Model, View and Controller for a Gap Buffer based one line text field in view...

views/controls/textfield/textfield_view.h

+// Copyright (c) 2010 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_CONTROLS_TEXTFIELD_TEXTFIELD_VIEW_H_
+#define VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_VIEW_H_
+#pragma once
+
+#include <algorithm>
+
+#include "gfx/canvas.h"
+#include "views/controls/label.h"
+#include "views/controls/textfield/textfield_model.h"
+#include "views/event.h"
+#include "views/view.h"
+
+namespace views {
+
+// View for a MVC of a single line textfield. The textfield inherits from Label
+// to re-use its font and color related code.
+class TextfieldView : public Label {
+ public:
+  TextfieldView();
+  explicit TextfieldView(const std::wstring& text);
+  explicit TextfieldView(TextfieldModel* model);
+
+  virtual void SetController(TextfieldController* controller);
+  // Returns the rectangle in which the text can be painted. This is essentially
+  // the bounds of the view minus the border (insets) width.
+  gfx::Rect GetTextBounds();
+
+
+  // View Overrides. Refer to view.h for documentation.
+  virtual bool SkipDefaultKeyEventProcessing(const views::KeyEvent& e);
+  virtual bool OnMousePressed(const views::MouseEvent& e);
+  virtual bool OnMouseDragged(const views::MouseEvent& e);
+  virtual void OnMouseReleased(const views::MouseEvent& e, bool canceled);
+  virtual bool OnKeyPressed(const views::KeyEvent& e);
+  virtual bool OnKeyReleased(const views::KeyEvent& e);
+  virtual void Paint(gfx::Canvas* canvas);
+  virtual void WillGainFocus();
+  virtual void DidGainFocus();
+  virtual void WillLoseFocus();
+  virtual std::wstring GetText();
+
+  // Getters
+  int onscreen_cursor_pos() { return onscreen_cursor_pos_; }
+  std::wstring visible_text() { return visible_text_; }
+
+  static const char kViewClassName[];
+
+ private:
+  // Computes the portion of string that can be painted to the left of cursor.
+  std::wstring GetStringToLeftOfCursor(std::wstring text, int cursor_pos,
+      int onscreen_cursor_pos, gfx::Rect text_bounds);
+
+  // Computes the portion of string that can be painted to the left of cursor.
+  std::wstring GetStringToRightOfCursor(std::wstring text, int cursor_pos,
+      int onscreen_cursor_pos, gfx::Rect text_bounds);
+
+  // Utility function. Gets the character corresponding to a key event.
+  wchar_t GetWritableChar(const KeyEvent& key_event);
+
+  // Utility function. Gets the character corresponding to a key_code.
+  wchar_t GetWritableChar(base::KeyboardCode key_code, bool shift);
+  bool HandleKeyEvent(const KeyEvent& key_event);
+  void Init(const std::wstring& text);
+  bool IsDirectionalKey(base::KeyboardCode key_code);
+  bool IsWritable(base::KeyboardCode key_code);
+  void PaintTextAndCursor(gfx::Canvas* canvas);
+
+  // Safely increments the onscreen position of the cursor (making sure it does
+  // not exceeds the view bounds).
+  void SafeIncCursorPos(int inc);
+
+  // Safely decrements the onscreen position of the cursor (making sure it does
+  // not go below 0).
+  void SafeDecCursorPos(int dec);
+
+  scoped_ptr<TextfieldModel> model_;
+  scoped_ptr<TextfieldController> controller_;
+  std::wstring visible_text_;
+  bool selection_on_;
+  int selection_start_;
+  int onscreen_cursor_pos_;
+};
+};
+#endif  // VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_VIEW_H_