Compute local Mac plugin coordinates from scratch

This a more drastic but more robust temporary workaround for the zoomed plugin bug. Instead of trying to guess whether the page is zoomed, which turns out not to be feasible if the page has been scrolled, we treat non-global mouse coordinates as suspect and compute our own instead.

BUG=26466
TEST=Mouse handling for Mac plugins, both Carbon and Cocoa, should work correctly at any zoom, with any amount of page scrolling.

Review URL: http://codereview.chromium.org/1528027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44246 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 30 insertions, 45 deletions

diff --git a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
index 3e86a7b..6a9dc07 100644
--- a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
+++ b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
@@ -1004,37 +1004,6 @@ static bool EventIsRelatedToDrag(const WebInputEvent& event, int drag_buttons) {
   return false;
 }
 
-float WebPluginDelegateImpl::ApparentEventZoomLevel(
-    const WebMouseEvent& event) {
-  float real_window_x = event.globalX - content_area_origin_.x();
-  float real_window_y = event.globalY - content_area_origin_.y();
-  if ((real_window_x == 0 && real_window_y == 0) ||
-      (event.windowX == 0 && event.windowY == 0))
-    return 1.0;
-  // There are two ways the window coordinates could be mismatched:
-  // 1) The plugin is zoomed (the event coordinates are scaled for the zoom
-  //    level, even though window_rect_ isn't: <http://crbug.com/9996>).
-  // 2) The tracking of where the window is has gotten out of sync with reality.
-  // To distinguish, see if a zoom would explain both the x and y offsets.
-  // If not, this isn't a zoom.
-
-  // Figure out the apparent zoom ratio using the larger value, since it's less
-  // affected by rounding error, then see if the other value is consistent.
-  float apparent_zoom = 1.0;
-  float discrepancy = 0.0;
-  if (event.windowY > event.windowX) {
-    apparent_zoom = real_window_y / event.windowY;
-    discrepancy = fabsf(event.windowX * apparent_zoom - real_window_x);
-  } else {
-    apparent_zoom = real_window_x / event.windowX;
-    discrepancy = fabsf(event.windowY * apparent_zoom - real_window_y);
-  }
-  if (discrepancy > 2.5)
-    return 1.0;
-
-  return apparent_zoom;
-}
-
 bool WebPluginDelegateImpl::PlatformHandleInputEvent(
     const WebInputEvent& event, WebCursorInfo* cursor_info) {
   DCHECK(cursor_info != NULL);
@@ -1049,10 +1018,14 @@ bool WebPluginDelegateImpl::PlatformHandleInputEvent(
   }
 #endif
 
-  float zoom_level = 1.0;
-  const float kEpsilon = 0.001;  // Smaller than an actual zoom would ever be.
   if (WebInputEvent::isMouseEventType(event.type) ||
       event.type == WebInputEvent::MouseWheel) {
+    // Ideally we would compute the content origin from the web event using the
+    // code below as a safety net for missed content area location changes.
+    // Because of <http://crbug.com/9996>, however, only globalX/Y are right if
+    // the page has been zoomed, so for now the coordinates we get aren't
+    // trustworthy enough to use for corrections.
+#if PLUGIN_SCALING_FIXED
     // Check our plugin location before we send the event to the plugin, just
     // in case we somehow missed a plugin frame change.
     const WebMouseEvent* mouse_event =
@@ -1062,16 +1035,12 @@ bool WebPluginDelegateImpl::PlatformHandleInputEvent(
         mouse_event->globalY - mouse_event->y - window_rect_.y());
     if (content_origin.x() != content_area_origin_.x() ||
         content_origin.y() != content_area_origin_.y()) {
-      // If there's a mismatch, figure out if it's due to zooming, or a missed
-      // window/plugin move (see comment in ApparentEventZoomLevel).
-      zoom_level = ApparentEventZoomLevel(*mouse_event);
-      if (fabsf(zoom_level - 1.0) < kEpsilon) {
-        DLOG(WARNING) << "Stale plugin content area location: "
-                      << content_area_origin_ << " instead of "
-                      << content_origin;
-        SetContentAreaOrigin(content_origin);
-      }
+      DLOG(WARNING) << "Stale plugin content area location: "
+                    << content_area_origin_ << " instead of "
+                    << content_origin;
+      SetContentAreaOrigin(content_origin);
     }
+#endif
 
     current_windowless_cursor_.GetCursorInfo(cursor_info);
   }
@@ -1140,9 +1109,6 @@ bool WebPluginDelegateImpl::PlatformHandleInputEvent(
   }
   void* plugin_event = event_converter->plugin_event();
 
-  if (fabsf(zoom_level - 1.0) > kEpsilon)
-    event_converter->SetZoomLevel(zoom_level);
-
   if (instance()->event_model() == NPEventModelCocoa) {
     // We recieve events related to drags starting outside the plugin, but the
     // NPAPI Cocoa event model spec says plugins shouldn't receive them, so
@@ -1164,6 +1130,25 @@ bool WebPluginDelegateImpl::PlatformHandleInputEvent(
     }
   }
 
+#ifndef PLUGIN_SCALING_FIXED
+  // Because of <http://crbug.com/9996>, the non-global coordinates we get for
+  // zoomed pages are wrong. As a temporary hack around that bug, override the
+  // coordinates we are given with ones computed based on our knowledge of where
+  // the plugin is on screen. We only need to do this for Cocoa, since Carbon
+  // only uses the global coordinates.
+  if (instance()->event_model() == NPEventModelCocoa &&
+      (WebInputEvent::isMouseEventType(event.type) ||
+       event.type == WebInputEvent::MouseWheel)) {
+    const WebMouseEvent* mouse_event =
+        static_cast<const WebMouseEvent*>(&event);
+    NPCocoaEvent* cocoa_event = static_cast<NPCocoaEvent*>(plugin_event);
+    cocoa_event->data.mouse.pluginX =
+        mouse_event->globalX - content_area_origin_.x() - window_rect_.x();
+    cocoa_event->data.mouse.pluginY =
+        mouse_event->globalY - content_area_origin_.y() - window_rect_.y();
+  }
+#endif
+
   // Send the plugin the event.
   scoped_ptr<NPAPI::ScopedCurrentPluginEvent> event_scope(NULL);
   if (instance()->event_model() == NPEventModelCocoa) {