Space rotates hints (to make hidden hints visible).

It is common for link-hint markers to be close togother, and
overlapping.

Here, `<Space>` rotates hint markers such that hidden markers become
visible.

For filtered hints we additionally require a modifier (because `<space>`
on its own is already a token separator).

The calculation of overlapping hints is quite expensive: O(n^2) in the
best case and O(n^3) in the worst cast.  The worst case is
extraordinarily unlikely to arise in practice.

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/unit_tests/rect_test.coffee b/tests/unit_tests/rect_test.coffee
index cfb26b05..0773dbcf 100644
--- a/tests/unit_tests/rect_test.coffee
+++ b/tests/unit_tests/rect_test.coffee
@@ -230,3 +230,59 @@ context "Rect subtraction",
             if resultComplement.length == 1
               complementRect = resultComplement[0]
               assert.isTrue Rect.contains subtractRect, complementRect
+
+context "Rect overlaps",
+  should "detect that a rect overlaps itself", ->
+    rect = Rect.create 2, 2, 4, 4
+    assert.isTrue Rect.rectsOverlap rect, rect
+
+  should "detect that non-overlapping rectangles do not overlap on the left", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 0, 2, 1, 4
+    assert.isFalse Rect.rectsOverlap rect1, rect2
+
+  should "detect that non-overlapping rectangles do not overlap on the right", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 5, 2, 6, 4
+    assert.isFalse Rect.rectsOverlap rect1, rect2
+
+  should "detect that non-overlapping rectangles do not overlap on the top", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 2, 0, 2, 1
+    assert.isFalse Rect.rectsOverlap rect1, rect2
+
+  should "detect that non-overlapping rectangles do not overlap on the bottom", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 2, 5, 2, 6
+    assert.isFalse Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles on the left", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 0, 2, 2, 4
+    assert.isTrue Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles on the right", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 4, 2, 5, 4
+    assert.isTrue Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles on the top", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 2, 4, 4, 5
+    assert.isTrue Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles on the bottom", ->
+    rect1 = Rect.create 2, 2, 4, 4
+    rect2 = Rect.create 2, 0, 4, 2
+    assert.isTrue Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles when second rectangle is contained in first", ->
+    rect1 = Rect.create 1, 1, 4, 4
+    rect2 = Rect.create 2, 2, 3, 3
+    assert.isTrue Rect.rectsOverlap rect1, rect2
+
+  should "detect overlapping rectangles when first rectangle is contained in second", ->
+    rect1 = Rect.create 1, 1, 4, 4
+    rect2 = Rect.create 2, 2, 3, 3
+    assert.isTrue Rect.rectsOverlap rect2, rect1
+