From 1840f5b15218c7ffdf592f2020bd6731be199e12 Mon Sep 17 00:00:00 2001
From: Simon Lydell <simon.lydell@gmail.com>
Date: Sun, 6 Nov 2016 10:33:51 +0100
Subject: [PATCH] Improve hint marker positioning

A pixel up, down, left or right _is_ visible. Using `Math.round` goes to
the most expected pixel. Previously, markers many times appeared to be
slightly too close to the top of elements, rather than at the center.
---
 extension/lib/markable-elements.coffee | 8 ++++----
 extension/lib/marker.coffee            | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/extension/lib/markable-elements.coffee b/extension/lib/markable-elements.coffee
index 63adf68..b648136 100644
--- a/extension/lib/markable-elements.coffee
+++ b/extension/lib/markable-elements.coffee
@@ -177,14 +177,14 @@ getElementShape = (elementData, tryRight, rects = null) ->
     offset = null
     if rects.length == 1
       lefts = boxQuads
-        .map(({bounds}) -> Math.floor(bounds.left))
-        .filter((left) -> left >= Math.floor(nonCoveredPointRect.left))
+        .map(({bounds}) -> Math.round(bounds.left))
+        .filter((left) -> left >= Math.round(nonCoveredPointRect.left))
       offset = if lefts.length == 0 then null else Math.min(lefts...)
     else
       {bounds: {left}} =
         boxQuads[Math.min(nonCoveredPointRect.index, boxQuads.length - 1)]
       offset = Math.max(nonCoveredPointRect.left, left)
-    result.textOffset = Math.floor(offset - nonCoveredPointRect.left) if offset?
+    result.textOffset = Math.round(offset - nonCoveredPointRect.left) if offset?
 
   return result
 
@@ -209,7 +209,7 @@ getFirstNonCoveredPoint = (elementData, elementRect, tryRight) ->
   {left, top, bottom, height} = elementRect
   return tryPoint(
     elementData, elementRect,
-    left, +1, Math.floor(top + height / 2), 0, tryRight
+    left, +1, Math.round(top + height / 2), 0, tryRight
   )
 
 # Tries a point `(x + dx, y + dy)`. Returns `(x, y)` (and the frame offset) if
diff --git a/extension/lib/marker.coffee b/extension/lib/marker.coffee
index 2f38246..afb8643 100644
--- a/extension/lib/marker.coffee
+++ b/extension/lib/marker.coffee
@@ -94,7 +94,7 @@ class Marker
       left -= Math.max(0, rect.width - elementWidth * @zoom)
 
     # Center the marker vertically on the non-covered point.
-    top -= Math.ceil(rect.height / 2)
+    top -= Math.round(rect.height / 2)
 
     # Make sure that the marker stays within the viewport.
     left = Math.min(left, @zoom * @viewport.right  - rect.width)
-- 
2.39.3