Add rect helper function to check closeness in a11y extensions

AX-Relnotes: n/a.
Bug: None.
Change-Id: I5bb22367303e0a84ce68ad6b4d083ec311d2b36c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2391596
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: Abigail Klein <abigailbklein@google.com>
Cr-Commit-Position: refs/heads/master@{#808593}

chrome/browser/resources/chromeos/accessibility/common/rect_util.js

@@ -78,6 +78,28 @@ const RectUtil = {
     return {x, y};
   },
 
+  /**
+   * Checks if the two specified rectangles are within at most a specified
+   * distance of each other both horizontally and vertically.
+   * @param {ScreenRect} rect1
+   * @param {ScreenRect} rect2
+   * @param {number} tolerance
+   * @return {boolean}
+   */
+  close: (rect1, rect2, tolerance) => {
+    const maxLeft = rect1.left > rect2.left ? rect1.left : rect2.left;
+    const minRight = RectUtil.right(rect1) < RectUtil.right(rect2) ?
+        RectUtil.right(rect1) :
+        RectUtil.right(rect2);
+    const maxTop = rect1.top > rect2.top ? rect1.top : rect2.top;
+    const minBottom = RectUtil.bottom(rect1) < RectUtil.bottom(rect2) ?
+        RectUtil.bottom(rect1) :
+        RectUtil.bottom(rect2);
+
+    // Negative values indicate the rectangles overlap in that dimension.
+    return maxLeft - minRight <= tolerance && maxTop - minBottom <= tolerance;
+  },
+
   /**
    * @param {ScreenRect} outer
    * @param {ScreenRect} inner

chrome/browser/resources/chromeos/accessibility/common/rect_util_unittest.js

@@ -71,6 +71,63 @@ TEST_F('RectUtilUnitTest', 'Adjacent', function() {
   }
 });
 
+TEST_F('RectUtilUnitTest', 'Close', function() {
+  const centerRect = {left: 10, top: 10, width: 10, height: 10};
+  assertTrue(RectUtil.close(centerRect, centerRect, 0));
+
+  // Adjacent to the left of centerRect.
+  const leftRect = {left: 5, top: 10, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, leftRect, 5));
+  assertTrue(RectUtil.close(centerRect, leftRect, 0));
+  assertTrue(RectUtil.close(leftRect, centerRect, 0));
+
+  // 2dp away to the right of centerRect.
+  const rightRect = {left: 22, top: 17, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, rightRect, 5));
+  assertTrue(RectUtil.close(rightRect, centerRect, 5));
+  assertFalse(RectUtil.close(centerRect, rightRect, 0));
+  assertFalse(RectUtil.close(rightRect, centerRect, 0));
+
+  // 5dp above centerRect.
+  const topRect = {left: 12, top: 0, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, topRect, 5));
+  assertTrue(RectUtil.close(topRect, centerRect, 5));
+  assertFalse(RectUtil.close(centerRect, topRect, 4));
+  assertFalse(RectUtil.close(topRect, centerRect, 4));
+
+  // Adjacent below centerRect.
+  const bottomRect = {left: 15, top: 20, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, bottomRect, 0));
+  assertTrue(RectUtil.close(bottomRect, centerRect, 0));
+
+  // Touching at the top left corner of centerRect.
+  const topLeftRect = {left: 5, top: 5, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, topLeftRect, 0));
+  assertTrue(RectUtil.close(topLeftRect, centerRect, 0));
+
+  // 1dp off in each dimension from the bottom right corner of centerRect.
+  const bottomRightRect = {left: 21, top: 21, width: 5, height: 5};
+  assertTrue(RectUtil.close(centerRect, bottomRightRect, 1));
+  assertTrue(RectUtil.close(bottomRightRect, centerRect, 1));
+  assertFalse(RectUtil.close(centerRect, bottomRightRect, 0));
+  assertFalse(RectUtil.close(bottomRightRect, centerRect, 0));
+
+  // Overlapping horizontally, but far vertically.
+  const verticallyFarRect = {left: 15, top: 100, width: 5, height: 5};
+  assertFalse(RectUtil.close(centerRect, verticallyFarRect, 5));
+  assertFalse(RectUtil.close(verticallyFarRect, centerRect, 5));
+
+  // Overlapping vertically, but far horizontally.
+  const horizontallyFarRect = {left: 100, top: 15, width: 5, height: 5};
+  assertFalse(RectUtil.close(centerRect, horizontallyFarRect, 5));
+  assertFalse(RectUtil.close(horizontallyFarRect, centerRect, 5));
+
+  // Far away in both dimensions from centerRect.
+  const farRect = {left: 100, top: 100, width: 1, height: 1};
+  assertFalse(RectUtil.close(centerRect, farRect, 20));
+  assertFalse(RectUtil.close(farRect, centerRect, 20));
+});
+
 TEST_F('RectUtilUnitTest', 'Equals', function() {
   const rect1 = {left: 0, top: 0, width: 10, height: 10};
   const rect2 = {left: 0, top: 0, width: 10, height: 10};