(#68) Moved edge detection in images to separate function

Author: s1hofmann

Diff for: lib/provider/opencv/find-edges.function.spec.ts

@@ -0,0 +1,22 @@
+import * as cv from "opencv4nodejs-prebuilt";
+import { mockPartial } from "sneer";
+import { findEdges } from "./find-edges.function";
+
+describe("findEdges", () => {
+  it("should convert an image to grayscale and run Canny edge detection", async () => {
+    // GIVEN
+    const grayImageMock = mockPartial<cv.Mat>({
+      cannyAsync: jest.fn()
+    });
+    const inputImageMock = mockPartial<cv.Mat>({
+      cvtColorAsync: jest.fn(() => Promise.resolve(grayImageMock))
+    });
+
+    // WHEN
+    await findEdges(inputImageMock);
+
+    // THEN
+    expect(inputImageMock.cvtColorAsync).toBeCalledWith(cv.COLOR_BGR2GRAY);
+    expect(grayImageMock.cannyAsync).toBeCalledWith(50, 200);
+  });
+});

Diff for: lib/provider/opencv/find-edges.function.ts

@@ -0,0 +1,6 @@
+import * as cv from "opencv4nodejs-prebuilt";
+
+export const findEdges = async (image: cv.Mat): Promise<cv.Mat> => {
+  const gray = await image.cvtColorAsync(cv.COLOR_BGR2GRAY);
+  return gray.cannyAsync(50, 200);
+};