ppapi/cpp/mouse_lock.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef PPAPI_CPP_MOUSE_LOCK_H_
   6 #define PPAPI_CPP_MOUSE_LOCK_H_
   7
   8 #include "ppapi/c/pp_stdint.h"
   9 #include "ppapi/cpp/instance_handle.h"
  10
  11 /// @file
  12 /// This file defines the API for locking the target of mouse events to a
  13 /// specific module instance.
  14
  15 namespace pp {
  16
  17 class CompletionCallback;
  18 class Instance;
  19
  20 /// This class allows you to associate the <code>PPP_MouseLock</code> and
  21 /// <code>PPB_MouseLock</code> C-based interfaces with an object. It associates
  22 /// itself with the given instance, and registers as the global handler for
  23 /// handling the <code>PPP_MouseLock</code> interface that the browser calls.
  24 ///
  25 /// You would typically use this class by inheritance on your instance or by
  26 /// composition.
  27 ///
  28 /// <strong>Example (inheritance):</strong>
  29 /// @code
  30 ///   class MyInstance : public pp::Instance, public pp::MouseLock {
  31 ///     class MyInstance() : pp::MouseLock(this) {
  32 ///     }
  33 ///     ...
  34 ///   };
  35 /// @endcode
  36 ///
  37 /// <strong>Example (composition):</strong>
  38 /// @code
  39 ///   class MyMouseLock : public pp::MouseLock {
  40 ///     ...
  41 ///   };
  42 ///
  43 ///   class MyInstance : public pp::Instance {
  44 ///     MyInstance() : mouse_lock_(this) {
  45 ///     }
  46 ///
  47 ///     MyMouseLock mouse_lock_;
  48 ///   };
  49 /// @endcode
  50 class MouseLock {
  51  public:
  52   /// A constructor for creating a <code>MouseLock</code>.
  53   ///
  54   /// @param[in] instance The instance with which this resource will be
  55   /// associated.
  56   explicit MouseLock(Instance* instance);
  57
  58   /// Destructor.
  59   virtual ~MouseLock();
  60
  61   /// PPP_MouseLock functions exposed as virtual functions for you to override.
  62   virtual void MouseLockLost() = 0;
  63
  64   /// LockMouse() requests the mouse to be locked.
  65   ///
  66   /// While the mouse is locked, the cursor is implicitly hidden from the user.
  67   /// Any movement of the mouse will generate a
  68   /// <code>PP_INPUTEVENT_TYPE_MOUSEMOVE</code> event. The
  69   /// <code>GetPosition()</code> function in <code>InputEvent()</code>
  70   /// reports the last known mouse position just as mouse lock was
  71   /// entered. The <code>GetMovement()</code> function provides relative
  72   /// movement information indicating what the change in position of the mouse
  73   /// would be had it not been locked.
  74   ///
  75   /// The browser may revoke the mouse lock for reasons including (but not
  76   /// limited to) the user pressing the ESC key, the user activating another
  77   /// program using a reserved keystroke (e.g. ALT+TAB), or some other system
  78   /// event.
  79   ///
  80   /// @param[in] cc A <code>CompletionCallback</code> to be called upon
  81   /// completion.
  82   ///
  83   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
  84   int32_t LockMouse(const CompletionCallback& cc);
  85
  86   /// UnlockMouse causes the mouse to be unlocked, allowing it to track user
  87   /// movement again. This is an asynchronous operation. The module instance
  88   /// will be notified using the <code>PPP_MouseLock</code> interface when it
  89   /// has lost the mouse lock.
  90   void UnlockMouse();
  91
  92  private:
  93   InstanceHandle associated_instance_;
  94 };
  95
  96 }  // namespace pp
  97
  98 #endif  // PPAPI_CPP_MOUSE_LOCK_H_