add spec to compare algebraic solution and OpenCV

Example/PerspectiveTransform.xcodeproj/project.pbxproj

@@ -33,6 +33,7 @@
 		4BDEE374200049CD007214F1 /* with-overlay.svg in Resources */ = {isa = PBXBuildFile; fileRef = 4B2D2E891C7C2E620045FD11 /* with-overlay.svg */; };
 		4BDEE37620005B6D007214F1 /* resetAnchorPoint.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BDEE37520005B6D007214F1 /* resetAnchorPoint.swift */; };
 		4BDEE37720005B6D007214F1 /* resetAnchorPoint.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BDEE37520005B6D007214F1 /* resetAnchorPoint.swift */; };
+		4BDF6470204691090022C5F8 /* OpenCV_Spec.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BDF646F204691090022C5F8 /* OpenCV_Spec.swift */; };
 		607FACD61AFB9204008FA782 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 607FACD51AFB9204008FA782 /* AppDelegate.swift */; };
 		607FACD81AFB9204008FA782 /* PanViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 607FACD71AFB9204008FA782 /* PanViewController.swift */; };
 		607FACDB1AFB9204008FA782 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 607FACD91AFB9204008FA782 /* Main.storyboard */; };
@@ -79,6 +80,7 @@
 		4BA7B14D1C7D710D00933779 /* ReferenceImages */ = {isa = PBXFileReference; lastKnownFileType = folder; path = ReferenceImages; sourceTree = "<group>"; };
 		4BDEE37220004185007214F1 /* PhotoViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PhotoViewController.swift; sourceTree = "<group>"; };
 		4BDEE37520005B6D007214F1 /* resetAnchorPoint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = resetAnchorPoint.swift; sourceTree = "<group>"; };
+		4BDF646F204691090022C5F8 /* OpenCV_Spec.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OpenCV_Spec.swift; sourceTree = "<group>"; };
 		4EA2244D76A3BF4D89D92FD5 /* README.md */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = net.daringfireball.markdown; name = README.md; path = ../README.md; sourceTree = "<group>"; };
 		54B21BF309BC78C5CEC00411 /* Pods-Example-Framework Unit Specs-Application Specs.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Example-Framework Unit Specs-Application Specs.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Example-Framework Unit Specs-Application Specs/Pods-Example-Framework Unit Specs-Application Specs.debug.xcconfig"; sourceTree = "<group>"; };
 		607FACD01AFB9204008FA782 /* Example.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Example.app; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -198,6 +200,7 @@
 		607FACE81AFB9204008FA782 /* Tests */ = {
 			isa = PBXGroup;
 			children = (
+				4BDF646F204691090022C5F8 /* OpenCV_Spec.swift */,
 				4BA7B14D1C7D710D00933779 /* ReferenceImages */,
 				4B2D2E861C7C2AD10045FD11 /* SnapshotSpec.swift */,
 				4B1B1C0C1C7A76C8003F8165 /* PerformanceTest.swift */,
@@ -611,6 +614,7 @@
 				4B2D2E871C7C2AD10045FD11 /* SnapshotSpec.swift in Sources */,
 				4BA3D17D1C771B560009B690 /* SpecHelper.swift in Sources */,
 				4B74DB47203BDA9C0030F41B /* PerformanceTest.swift in Sources */,
+				4BDF6470204691090022C5F8 /* OpenCV_Spec.swift in Sources */,
 				4BDEE37720005B6D007214F1 /* resetAnchorPoint.swift in Sources */,
 				4B4009952042575A00B7CE37 /* QuadrilateralCalc.swift in Sources */,
 			);
@@ -835,7 +839,6 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
-				SWIFT_OBJC_BRIDGING_HEADER = "Tests/Application Specs-Bridging-Header.h";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Example.app/Example";
 			};
@@ -855,7 +858,6 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
-				SWIFT_OBJC_BRIDGING_HEADER = "Tests/Application Specs-Bridging-Header.h";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Example.app/Example";
 			};
 			name = Release;

Example/Tests/OpenCV_Spec.swift

@@ -0,0 +1,87 @@
+import Quick
+import Nimble
+
+struct Quadrilateral {
+    var upperLeft, upperRight, lowerRight, lowerLeft:CGPoint
+}
+
+class OpenCVWrapper: NSObject {
+    func canBeCalledFromSwift() -> Bool {
+        return true
+    }
+
+    static func transform(_ from:Quadrilateral, to:Quadrilateral) -> CATransform3D {
+        return CATransform3DIdentity
+    }
+}
+
+class OpenCV_Spec: QuickSpec {
+    override func spec() {
+        describe("opencv") {
+            context("OpenCVWrapper") {
+                it("can be called from swift") {
+                    let wrapper = OpenCVWrapper()
+                    expect(wrapper).notTo(beNil())
+                    expect(wrapper.canBeCalledFromSwift()) == true
+                }
+
+                context("transform") {
+                    it("should be identity for same") {
+                        let start = Quadrilateral(upperLeft: CGPoint.zero,
+                                                  upperRight: CGPoint(x: 10, y: 0),
+                                                  lowerRight: CGPoint(x: 0, y: 10),
+                                                  lowerLeft: CGPoint(x: 10, y: 10))
+                        let desination = start
+                        let transform = OpenCVWrapper.transform(start, to: desination)
+                        expect(CATransform3DIsIdentity(transform)) == true
+                    }
+                }
+
+                context("compare with algebraic solution") {
+                    let points = [
+                        CGPoint(x: 108.315837, y: 80.1687782),
+                        CGPoint(x: 377.282671, y: 41.4352201),
+                        CGPoint(x: 193.321418, y: 330.023027),
+                        CGPoint(x: 459.781253, y: 251.836131),
+                        ]
+                    let frame = CGRect(origin: CGPoint.zero,
+                                       size: CGSize(width: 20, height: 10))
+
+                    func openCVTransform() -> CATransform3D {
+                        let start = Quadrilateral(upperLeft: CGPoint(x: frame.minX, y: frame.minY),
+                                                  upperRight: CGPoint(x: frame.maxX, y: frame.minY),
+                                                  lowerRight: CGPoint(x: frame.maxX, y: frame.maxY),
+                                                  lowerLeft: CGPoint(x: frame.minX, y: frame.maxY))
+                        let destination = Quadrilateral(upperLeft: points[0],
+                                                        upperRight: points[1],
+                                                        lowerRight: points[3],
+                                                        lowerLeft: points[2])
+                        return OpenCVWrapper.transform(start, to: destination)
+                    }
+
+                    func algebraTransform() -> CATransform3D {
+                        let destination = QuadrilateralCalc()
+                        destination.topLeft = points[0]
+                        destination.topRight = points[1]
+                        destination.bottomLeft = points[2]
+                        destination.bottomRight = points[3]
+
+                        let start = QuadrilateralCalc()
+                        start.topLeft = CGPoint(x: frame.minX, y: frame.minY)
+                        start.topRight = CGPoint(x: frame.maxX, y: frame.minY)
+                        start.bottomLeft = CGPoint(x: frame.minX, y: frame.maxY)
+                        start.bottomRight = CGPoint(x: frame.maxX, y: frame.maxY)
+
+                        return start.rectToQuad(rect: start.box(), quad: destination)
+                    }
+
+                    it("should be same") {
+                        let openCV = openCVTransform()
+                        let algebra = algebraTransform()
+                        expect(openCV) ≈ algebra
+                    }
+                }
+            }
+        }
+    }
+}

Example/Tests/SpecHelper.swift

@@ -34,6 +34,41 @@ func beCloseTo(_ expectedValue: Vector3Type, within delta: Double = 0.00001) ->
     }
 }
 
+
+extension CATransform3D {
+    func flattened() -> [CGFloat] {
+        return [
+            m11, m12, m13, m14,
+            m21, m22, m23, m24,
+            m31, m32, m33, m34,
+            m41, m42, m43, m44,
+        ]
+    }
+}
+
+public func beCloseTo(_ expectedValue: CATransform3D, within delta: CGFloat = CGFloat(DefaultDelta)) -> Predicate<CATransform3D> {
+    let errorMessage = "be close to <\(stringify(expectedValue))> (each within \(stringify(delta)))"
+    return Predicate.simple(errorMessage) { actualExpression in
+        if let actual = try actualExpression.evaluate() {
+            if CATransform3DEqualToTransform(actual, expectedValue) {
+                return .matches
+            } else {
+                let expected = expectedValue.flattened()
+                for (index, m) in actual.flattened().enumerated() {
+                    if fabs(m - expected[index]) > delta {
+                        return .doesNotMatch
+                    }
+                }
+                return .matches
+            }
+        }
+        return .doesNotMatch
+    }
+}
+
+public func ≈(lhs: Expectation<CATransform3D>, rhs: CATransform3D) {
+    lhs.to(beCloseTo(rhs))
+}
 public func ≈(lhs: Expectation<Matrix3x3Type>, rhs: Matrix3x3Type) {
     lhs.to(beCloseTo(rhs))
 }
@@ -110,7 +145,7 @@ extension GKRandomSource {
         return CGPoint(x: nextDouble(), y: nextDouble())
     }
 
-    func nextQuadrilateral() -> Quadrilateral {
-        return Quadrilateral(Array(0...3).map {_ in nextPoint()})
+    func nextQuadrilateral() -> PerspectiveTransform.Quadrilateral {
+        return PerspectiveTransform.Quadrilateral(Array(0...3).map {_ in nextPoint()})
     }
 }