Update Filter Demo (#252)

Dev/Sources/SwiftUIDemo/DemoFilterView.swift

@@ -34,12 +34,71 @@ struct DemoFilterView: View {
     }
   }
 
+  struct MotionBlurFilter: Filtering {
+
+    let kernel = CIKernel(source:
+"""
+    kernel vec4 motionBlur(sampler image, vec2 size, float sampleCount, float blur) {
+            int sampleCountInt = int(floor(sampleCount));
+            vec4 accumulator = vec4(0.0);
+            vec2 dc = destCoord();
+            float normalisedValue = length(((dc / size) - 0.5) * 2.0);
+            float strength = clamp((normalisedValue), 0.0, 1.0);
+            vec2 vector = normalize((dc - (size / 2.0)) / size);
+            vec2 velocity = vector * strength * blur;
+            vec2 redOffset = -vector * strength * (blur * 1.0);
+            vec2 greenOffset = -vector * strength * (blur * 1.5);
+            vec2 blueOffset = -vector * strength * (blur * 2.0);
+            for (int i=0; i < sampleCountInt; i++) {
+                accumulator.r += sample(image, samplerTransform(image, dc + redOffset)).r;
+                redOffset -= velocity / sampleCount;
+                accumulator.g += sample(image, samplerTransform(image, dc + greenOffset)).g;
+                greenOffset -= velocity / sampleCount;
+                accumulator.b += sample(image, samplerTransform(image, dc + blueOffset)).b;
+                blueOffset -= velocity / sampleCount;
+            }
+            return vec4(vec3(accumulator / float(sampleCountInt)), 1.0);
+        }
+""")!
+
+    func apply(to image: CIImage, sourceImage: CIImage) -> CIImage {
+
+      let width = image.extent.width + image.extent.minX*2
+      let height = image.extent.height + image.extent.minY*2
+
+      let base = Double(sqrt(pow(width, 2) + pow(height, 2)))
+      let radius = base / 40
+
+      let args = [
+        image,
+        CIVector(
+          x: width,
+          y: height
+        ),
+        20,
+        radius,
+      ] as [Any]
+
+      return kernel.apply(
+        extent: image.extent,
+        roiCallback: { _, rect in
+          rect
+        },
+        arguments: args
+      )!
+    }
+  }
+
   let invertFilter: InvertFilter = .init()
   let grayscaleFilter: GrayscaleFilter = .init()
+  let motionBlurFilter: MotionBlurFilter = .init()
 
   @StateObject var editingStack: EditingStack
   @State var invertToggle: Bool = false
-  @State var grascaleToggle: Bool = false
+  @State var grayscaleToggle: Bool = false
+  @State var motionBlurToggle: Bool = false
+
+  @State var resultImage: ResultImage?
 
   init(
     editingStack: @escaping () -> EditingStack
@@ -52,33 +111,44 @@ struct DemoFilterView: View {
 
       ViewHost(instantiated: ImagePreviewView(editingStack: editingStack))
 
+      SwiftUICropView(editingStack: editingStack, contentInset: .zero)
+        .clipped()
+
       VStack {
         Toggle("Invert", isOn: $invertToggle)
-          .onChange(of: invertToggle) { newValue in
-            editingStack.set(filters: {
-              $0.additionalFilters = [
-                grascaleToggle ? grayscaleFilter.asAny() : nil,
-                invertToggle ? invertFilter.asAny() : nil,
-              ].compactMap({ $0 })
-            })
-          }
+        Toggle("Grayscale", isOn: $grayscaleToggle)
+        Toggle("MotionBlur", isOn: $motionBlurToggle)
+      }
+      .onChange(of: [invertToggle, grayscaleToggle, motionBlurToggle], perform: { _ in
+        editingStack.set(filters: {
+          $0.additionalFilters = [
+            grayscaleToggle ? grayscaleFilter.asAny() : nil,
+            invertToggle ? invertFilter.asAny() : nil,
+            motionBlurToggle ? motionBlurFilter.asAny() : nil,
+          ].compactMap({ $0 })
+        })
+      })
+      .padding()
 
-        Toggle("Grayscale", isOn: $grascaleToggle)
-          .onChange(of: grascaleToggle) { newValue in
-            editingStack.set(filters: {
-              $0.additionalFilters = [
-                grascaleToggle ? grayscaleFilter.asAny() : nil,
-                invertToggle ? invertFilter.asAny() : nil,
-              ].compactMap({ $0 })
-            })
+      Button("Done") {
+        try! editingStack.makeRenderer().render { result in
+          switch result {
+          case let .success(rendered):
+            self.resultImage = .init(cgImage: rendered.cgImage)
+          case let .failure(error):
+            print(error)
           }
+        }
       }
-      .padding()
 
     }
     .onAppear {
       editingStack.start()
     }
+    .sheet(item: $resultImage) {
+      RenderedResultView(result: $0)
+    }
+
   }
 
 }