Nicer toolbar buttons

App/Common UI/GradientView.swift

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+//
+//  GradientView.swift
+//  App
+//
+//  Created by James Magahern on 8/14/20.
+//
+
+import UIKit
+
+class GradientView: UIImageView
+{
+    enum Direction {
+        case horizontal
+        case vertical
+    }
+    
+    var direction: Direction = .horizontal {
+        didSet { image = nil; setNeedsLayout() }
+    }
+    
+    var colors: [UIColor] = [] {
+        didSet { image = nil; setNeedsLayout() }
+    }
+    
+    private var generatedImageSize: CGSize?
+    
+    convenience init(direction: Direction, colors: [UIColor]) {
+        self.init(image: nil)
+        self.direction = direction
+        self.colors = colors
+    }
+    
+    private func gradientImage(forSize size: CGSize) -> UIImage? {
+        var image: UIImage? = nil
+        
+        UIGraphicsBeginImageContext(size)
+        if let context = UIGraphicsGetCurrentContext() {
+            let gradientColorsArray = self.colors.map { $0.cgColor }
+            
+            if let gradient = CGGradient(colorsSpace: nil, colors: gradientColorsArray as CFArray, locations: nil) {
+                if direction == .horizontal {
+                    context.drawLinearGradient(gradient, start: .zero, end: CGPoint(x: size.width, y: 0.0), options: CGGradientDrawingOptions())
+                } else if direction == .vertical {
+                    context.drawLinearGradient(gradient, start: CGPoint(x: size.width / 2, y: 0), end: CGPoint(x: size.width / 2, y: size.height), options: CGGradientDrawingOptions())
+                }
+            }
+            
+            image = UIGraphicsGetImageFromCurrentImageContext()
+            UIGraphicsEndImageContext();
+        }
+        
+        return image
+    }
+    
+    override func layoutSubviews() {
+        super.layoutSubviews()
+        
+        var needsNewImage: Bool = image == nil
+        if let generatedImageSize = generatedImageSize {
+            if generatedImageSize != bounds.size {
+                needsNewImage = true
+            }
+        } else {
+            needsNewImage = true
+        }
+        
+        if needsNewImage {
+            image = gradientImage(forSize: bounds.size)
+            generatedImageSize = bounds.size
+        }
+    }
+}