Ozone keyboard layout

ui/events/ozone/layout/keyboard_layout_engine.h

+// Copyright 2014 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 UI_OZONE_PUBLIC_KEYBOARD_LAYOUT_ENGINE_H_
+#define UI_OZONE_PUBLIC_KEYBOARD_LAYOUT_ENGINE_H_
+
+#include <string>
+
+#include "base/strings/string16.h"
+#include "ui/events/keycodes/keyboard_codes.h"
+#include "ui/events/ozone/layout/events_ozone_layout_export.h"
+
+namespace ui {
+
+enum class DomCode;
+enum class DomKey;
+
+// A KeyboardLayoutEngine provides a platform-independent interface to
+// key mapping. Key mapping provides a meaning (DomKey and character,
+// and optionally Windows key code) for a physical key press (DomCode
+// and modifier flags).
+//
+// This interface does not expose individual layouts because it must support
+// platforms that only provide for one active system layout, and/or platforms
+// where layouts have no accessible representation.
+class EVENTS_OZONE_LAYOUT_EXPORT KeyboardLayoutEngine {
+ public:
+  KeyboardLayoutEngine() {}
+  virtual ~KeyboardLayoutEngine() {}
+
+  // Returns true if it is possible to change the current layout.
+  virtual bool CanSetCurrentLayout() const = 0;
+
+  // Sets the current layout; returns true on success.
+  // Drop-in replacement for ImeKeyboard::SetCurrentKeyboardLayoutByName().
+  virtual bool SetCurrentLayoutByName(const std::string& layout_name) = 0;
+
+  // Returns true if the current layout makes use of the ISO Level 5 Shift key.
+  // Drop-in replacement for ImeKeyboard::IsISOLevel5ShiftAvailable().
+  virtual bool UsesISOLevel5Shift() const = 0;
+
+  // Returns true if the current layout makes use of the AltGr
+  // (ISO Level 3 Shift) key.
+  // Drop-in replacement for ImeKeyboard::IsAltGrAvailable().
+  virtual bool UsesAltGr() const = 0;
+
+  // Provides the meaning of a physical key.
+  //
+  // The caller must supply valid addresses for all the output parameters;
+  // the function must not use their initial values.
+  //
+  // Returns true if it can determine the meaning of the (dom_code, flags)
+  // values and the corresponding key_code, OR if it can determine that they
+  // have no meaning in the current layout (e.g. the key is unbound). In the
+  // latter case, the function sets *dom_key to UNIDENTIFIED, *character to 0,
+  // and *key_code to VKEY_UNKNOWN.

[Wez, 2014/12/12 20:04:18]

What does it set key_code to?

Do you need the return-value, or could callers just check the |dom_key| value,
for example?

[kpschoedel, 2014/12/12 21:20:39]

The Windows-compatible code for the ‘equivalent’ layout. For the initial
Ozone/XKB implementation, I've based this on the tables in
keyboard_code_conversion_x.cc, but I'm not entirely happy with its current
state.
They could. I'll leave it as is for today, because fengyuan@ has some work in
progress using patches with this signature.

+  //
+  // Returns false if it cannot determine the meaning (and cannot determine
+  // that there is none); in this case it does not set any of the output
+  // parameters.
+  virtual bool Lookup(DomCode dom_code,
+                      int event_flags,
+                      DomKey* dom_key,
+                      base::char16* character,
+                      KeyboardCode* key_code) const = 0;
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PUBLIC_KEYBOARD_LAYOUT_ENGINE_H_