NSImage is a powerful class in the Cocoa framework that allows developers to manage and manipulate images in macOS applications. It is part of the AppKit framework and provides a convenient way to handle image data, render images in views, and perform various image-related tasks. Understanding how to use NSImage is essential for macOS developers who want to create visually appealing and functional applications.

NSImage is crucial for tasks such as loading images from files, creating images programmatically, drawing images in custom views, and even manipulating image data. This article will provide practical examples and sample code to help you get started with NSImage in your macOS applications.

Examples:

1. Loading an Image from a File:

   import Cocoa
   
   let imagePath = "/path/to/your/image.png"
   if let image = NSImage(contentsOfFile: imagePath) {
       print("Image loaded successfully")
   } else {
       print("Failed to load image")
   }

2. Creating an Image Programmatically:

   import Cocoa
   
   let size = NSSize(width: 100, height: 100)
   let image = NSImage(size: size)
   
   image.lockFocus()
   NSColor.red.setFill()
   NSBezierPath(rect: NSRect(x: 0, y: 0, width: 100, height: 100)).fill()
   image.unlockFocus()
   
   // Now you can use the image in your application

3. Drawing an Image in a Custom View:

   import Cocoa
   
   class CustomImageView: NSView {
       var image: NSImage?
   
       override func draw(_ dirtyRect: NSRect) {
           super.draw(dirtyRect)
   
           if let image = image {
               image.draw(in: dirtyRect)
           }
       }
   }
   
   // Usage
   let imageView = CustomImageView(frame: NSRect(x: 0, y: 0, width: 200, height: 200))
   imageView.image = NSImage(named: NSImage.Name("exampleImage"))

4. Manipulating Image Data:

   import Cocoa
   
   if let image = NSImage(named: NSImage.Name("exampleImage")),
      let tiffData = image.tiffRepresentation,
      let bitmap = NSBitmapImageRep(data: tiffData) {
   
       let invertedImage = bitmap.representations.first {
           if let bitmapRep = $0 as? NSBitmapImageRep {
               for y in 0..<bitmapRep.pixelsHigh {
                   for x in 0..<bitmapRep.pixelsWide {
                       let color = bitmapRep.colorAt(x: x, y: y)
                       let invertedColor = NSColor(calibratedRed: 1.0 - color!.redComponent,
                                                   green: 1.0 - color!.greenComponent,
                                                   blue: 1.0 - color!.blueComponent,
                                                   alpha: color!.alphaComponent)
                       bitmapRep.setColor(invertedColor, atX: x, y: y)
                   }
               }
               return true
           }
           return false
       }
   
       if invertedImage {
           let newImage = NSImage(size: bitmap.size)
           newImage.addRepresentation(bitmap)
           // Use the newImage as needed
       }
   }