Merge pull request #3 from trafi/feature/shadow

Shadow
trafi · Jul 24, 2020 · 5b81ee2 · 5b81ee2
2 parents a4278b6 + 4a29685
commit 5b81ee2
Show file tree

Hide file tree

Showing 5 changed files with 98 additions and 2 deletions.
diff --git a/Sources/ImageMod/ImageMod.swift b/Sources/ImageMod/ImageMod.swift
@@ -6,11 +6,13 @@ public struct ImageMod {
         var canvasSize: CGSize
         var drawRect: CGRect
         var tint: UIColor?
+        var shadow: (offset: CGPoint, blur: CGFloat, color: UIColor)?
 
         init(_ size: CGSize) {
             canvasSize = size
             drawRect = CGRect(origin: .zero, size: size)
             tint = nil
+            shadow = nil
         }
     }
 

diff --git a/Sources/ImageMod/ImageModable.swift b/Sources/ImageMod/ImageModable.swift
@@ -18,6 +18,18 @@ public extension ImageModable {
         }
     }
 
+    // MARK: Shadowed
+
+    func shadowed(offset: CGPoint = .zero, blur: CGFloat, color: UIColor = UIColor.black.withAlphaComponent(1/3)) -> ImageModable {
+        padded(top: max(0, blur - offset.y),
+               left: max(0, blur - offset.x),
+               bottom: max(0, blur + offset.y),
+               right: max(0, blur + offset.x))
+            .with {
+                $0.shadow = (offset, blur, color)
+            }
+    }
+
     // MARK: Padded
 
     func padded(top: CGFloat = 0, left: CGFloat = 0, bottom: CGFloat = 0, right: CGFloat = 0) -> ImageModable {

diff --git a/Sources/ImageMod/UIImage.swift b/Sources/ImageMod/UIImage.swift
@@ -6,7 +6,7 @@ extension UIImage: ImageModable {
         ImageMod(info: .init(size),
                  draw: { info in
                     self.withTintColor(info.tint, optimizedFor: info.drawRect.size)
-                        .draw(in: info.drawRect)
+                        .draw(in: info.drawRect, with: info.shadow)
         })
     }
 
@@ -23,4 +23,19 @@ extension UIImage: ImageModable {
             }
         }
     }
+
+    private func draw(in rect: CGRect, with shadow: (offset: CGPoint, blur: CGFloat, color: UIColor)?) {
+
+        let ctx = UIGraphicsGetCurrentContext()!
+        ctx.saveGState()
+        defer { ctx.restoreGState() }
+
+        if let shadow = shadow {
+            ctx.setShadow(offset: CGSize(width: shadow.offset.x, height: shadow.offset.y),
+                          blur: shadow.blur,
+                          color: shadow.color.cgColor)
+        }
+
+        draw(in: rect)
+    }
 }
diff --git a/Tests/ImageModTests/ShadowTests.swift b/Tests/ImageModTests/ShadowTests.swift
@@ -0,0 +1,55 @@
+import XCTest
+@testable import ImageMod
+
+final class ShadowTests: ModTests {
+
+    func test_itUsesShadowAndAddsPaddingForIt() {
+
+        _ = mod
+            .shadowed(offset: CGPoint(x: 2, y: 4), blur: 10, color: .red)
+            .image
+
+        XCTAssertEqual(mod.info.shadow?.offset, CGPoint(x: 2, y: 4))
+        XCTAssertEqual(mod.info.shadow?.blur, 10)
+        XCTAssertEqual(mod.info.shadow?.color, .red)
+
+        XCTAssertEqual(mod.info.canvasSize, CGSize(width: 120, height: 120))
+        XCTAssertEqual(mod.info.drawRect, CGRect(x: 8, y: 6, width: 100, height: 100))
+    }
+
+    func test_itHandlesOffsetLargerThanBlur() {
+
+        _ = mod
+            .shadowed(offset: CGPoint(x: 20, y: 40), blur: 10)
+            .image
+
+        XCTAssertEqual(mod.info.shadow?.offset, CGPoint(x: 20, y: 40))
+        XCTAssertEqual(mod.info.shadow?.blur, 10)
+
+        XCTAssertEqual(mod.info.canvasSize, CGSize(width: 130, height: 150))
+        XCTAssertEqual(mod.info.drawRect, CGRect(x: 0, y: 0, width: 100, height: 100))
+
+    }
+
+    func test_itUsesDefaultOffsetAndColor() {
+
+        _ = mod
+            .shadowed(blur: 10)
+            .image
+
+        XCTAssertEqual(mod.info.shadow?.offset, .zero)
+        XCTAssertEqual(mod.info.shadow?.blur, 10)
+        XCTAssertEqual(mod.info.shadow?.color, UIColor.black.withAlphaComponent(1/3))
+    }
+
+    func testChaining_itUsesLastShadow() {
+
+        _ = mod
+            .shadowed(blur: 10, color: .red)
+            .shadowed(blur: 20, color: .blue)
+            .image
+
+        XCTAssertEqual(mod.info.shadow?.blur, 20)
+        XCTAssertEqual(mod.info.shadow?.color, .blue)
+    }
+}
diff --git a/Tests/ImageModTests/UIImageTests.swift b/Tests/ImageModTests/UIImageTests.swift
@@ -14,11 +14,23 @@ final class UIImageTests: XCTestCase {
             .scaled(to: CGSize(width: 200, height: 100))
             .padded(by: 10)
             .tinted(.red)
+            .zStack(blackSquare
+                .shadowed(offset: CGPoint(x: 2, y: 4), blur: 8, color: .green)
+                .padded(top: 8, left: 4)
+            )
+            .hStack(blackSquare, spacing: 10, alignment: .top)
             .image
 
-        let image = UIGraphicsImageRenderer(size: CGSize(width: 220, height: 120)).image { context in
+        let image = UIGraphicsImageRenderer(size: CGSize(width: 240, height: 120)).image { context in
             UIColor.red.setFill()
             context.fill(CGRect(x: 10, y: 10, width: 200, height: 100))
+
+            UIColor.black.setFill()
+            context.cgContext.setShadow(offset: CGSize(width: 2, height: 4), blur: 8, color: UIColor.green.cgColor)
+            context.fill(CGRect(x: 105, y: 55, width: 10, height: 10))
+
+            context.cgContext.setShadow(offset: .zero, blur: 0, color: nil)
+            context.fill(CGRect(x: 230, y: 0, width: 10, height: 10))
         }
 
         XCTAssertEqual(sut.pngData(), image.pngData())