Backport SVGView to iOS 13 / macOS 10.15

SwiftDraw/Sources/CanvasNSView.swift

@@ -0,0 +1,80 @@
+//
+//  CanvasNSView.swift
+//  SwiftDraw
+//
+//  Created by Simon Whitty on 07/9/25.
+//  Copyright 2025 Simon Whitty
+//
+//  Distributed under the permissive zlib license
+//  Get the latest version from here:
+//
+//  https://github.com/swhitty/SwiftDraw
+//
+//  This software is provided 'as-is', without any express or implied
+//  warranty.  In no event will the authors be held liable for any damages
+//  arising from the use of this software.
+//
+//  Permission is granted to anyone to use this software for any purpose,
+//  including commercial applications, and to alter it and redistribute it
+//  freely, subject to the following restrictions:
+//
+//  1. The origin of this software must not be misrepresented; you must not
+//  claim that you wrote the original software. If you use this software
+//  in a product, an acknowledgment in the product documentation would be
+//  appreciated but is not required.
+//
+//  2. Altered source versions must be plainly marked as such, and must not be
+//  misrepresented as being the original software.
+//
+//  3. This notice may not be removed or altered from any source distribution.
+//
+
+#if canImport(AppKit)
+import AppKit
+import SwiftUI
+
+@available(macOS, deprecated: 12.0, message: "use SwiftUI.Canvas")
+struct CanvasFallbackView: NSViewRepresentable {
+
+    var svg: SVG
+    var capInsets: EdgeInsets
+    var resizingMode: SVGView.ResizingMode
+
+    func makeNSView(context: Context) -> CanvasNSView {
+        let nsView = CanvasNSView()
+        nsView.wantsLayer = true
+        nsView.layerContentsRedrawPolicy = .duringViewResize
+        nsView.layer?.needsDisplayOnBoundsChange = true
+        return nsView
+    }
+
+    func updateNSView(_ nsView: CanvasNSView, context: Context) {
+        nsView.svg = svg
+        nsView.resizeMode = resizingMode
+        nsView.capInsets = (capInsets.top, capInsets.leading, capInsets.bottom, capInsets.trailing)
+        nsView.needsDisplay = true
+    }
+}
+
+final class CanvasNSView: NSView {
+
+    var svg: SVG?
+    var resizeMode: SVGView.ResizingMode = .stretch
+    var capInsets: (top: CGFloat, left: CGFloat, bottom: CGFloat, right: CGFloat) = (0, 0, 0, 0)
+
+    override var isFlipped: Bool { true }
+
+    override func draw(_ dirtyRect: NSRect) {
+        guard let svg,
+              let ctx = NSGraphicsContext.current?.cgContext else { return }
+
+        ctx.draw(
+            svg,
+            in: bounds,
+            capInsets: capInsets,
+            byTiling: resizeMode == .tile
+        )
+    }
+}
+
+#endif

SwiftDraw/Sources/CanvasUIView.swift

@@ -0,0 +1,77 @@
+//
+//  CanvasUIView.swift
+//  SwiftDraw
+//
+//  Created by Simon Whitty on 07/9/25.
+//  Copyright 2025 Simon Whitty
+//
+//  Distributed under the permissive zlib license
+//  Get the latest version from here:
+//
+//  https://github.com/swhitty/SwiftDraw
+//
+//  This software is provided 'as-is', without any express or implied
+//  warranty.  In no event will the authors be held liable for any damages
+//  arising from the use of this software.
+//
+//  Permission is granted to anyone to use this software for any purpose,
+//  including commercial applications, and to alter it and redistribute it
+//  freely, subject to the following restrictions:
+//
+//  1. The origin of this software must not be misrepresented; you must not
+//  claim that you wrote the original software. If you use this software
+//  in a product, an acknowledgment in the product documentation would be
+//  appreciated but is not required.
+//
+//  2. Altered source versions must be plainly marked as such, and must not be
+//  misrepresented as being the original software.
+//
+//  3. This notice may not be removed or altered from any source distribution.
+//
+
+#if canImport(UIKit)
+import UIKit
+import SwiftUI
+
+@available(iOS, deprecated: 15.0, message: "use SwiftUI.Canvas")
+struct CanvasFallbackView: UIViewRepresentable {
+
+    var svg: SVG
+    var capInsets: EdgeInsets
+    var resizingMode: SVGView.ResizingMode
+
+    func makeUIView(context: Context) -> CanvasUIView {
+        let uiView = CanvasUIView()
+        uiView.isOpaque = false
+        uiView.contentMode = .redraw
+        return uiView
+    }
+
+    func updateUIView(_ uiView: CanvasUIView, context: Context) {
+        uiView.svg = svg
+        uiView.resizeMode = resizingMode
+        uiView.capInsets = (capInsets.top, capInsets.leading, capInsets.bottom, capInsets.trailing)
+        uiView.setNeedsDisplay()
+    }
+}
+
+final class CanvasUIView: UIView {
+
+    var svg: SVG?
+    var resizeMode: SVGView.ResizingMode = .stretch
+    var capInsets: (top: CGFloat, left: CGFloat, bottom: CGFloat, right: CGFloat) = (0, 0, 0, 0)
+
+    override func draw(_ rect: CGRect) {
+        guard let svg,
+              let ctx = UIGraphicsGetCurrentContext() else { return }
+
+        ctx.draw(
+            svg,
+            in: rect,
+            capInsets: capInsets,
+            byTiling: resizeMode == .tile
+        )
+    }
+}
+
+#endif

SwiftDraw/Sources/SVGView.swift

@@ -32,7 +32,6 @@
 #if canImport(SwiftUI)
 public import SwiftUI
 
-@available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *)
 public struct SVGView: View {
 
     public init(_ name: String, bundle: Bundle = .main) {
@@ -83,17 +82,26 @@ public struct SVGView: View {
         return copy
     }
 
+    @ViewBuilder
     private static func makeCanvas(svg: SVG, capInsets: EdgeInsets = .init(), resizingMode: ResizingMode) -> some View {
-        Canvas(
-            opaque: false,
-            colorMode: .linear,
-            rendersAsynchronously: false
-        ) { ctx, size in
-            ctx.draw(
-                svg,
-                in: CGRect(origin: .zero, size: size),
+        if #available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *) {
+            Canvas(
+                opaque: false,
+                colorMode: .linear,
+                rendersAsynchronously: false
+            ) { ctx, size in
+                ctx.draw(
+                    svg,
+                    in: CGRect(origin: .zero, size: size),
+                    capInsets: capInsets,
+                    byTiling: resizingMode == .tile
+                )
+            }
+        } else {
+            CanvasFallbackView(
+                svg: svg,
                 capInsets: capInsets,
-                byTiling: resizingMode == .tile
+                resizingMode: resizingMode
             )
         }
     }