Identity the mouse pointer type from low-level events for Mac

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 #include <stdint.h>
@@ skipping 1237 matching lines @@
   NSPoint location = [window mouseLocationOutsideOfEventStream];
   NSEvent* event = [NSEvent mouseEventWithType:NSMouseMoved
                                       location:location
                                  modifierFlags:0
                                      timestamp:0
                                   windowNumber:window_number()
                                        context:nil
                                    eventNumber:0
                                     clickCount:0
                                       pressure:0];
-  WebMouseEvent web_event = WebMouseEventBuilder::Build(event, cocoa_view_);
+  WebMouseEvent web_event = WebMouseEventBuilder::Build(
+      event, cocoa_view_, blink::WebPointerProperties::PointerType::Mouse);
   if (showing)
     web_event.type = WebInputEvent::MouseLeave;
   ForwardMouseEvent(web_event);
 }
 
 bool RenderWidgetHostViewMac::IsPopup() const {
   return popup_type_ != blink::WebPopupTypeNone;
 }
 
 void RenderWidgetHostViewMac::CopyFromCompositingSurface(
@@ skipping 713 matching lines @@
 
 - (void)mouseEvent:(NSEvent*)theEvent {
   TRACE_EVENT0("browser", "RenderWidgetHostViewCocoa::mouseEvent");
   if (responderDelegate_ &&
       [responderDelegate_ respondsToSelector:@selector(handleEvent:)]) {
     BOOL handled = [responderDelegate_ handleEvent:theEvent];
     if (handled)
       return;
   }
 
+  // If the pointing device enters proximity of its tablet and does not leave,
+  // the pointer type should be pen, otherwise is mouse.

[Navid Zolghadr, 2016/05/31 04:18:12]

Just a quick question for clarification. Does this comment implies that we are
getting an event when the pen enters/leaves the range of the digitizer? What
event type do we send to Blink in that case?

[lanwei, 2016/05/31 14:33:35]

Even without actually touching the tablet screen, first a NSTabletProximity
event, then MouseEnter, MouseMove events which have a subtype of
NSTabletPointEventSubtype. MouseEnter and MouseExited do not have subtype.

[mustaq, 2016/05/31 14:43:50]

Navid: Blink gets move & leave respectively, defined in
web_input_event_builders_mac.mm. That means the w3c test
pointerevent_pointerleave_pen-manual should pass (before/after this CL,
depending on dependece on pointerType) for mac, right?

+  blink::WebPointerProperties::PointerType pointerType =
+      stylusEnteringProximity_

[dtapuska, 2016/05/31 13:31:05]

Can we not always just use the subtype?  It looks like you fill the type in
always except for mouse enter/exit.

Is it a problem with these events that mouse enter and exit don't have a
subtype?

Perhaps we should be listening to tabletPoint and tabletProximity events and
generate appropriate events.

[lanwei, 2016/05/31 14:33:35]

Sorry, I forgot to add the comment that MouseEnter and MouseExited do not have
subtype. "Some event types might have subtypes, ..." They mentioned this in the
doc I attached to this CL, and I tested, only MouseEnter and MouseExited do not
have subtype. I am not sure why they design this way. 

If all mouse events have subtypes then we can easily decide what are stylus
events, but now we have to use TabletProximity as well to decide the pointer
types for MouseEnter and MouseExited events.

I have not tried to listen to tabletPoint, " A pointer event is an NSEvent
object of type NSTabletPoint or an object representing a mouse-down,
mouse-dragged, or mouse-up event with a subtype of NSTabletPointEventSubtype."
Maybe for stylus, we should listen to both NSTabletPoint and mouse events?

[mustaq, 2016/05/31 14:43:50]

The following link seems to suggest that subtype is "valid for mouse events", so
MouseEnter & MouseExited not having this seems to contradict the spec. It would
be great to have a second stylus device, this cold be device or driver specific
problem.

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Applica...

+          ? blink::WebPointerProperties::PointerType::Pen
+          : blink::WebPointerProperties::PointerType::Mouse;
   if ([self shouldIgnoreMouseEvent:theEvent]) {
     // If this is the first such event, send a mouse exit to the host view.
     if (!mouseEventWasIgnored_ && renderWidgetHostView_->render_widget_host_) {
-      WebMouseEvent exitEvent = WebMouseEventBuilder::Build(theEvent, self);
+      WebMouseEvent exitEvent =
+          WebMouseEventBuilder::Build(theEvent, self, pointerType);
       exitEvent.type = WebInputEvent::MouseLeave;
       exitEvent.button = WebMouseEvent::ButtonNone;
       renderWidgetHostView_->ForwardMouseEvent(exitEvent);
     }
     mouseEventWasIgnored_ = YES;
     return;
   }
 
   if (mouseEventWasIgnored_) {
     // If this is the first mouse event after a previous event that was ignored
     // due to the hitTest, send a mouse enter event to the host view.
     if (renderWidgetHostView_->render_widget_host_) {
-      WebMouseEvent enterEvent = WebMouseEventBuilder::Build(theEvent, self);
+      WebMouseEvent enterEvent =
+          WebMouseEventBuilder::Build(theEvent, self, pointerType);
       enterEvent.type = WebInputEvent::MouseMove;
       enterEvent.button = WebMouseEvent::ButtonNone;
       if (renderWidgetHostView_->ShouldRouteEvent(enterEvent)) {
         renderWidgetHostView_->render_widget_host_->delegate()
             ->GetInputEventRouter()
             ->RouteMouseEvent(renderWidgetHostView_.get(), &enterEvent);
       } else {
         renderWidgetHostView_->ProcessMouseEvent(enterEvent);
       }
     }
@@ skipping 16 matching lines @@
   // wants to handle them. But it won't work without implementing method
   // - (NSUInteger)characterIndexForPoint:.
   // See: http://code.google.com/p/chromium/issues/detail?id=47141
   // Instead of sending mouse events to the input method first, we now just
   // simply confirm all ongoing composition here.
   if (type == NSLeftMouseDown || type == NSRightMouseDown ||
       type == NSOtherMouseDown) {
     [self confirmComposition];
   }
 
-  WebMouseEvent event = WebMouseEventBuilder::Build(theEvent, self);
+  WebMouseEvent event =
+      WebMouseEventBuilder::Build(theEvent, self, pointerType);
   if (renderWidgetHostView_->ShouldRouteEvent(event)) {
     renderWidgetHostView_->render_widget_host_->delegate()
         ->GetInputEventRouter()
         ->RouteMouseEvent(renderWidgetHostView_.get(), &event);
   } else {
     renderWidgetHostView_->ProcessMouseEvent(event);
   }
 }
 
+- (void)tabletEvent:(NSEvent*)theEvent {
+  stylusEnteringProximity_ = [theEvent isEnteringProximity];
+}
+
 - (BOOL)performKeyEquivalent:(NSEvent*)theEvent {
   // |performKeyEquivalent:| is sent to all views of a window, not only down the
   // responder chain (cf. "Handling Key Equivalents" in
   // http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/EventOverview/HandlingKeyEvents/HandlingKeyEvents.html
   // ). We only want to handle key equivalents if we're first responder.
   if ([[self window] firstResponder] != self)
     return NO;
 
   // If the event is reserved by the system, then do not pass it to web content.
   if (EventIsReservedBySystem(theEvent))
@@ skipping 1385 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end