From 47d6f90dd72f0d0d93ef4b405a2ddf330cfe8a7b Mon Sep 17 00:00:00 2001
From: Simon Whitty <simon.whitty@coles.com.au>
Date: Sat, 6 Sep 2025 21:39:33 +1000
Subject: [PATCH] resizable()

---
 Examples/Sources/GalleryView.swift       |  3 +-
 README.md                                | 18 +++--
 SwiftDraw/Sources/SVG+CoreGraphics.swift | 32 +++++++--
 SwiftDraw/Sources/SVGView.swift          | 86 +++++++++++++++++++++---
 4 files changed, 117 insertions(+), 22 deletions(-)

diff --git a/Examples/Sources/GalleryView.swift b/Examples/Sources/GalleryView.swift
index b23b0e2..9894189 100644
--- a/Examples/Sources/GalleryView.swift
+++ b/Examples/Sources/GalleryView.swift
@@ -61,7 +61,8 @@ struct GalleryView: View {
             LazyVStack(spacing: 20) {
                 ForEach(images, id: \.self) { image in
                     SVGView(image, bundle: .samples)
-                        .aspectRatio(contentMode: .fit)
+                        .resizable()
+                        .scaledToFit()
                         .padding([.leading, .trailing], 10)
                 }
             }
diff --git a/README.md b/README.md
index 510269c..431bd17 100644
--- a/README.md
+++ b/README.md
@@ -38,16 +38,22 @@ imageView.image = svg.rasterize()   // 240x200
 
 ### SwiftUI
 
-Display an image within `SVGView`:
+SVGs can be displayed within `SVGView` just like using SwiftUI's built-in `Image`:
 
 ```swift
-var body: some View {
-    SVGView("sample.svg")
-        .aspectRatio(contentMode: .fit)
-        .padding()
-}
+SVGView("sample.svg")
 ```
 
+By default, SVGs are rendered at their original (intrinsic) size. To make them flexible within layouts, mark them as resizable — exactly like `Image`:    
+
+```swift
+SVGView("sample.svg")
+   .resizable()
+   .scaledToFit()
+```
+
+This allows the SVG to scale proportionally to fit within its container.  Use `.scaledToFill()` to completely cover the container and use `.resizable(resizingMode: .tile)` to draw the SVG in repeating tiles filling the available space.
+
 When you load by name, SVGView uses an internal cache so repeated lookups are efficient.
 For more predictable performance (avoiding any cache lookup or parsing), you can pass an already-created SVG instance:
 
diff --git a/SwiftDraw/Sources/SVG+CoreGraphics.swift b/SwiftDraw/Sources/SVG+CoreGraphics.swift
index 2ad87b0..3be747f 100644
--- a/SwiftDraw/Sources/SVG+CoreGraphics.swift
+++ b/SwiftDraw/Sources/SVG+CoreGraphics.swift
@@ -35,22 +35,44 @@ public import Foundation
 
 public extension CGContext {
 
-    func draw(_ image: SVG, in rect: CGRect? = nil)  {
-        let defaultRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)
+    func draw(_ svg: SVG, in rect: CGRect? = nil)  {
+        let defaultRect = CGRect(x: 0, y: 0, width: svg.size.width, height: svg.size.height)
         let renderer = CGRenderer(context: self)
         saveGState()
 
         if let rect = rect, rect != defaultRect {
             translateBy(x: rect.origin.x, y: rect.origin.y)
             scaleBy(
-                x: rect.width / image.size.width,
-                y: rect.height / image.size.height
+                x: rect.width / svg.size.width,
+                y: rect.height / svg.size.height
             )
         }
-        renderer.perform(image.commands)
+        renderer.perform(svg.commands)
 
         restoreGState()
     }
+
+    func draw(_ svg: SVG, in rect: CGRect, byTiling: Bool) {
+        guard byTiling else {
+            draw(svg, in: rect)
+            return
+        }
+
+        let cols = Int(ceil(rect.size.width / svg.size.width))
+        let rows = Int(ceil(rect.size.height / svg.size.height))
+
+        for r in 0..<rows {
+            for c in 0..<cols {
+                let tile = CGRect(
+                    x: rect.minX + CGFloat(r) * svg.size.width,
+                    y: rect.minY + CGFloat(c) * svg.size.height,
+                    width: svg.size.width,
+                    height: svg.size.height
+                )
+                draw(svg, in: tile)
+            }
+        }
+    }
 }
 
 public extension SVG {
diff --git a/SwiftDraw/Sources/SVGView.swift b/SwiftDraw/Sources/SVGView.swift
index 30303ac..7b6d0a3 100644
--- a/SwiftDraw/Sources/SVGView.swift
+++ b/SwiftDraw/Sources/SVGView.swift
@@ -44,17 +44,52 @@ public struct SVGView: View {
     }
 
     private let svg: SVG?
+    private var resizingMode: ResizingMode?
 
     public var body: some View {
         if let svg {
-            Canvas(
-                 opaque: false,
-                 colorMode: .linear,
-                 rendersAsynchronously: false
-             ) { ctx, size in
-                 ctx.draw(svg, in: CGRect(origin: .zero, size: size))
-             }
-             .frame(idealWidth: svg.size.width, idealHeight: svg.size.height)
+            if let resizingMode {
+                SVGView.makeCanvas(svg: svg, resizingMode: resizingMode)
+                    .frame(idealWidth: svg.size.width, idealHeight: svg.size.height)
+            } else {
+                SVGView.makeCanvas(svg: svg, resizingMode: .stretch)
+                    .frame(width: svg.size.width, height: svg.size.height)
+            }
+        }
+    }
+
+    public enum ResizingMode: Sendable, Hashable {
+        /// A mode to repeat the image at its original size, as many
+        /// times as necessary to fill the available space.
+        case tile
+
+        /// A mode to enlarge or reduce the size of an image so that it
+        /// fills the available space.
+        case stretch
+    }
+
+    /// Sets the mode by which SwiftUI resizes an SVG to fit its space.
+    /// - Parameters:
+    ///   - resizingMode: The mode by which SwiftUI resizes the image.
+    /// - Returns: An SVGView, with the new resizing behavior set.
+    public func resizable(resizingMode: ResizingMode = .stretch) -> Self {
+        var copy = self
+        copy.resizingMode = resizingMode
+        return copy
+    }
+
+    private static func makeCanvas(svg: SVG, resizingMode: ResizingMode) -> some View {
+        Canvas(
+            opaque: false,
+            colorMode: .linear,
+            rendersAsynchronously: false
+        ) { ctx, size in
+            switch resizingMode {
+            case .tile:
+                ctx.draw(svg, in: CGRect(origin: .zero, size: size), byTiling: true)
+            case .stretch:
+                ctx.draw(svg, in: CGRect(origin: .zero, size: size))
+            }
         }
     }
 }
@@ -62,10 +97,41 @@ public struct SVGView: View {
 @available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *)
 public extension GraphicsContext {
 
-    func draw(_ image: SVG, in rect: CGRect? = nil)  {
+    func draw(_ svg: SVG, in rect: CGRect? = nil)  {
+        withCGContext {
+            $0.draw(svg, in: rect)
+        }
+    }
+
+    func draw(_ svg: SVG, in rect: CGRect, byTiling: Bool)  {
         withCGContext {
-            $0.draw(image, in: rect)
+            $0.draw(svg, in: rect, byTiling: byTiling)
         }
     }
 }
+
+@available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *)
+#Preview {
+    SVGView(svg: .circle)
+
+    SVGView(svg: .circle)
+        .resizable(resizingMode: .stretch)
+
+    SVGView(svg: .circle)
+        .resizable(resizingMode: .tile)
+}
+
+#if DEBUG
+private extension SVG {
+
+    static var circle: SVG {
+        SVG(xml: """
+        <svg version="1.1" xmlns="http://www.w3.org/2000/svg" width="100" height="100">
+          <circle cx="50" cy="50" r="50" fill="orange" />
+        </svg>
+        """)!
+    }
+}
+#endif
+
 #endif