func thumbImage(image: UIImage) -> UIImage {
let cgSize: CGSize = CGSize(width: 100, height: 100)
let thumb = UIGraphicsImageRenderer(size: cgSize)
return thumb.image { _ in
image.draw(in: CGRect(origin: .zero, size: cgSize))
}
}
The final image is 300x300.
I would like, not matter the iPhone screen resolution, to have the image to be 100x100 (it is a square image of course).
How modify this code to achieve this result?
(I'm open to alternate ways of achieving this)
func thumbImage(image: UIImage, pxWidth: Int, pxHeight:Int ) -> UIImage {
let cgSize: CGSize = CGSize(width: pxWidth, height: pxHeight)
let rect = CGRect(x: 0, y: 0, width: pxWidth, height: pxHeight)
UIGraphicsBeginImageContextWithOptions(cgSize, false, 1.0)
image.draw(in: rect)
let thumb = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let compressedThumb = thumb!.jpegData(compressionQuality: 0.70)
return UIImage(data: compressedThumb!)!
}
This alternative with UIGraphicsBeginImageContextWithOptions works and keeps the code as short as the initial one. (I also added some compression and conversion code).
Related
I have the following functions.
extension UIImage
{
var width: CGFloat
{
return size.width
}
var height: CGFloat
{
return size.height
}
private static func circularImage(diameter: CGFloat, color: UIColor) -> UIImage
{
UIGraphicsBeginImageContextWithOptions(CGSize(width: diameter, height: diameter), false, 0)
let context = UIGraphicsGetCurrentContext()!
context.saveGState()
let rect = CGRect(x: 0, y: 0, width: diameter, height: diameter)
context.setFillColor(color.cgColor)
context.fillEllipse(in: rect)
context.restoreGState()
let image = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return image
}
private func addCentered(image: UIImage, tintColor: UIColor) -> UIImage
{
let topImage = image.withTintColor(tintColor, renderingMode: .alwaysTemplate)
let bottomImage = self
UIGraphicsBeginImageContext(size)
let bottomRect = CGRect(x: 0, y: 0, width: bottomImage.width, height: bottomImage.height)
bottomImage.draw(in: bottomRect)
let topRect = CGRect(x: (bottomImage.width - topImage.width) / 2.0,
y: (bottomImage.height - topImage.height) / 2.0,
width: topImage.width,
height: topImage.height)
topImage.draw(in: topRect, blendMode: .normal, alpha: 1.0)
let mergedImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return mergedImage
}
}
They work fine, but how do I properly apply UIScreen.main.scale to support retina screens?
I've looked at what's been done here but can't figure it out yet.
Any ideas?
Accessing UIScreen.main.scale itself is a bit problematic, as you have to access it only from main thread (while you usually want to put a heavier image processing on a background thread). So I suggest one of these ways instead.
First of all, you can replace UIGraphicsBeginImageContext(size) with
UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
The last argument (0.0) is a scale, and based on docs "if you specify a value of 0.0, the scale factor is set to the scale factor of the device’s main screen."
If instead you want to retain original image's scale on resulting UIImage, you can do this: after topImage.draw, instead of getting the UIImage with UIGraphicsGetImageFromCurrentImageContext, get CGImage with
let cgImage = context.makeImage()
and then construct UIImage with the scale and orientation of the original image (as opposed to defaults)
let mergedImage = UIImage(
cgImage: cgImage,
scale: image.scale,
orientation: image.opientation)
I am using a extension function to save a uiview as a uiimage. The code works to save the uiimage. However what I am trying to do is save a transparent image over the image being saved to the photo gallery. So I am trying to save a layered image using a extension function. Right now only the uiivew is being save and the 2nd layer is not being saved.
class ViewController: UIViewController,UINavigationControllerDelegate {
#IBAction func press(_ sender: Any) {
let jake = drawingView.takeSnapshotOfView(view: drawingView)
guard let selectedImage = jake else {
print("Image not found!")
return
}
UIImageWriteToSavedPhotosAlbum(selectedImage, self, #selector(image(_:didFinishSavingWithError:contextInfo:)), nil)
}}
func takeSnapshotOfView(view:UIView) -> UIImage? {
UIGraphicsBeginImageContext(CGSize(width: view.frame.size.width, height: view.frame.size.height))
view.drawHierarchy(in: CGRect(x: 0.0, y: 0.0, width: view.frame.size.width, height: view.frame.size.height), afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let star:UIImage = UIImage(named: "e.png")!
let newSize = CGSize(width: star.size.width, height: star.size.height )
UIGraphicsBeginImageContextWithOptions(newSize, false, star.scale)
star.draw(in: CGRect(x: newSize.width/12,
y: newSize.height/8,
width: newSize.width/1.2,
height: newSize.height/1.2),
blendMode:CGBlendMode.normal, alpha:1)
UIGraphicsEndImageContext()
return image
}
Here is a UIView extension that takes in CGRect and UIImage, and alternitavely you can also supply it another CGRect or CGSize to make it more dynamic for the watermark placement/size
extension UIView {
/// Takes a screenshot of a UIView, with an option to clip to view bounds and place a waterwark image
/// - Parameter rect: offset and size of the screenshot to take
/// - Parameter clipToBounds: Bool to check where self.bounds and rect intersect and adjust size so there is no empty space
/// - Parameter watermark: UIImage of the watermark to place on top
func screenshot(for rect: CGRect, clipToBounds: Bool = true, with watermark: UIImage? = nil) -> UIImage {
var imageRect = rect
if clipToBounds {
imageRect = bounds.intersection(rect)
}
return UIGraphicsImageRenderer(bounds: imageRect).image { _ in
drawHierarchy(in: CGRect(origin: .zero, size: bounds.size), afterScreenUpdates: true)
watermark?.draw(in: CGRect(origin: imageRect.origin, size: CGSize(width: 32, height: 32))) // update origin to place watermark where you want, with this update it will place it in top left or screenshot.
}
}
}
You can call it like so:
let image = self.view.screenshot(for: CGRect(x: 0, y: 0, width: 200, height: 200), with: UIImage(named: "star"))
This will work for all subviews of the view that calls screenshot(...)
For a anyone using the above extension, I added additional info in this answer
Why does Xcode shows a image bigger then AS-IS?
http://users.telenet.be/thomazz/ScreenShot4.png
http://users.telenet.be/thomazz/ScreenShot3.png
Scenario:
I got an image.
I resize this UIImage.
I export the resized UIImage.
I comment out my resize code.
I import the resized image in Xcode.
problem 1: Xcode shows the image twice as big as normal.
problem 2: when I run my app with the exported-resized image, it is twice as big.
view screenshots.
This totally depends on your frame of your UIImageView and not its dimensions.
So if you have an 1024x1024 image and you place it in a 10x10 frame, it will render to 10x10 size and vice versa.
If you want it bigger, then make your UIImageView bigger
Edit: so it is a google maps icon
Set the resized image as marker icon ,i.e,
marker.icon = self.imageWithImage(image: UIImage(named: "imageName")!, scaledToSize: CGSize(width: 3.0, height: 3.0))
Add this function
func imageWithImage(image:UIImage, scaledToSize newSize:CGSize) -> UIImage{
UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0);
image.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
Dear Mohammad Bashir Sidani, I have this code.
And this code works. but it creates a new UIImage.
Then I use UIImagePNGRepresentation(resizedImage) to export the image.
I disable the code below to use the "programmatically-resized image".
this new resized image is blown up by Xcode... :(
extension UIImage {
func resizeImage(_ dimension: CGFloat, opaque: Bool, contentMode: UIViewContentMode = .scaleAspectFit) -> UIImage {
var width: CGFloat
var height: CGFloat
var newImage: UIImage
let size = self.size
let aspectRatio = size.width/size.height
switch contentMode {
case .scaleAspectFit:
if aspectRatio > 1 { // Landscape image
width = dimension
height = dimension / aspectRatio
} else { // Portrait image
height = dimension
width = dimension * aspectRatio
}
default:
fatalError("UIIMage.resizeToFit(): FATAL: Unimplemented ContentMode")
}
if #available(iOS 10.0, *) {
let renderFormat = UIGraphicsImageRendererFormat.default()
renderFormat.opaque = opaque
let renderer = UIGraphicsImageRenderer(size: CGSize(width: width, height: height), format: renderFormat)
newImage = renderer.image {
(context) in
self.draw(in: CGRect(x: 0, y: 0, width: width, height: height))
}
} else {
UIGraphicsBeginImageContextWithOptions(CGSize(width: width, height: height), opaque, 0)
self.draw(in: CGRect(x: 0, y: 0, width: width, height: height))
newImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
}
return newImage
}
}
i read here many guides how to create a new image merging two existing ones, using the UIGraphics and the layer.render methods for the two UIImageViews, and finally i can create an then save my new image. The problem is that i can't understand how to put the second UIImageView where i want, at the bottom for example. I 'll post now a image of an merged image and the function that my code run making this possible.
Captured merged photo
And here's my code that do the trick:
extension UIImage {
class func imageWithWatermark(image1: UIImageView, image2: UIImageView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(image1.bounds.size, false, 0.0)
let frame = image1.frame
image2.frame = CGRect(x: 0, y: frame.size.height * 0.80, width: frame.size.width, height: frame.size.height * 0.20 )
image1.layer.render(in: UIGraphicsGetCurrentContext()!)
image2.layer.render(in: UIGraphicsGetCurrentContext()!)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img!
}
}
And then my func that saves the merged image:
func addWatermark() {
let newImage = UIImage.imageWithWatermark(image1: cameraPreview, image2: provaImage)
UIImageWriteToSavedPhotosAlbum(newImage, nil,nil,nil)
}
You can use this function which merge two images and the second will be replaces on bottom
func mergeTwoImageSeconInBottom(backgroundImage: UIImage, imageOnBottom: UIImage) -> UIImage {
let size = YOUR_CG_SIZE
UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
backgroundImage.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
imageOnBottom.draw(at: CGPoint(x: (size.width - imageOnBottom.size.width) / 2, y: size.height - imageOnBottom.size.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
I'm hoping to accomplish this without the use of images, if at all possible. Is there a way to create the effect shown in the image programmatically without have to render each tab out as an image?
Every question I've reviewed on SO has the tabs saved as JPGs, which is more work than I feel it should be.
Any ideas?
I took a similar approach to #matcartmill but without the need for a special image. This solution is just based on your color.
// set red as selected background color
let numberOfItems = CGFloat(tabBar.items!.count)
let tabBarItemSize = CGSize(width: tabBar.frame.width / numberOfItems, height: tabBar.frame.height)
tabBar.selectionIndicatorImage = UIImage.imageWithColor(color: UIColor.red, size: tabBarItemSize).resizableImage(withCapInsets: UIEdgeInsets.zero)
// remove default border
tabBar.frame.size.width = self.view.frame.width + 4
tabBar.frame.origin.x = -2
I'm making use of the following extension of UIImage:
extension UIImage {
class func imageWithColor(color: UIColor, size: CGSize) -> UIImage {
let rect: CGRect = CGRectMake(0, 0, size.width, size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0)
color.setFill()
UIRectFill(rect)
let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
I hope this helps!
for swift 4
extension UIImage {
class func imageWithColor(color: UIColor, size: CGSize) -> UIImage {
let rect: CGRect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0)
color.setFill()
UIRectFill(rect)
let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return image
}
}
Update to SWIFT 3:
let numberOfItems = CGFloat((tabBarController?.tabBar.items!.count)!)
let tabBarItemSize = CGSize(width: (tabBarController?.tabBar.frame.width)! / numberOfItems,
height: (tabBarController?.tabBar.frame.height)!)
tabBarController?.tabBar.selectionIndicatorImage
= UIImage.imageWithColor(color: UIColor.black,
size: tabBarItemSize).resizableImage(withCapInsets: .zero)
tabBarController?.tabBar.frame.size.width = self.view.frame.width + 4
tabBarController?.tabBar.frame.origin.x = -2
extension UIImage
{
class func imageWithColor(color: UIColor, size: CGSize) -> UIImage
{
let rect: CGRect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0)
color.setFill()
UIRectFill(rect)
let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return image
}
}
So here's what I ended up doing. It's a mix of using a 640x49 PNG that's the color of the blue "highlighted" background I need.
In AppDelegate.swift:
var selectedBG = UIImage(named:"tab-selected-full")?.resizableImageWithCapInsets(UIEdgeInsetsMake(0, 0, 0, 0))
UITabBar.appearance().selectionIndicatorImage = selectedBG
And then in the first View Controller that gets loaded, I have:
tabBarController?.tabBar.frame.size.width = self.view.frame.width+4
tabBarController?.tabBar.frame.origin.x = -2
The reason for the above two lines is that, by default, Apple has a 2px border between the left and right sides of the tab bar and the tab bar items.
In the above I simply make the tab bar 4px wider, and then offset it so the border on the left falls just outside of the view, thus the border on the right will also fall outside of the view.