Merge left and right cursor movement code in RenderText, and misc fixes

* Combine method pairs for left/right cursor motion in RenderText{,Linux,Win}, eliminating a lot of duplicate logic. The merged functions use new enums VisualTextDirection {VISUAL_LEFT, VISUAL_RIGHT} and LogicalTextDirection {LOGICAL_PREVIOUS, LOGICAL_NEXT}.

* Make CalculateSubstringBounds and GetSelectionBounds return the result instead of taking it as an out pointer argument.

* Remove Utf16IndexOfAdjacentGrapheme for clarity (it took a UTF-8 index as its argument)

* Delete some unused obsolete methods in RenderText, remove some logging code, and fix some comments.

The logic should be unchanged except that in the Backspace handler in NativeTextfieldViews, cursor_changed is now set to true only if the text changed (like Delete). Formerly it was always set to true, which appears to be a bug.

BUG=none
TEST=existing unit tests


Review URL: http://codereview.chromium.org/8958024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@118580 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 57 insertions, 43 deletions

diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index 65057ab..e784f1d 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -57,16 +57,6 @@ class SkiaTextRenderer {
 
 }  // namespace internal
 
-// Color settings for text, backgrounds and cursor.
-// These are tentative, and should be derived from theme, system
-// settings and current settings.
-// TODO(oshima): Change this to match the standard chrome
-// before dogfooding textfield views.
-const SkColor kSelectedTextColor = SK_ColorWHITE;
-const SkColor kFocusedSelectionColor = SkColorSetRGB(30, 144, 255);
-const SkColor kUnfocusedSelectionColor = SK_ColorLTGRAY;
-const SkColor kCursorColor = SK_ColorBLACK;
-
 // A visual style applicable to a range of text.
 struct UI_EXPORT StyleRange {
   StyleRange();
@@ -91,7 +81,22 @@ enum BreakType {
   LINE_BREAK,
 };
 
-// TODO(msw): Implement RenderText[Win|Linux] for Uniscribe/Pango BiDi...
+// VisualCursorDirection and LogicalCursorDirection represent directions of
+// motion of the cursor in BiDi text. The combinations that make sense are:
+//
+//  base::i18n::TextDirection  VisualCursorDirection  LogicalCursorDirection
+//       LEFT_TO_RIGHT             CURSOR_LEFT           CURSOR_BACKWARD
+//       LEFT_TO_RIGHT             CURSOR_RIGHT          CURSOR_FORWARD
+//       RIGHT_TO_LEFT             CURSOR_RIGHT          CURSOR_BACKWARD
+//       RIGHT_TO_LEFT             CURSOR_LEFT           CURSOR_FORWARD
+enum VisualCursorDirection {
+  CURSOR_LEFT,
+  CURSOR_RIGHT
+};
+enum LogicalCursorDirection {
+  CURSOR_BACKWARD,
+  CURSOR_FORWARD
+};
 
 // RenderText represents an abstract model of styled text and its corresponding
 // visual layout. Support is built in for a cursor, a selection, simple styling,
@@ -144,8 +149,9 @@ class UI_EXPORT RenderText {
   // 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 start is moved to the same position.
-  void MoveCursorLeft(BreakType break_type, bool select);
-  void MoveCursorRight(BreakType break_type, bool select);
+  void MoveCursor(BreakType break_type,
+                  VisualCursorDirection direction,
+                  bool select);
 
   // Set the selection_model_ to the value of |selection|.
   // The selection model components are modified if invalid.
@@ -197,7 +203,13 @@ class UI_EXPORT RenderText {
   // Apply |default_style_| over the entire text range.
   void ApplyDefaultStyle();
 
-  virtual base::i18n::TextDirection GetTextDirection();
+  // Returns the dominant direction of the current text.
+  virtual base::i18n::TextDirection GetTextDirection() = 0;
+
+  // Returns the visual movement direction corresponding to the logical end
+  // of the text, considering only the dominant direction returned by
+  // |GetTextDirection()|, not the direction of a particular run.
+  VisualCursorDirection GetVisualDirectionOfLogicalEnd();
 
   // Get the width of the entire string.
   virtual int GetStringWidth() = 0;
@@ -220,8 +232,14 @@ class UI_EXPORT RenderText {
   // Subsequent text, cursor, or bounds changes may invalidate returned values.
   const Rect& GetUpdatedCursorBounds();
 
-  // Get the logical index of the grapheme following the argument |position|.
-  size_t GetIndexOfNextGrapheme(size_t position);
+  // Given an |index| in text(), return the next or previous grapheme boundary
+  // in logical order (that is, the nearest index for which
+  // |IsCursorablePosition(index)| returns true). The return value is in the
+  // range 0 to text().length() inclusive (the input is clamped if it is out of
+  // that range). Always moves by at least one character index unless the
+  // supplied index is already at the boundary of the string.
+  virtual size_t IndexOfAdjacentGrapheme(size_t index,
+                                         LogicalCursorDirection direction) = 0;
 
   // Return a SelectionModel with the cursor at the current selection's start.
   // The returned value represents a cursor/caret position without a selection.
@@ -240,28 +258,37 @@ class UI_EXPORT RenderText {
 
   // 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);
+  SelectionModel GetAdjacentSelectionModel(const SelectionModel& current,
+                                           BreakType break_type,
+                                           VisualCursorDirection direction);
+
+  // Get the selection model visually left/right of |selection| by one grapheme.
+  // The returned value represents a cursor/caret position without a selection.
+  virtual SelectionModel AdjacentCharSelectionModel(
+      const SelectionModel& selection,
+      VisualCursorDirection direction) = 0;
+
+  // Get the selection model visually left/right of |selection| by one word.
+  // The returned value represents a cursor/caret position without a selection.
+  virtual SelectionModel AdjacentWordSelectionModel(
+      const SelectionModel& selection,
+      VisualCursorDirection direction) = 0;
 
   // Get the SelectionModels corresponding to visual text ends.
   // The returned value represents a cursor/caret position without a selection.
-  virtual SelectionModel LeftEndSelectionModel();
-  virtual SelectionModel RightEndSelectionModel();
+  virtual SelectionModel EdgeSelectionModel(
+      VisualCursorDirection direction) = 0;
 
   // Sets the selection model, the argument is assumed to be valid.
   virtual void SetSelectionModel(const SelectionModel& model);
 
   // Get the visual bounds containing the logical substring within |from| to
-  // |to| into |bounds|. If |from| equals to |to|, |bounds| is set as empty.
-  // These bounds could be visually discontinuous if the substring is split by a
-  // LTR/RTL level change. These bounds are in local coordinates, but may be
-  // outside the visible region if the text is longer than the textfield.
-  // Subsequent text, cursor, or bounds changes may invalidate returned values.
-  virtual void GetSubstringBounds(size_t from,
-                                  size_t to,
-                                  std::vector<Rect>* bounds) = 0;
+  // |to|. If |from| equals |to|, the result is empty. These bounds could be
+  // visually discontinuous if the substring is split by a LTR/RTL level change.
+  // These bounds are in local coordinates, but may be outside the visible
+  // region if the text is longer than the textfield. Subsequent text, cursor,
+  // or bounds changes may invalidate returned values.
+  virtual std::vector<Rect> GetSubstringBounds(size_t from, size_t to) = 0;
 
   // Return true if cursor can appear in front of the character at |position|,
   // which means it is a grapheme boundary or the first character in the text.
@@ -277,12 +304,6 @@ class UI_EXPORT RenderText {
   // Draw the text.
   virtual void DrawVisualText(Canvas* canvas) = 0;
 
-  // Get the logical index of the grapheme preceding the argument |position|.
-  // If |IsCursorablePosition(position)| is true, the result will be the start
-  // of the previous grapheme, if any. Otherwise, the result will be the start
-  // of the grapheme containing |position|.
-  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);
@@ -314,13 +335,6 @@ class UI_EXPORT RenderText {
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, SelectionModels);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, OriginForSkiaDrawing);
 
-  // Return an index belonging to the |next| or previous logical grapheme.
-  // If |next| is false and |IsCursorablePosition(index)| is true, the result
-  // will be the start of the previous grapheme, if any. Otherwise, the result
-  // will be the start of the grapheme containing |index|.
-  // The return value is bounded by 0 and the text length, inclusive.
-  virtual size_t IndexOfAdjacentGrapheme(size_t index, bool next) = 0;
-
   // 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.