From f7fe3fa3868f4e7d84c7d0c8b04ccf6f0727f6bb Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Tue, 16 Nov 2010 15:20:37 -0800
Subject: Less redrawing of bits in the link thumbnail preview

---
 plugins/LinkPreview/linkpreview.js | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

(limited to 'plugins/LinkPreview')

diff --git a/plugins/LinkPreview/linkpreview.js b/plugins/LinkPreview/linkpreview.js
index 37b0241a5..5dca3a807 100644
--- a/plugins/LinkPreview/linkpreview.js
+++ b/plugins/LinkPreview/linkpreview.js
@@ -133,13 +133,34 @@
          */
         previewLinks: function(text)
         {
+            var old = LinkPreview.links;
             var links = LinkPreview.findLinks(text);
-            $('#link-preview').html('');
-            for (var i = 0; i < links.length; i++) {
-                var id = 'link-preview-' + i;
-                $('#link-preview').append('<span id="' + id + '"></span>');
-                LinkPreview.prepLinkPreview(id, links[i]);
+
+            // Check for existing common elements...
+            for (var i = 0; i < old.length && i < links.length; i++) {
+                if (links[i] != old[i]) {
+                    // Change an existing entry!
+                    var id = 'link-preview-' + i;
+                    $('#' + id).html('');
+                    LinkPreview.prepLinkPreview(id, links[i]);
+                }
+            }
+            if (links.length > old.length) {
+                // Adding new entries, whee!
+                for (var i = old.length; i < links.length; i++) {
+                    var id = 'link-preview-' + i;
+                    $('#link-preview').append('<span id="' + id + '"></span>');
+                    LinkPreview.prepLinkPreview(id, links[i]);
+                }
+            } else if (old.length > links.length) {
+                // Remove preview entries for links that have been removed.
+                for (var i = links.length; i < old.length; i++) {
+                    var id = 'link-preview-' + i;
+                    $('#' + id).remove();
+                }
             }
+
+            LinkPreview.links = links;
         }
     };
 
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