Introduce WM_POINTER to Handle pointer events with pen type

ui/views/win/hwnd_message_handler.cc

Index: ui/views/win/hwnd_message_handler.cc
diff --git a/ui/views/win/hwnd_message_handler.cc b/ui/views/win/hwnd_message_handler.cc
index 1dbcea22c11137511a37a9d744ab15e6b0b1e8ff..f47aa0eee5946a7a02ac4dfe567ffb3abbcf0cde 100644
--- a/ui/views/win/hwnd_message_handler.cc
+++ b/ui/views/win/hwnd_message_handler.cc
@@ -31,6 +31,7 @@
 #include "ui/display/win/dpi.h"
 #include "ui/display/win/screen_win.h"
 #include "ui/events/event.h"
+#include "ui/events/event_constants.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/keycodes/keyboard_code_conversion_win.h"
 #include "ui/events/win/system_event_state_lookup.h"
@@ -974,6 +975,16 @@ LRESULT HWNDMessageHandler::HandleTouchMessage(unsigned int message,
   return ret;
 }
 
+LRESULT HWNDMessageHandler::HandlePointerMessage(unsigned int message,
+                                                 WPARAM w_param,
+                                                 LPARAM l_param,
+                                                 bool* handled) {
+  base::WeakPtr<HWNDMessageHandler> ref(weak_factory_.GetWeakPtr());

[sadrul, 2017/03/23 19:59:38]

I am not sure what the WeakPtr<> is useful for (I notice that we use in
HandleTouchMessage etc. functions too).

[dtapuska, 2017/03/23 20:02:51]

IsMsgHandled is a macro written by sky here:
https://chromium.googlesource.com/chromium/src/+/c169c53%5E%21/#F0

[ananta, 2017/03/23 20:04:38]

The instance can be destroyed while processing a message. Hence the weakptr.

+  LRESULT ret = OnPointerEvent(message, w_param, l_param);
+  *handled = IsMsgHandled();
+  return ret;
+}
+
 LRESULT HWNDMessageHandler::HandleScrollMessage(unsigned int message,
                                                 WPARAM w_param,
                                                 LPARAM l_param,
@@ -1642,6 +1653,92 @@ LRESULT HWNDMessageHandler::OnPointerActivate(UINT message,
   return -1;
 }
 
+LRESULT HWNDMessageHandler::OnPointerEvent(UINT message,
+                                           WPARAM w_param,
+                                           LPARAM l_param) {
+  // WM_POINTER is not supported on Windows 7 or lower.
+  if (base::win::GetVersion() <= base::win::VERSION_WIN7) {

[sky, 2017/03/27 15:33:58]

Should this be a DCHECK? How can we end up here if WM_POINTER isn't supported on
win7 or lower?

[ananta, 2017/03/27 18:32:45]

Shouldn't be a DCHECK i think. We may have drivers who post these messages?. The
WM_POINTER messages AFAIK are generated by the OS only on Windows 8+

+    SetMsgHandled(FALSE);
+    return -1;
+  }
+
+  UINT32 pointer_id = GET_POINTERID_WPARAM(w_param);
+  using GetPointerTypeFn = BOOL(WINAPI*)(UINT32, POINTER_INPUT_TYPE*);
+  POINTER_INPUT_TYPE pointer_type;
+  static GetPointerTypeFn get_pointer_type = reinterpret_cast<GetPointerTypeFn>(
+      GetProcAddress(GetModuleHandleA("user32.dll"), "GetPointerType"));
+  CHECK(get_pointer_type);

[sky, 2017/03/27 15:33:58]

Generally we don't assume we can get the function. Is there a reason this code
is different? Seem similar code in this class that uses conditional with return
type rather than CHECK.

[lanwei, 2017/03/28 21:24:36]

Done.

+  // If the WM_POINTER messages are not sent from a stylus device, then we do
+  // not handle them to make sure we do not change the current behavior of
+  // touch and mouse inputs.
+  if (!get_pointer_type(pointer_id, &pointer_type) || pointer_type != PT_PEN) {
+    SetMsgHandled(FALSE);
+    return -1;
+  }
+
+  using GetPointerPenInfoFn = BOOL(WINAPI*)(UINT32, POINTER_PEN_INFO*);
+  POINTER_PEN_INFO pointer_pen_info;
+  static GetPointerPenInfoFn get_pointer_pen_info =
+      reinterpret_cast<GetPointerPenInfoFn>(
+          GetProcAddress(GetModuleHandleA("user32.dll"), "GetPointerPenInfo"));
+  CHECK(get_pointer_pen_info);

[sky, 2017/03/27 15:33:58]

Similar comment about CHECK.

[lanwei, 2017/03/28 21:24:36]

Done.

+  if (!get_pointer_pen_info(pointer_id, &pointer_pen_info)) {
+    SetMsgHandled(FALSE);
+    return -1;
+  }
+
+  // We are now creating a fake mouse event with pointer type of pen from
+  // the WM_POINTER message and then setting up an associated pointer
+  // details in the MouseEvent which contains the pen's information.
+  float pressure = static_cast<float>(pointer_pen_info.pressure) / 1024;
+  float rotation = pointer_pen_info.rotation;
+  int tiltX = pointer_pen_info.tiltX;

[sky, 2017/03/27 15:33:58]

titl_x (and tilt_y below)

[lanwei, 2017/03/28 21:24:36]

Done.

+  int tiltY = pointer_pen_info.tiltY;

[sadrul, 2017/03/23 19:59:39]

tilt_x, tilt_y

[lanwei, 2017/03/28 21:24:36]

Done.

+  POINT client_point = pointer_pen_info.pointerInfo.ptPixelLocationRaw;
+  ScreenToClient(hwnd(), &client_point);
+  gfx::Point point = gfx::Point(client_point.x, client_point.y);

[sky, 2017/03/27 15:33:58]

Do you need to convert to dips?

[lanwei, 2017/03/28 21:24:36]

https://codesearch.chromium.org/chromium/src/ui/events/win/events_win.cc?type...
The position is directly used from the value of lParam if it is a client mouse
event. I think the conversion happens later.

https://codesearch.chromium.org/chromium/src/content/browser/renderer_host/re...

+  ui::EventType event_type = ui::ET_MOUSE_MOVED;
+  int flag = -1;
+  int click_count = 0;
+  switch (message) {
+    case WM_POINTERDOWN:
+      event_type = ui::ET_MOUSE_PRESSED;
+      flag = ui::EF_LEFT_MOUSE_BUTTON;
+      click_count = 1;
+      break;
+    case WM_POINTERUP:
+      event_type = ui::ET_MOUSE_RELEASED;
+      flag = ui::EF_LEFT_MOUSE_BUTTON;
+      click_count = 1;
+      break;
+    case WM_POINTERUPDATE:
+      event_type = ui::ET_MOUSE_MOVED;
+      break;
+    case WM_POINTERLEAVE:
+      event_type = ui::ET_MOUSE_EXITED;
+      break;
+    default:

[sky, 2017/03/27 15:33:58]

Should WM_POINTERENTER generate ET_MOUSE_ENTERED?

[lanwei, 2017/03/28 21:24:36]

Done.

+      break;
+  }
+  ui::MouseEvent event(event_type, point, point, base::TimeTicks::Now(), flag,

[sky, 2017/03/27 15:33:58]

Doesn't the event have a time? Also, how come you are using the same location
for both points? One should be screen.

[lanwei, 2017/03/28 21:24:36]

https://codesearch.chromium.org/chromium/src/ui/events/event.cc?type=cs&l=482
I saw here location_ and root_location_ are set to the same value.

https://codesearch.chromium.org/chromium/src/ui/events/win/events_win.cc?type...
We are now using |TimeTicks::Now()| for event timestamp instead of the native
timestamp.

+                       flag);
+  ui::PointerDetails pointer_details(
+      ui::EventPointerType::POINTER_TYPE_PEN, pointer_id,
+      /* radius_x */ 0.0f, /* radius_y */ 0.0f, pressure, tiltX, tiltY,
+      /* tangential_pressure */ 0.0f, rotation);
+  event.set_pointer_details(pointer_details);
+  event.SetClickCount(click_count);
+
+  // There are cases where the code handling the message destroys the
+  // window, so use the weak ptr to check if destruction occured or not.
+  base::WeakPtr<HWNDMessageHandler> ref(weak_factory_.GetWeakPtr());
+  bool handled = delegate_->HandleMouseEvent(event);
+
+  if (ref.get())

[sadrul, 2017/03/23 19:59:38]

if (ref) should work too

[lanwei, 2017/03/28 21:24:36]

Done.

+    SetMsgHandled(handled);
+  return 0;
+}
+
 void HWNDMessageHandler::OnMove(const gfx::Point& point) {
   delegate_->HandleMove();
   SetMsgHandled(FALSE);