author James Teh <>
Wed, 01 Feb 2023 05:02:01 +0000
changeset 651150 dd0fdd1daa69783be36acd5c50544f3694eaa8f9
parent 275126 e52c8b7764e24cdfcd1a9b4a65701f5705af540d
permissions -rw-r--r--
Bug 1813980: Check IsDoc before Parent in RemoteAccessibleBase::ApplyCrossDocOffset. r=morgan We call this function on every ancestor when calculating bounds. RemoteParent() currently requires a hash lookup, so it's more efficient to early return for !IsDoc() first. This is a micro-optimisation, but it might have some impact given that we call this on every ancestor, especially when hit testing, where we call Bounds() a lot. As a bit of drive-by cleanup, use RemoteParent() rather than calling Parent() and IsRemote/AsRemote(). Differential Revision:

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  <meta charset="utf-8">
  <title>Reference: margin:auto on grid abs.pos. child</title>
  <link rel="author" title="Mats Palmgren" href="">
  <style type="text/css">

div {
  display: block;
  position: relative;
  grid-template-columns: 100px;
  grid-template-rows: 100px;
  width: 100px;
  height: 100px;
  border: 1px solid;

span {
  display: block;
  position: absolute;
  background: lime;
  width: 20px;
  height: 20px;
  margin: 5px 7px 11px 13px;
  top:0; left:0; right:0; bottom:0;


<div><span style="margin-left:auto"></span></div>
<div><span style="margin-right:auto"></span></div>
<div><span style="margin-left:auto; margin-right:auto"></span></div>
<div><span style="margin-top:auto"></span></div>
<div><span style="margin-bottom:auto"></span></div>
<div><span style="margin-top:auto; margin-bottom:auto"></span></div>
<div><span style="margin:auto"></span></div>