text: // Copyright 2015 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.
  
  #ifndef COMPONENTS_EXO_POINTER_H_
  #define COMPONENTS_EXO_POINTER_H_
  
  #include <memory>
  
  #include "base/memory/weak_ptr.h"
  #include "base/unguessable_token.h"
  #include "components/exo/surface_observer.h"
  #include "components/exo/surface_tree_host.h"
  #include "components/exo/wm_helper.h"
  #include "third_party/abseil-cpp/absl/types/optional.h"
  #include "third_party/skia/include/core/SkBitmap.h"
  #include "ui/aura/client/cursor_client_observer.h"
  #include "ui/aura/client/focus_change_observer.h"
  #include "ui/base/cursor/cursor.h"
  #include "ui/base/cursor/mojom/cursor_type.mojom-forward.h"
  #include "ui/events/event_handler.h"
  #include "ui/events/types/event_type.h"
  #include "ui/gfx/geometry/point.h"
  #include "ui/gfx/geometry/point_f.h"
  #include "ui/gfx/native_widget_types.h"
  
  namespace viz {
  class CopyOutputResult;
  }
  
  namespace ui {
  class LocatedEvent;
  class MouseEvent;
  }  // namespace ui
  
  namespace exo {
  class PointerConstraintDelegate;
  class PointerDelegate;
  class PointerGesturePinchDelegate;
  class PointerStylusDelegate;
  class RelativePointerDelegate;
  class Seat;
  class Surface;
  class SurfaceTreeHost;
  
  // This class implements a client pointer that represents one or more input
  // devices, such as mice, which control the pointer location and pointer focus.
  class Pointer : public SurfaceTreeHost,
                  public SurfaceObserver,
                  public ui::EventHandler,
                  public aura::client::CursorClientObserver,
                  public aura::client::FocusChangeObserver {
   public:
    Pointer(PointerDelegate* delegate, Seat* seat);
  
    Pointer(const Pointer&) = delete;
    Pointer& operator=(const Pointer&) = delete;
  
    ~Pointer() override;
  
    PointerDelegate* delegate() const { return delegate_; }
  
    // Set the pointer surface, i.e., the surface that contains the pointer image
    // (cursor). The |hotspot| argument defines the position of the pointer
    // surface relative to the pointer location. Its top-left corner is always at
    // (x, y) - (hotspot.x, hotspot.y), where (x, y) are the coordinates of the
    // pointer location, in surface local coordinates.
    void SetCursor(Surface* surface, const gfx::Point& hotspot);
  
    // Set the pointer cursor type. This is similar to SetCursor, but this method
    // accepts ui::mojom::CursorType instead of the surface for the pointer image.
    void SetCursorType(ui::mojom::CursorType cursor_type);
  
    // Set delegate for pinch events.
    void SetGesturePinchDelegate(PointerGesturePinchDelegate* delegate);
  
    // Overridden from SurfaceDelegate:
    void OnSurfaceCommit() override;
  
    // Overridden from SurfaceObserver:
    void OnSurfaceDestroying(Surface* surface) override;
  
    // Overridden from ui::EventHandler:
    void OnMouseEvent(ui::MouseEvent* event) override;
    void OnScrollEvent(ui::ScrollEvent* event) override;
    void OnGestureEvent(ui::GestureEvent* event) override;
  
    // Overridden from aura::client::CursorClientObserver:
    void OnCursorSizeChanged(ui::CursorSize cursor_size) override;
    void OnCursorDisplayChanged(const display::Display& display) override;
  
    // Overridden from aura::client::FocusChangeObserver;
    void OnWindowFocused(aura::Window* gained_focus,
                         aura::Window* lost_focus) override;
  
    // Relative motion registration.
    void RegisterRelativePointerDelegate(RelativePointerDelegate* delegate);
    void UnregisterRelativePointerDelegate(RelativePointerDelegate* delegate);
  
    // Enable the pointer constraint on the given surface. Returns true if the
    // lock was granted, false otherwise.
    //
    // TODO(crbug.com/957455): For legacy reasons, locking the pointer will also
    // hide the cursor.
    bool ConstrainPointer(PointerConstraintDelegate* delegate);
  
    // Disable the pointer constraint. This is designed to be called by the
    // delegate, so it does not call OnConstraintBroken(), which should be done
    // separately if the constraint was broken by something other than the
    // delegate.
    void UnconstrainPointer();
  
    // Set the stylus delegate for handling stylus events.
    void SetStylusDelegate(PointerStylusDelegate* delegate);
    bool HasStylusDelegate() const;
  
   private:
    // Capture the pointer for the given surface. Returns true iff the capture
    // succeeded.
    bool EnablePointerCapture(Surface* capture_surface);
  
    // Remove the currently active pointer capture (if there is one).
    void DisablePointerCapture();
  
    // Returns the effective target for |event|.
    Surface* GetEffectiveTargetForEvent(const ui::LocatedEvent* event) const;
  
    // Change pointer focus to |surface|.
    void SetFocus(Surface* surface,
                  const gfx::PointF& location,
                  int button_flags);
  
    // Updates the root_surface in |SurfaceTreeHost| from which the cursor
    // is captured.
    void UpdatePointerSurface(Surface* surface);
  
    // Asynchronously update the cursor by capturing a snapshot of
    // |SurfaceTreeHost::root_surface()|.
    void CaptureCursor(const gfx::Point& hotspot);
  
    // Called when cursor snapshot has been captured.
    void OnCursorCaptured(const gfx::Point& hotspot,
                          std::unique_ptr<viz::CopyOutputResult> result);
  
    // Update |cursor_| to |cursor_bitmap_| transformed for the current display.
    void UpdateCursor();
  
    // Convert the given |location_in_target| to coordinates in the root window.
    gfx::PointF GetLocationInRoot(Surface* target,
                                  gfx::PointF location_in_target);
  
    // Called to check if cursor should be moved to the center of the window when
    // sending relative movements.
    bool ShouldMoveToCenter();
  
    // Moves the cursor to center of the active display.
    void MoveCursorToCenterOfActiveDisplay();
  
    // Process the delta for relative pointer motion. Returns true if relative
    // motion was sent to the delegate, false otherwise. If |ordinal_motion| is
    // supplied, it will be used for determining physical motion, otherwise
    // physical motion will be the relative delta.
    bool HandleRelativePointerMotion(
        base::TimeTicks time_stamp,
        gfx::PointF location_in_target,
        const absl::optional<gfx::Vector2dF>& ordinal_motion);
  
    // The delegate instance that all events are dispatched to.
    PointerDelegate* const delegate_;
  
    Seat* const seat_;
  
    // The delegate instance that all pinch related events are dispatched to.
    PointerGesturePinchDelegate* pinch_delegate_ = nullptr;
  
    // The delegate instance that relative movement events are dispatched to.
    RelativePointerDelegate* relative_pointer_delegate_ = nullptr;
  
    // The delegate instance that controls when to lock/unlock this pointer.
    PointerConstraintDelegate* pointer_constraint_delegate_ = nullptr;
  
    // The delegate instance that stylus/pen events are dispatched to.
    PointerStylusDelegate* stylus_delegate_ = nullptr;
  
    // The current focus surface for the pointer.
    Surface* focus_surface_ = nullptr;
  
    // The location of the pointer in the current focus surface.
    gfx::PointF location_;
  
    // The location of the pointer when pointer capture is first enabled.
    absl::optional<gfx::Point> location_when_pointer_capture_enabled_;
  
    // If this is not nullptr, a synthetic move was sent and this points to the
    // location of a generated move that was sent which should not be forwarded.
    absl::optional<gfx::Point> location_synthetic_move_;
  
    // The window with pointer capture. Pointer capture is enabled if and only if
    // this is not null.
    aura::Window* capture_window_ = nullptr;
  
    // The position of the pointer surface relative to the pointer location.
    gfx::Point hotspot_;
  
    // Latest cursor snapshot.
    SkBitmap cursor_bitmap_;
  
    // The current cursor.
    ui::Cursor cursor_;
  
    // Hotspot to use with latest cursor snapshot.
    gfx::Point cursor_hotspot_;
  
    // Scale at which cursor snapshot is captured.
    float capture_scale_;
  
    // Source used for cursor capture copy output requests.
    const base::UnguessableToken cursor_capture_source_id_;
  
    // Last received event type.
    ui::EventType last_event_type_ = ui::ET_UNKNOWN;
  
    // Last reported stylus values.
    ui::EventPointerType last_pointer_type_ = ui::EventPointerType::kUnknown;
    float last_force_ = std::numeric_limits<float>::quiet_NaN();
    gfx::Vector2dF last_tilt_;
  
    // Weak pointer factory used for cursor capture callbacks.
    base::WeakPtrFactory<Pointer> cursor_capture_weak_ptr_factory_{this};
  };
  
  }  // namespace exo
  
  #endif  // COMPONENTS_EXO_POINTER_H_
  