Resize NSImage Proportionally (Swift)

I wanted a simple function to resize an image to a desired height, while keeping proportions. Here’s what I came up with:

    func resizeImage(image: NSImage, toHeight: CGFloat) -> NSImage {

        let toWidth = image.size.width * (toHeight/image.size.height)

        if toWidth > image.size.width {

            print(“No need to resize, image small enough at \(image.size)”)

            return image

        }

        let resizedCanvasSize = NSSize(width: toWidth, height: toHeight)

        

        //Prepare a CGImage to apply transformation

        var imageRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)

        let imageCGTransformed = image.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)

        //Get new NSImage of smaller size

        let resizedImage = NSImage(cgImage: imageCGTransformed!, size: resizedCanvasSize)

        

        return resizedImage

 

    }

 

Questions / comments / suggestions? I’m at @MarcMasVi 

Marc

NSWindow min and max size (Swift 4)

You can force the views to keep a inferred min and max width/height by using AutoLayout, but what if you’re working with several views simultaneously? Wouldn’t it be simpler to have a window min and max width/height? 

Just add the following in your NSWindowController:

override func windowDidLoad() {

        super.windowDidLoad()

        window?.minSize = NSSize(width: 410, height: 600 )

        window?.manSize = NSSize(width: 600, height: 1200

}

 

Questions / comments? I’m at @MarcMasVi 

Marc

NSImageView Aspect Fill

Setting an image to use AspectFill in iOS is trivial, you can set it by code or directly in storyboard. 

But how do you do it in macOS? In Cocoa/App Kit there is no property for that, you may scale it , but there is no option for AspectFill (or AspectFit for that matter). So, how do we do it?

Once you find the way is quite easy actually. We’ll create a subclass of NSImageView and we’ll override the image property, then, we’ll place the image in a CALayer; and finally we’ll use this CALayer to resize it with the desired AspectFill. 

import Cocoa

 

class ImageAspectFillView: NSImageView {

 

    override var image: NSImage? {

        set {

            self.layer = CALayer()

            self.layer?.contentsGravity = kCAGravityResizeAspectFill

            self.layer?.contents = newValue

            self.wantsLayer = true

            

            super.image = newValue

        }

        

        get {

            return super.image

        }

    }

 

 

}

 

And that’s it! I hope it helped, took me quite a while to find this solution but works like a charm. Questions, comments? I’m at @MarcMasVi

 

Marc

Open links in the Background

Here’s a quick tip on how to open a URL in the background or foreground depending on a user-set preference. 

if(openInBackgroundPreferenceSet == true){ 
                 NSWorkspace.shared.open([linkToOpen], withAppBundleIdentifier: nil, options: NSWorkspace.LaunchOptions.withoutActivation, additionalEventParamDescriptor: nil, launchIdentifiers: nil)
}else{
                 NSWorkspace.shared.open(linkToOpen)
}

 

Questions / comments? I’m at @MarcMasVi 

 

 Marc

Denarius 1.6 & the slippery bug

This last couple of months I’ve been hard at work on two new projects, the first of which will be released fairly soon! But, today I wanted to write about something else: CoreData Concurrency.

Since the release of Denarius about a year ago I’ve been regularly improving the personal finance app with new features and, of course, bug fixes. However there was this one bug that kept popping up in crash logs but that I was unable to track down. I knew it had something to do with Core Data but that’s the extend of it. 

CoreData in Denarius is implemented with two Managed Object Context, one of them being the background one for complex tasks and a second one for standard operation (as explained in this post).  So, everything was supposedly working as intended. 

However, after way too many hours I saw what was going on: I was doing a change in the main thread with information computed on the background thread… So, how did I solve it? Using objectID of course, the only safe way to transfer objects between threads. 

So instead of:

mainThreadObject.attributeX = computedThreadObjectInBackgroundQueue.attributeX

Now I had (and remember this piece of code is being executed in the background):

let transactionObjectId = mainThreadObject1.objectID
let typeObjectId = computedThreadObject2InBackgroundQueue.objectID
DispatchQueue.main.async { //Here I’m calling the main thread and push the complex background computation to the right object
      (self.managedObjectContext.object(with: transactionObjectId) as! object1).attributeX = (self.managedObjectContext.object(with: typeObjectId) as! object2).attributeX

}

A bit longer, but did the trick! This improvement will ship very soon with the new Denarius 1.6 release. 

Questions / comments? I’m at @MarcMasVi 

Marc

Shoe Dog: A Memoir by the Creator of Nike

Just finished “Shoe Dog: A Memoir by the Creator of Nike” and it’s great:  well written and refreshingly honest.

Even if you’re not into business books, I believe this one is worth your time. 

Bill Gates could not have said it better in his book review:

“Shoe Dog, Phil Knight’s memoir about creating Nike, is a refreshingly honest reminder of what the path to business success really looks like. It’s a messy, perilous, and chaotic journey riddled with mistakes, endless struggles, and sacrifice. In fact, the only thing that seems inevitable in page after page of Knight’s story is that his company will end in failure.” Source

 

Marc

Get Date Day, Month or Year in Swift 3.0

Just a quick update to show how to get Date Day, Month or Year in Swift 3

//Here I’m creating the calendar instance that we will operate with:

let calendar = NSCalendar.init(calendarIdentifier: NSCalendar.Identifier.gregorian)

     

 

//Now asking the calendar what month are we in today’s date:

let currentMonthInt = (calendar?.component(NSCalendar.Unit.month, from: Date()))!

       

 

//Now asking the calendar what year are we in today’s date:

let currentYearInt = (calendar?.component(NSCalendar.Unit.year, from: Date()))!

 

Hope this proves useful.

If you would have any suggestions on how to improve reach me @MarcMasVi in Twitter. 

 Marc