From 8c553818f9860460fc48078c4cea49b4a9709c0c Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Wed, 16 Jun 2021 13:21:24 -0400
Subject: [PATCH] Add information about lazy typesetting

---
 index.rst       |  1 +
 output/lazy.rst | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 output/lazy.rst

diff --git a/index.rst b/index.rst
index 3521a90..dac3930 100644
--- a/index.rst
+++ b/index.rst
@@ -64,6 +64,7 @@ need it.
    :titlesonly:
 
    Output Formats                     <output/index>
+   Lazy Typesetting                   <output/lazy>
    Line Breaking                      <output/linebreaks>
    Font Support                       <output/fonts>
    Browser Support                    <output/browser>
diff --git a/output/lazy.rst b/output/lazy.rst
new file mode 100644
index 0000000..2f0604b
--- /dev/null
+++ b/output/lazy.rst
@@ -0,0 +1,50 @@
+.. _lazy-typesetting:
+
+################
+Lazy Typesetting
+################
+
+MathJax offers an extension that is designed to improve the
+performance of pages with large numbers of equations. It implements a
+"lazy typesetting" approach that only processes an expression when it
+comes into view.  This means that expressions will not be typeset when
+they are not visible, and your readers will not have to wait for the
+entire document to typeset, speeding up their initial view of the
+page. Furthermore, any expressions that are never seen will not be
+typeset, saving the processing time that would normally have been
+spent on those expressions.
+
+This also helps with the situation where you may link to a particular
+location in your page (via a URL with a hash); typesetting the
+material above that point can cause the browser to change the scroll
+position, and so the user may not end up at the proper location in the
+page. With the lazy extension, the material above that point is not
+typeset until the user scrolls upwards, and so there is no position
+change.
+
+To use the lazy typesetting extension, simply add it to your
+configuration as follows:
+
+.. code-block:: latex
+
+   MathJax = {
+     loader: {load: ['ui/lazy']}
+   };
+
+This will adjust the typesetting pipeline to implement the
+lazy-typesetting functionality.
+
+Lazy typesetting works best with SVG output, but changes with the way
+the CommonHTML output handles its stylesheet updates make the CHTML
+output nearly as fast. With TeX input, the lazy extension makes sure
+that previous expressions are processed by TeX (though not output to
+the page) so that any macro definitions or automatic equation numbers
+are in place when the visible expressions are processed. Currently,
+documents that contain ``\ref`` or ``\eqref`` links may not yet work
+properly, since target equations may not have been typeset, and so the
+link location may not be marked in the document. In particular,
+forward references are unlikely to work, and backward references will
+work only if the target expression has already been typeset. We hope
+to improve this situation in a future release.
+
+|-----|