Add input method support for views and integrate ibus input framework

views/ime/ime_context.h

+// Copyright (c) 2011 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 VIEWS_IME_IME_CONTEXT_H_
+#define VIEWS_IME_IME_CONTEXT_H_
+#pragma once
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/string16.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace views {
+
+class IMEContext;
+class KeyEvent;
+class View;
+
+// Duplicate WebKit::WebCompositionUnderline
+struct CompositionUnderline {
+  CompositionUnderline()
+    : start_offset(0),
+      end_offset(0),
+      color(0),
+      thick(false) {}
+
+  CompositionUnderline(uint32 s, uint32 e, SkColor c, bool t)
+    : start_offset(s),
+      end_offset(e),
+      color(c),
+      thick(t) {}
+
+  uint32 start_offset;
+  uint32 end_offset;
+  SkColor color;
+  bool thick;
+};
+
+// WebKit only supports underline attribue for composition, so we use
+// CompositionUnderline as CompositionAttribute right now.
+typedef struct CompositionUnderline CompositionAttribute;
+typedef std::vector<CompositionAttribute> CompositionAttributeList;
+
+// TODO(penghuang) more attributes (background, foreground color and etc)
+// class CompositionAttribute {
+//  public:
+//   enum CompositionAttributeType{
+//     CAT_UNDERLINE = 1,
+//     CAT_FORGROUND = 2,
+//     CAT_BACKGRUND = 3,
+//   };
+//
+//   CompositionAttributeType GetType() const { return type_; }
+//   unsigned GetStartOffset() const { return start_offset_; }
+//   unsigned GetEndOffset() const { return end_offset_; }
+//   unsigned GetValue() const { return value_; }
+//
+//  private:
+//   CompositionAttributeType type_;
+//   unsigned start_offset_;
+//   unsigned end_offset_;
+//   unsigned value_;
+// };
+
+// CommitTextListener is notified when a text is commited from the context.
+class CommitTextListener {
+ public:
+  virtual void OnCommitText(IMEContext* sender,
+                            const string16& text) = 0;
+
+ protected:
+  virtual ~CommitTextListener() {}
+};
+
+// CompositionListener is notified when composition of the context is changed.
+class CompositionListener {
+ public:
+  virtual void OnStartComposition(IMEContext* sender) = 0;
+  virtual void OnEndComposition(IMEContext* sender) = 0;
+  virtual void OnSetComposition(IMEContext* sender,
+                                const string16& text,
+                                const CompositionAttributeList& attributes,
+                                uint32 cursor_pos) = 0;
+
+ protected:
+  virtual ~CompositionListener() {}
+};
+
+// CompositionListener is notified when a key event is forwarded from
+// the context.
+class ForwardKeyEventListener {
+ public:
+  virtual void OnForwardKeyEvent(IMEContext* sender,
+                                 const KeyEvent& event) = 0;
+
+ protected:
+  virtual ~ForwardKeyEventListener() {}
+};
+
+// SurroundingListener is notified when an input method context needs to
+// manipulate the text surround the input cursor. If associated view supports
+// surrounding, it should set the listener to input method context. Some input
+// methods generate different result depends on the chars before or after the
+// input cursor.
+//
+// For example:
+// Some Korean input method:
+//      Key events                  Unicode char
+// 1    'C'                          +U314a
+// 2    'K'                          +U314f
+// 3    'C' 'K'                      +Ucc28
+//
+// In case 2 and 3, when users press 'K', the input method will check the char
+// before input cursor. If the char is +U314a, it will remove the char and
+// insert a new char +Ucc28. If no char before input cursor, it will insert char
+// +U314f.
+//
+// See also OnSetSurroundingActive() and OnDeleteSurrounding().
+class SurroundingListener {
+ public:
+  // Activate or inactivate surrounding support. When surrounding is activated,
+  // The assoicated view should call SetSurrounding() to notify any changes of
+  // text surround the input cursor.
+  // Return true if associated view can support surrounding.
+  virtual bool OnSetSurroundingActive(IMEContext* sender,
+                                      bool activate) = 0;
+
+  // Delete a picse of text surround the input cursor.
+  // Return true if associated view delete the surrounding text successfully.
+  virtual bool OnDeleteSurrounding(IMEContext* sender,
+                                   int offset,
+                                   int chars) = 0;
+ protected:
+  virtual ~SurroundingListener() {}
+};
+
+class IMEContext {
+ public:
+  virtual ~IMEContext() {}
+
+  // Set associated view.
+  void set_view(View* view) { view_ = view; }
+
+  // Get associated view.
+  const View* view() const { return view_; }
+
+  // Set a listener to receive a callback when im context commits a text.
+  void set_commit_text_listener(CommitTextListener* listener) {
+    commit_text_listener_ = listener;
+  }
+
+  // Set a listener to receive a callback when im context changes composition.
+  void set_composition_listener(CompositionListener* listener) {
+    composition_listener_ = listener;
+  }
+
+  // Set a listener to receive a callback when im context forwards a key event.
+  void set_forward_key_event_listener(ForwardKeyEventListener* listener) {
+    forward_key_event_listener_ = listener;
+  }
+
+  // Set a listener to receive a callback when im context need operater
+  // surrounding.
+  void set_surrounding_listener(SurroundingListener* listener) {
+    surrounding_listener_ = listener;
+  }
+
+  // Tell the context it got/lost focus.
+  virtual void Focus() = 0;
+  virtual void Blur() = 0;
+
+  // Reset context, context will be reset to initial state.
+  virtual void Reset()  = 0;
+
+  // Filter key event, returns true, if the key event is handled,
+  // associated widget should ignore it.
+  virtual bool FilterKeyEvent(const views::KeyEvent& event) = 0;
+
+  // Set text input cursor location on screen.
+  virtual void SetCursorLocation(const gfx::Rect& caret_rect) = 0;
+
+  // Set surrounding context.
+  virtual void SetSurrounding(const string16& text,
+                              int cursor_pos) = 0;
+
+  // Create an im context.
+  static IMEContext* Create(View* view);
+
+ protected:
+  explicit IMEContext(View* view);
+
+  // Commit text.
+  void CommitText(const string16& text);
+
+  // Start compostion.
+  void StartComposition();
+
+  // End composition.
+  void EndComposition();
+
+  // Set composition.
+  void SetComposition(const string16& text,
+                      const CompositionAttributeList& attributes,
+                      uint32 cursor_pos);
+
+  // Forward key event.
+  void ForwardKeyEvent(const KeyEvent& event);
+
+  // Notify the associated view whether or not the input context needs
+  // surrounding. When surrounding is activated, associated view should
+  // call SetSurrounding() to update any changes of text arround the input
+  // cursor.
+  // Return true if associated view can support surrounding.
+  bool SetSurroundingActive(bool activate);
+
+  // Delete surrouding arround cursor. Return true, if it is handled.
+  bool DeleteSurrounding(int offset, int nchars);
+
+ private:
+  // Client view.
+  View* view_;
+
+  // Listeners:
+  CommitTextListener* commit_text_listener_;
+  CompositionListener* composition_listener_;
+  ForwardKeyEventListener* forward_key_event_listener_;
+  SurroundingListener* surrounding_listener_;
+
+  DISALLOW_COPY_AND_ASSIGN(IMEContext);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_IME_IM_CONTEXT_H_