Bug 304563 Add autoscroll support to SeaMonkey (browser only, for now)

r=db48x sr=neil

themes/classic/communicator/communicator.css

@@ -92,3 +92,13 @@
   margin-right: 2px;
 }
 
+/* :::::: autoscroll popup ::::: */
+
+#autoscroller { 
+  height: 28px;
+  width: 28px;
+  border: 0px;
+  margin: -14px;
+  padding: 0px;
+  background-image: url("chrome://communicator/skin/icons/autoscroll.gif");
+}

themes/classic/jar.mn

@@ -55,6 +55,7 @@ classic.jar:
   skin/classic/communicator/brand/throbber-anim.gif                     (communicator/brand/throbber-anim.gif)
   skin/classic/communicator/brand/throbber16-single.gif                 (communicator/brand/throbber16-single.gif)
   skin/classic/communicator/brand/throbber16-anim.gif                   (communicator/brand/throbber16-anim.gif)
+  skin/classic/communicator/icons/autoscroll.gif                        (communicator/icons/autoscroll.gif)
   skin/classic/communicator/icons/offline.gif                           (communicator/icons/offline.gif)
   skin/classic/communicator/icons/online.gif                            (communicator/icons/online.gif)
   skin/classic/communicator/icons/search-act.gif                        (communicator/icons/search-act.gif)

themes/modern/communicator/communicator.css

@@ -89,3 +89,13 @@
   margin-right: 2px;
 }
 
+/* :::::: autoscroll popup ::::: */
+
+#autoscroller { 
+  height: 28px;
+  width: 28px;
+  border: 0px;
+  margin: -14px;
+  padding: 0px;
+  background-image: url("chrome://communicator/skin/icons/autoscroll.gif");
+}

themes/modern/jar.mn

@@ -28,6 +28,7 @@ modern.jar:
   skin/modern/communicator/directory/file-folder-open.gif          (communicator/directory/file-folder-open.gif)
   skin/modern/communicator/directory/file-icon.gif                 (communicator/directory/file-icon.gif)
   skin/modern/communicator/directory/directory.css                 (communicator/directory/directory.css)
+  skin/modern/communicator/icons/autoscroll.gif                    (communicator/icons/autoscroll.gif)
   skin/modern/communicator/icons/loading.gif                       (communicator/icons/loading.gif)
   skin/modern/communicator/icons/lock-broken.gif                   (communicator/icons/lock-broken.gif)
   skin/modern/communicator/icons/lock-insecure.gif                 (communicator/icons/lock-insecure.gif)

xpfe/browser/resources/content/navigator.xul

@@ -139,6 +139,8 @@
   <!-- context menu -->
   <popupset id="contentAreaContextSet"/>
 
+  <popup id="autoscroller" onpopuphidden="stopScrolling()"/>
+
   <toolbox id="navigator-toolbox" class="toolbox-top" deferattached="true">
     <!-- Menu -->
     <menubar id="main-menubar" persist="collapsed" grippytooltiptext="&menuBar.tooltip;"/>
@@ -346,6 +348,7 @@
                     contentcontextmenu="contentAreaContextMenu"
                     onnewtab="BrowserOpenTab();"
                     onbookmarkgroup="addGroupmarkAs();"
+                    onmousedown="return contentAreaMouseDown(event);"
                     onclick="return contentAreaClick(event);"/>
       </hbox>
     </vbox>  

xpfe/communicator/resources/content/contentAreaClick.js

@@ -49,6 +49,14 @@
   pref = Components.classes["@mozilla.org/preferences-service;1"]
                    .getService(Components.interfaces.nsIPrefBranch);
 
+  var startX;
+  var startY;
+  var currX;
+  var currY;
+  var scrollingView;
+  var autoScrollTimer;
+  var ignoreMouseEvents;
+
   // Prefill a single text field
   function prefillTextBox(target) {
     // obtain values to be used for prefilling
@@ -201,6 +209,71 @@
     return true;
   }
 
+  function contentAreaMouseDown(event)
+  {
+    if (event.button == 1 && (event.target != event.currentTarget)
+        && !hrefAndLinkNodeForClickEvent(event)
+        && (!pref || !pref.getBoolPref("middlemouse.contentLoadURL"))) {
+      startScrolling(event);
+      ignoreMouseEvents = true;
+      return false;
+    }
+    return true;
+  }
+
+  function startScrolling(event)
+  {
+    var scroller = document.getElementById("autoscroller");
+    if (scrollingView || !scroller)
+      return;
+    document.popupNode = null;
+    scroller.showPopup(scroller.parentNode, event.screenX, event.screenY,
+                       "popup", null, null);
+    startX = event.screenX;
+    startY = event.screenY;
+    currX = event.screenX;
+    currY = event.screenY;
+    addEventListener('mousemove', handleMouseMove, true);
+    addEventListener('mouseup', handleMouseUpDown, true);
+    addEventListener('mousedown', handleMouseUpDown, true);
+    autoScrollTimer = setInterval(autoScrollLoop, 10);
+    scrollingView = event.originalTarget.ownerDocument.defaultView;
+  }
+
+  function handleMouseMove(event)
+  {
+    currX = event.screenX;
+    currY = event.screenY;
+  }
+
+  function autoScrollLoop()
+  {
+    var x = currX - startX;
+    var y = currY - startY;
+    const speed = 4;
+    if (Math.abs(x) >= speed || Math.abs(y) >= speed)
+      ignoreMouseEvents = false;
+    scrollingView.scrollBy(x / speed, y / speed);
+  }
+
+  function handleMouseUpDown(event)
+  {
+    if (!ignoreMouseEvents)
+      document.getElementById("autoscroller").hidePopup();
+    ignoreMouseEvents = false;
+  }
+
+  function stopScrolling()
+  {
+    if (scrollingView) {
+      scrollingView = null;
+      removeEventListener('mousemove', handleMouseMove, true);
+      removeEventListener('mousedown', handleMouseUpDown, true);
+      removeEventListener('mouseup', handleMouseUpDown, true);
+      clearInterval(autoScrollTimer);
+    }
+  }
+
   function openNewTabOrWindow(event, href, sendReferrer)
   {
     // should we open it in a new tab?