1 // Copyright 2014 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.
5 #ifndef UI_EVENTS_EVENT_MODIFIERS_H_
6 #define UI_EVENTS_EVENT_MODIFIERS_H_
8 #include "base/macros.h"
9 #include "ui/events/events_export.h"
22 MODIFIER_LEFT_MOUSE_BUTTON,
23 MODIFIER_MIDDLE_MOUSE_BUTTON,
24 MODIFIER_RIGHT_MOUSE_BUTTON,
25 MODIFIER_BACK_MOUSE_BUTTON,
26 MODIFIER_FORWARD_MOUSE_BUTTON,
27 MODIFIER_NUM_MODIFIERS
30 // Modifier key state for Evdev.
32 // Chrome relies on the underlying OS to interpret modifier keys such as Shift,
33 // Ctrl, and Alt. The Linux input subsystem does not assign any special meaning
34 // to these keys, so this work must happen at a higher layer (normally X11 or
35 // the console driver). When using evdev directly, we must do it ourselves.
37 // The modifier state is shared between all input devices connected to the
38 // system. This is to support actions such as Shift-Clicking that use multiple
41 // Normally a modifier is set if any of the keys or buttons assigned to it are
42 // currently pressed. However some keys toggle a persistent "lock" for the
43 // modifier instead, such as CapsLock. If a modifier is "locked" then its state
44 // is inverted until it is unlocked.
45 class EVENTS_EXPORT EventModifiers {
50 // Record key press or release for regular modifier key (shift, alt, etc).
51 void UpdateModifier(unsigned int modifier, bool down);
53 // Record key press or release for locking modifier key (caps lock).
54 void UpdateModifierLock(unsigned int modifier, bool down);
56 // Directly set the state of a locking modifier key (caps lock).
57 void SetModifierLock(unsigned int modifier, bool locked);
59 // Return current flags to use for incoming events.
60 int GetModifierFlags();
62 // Release modifier keys.
63 void ResetKeyboardModifiers();
65 // Return the mask for the specified modifier.
66 static int GetEventFlagFromModifier(unsigned int modifier);
68 // Return the modifier for the specified mask.
69 static int GetModifierFromEventFlag(int flag);
72 // Count of keys pressed for each modifier.
73 int modifiers_down_[MODIFIER_NUM_MODIFIERS];
75 // Mask of modifier flags currently "locked".
76 int modifier_flags_locked_ = 0;
78 // Mask of modifier flags currently active (nonzero keys pressed xor locked).
79 int modifier_flags_ = 0;
81 // Update modifier_flags_ from modifiers_down_ and modifier_flags_locked_.
82 void UpdateFlags(unsigned int modifier);
84 DISALLOW_COPY_AND_ASSIGN(EventModifiers);
89 #endif // UI_EVENTS_EVENT_MODIFIERS_H_