ozone/platform/wayland: Implement pointer handling

ui/ozone/platform/wayland/wayland_pointer.cc

+// Copyright 2016 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 "ui/ozone/platform/wayland/wayland_pointer.h"
+
+#include <linux/input.h>
+#include <wayland-client.h>
+
+#include "ui/events/event.h"
+#include "ui/ozone/platform/wayland/wayland_window.h"
+
+// TODO(forney): Handle version 5 of wl_pointer.
+
+namespace ui {
+
+WaylandPointer::WaylandPointer(wl_pointer* pointer,
+                               const EventDispatchCallback& callback)
+    : obj_(pointer), callback_(callback) {
+  static const wl_pointer_listener listener = {
+      &WaylandPointer::Enter,  &WaylandPointer::Leave, &WaylandPointer::Motion,
+      &WaylandPointer::Button, &WaylandPointer::Axis,
+  };
+
+  wl_pointer_add_listener(obj_.get(), &listener, this);
+}
+
+WaylandPointer::~WaylandPointer() {}
+
+// static
+void WaylandPointer::Enter(void* data,
+                           wl_pointer* obj,
+                           uint32_t serial,
+                           wl_surface* surface,
+                           wl_fixed_t surface_x,
+                           wl_fixed_t surface_y) {
+  WaylandPointer* pointer = static_cast<WaylandPointer*>(data);
+  pointer->location_.SetPoint(wl_fixed_to_double(surface_x),
+                              wl_fixed_to_double(surface_y));
+  WaylandWindow::FromSurface(surface)->set_pointer_focus(true);
+}
+
+// static
+void WaylandPointer::Leave(void* data,
+                           wl_pointer* obj,
+                           uint32_t serial,
+                           wl_surface* surface) {
+  WaylandWindow::FromSurface(surface)->set_pointer_focus(false);
+}
+
+// static
+void WaylandPointer::Motion(void* data,
+                            wl_pointer* obj,
+                            uint32_t time,
+                            wl_fixed_t surface_x,
+                            wl_fixed_t surface_y) {
+  WaylandPointer* pointer = static_cast<WaylandPointer*>(data);
+  pointer->location_.SetPoint(wl_fixed_to_double(surface_x),
+                              wl_fixed_to_double(surface_y));
+  MouseEvent event(ET_MOUSE_MOVED, gfx::Point(), gfx::Point(),
+                   base::TimeDelta::FromMilliseconds(time), pointer->flags_, 0);

[spang, 2016/02/24 16:42:21]

Which clock does wayland use for events?

[Michael Forney, 2016/02/24 19:32:21]

The spec says

"The time argument is a timestamp with millisecond granularity, with an
undefined base."

In practice, for compositors that use libinput with evdev, this comes from
CLOCK_MONOTONIC.

[spang, 2016/02/25 23:14:32]

Ok good, we require CLOCK_MONOTONIC. Compositors that don't use it will break
chrome.

+  event.set_location_f(pointer->location_);
+  event.set_root_location_f(pointer->location_);
+  pointer->callback_.Run(&event);
+}
+
+// static
+void WaylandPointer::Button(void* data,
+                            wl_pointer* obj,
+                            uint32_t serial,
+                            uint32_t time,
+                            uint32_t button,
+                            uint32_t state) {
+  WaylandPointer* pointer = static_cast<WaylandPointer*>(data);
+  int flag;
+  switch (button) {
+    case BTN_LEFT:
+      flag = EF_LEFT_MOUSE_BUTTON;
+      break;
+    case BTN_MIDDLE:
+      flag = EF_MIDDLE_MOUSE_BUTTON;
+      break;
+    case BTN_RIGHT:
+      flag = EF_RIGHT_MOUSE_BUTTON;
+      break;
+    case BTN_BACK:
+      flag = EF_BACK_MOUSE_BUTTON;
+      break;
+    case BTN_FORWARD:
+      flag = EF_FORWARD_MOUSE_BUTTON;
+      break;
+    default:
+      return;
+  }
+  int flags = pointer->flags_ | flag;
+  EventType type;
+  if (state == WL_POINTER_BUTTON_STATE_PRESSED) {
+    type = ET_MOUSE_PRESSED;
+    pointer->flags_ |= flag;
+  } else {
+    type = ET_MOUSE_RELEASED;
+    pointer->flags_ &= ~flag;
+  }
+  MouseEvent event(type, gfx::Point(), gfx::Point(),
+                   base::TimeDelta::FromMilliseconds(time), flags, flag);
+  event.set_location_f(pointer->location_);
+  event.set_root_location_f(pointer->location_);
+  pointer->callback_.Run(&event);
+}
+
+// static
+void WaylandPointer::Axis(void* data,
+                          wl_pointer* obj,
+                          uint32_t time,
+                          uint32_t axis,
+                          wl_fixed_t value) {
+  static const double kAxisValueScale = 10.0;
+  WaylandPointer* pointer = static_cast<WaylandPointer*>(data);
+  gfx::Vector2d offset;
+  // Wayland compositors send axis events with values in the surface coordinate
+  // space. They send a value of 10 per mouse wheel click by convention, so
+  // clients (e.g. GTK+) typically scale down by this amount to convert to
+  // discrete step coordinates. wl_pointer version 5 improves the situation by
+  // adding axis sources and discrete axis events.
+  if (axis == WL_POINTER_AXIS_VERTICAL_SCROLL)
+    offset.set_y(-wl_fixed_to_double(value) / kAxisValueScale *
+                 MouseWheelEvent::kWheelDelta);
+  else
+    offset.set_x(wl_fixed_to_double(value) / kAxisValueScale *

[spang, 2016/02/24 16:42:21]

Why under "else"?

Surely |axis| is set for horizontal scrolling too?

[Michael Forney, 2016/02/24 19:32:21]

Done.

+                 MouseWheelEvent::kWheelDelta);
+  MouseWheelEvent event(offset, gfx::Point(), gfx::Point(),
+                        base::TimeDelta::FromMilliseconds(time),
+                        pointer->flags_, 0);
+  event.set_location_f(pointer->location_);
+  event.set_root_location_f(pointer->location_);
+  pointer->callback_.Run(&event);
+}
+
+}  // namespace ui