From 0c53ded3dcf513a8f082148c89364563850642ec Mon Sep 17 00:00:00 2001
From: Igor Shymko <igor.shimko@gmail.com>
Date: Thu, 23 Oct 2014 02:14:12 +0300
Subject: [PATCH] preview window is scrolling according to cursor position in
 markdown buffer

---
 markdown-preview-mode.el | 39 +++++++++++++++++++++++++--------------
 preview.html             |  7 +++++++
 2 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/markdown-preview-mode.el b/markdown-preview-mode.el
index 95abdb7..25e8cc0 100644
--- a/markdown-preview-mode.el
+++ b/markdown-preview-mode.el
@@ -95,20 +95,31 @@
   (mdpm:sent-preview-to mdpm:local-client))
 
 (defun mdpm:sent-preview-to (websocket)
-  (when markdown-preview-mode
-    (markdown markdown-output-buffer-name))
-  (with-current-buffer (get-buffer markdown-output-buffer-name)
-    (websocket-send-text websocket
-                         (concat
-                          "<div>"
-                          "<span id='style'>"
-                          markdown-preview-style
-                          "</span>"
-                          "<div id='content'>"
-                          (buffer-substring-no-properties (point-min) (point-max))
-                          "</div>"
-                          "</div>")
-                         )))
+  (let ((mark-position-percent
+         (number-to-string
+          (truncate
+           (* 100
+              (/
+               (float (line-number-at-pos))
+               (count-lines (point-min) (point-max))))))))
+
+    (when markdown-preview-mode
+      (markdown markdown-output-buffer-name))
+    (with-current-buffer (get-buffer markdown-output-buffer-name)
+      (websocket-send-text websocket
+                           (concat
+                            "<div>"
+                            "<span id='style'>"
+                            markdown-preview-style
+                            "</span>"
+                            "<span id='position-percentage'>"
+                            mark-position-percent
+                            "</span>"
+                            "<div id='content'>"
+                            (buffer-substring-no-properties (point-min) (point-max))
+                            "</div>"
+                            "</div>")
+                           ))))
 
 (defun mdpm:start ()
   (mdpm:start-websocket-server)
diff --git a/preview.html b/preview.html
index b2af54b..0a0e29f 100644
--- a/preview.html
+++ b/preview.html
@@ -5,6 +5,11 @@
     <meta name="viewport" content="width=device-width, initial-scale=1, minimal-ui">
     <title>Markdown preview</title>
     <link href="http://thomasf.github.io/solarized-css/solarized-dark.min.css" rel="stylesheet"></link>
+    <style>
+     code, kbd, pre, samp {
+         line-height: 1.2em;
+     }
+    </style>
     <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
     <script>
      (function($, undefined) {
@@ -23,6 +28,8 @@
          socket.onmessage = function(event) {
              loadCSS($(event.data).find("#style").text());
              $("#markdown-body").html($(event.data).find("#content").html());
+             var scroll = $(document).height() * ($(event.data).find("#position-percentage").html() / 100);
+             $("html, body").animate({ scrollTop: scroll }, 600);
          };
          socket.onerror = function(error) {
              alert("Error: " + error.message);