(self.frame.size)
self.layer.render(in:UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return UIImage(cgImage: image!.cgImage!)
}
}
}
you can use extension
extension UIImage {
convenience init(view: UIView) {
UIGraphicsBeginImageContext(view.frame.size)
view.layer.render(in:UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.init(cgImage: image!.cgImage!)
}
}
Convert your UIView to image by drawViewHierarchyInRect:afterScreenUpdates: which is many times faster than renderInContext
Important note: do not call this function from viewDidLoad or viewWillAppear , make sure you are capturing a view after it is it displayed /loaded fully
Obj C
UIGraphicsBeginImageContextWithOptions(myView.bounds.size, myView.opaque, 0.0f);
[myView drawViewHierarchyInRect:myView.bounds afterScreenUpdates:NO];
UIImage *snapshotImageFromMyView = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
myImageView.image = snapshotImageFromMyView;
Save the edited image Photo album
UIImageWriteToSavedPhotosAlbum(snapshotImageFromMyView, nil,nil, nil);
Swift 3/4
UIGraphicsBeginImageContextWithOptions(myView.bounds.size, myView.isOpaque, 0.0)
myView.drawHierarchy(in: myView.bounds, afterScreenUpdates: false)
let snapshotImageFromMyView = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
print(snapshotImageFromMyView)
myImageView.image = snapshotImageFromMyView
Super easy generalization with extension , iOS11 , swift3/4
extension UIImage{
convenience init(view: UIView) {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
view.drawHierarchy(in: view.bounds, afterScreenUpdates: false)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.init(cgImage: (image?.cgImage)!)
}
}
Use :
//myView is completly loaded/visible , calling this code after only after viewDidAppear is call
imgVV.image = UIImage.init(view: myView)
// Simple image object
let img = UIImage.init(view: myView)
On iOS 10:
extension UIImage {
convenience init(view: UIView) {
UIGraphicsBeginImageContext(view.frame.size)
view.layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.init(cgImage: (image?.cgImage)!)
}
}
Best practice as of iOS 10 and Swift 3
while still supporting iOS 9 and earlier
still works as of iOS 13, Xcode 11.1, Swift 5.1
extension UIView {
func asImage() -> UIImage? {
if #available(iOS 10.0, *) {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
} else {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0.0)
defer { UIGraphicsEndImageContext() }
guard let currentContext = UIGraphicsGetCurrentContext() else {
return nil
}
self.layer.render(in: currentContext)
return UIGraphicsGetImageFromCurrentImageContext()
}
}
}
I am unsure what the question means by:
what is the best way to save it in an app (Not camera roll)?
UIGraphicsBeginImageContext(self.view.bounds.size);
self.view.layer.renderInContext(UIGraphicsGetCurrentContext())
var screenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
For example if I have a view of size: 50 50 at 100,100. I can use the following to take a screenshot:
UIGraphicsBeginImageContextWithOptions(CGSizeMake(100, 100), false, 0);
self.view.drawViewHierarchyInRect(CGRectMake(-50,-5-,view.bounds.size.width,view.bounds.size.height), afterScreenUpdates: true)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
In my opinion, the approach with the initialiser isn't that great because it creates two images.
I prefer this:
extension UIView {
var snapshot: UIImage? {
UIGraphicsBeginImageContext(self.frame.size)
guard let context = UIGraphicsGetCurrentContext() else {
return nil
}
layer.render(in: context)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
Swift 4.2, iOS 10
extension UIView {
// If Swift version is lower than 4.2,
// You should change the name. (ex. var renderedImage: UIImage?)
var image: UIImage? {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in layer.render(in: rendererContext.cgContext) }
}
}
Sample
let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
view.backgroundColor = .blue
let view2 = UIView(frame: CGRect(x: 10, y: 10, width: 20, height: 20))
view2.backgroundColor = .red
view.addSubview(view2)
let imageView = UIImageView(image: view.image)
This works for me for Xcode 9/Swift 3.2/Swift 4 and Xcode 8/Swift 3
if #available(iOS 10.0, *) {
// for Xcode 9/Swift 3.2/Swift 4 -Paul Hudson's code
let renderer = UIGraphicsImageRenderer(size: view!.bounds.size)
let capturedImage = renderer.image {
(ctx) in
view!.drawHierarchy(in: view!.bounds, afterScreenUpdates: true)
}
return capturedImage
} else {
// for Xcode 8/Swift 3
UIGraphicsBeginImageContextWithOptions((view!.bounds.size), view!.isOpaque, 0.0)
view!.drawHierarchy(in: view!.bounds, afterScreenUpdates: false)
let capturedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return capturedImage!
}
Here's how to use it inside a function:
fileprivate func captureUIImageFromUIView(_ view:UIView?) -> UIImage {
guard (view != nil) else{
// if the view is nil (it's happened to me) return an alternative image
let errorImage = UIImage(named: "Error Image")
return errorImage
}
// if the view is all good then convert the image inside the view to a uiimage
if #available(iOS 10.0, *) {
let renderer = UIGraphicsImageRenderer(size: view!.bounds.size)
let capturedImage = renderer.image {
(ctx) in
view!.drawHierarchy(in: view!.bounds, afterScreenUpdates: true)
}
return capturedImage
} else {
UIGraphicsBeginImageContextWithOptions((view!.bounds.size), view!.isOpaque, 0.0)
view!.drawHierarchy(in: view!.bounds, afterScreenUpdates: false)
let capturedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return capturedImage!
}
}
Here's how to do something with the image returned from the function:
#IBOutlet weak fileprivate var myCustomView: UIView!
var myPic: UIImage?
let myImageView = UIImageView()
#IBAction fileprivate func saveImageButtonTapped(_ sender: UIButton) {
myPic = captureUIImageFromUIView(myCustomView)
// display the pic inside a UIImageView
myImageView.image = myPic!
}
I got the Xcode 9/Swift 3.2/Swift 4 answer from Paul Hudson convert uiview to uiimage
I got the Xcode 8/Swift 3 from somewhere on SO a longgg time ago and I forgot where :(
var snapshot = overView.snapshotViewAfterScreenUpdates(false)
or in objective-c
UIView* snapshot = [overView snapshotViewAfterScreenUpdates:NO];
You can use it easily by using the extension like this
// Take a snapshot from a view (just one view)
let viewSnapshot = myView.snapshot
// Take a screenshot (with every views in screen)
let screenSnapshot = UIApplication.shared.snapshot
// Take a snapshot from UIImage initialization
UIImage(view: self.view)
If you wanna use those extension method/variables, implement this
UIImage extension
extension UIImage {
convenience init(view: UIView) {
if let cgImage = view.snapshot?.cgImage {
self.init(cgImage: cgImage)
} else {
self.init()
}
}
}
UIView extension
extension UIView {
var snapshot: UIImage? {
UIGraphicsBeginImageContextWithOptions(bounds.size, isOpaque, 0.0)
if UIGraphicsGetCurrentContext() != nil {
drawHierarchy(in: bounds, afterScreenUpdates: true)
let screenshot = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return screenshot
}
return nil
}
}
UIApplication extension
extension UIApplication {
var snapshot: UIImage? {
return keyWindow?.rootViewController?.view.snapshot
}
}
or iOS 10+ you can use the new UIGraphicsImageRenderer + the recommended drawHierarchy, which in some situations can be much faster than layer.renderInContext
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(size: self.bounds.size)
return renderer.image { _ in
self.drawHierarchy(in: CGRect(x: 0, y: 0, width: bounds.size.width, height: bounds.size.height), afterScreenUpdates: false)
}
}
}
Thanks #Bao Tuan Diep ! I want add a supplement.
When you use the code:
yourView.layer.render(in:UIGraphicsGetCurrentContext()!)
You must notice that:
- If you had used `autoLayout` or `Masonry` in `yourView` (that you want to convert) .
- If you did not add `yourView` to another view which means that `yourView` was not used as a subview but just an object.
Then, your must use :
[yourView setNeedsLayout];
[yourView layoutIfNeeded];
to update yourView before yourView.layer.render(in:UIGraphicsGetCurrentContext()!).
Otherwise you may get an image object that contains no elements
Swift 4.2
import Foundation
import UIKit
extension UIImage {
convenience init(view: UIView) {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
view.drawHierarchy(in: view.bounds, afterScreenUpdates: false)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.init(cgImage: (image?.cgImage)!)
}
}
using:
let img = UIImage.init(view: self.holderView)
Implementation in Swift 3 :
Add the code below , out of class scope .
extension UIImage {
convenience init(_ view: UIView) {
UIGraphicsBeginImageContext(view.frame.size)
view.layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.init(cgImage: (image?.cgImage)!)
}
}
Usage :
let image = UIImage( Your_View_Outlet )
Resorting to an extension, as some have suggested, might be okay for the common case yet not ideal in every application, depending on how one is drawing the view, i.e. as layers, or trying to display a view to its subviews.
If one is creating an image of the subview hierarchy:
let renderer = UIGraphicsImageRenderer(bounds: view.bounds)
let image = renderer.image { ctx in
self.drawHierarchy(in: self.bounds, afterScreenUpdates:
However, if your view consists of sublayers, for example CALayer, including CAShapeLayer comprised of UIBezierCurve... Something more like this may be in order:
let renderer = UIGraphicsImageRenderer(bounds: view.bounds)
let image = renderer.image { rendererContext in
for sublayer in self.layer.sublayers!.reversed() {
sublayer.render(in: rendererContext.cgContext)
}
}
And of course one might want to display a view with subviews which are layered. And since UIView.drawHierarchy() doesn't include sublayers... well, it could get more complicated
I use this for small images (because it does not work for big images):
extension UIView {
public func drawHierarchyAsImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(size: self.bounds.size)
let image = renderer.image { _ in
self.drawHierarchy(in: self.bounds, afterScreenUpdates: true)
}
return image
}
}
For high resolution images i use this:
extension UIView {
public func renderAsImage(scale: CGFloat) -> UIImage {
let format = UIGraphicsImageRendererFormat()
format.scale = scale
let renderer = UIGraphicsImageRenderer(bounds: bounds, format: format)
return renderer.image { rendererContext in
if let presentation = layer.presentation() {
presentation.render(in: rendererContext.cgContext)
}
}
}
}
In my view hierarchy i have rotated views and thats why i use the presentation layer as mentioned here:
renderInContext does not capture rotated subviews
I implemented #Naveed J.'s method like this, and it worked like a charm.
Here was his extentsion:
extension UIView {
// Using a function since `var image` might conflict with an existing variable
// (like on `UIImageView`)
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
}
}
Here is how I implemented it.
//create an image from yourView to display
//determine the frame of the view/imageimage
let screen = self.superview!.bounds
let width = screen.width / 4 //make image 1/4 width of screen
let height = width
let frame = CGRect(x: 0, y: 0, width: width, height: height)
let x = (screen.size.width - frame.size.width) * 0.5
let y = (screen.size.height - frame.size.height) * 0.5
let mainFrame = CGRect(x: x, y: y, width: frame.size.width, height: frame.size.height)
let yourView = YourView() //instantiate yourView
yourView.frame = mainFrame //give it the frame
yourView.setNeedsDisplay() //tell it to display (I am not 100% sure this is needed)
let characterViewImage = yourView.asImage()
Initializer with the new UIGraphicsImageRenderer available since iOS 10:
extension UIImage{
convenience init(view: UIView) {
let renderer = UIGraphicsImageRenderer(size: self.bounds.size)
let canvas = CGRect(x: 0, y: 0, width: bounds.size.width, height: bounds.size.height)
let image = renderer.image { _ in
self.drawHierarchy(in: canvas, afterScreenUpdates: false)
}
self.init(cgImage: (image?.cgImage)!)
}
}
work fine with me !
Swift4
extension UIView {
func toImage() -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0.0)
self.drawHierarchy(in: self.bounds, afterScreenUpdates: false)
let snapshotImageFromMyView = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return snapshotImageFromMyView!
}
}
For view contains blurred subview (e.g. UIVisualEffectView instance), only drawViewHierarchyInRect:afterScreenUpdates works.
#ViJay Avhad's answer is correct for this case.
Using UIGraphicsImageRenderer doesn't work when the view contains Scene Kit subviews, Metal or Sprite Kit ones. In these cases, use
let renderer = UIGraphicsImageRenderer(size: view.bounds.size)
let image = renderer.image { ctx in
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
}
please try below code.
-(UIImage *)getMainImageFromContext
{
UIGraphicsBeginImageContextWithOptions(viewBG.bounds.size, viewBG.opaque, 0.0);
[viewBG.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
I have a UIImage that is a small symbol that is all black. The UIImage is getting set in a custom UIButton subclass I have. Is it possible to have the image to apply the tintColor to it, so instead of the black image it changes colors to whatever the tintColor is?
I'm just trying to avoid creating new assets.
// here I want defaultImageName (that is black) to use the tintColor (that is white)
[self setImage:[UIImage imageNamed:defaultImageName] forState:UIControlStateNormal];
If you are just supporting iOS 7 you can use tintColor and UIImageRenderingModeAlwaysTemplate
This article covers that:
https://www.captechconsulting.com/blogs/ios-7-tutorial-series-tint-color-and-easy-app-theming
If you need to support an earlier version you may want to consider this thread
How would I tint an image programmatically on the iPhone?
Swift 4, copy-paste solution
#IBOutlet weak var iconImageView: UIImageView!
iconImageView.image = UIImage(imageLiteralResourceName: "myImageName").withRenderingMode(.alwaysTemplate)
iconImageView.tintColor = UIColor.red
On iOS 13+ you can use the following:
UIImage(named: "img_name")?.withTintColor(.red)
https://developer.apple.com/documentation/uikit/uiimage/3327300-withtintcolor
Try this:
func tinted(with color: UIColor) -> UIImage? {
defer { UIGraphicsEndImageContext() }
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
color.set()
self.withRenderingMode(.alwaysTemplate).draw(in: CGRect(origin: .zero, size: self.size))
return UIGraphicsGetImageFromCurrentImageContext()
}
For example:
button.setImage(UIImage(systemName: "checkmark.circle")?.tinted(with: .systemGray), for: .normal)
Here's how I use tint colors and opacities in IOS 9 with Swift -
//apply a color to an image
//ref - http://stackoverflow.com/questions/28427935/how-can-i-change-image-tintcolor
//ref - https://www.captechconsulting.com/blogs/ios-7-tutorial-series-tint-color-and-easy-app-theming
func getTintedImage() -> UIImageView {
var image :UIImage
var imageView :UIImageView
image = UIImage(named: "someAsset")!
let size : CGSize = image.size
let frame : CGRect = CGRectMake((UIScreen.mainScreen().bounds.width-86)/2, 600, size.width, size.height)
let redCover : UIView = UIView(frame: frame)
redCover.backgroundColor = UIColor.redColor()
redCover.layer.opacity = 0.75
imageView = UIImageView();
imageView.image = image.imageWithRenderingMode(UIImageRenderingMode.Automatic)
imageView.addSubview(redCover)
return imageView
}
Why not use image filtering
btn.setImage(image, for: UIControl.State.normal)
btn.setImage(image.disabled, for: UIControl.State.disabled)
Use CoreImage to do image filter
extension UIImage
{
/// Create a grayscale image with alpha channel. Is 5 times faster than grayscaleImage().
/// - Returns: The grayscale image of self if available.
var disabled: UIImage?
{
// Create image rectangle with current image width/height * scale
let pixelSize = CGSize(width: self.size.width * self.scale, height: self.size.height * self.scale)
let imageRect = CGRect(origin: CGPoint.zero, size: pixelSize)
// Grayscale color space
let colorSpace: CGColorSpace = CGColorSpaceCreateDeviceGray()
// Create bitmap content with current image size and grayscale colorspace
let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue)
if let context: CGContext = CGContext(data: nil, width: Int(pixelSize.width), height: Int(pixelSize.height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfo.rawValue)
{
// Draw image into current context, with specified rectangle
// using previously defined context (with grayscale colorspace)
guard let cg = self.cgImage else{
return nil
}
context.draw(cg, in: imageRect)
// Create bitmap image info from pixel data in current context
if let imageRef: CGImage = context.makeImage(){
let bitmapInfoAlphaOnly = CGBitmapInfo(rawValue: CGImageAlphaInfo.alphaOnly.rawValue)
guard let context = CGContext(data: nil, width: Int(pixelSize.width), height: Int(pixelSize.height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfoAlphaOnly.rawValue) else{
return nil
}
context.draw(cg, in: imageRect)
if let mask: CGImage = context.makeImage() {
// Create a new UIImage object
if let newCGImage = imageRef.masking(mask){
// Return the new grayscale image
return UIImage(cgImage: newCGImage, scale: self.scale, orientation: self.imageOrientation)
}
}
}
}
// A required variable was unexpected nil
return nil
}
}
Of course, in Swift 5
Swift5 Extension
extension UIImage {
var template: UIImage? {
return self.withRenderingMode(.alwaysTemplate)
}
}
Usage:
UIImageView
let imgView = UIImageView()
imgView.tintColor = UIColor.red
imgView.image = UIImage(named: "IMAGE_NAME_HERE")?.template
UIButton
let button = UIButton(type: .custom)
button.tintColor = UIColor.red
button.setImage(UIImage(named: "IMAGE_NAME_HERE")?.template, for: .normal)
Use this simple extension to UIImageView
#IBInspectable var tintedColor: UIColor{
get{
return tintColor
}
set{
image = image?.withRenderingMode(.alwaysTemplate)
tintColor = newValue
}
}