Implement Pango RenderText for Linux.

ui/gfx/render_text.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 UI_GFX_RENDER_TEXT_H_
 #define UI_GFX_RENDER_TEXT_H_
 #pragma once
 
 #include <algorithm>
 #include <vector>
@@ skipping 103 matching lines @@
   CaretPlacement caret_placement() const { return caret_placement_; }
   void set_caret_placement(CaretPlacement placement) {
     caret_placement_ = placement;
   }
 
   bool Equals(const SelectionModel& sel) const;
 
  private:
   void Init(size_t start, size_t end, size_t pos, CaretPlacement status);
 
-  // Logical selection start. If there is non-empty selection, the selection
-  // always starts visually at the leading edge of the selection_start. So, we
-  // do not need extra information for visual selection bounding.
+  // Logical selection start. If there is non-empty selection, if
+  // selection_start_ is less than selection_end_, the selection starts visually
+  // at the leading edge of the selection_start_. If selection_start_ is greater
+  // than selection_end_, the selection starts visually at the trailing edge of
+  // selection_start_'s previous grapheme. So, we do not need extra information
+  // for visual bounding.
   size_t selection_start_;
 
   // The logical cursor position that next character will be inserted into.
   // It is also the end of the selection.
   size_t selection_end_;
 
   // The following two fields are used to guide cursor visual position.
   // The index of the character that cursor is visually attached to.
   size_t caret_pos_;
   // The visual placement of the cursor, relative to its associated character.
@@ skipping 32 matching lines @@
   void set_default_style(StyleRange style) { default_style_ = style; }
 
   const Rect& display_rect() const { return display_rect_; }
   virtual void SetDisplayRect(const Rect& r);
 
   // This cursor position corresponds to SelectionModel::selection_end. In
   // addition to representing the selection end, it's also where logical text
   // edits take place, and doesn't necessarily correspond to
   // SelectionModel::caret_pos.
   size_t GetCursorPosition() const;
-  void SetCursorPosition(const size_t position);
+  void SetCursorPosition(size_t position);
 
   void SetCaretPlacement(SelectionModel::CaretPlacement placement) {
       selection_model_.set_caret_placement(placement);
   }
 
   // Moves the cursor left or right. Cursor movement is visual, meaning that
   // left and right are relative to screen, not the directionality of the text.
   // If |select| is false, the selection range is emptied at the new position.
   void MoveCursorLeft(BreakType break_type, bool select);
   void MoveCursorRight(BreakType break_type, bool select);
@@ skipping 29 matching lines @@
 
   const ui::Range& GetCompositionRange() const;
   void SetCompositionRange(const ui::Range& composition_range);
 
   // Apply |style_range| to the internal style model.
   virtual void ApplyStyleRange(StyleRange style_range);
 
   // Apply |default_style_| over the entire text range.
   virtual void ApplyDefaultStyle();
 
-  base::i18n::TextDirection GetTextDirection() const;
+  virtual base::i18n::TextDirection GetTextDirection();
 
   // Get the width of the entire string.
   virtual int GetStringWidth();
 
   virtual void Draw(Canvas* canvas);
 
   // Gets the SelectionModel from a visual point in local coordinates.
   virtual SelectionModel FindCursorPosition(const Point& point);
 
   // Get the visual bounds containing the logical substring within |from| to
@@ skipping 27 matching lines @@
 
   const StyleRanges& style_ranges() const { return style_ranges_; }
 
   // Get the selection model that visually neighbors |position| by |break_type|.
   // The returned value represents a cursor/caret position without a selection.
   virtual SelectionModel GetLeftSelectionModel(const SelectionModel& current,
                                                BreakType break_type);
   virtual SelectionModel GetRightSelectionModel(const SelectionModel& current,
                                                 BreakType break_type);
 
-  // Get the logical index of the grapheme preceeding the argument |position|.
+  // Get the logical index of the grapheme preceding the argument |position|.
   virtual size_t GetIndexOfPreviousGrapheme(size_t position);
 
   // Apply composition style (underline) to composition range and selection
   // style (foreground) to selection range.
   void ApplyCompositionAndSelectionStyles(StyleRanges* style_ranges) const;
 
+  // Convert points from the text space to the view space and back.
+  // Handles the display area, display offset, and the application LTR/RTL mode.
+  Point ToTextPoint(const Point& point);
+  Point ToViewPoint(const Point& point);
+
  private:
   friend class RenderTextTest;
 
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, DefaultStyle);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, CustomDefaultStyle);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ApplyStyleRange);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, StyleRangesAdjust);
 
   // Clear out |style_ranges_|.
   void ClearStyleRanges();
 
+  // Set the cursor to |position|, with the caret trailing the previous
+  // grapheme, or if there is no previous grapheme, leading the cursor position.
+  // If |select| is false, the selection start is moved to the same position.
+  void MoveCursorTo(size_t position, bool select);
+
   bool IsPositionAtWordSelectionBoundary(size_t pos);
 
   // Update the cached bounds and display offset to ensure that the current
   // cursor is within the visible display area.
   void UpdateCachedBoundsAndOffset();
 
+  // Returns the selection model of selection_start_. This should be called only
+  // when selection is not empty, i.e. selection_end_ != selection_start_.

[msw, 2011/08/24 08:55:30]

I would hope that this function does something reasonable when the selection is
empty... You should remove this comment constraintor enforce it as a DCHECK in
the function body.

[xji, 2011/08/25 03:15:19]

changed the implementation to return selection_model_ when selection is empty.

+  // The returned value represents a cursor/caret position without a selection.
+  SelectionModel GetSelectionModelForSelectionStart();
+
   // Logical UTF-16 string data to be drawn.
   string16 text_;
 
   // Logical selection range and visual cursor position.
   SelectionModel selection_model_;
 
   // The cached cursor bounds; get these bounds with GetUpdatedCursorBounds.
   Rect cursor_bounds_;
 
   // The cursor visibility and insert mode.
@@ skipping 21 matching lines @@
   // SetCursorPosition, SetSelectionModel, Font related style change, and other
   // operations that adjust the visible text bounds.
   bool cached_bounds_and_offset_valid_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_