1 files changed, 153 insertions, 0 deletions
diff --git a/browser/tools/mozscreenshots/tests/browser/browser_screenshots_cropping.js b/browser/tools/mozscreenshots/tests/browser/browser_screenshots_cropping.js
new file mode 100644
index 0000000000..80fcde5d68
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+++ b/browser/tools/mozscreenshots/tests/browser/browser_screenshots_cropping.js
@@ -0,0 +1,153 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* import-globals-from ../../head.js */
+
+const { Rect } = ChromeUtils.importESModule(
+  "resource://gre/modules/Geometry.sys.mjs"
+);
+
+async function draw(window, src) {
+  const { document, Image } = window;
+
+  const promise = new Promise((resolve, reject) => {
+    const img = new Image();
+
+    img.onload = function () {
+      // Create a new offscreen canvas
+      const canvas = document.createElementNS(
+        "http://www.w3.org/1999/xhtml",
+        "canvas"
+      );
+      canvas.width = img.naturalWidth;
+      canvas.height = img.naturalHeight;
+      const ctx = canvas.getContext("2d");
+
+      ctx.drawImage(img, 0, 0);
+
+      resolve(canvas);
+    };
+
+    img.onerror = function () {
+      reject(`error loading image ${src}`);
+    };
+
+    // Load the src image for drawing
+    img.src = src;
+  });
+
+  return promise;
+}
+
+async function compareImages(window, expected, test) {
+  const testCanvas = await draw(window, test);
+  const expectedCanvas = await draw(window, expected);
+
+  is(
+    testCanvas.width,
+    expectedCanvas.width,
+    "The test and expected images must be the same size"
+  );
+  is(
+    testCanvas.height,
+    expectedCanvas.height,
+    "The test and expected images must be the same size"
+  );
+
+  var maxDifference = {};
+  var differences = window.windowUtils.compareCanvases(
+    expectedCanvas,
+    testCanvas,
+    maxDifference
+  );
+
+  // Fuzz for minor differences that can be caused by the encoder.
+  if (maxDifference.value > 1) {
+    return differences;
+  }
+  return 0;
+}
+
+async function cropAndCompare(window, src, expected, test, region, subregions) {
+  await TestRunner._cropImage(window, src, region, subregions, test);
+
+  return compareImages(window, expected, PathUtils.toFileURI(test));
+}
+
+add_task(async function crop() {
+  const window = Services.wm.getMostRecentWindow("navigator:browser");
+
+  const tmp = PathUtils.tempDir;
+  is(
+    await cropAndCompare(
+      window,
+      "resource://mozscreenshots/lib/robot.png",
+      "resource://mozscreenshots/lib/robot_upperleft.png",
+      PathUtils.join(tmp, "test_cropped_upperleft.png"),
+      new Rect(0, 0, 32, 32),
+      [new Rect(0, 0, 32, 32)]
+    ),
+    0,
+    "The image should be cropped to the upper left quadrant"
+  );
+
+  is(
+    await cropAndCompare(
+      window,
+      "resource://mozscreenshots/lib/robot.png",
+      "resource://mozscreenshots/lib/robot_center.png",
+      PathUtils.join(tmp, "test_cropped_center.png"),
+      new Rect(16, 16, 32, 32),
+      [new Rect(16, 16, 32, 32)]
+    ),
+    0,
+    "The image should be cropped to the center of the image"
+  );
+
+  is(
+    await cropAndCompare(
+      window,
+      "resource://mozscreenshots/lib/robot.png",
+      "resource://mozscreenshots/lib/robot_uncropped.png",
+      PathUtils.join(tmp, "test_uncropped.png"),
+      new Rect(-8, -9, 80, 80),
+      [new Rect(-8, -9, 80, 80)]
+    ),
+    0,
+    "The image should be not be cropped, and the cropping region should be clipped to the size of the image"
+  );
+
+  is(
+    await cropAndCompare(
+      window,
+      "resource://mozscreenshots/lib/robot.png",
+      "resource://mozscreenshots/lib/robot_diagonal.png",
+      PathUtils.join(tmp, "test_diagonal.png"),
+      new Rect(0, 0, 64, 64),
+      [
+        new Rect(0, 0, 16, 16),
+        new Rect(16, 16, 16, 16),
+        new Rect(32, 32, 16, 16),
+        new Rect(48, 48, 16, 16),
+      ]
+    ),
+    0,
+    "The image should be contain squares across the diagonal"
+  );
+
+  is(
+    await cropAndCompare(
+      window,
+      "resource://mozscreenshots/lib/robot.png",
+      "resource://mozscreenshots/lib/robot_cropped_diagonal.png",
+      PathUtils.join(tmp, "test_cropped_diagonal.png"),
+      new Rect(16, 16, 48, 48),
+      [new Rect(16, 16, 16, 16), new Rect(32, 32, 16, 16)]
+    ),
+    0,
+    "The image should be cropped with squares across the diagonal"
+  );
+});