Implement Uniscribe RenderText for Windows.

Follow the I18N recommendations for BiDi text editing.
Visual cursor movement and logical selection over BiDi text.
Cleanup some common RenderText code and interfaces.
Fixup TextfieldExample for views_examples.

Known issues:
Word breaking is not well implemented.
Font sizes and vertical alignments are slightly off.
Text styles break runs (colors can affect glyph shaping).
Composition/selection ranges aren't stylized.

BUG=90426
TEST=--use-pure-views text editing

Review URL: http://codereview.chromium.org/7458014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@98785 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 98 insertions, 44 deletions

diff --git a/ui/gfx/render_text.cc b/ui/gfx/render_text.cc
index 498bb3b..26518d1 100644
--- a/ui/gfx/render_text.cc
+++ b/ui/gfx/render_text.cc
@@ -164,14 +164,8 @@ void RenderText::SetText(const string16& text) {
   cached_bounds_and_offset_valid_ = false;
 }
 
-void RenderText::SetSelectionModel(const SelectionModel& sel) {
-  size_t start = sel.selection_start();
-  size_t end = sel.selection_end();
-  selection_model_.set_selection_start(std::min(start, text().length()));
-  selection_model_.set_selection_end(std::min(end, text().length()));
-  selection_model_.set_caret_pos(std::min(sel.caret_pos(), text().length()));
-  selection_model_.set_caret_placement(sel.caret_placement());
-
+void RenderText::ToggleInsertMode() {
+  insert_mode_ = !insert_mode_;
   cached_bounds_and_offset_valid_ = false;
 }
 
@@ -184,13 +178,8 @@ size_t RenderText::GetCursorPosition() const {
   return selection_model_.selection_end();
 }
 
-void RenderText::SetCursorPosition(const size_t position) {
-  SelectionModel sel(selection_model());
-  sel.set_selection_start(position);
-  sel.set_selection_end(position);
-  sel.set_caret_pos(GetIndexOfPreviousGrapheme(position));
-  sel.set_caret_placement(SelectionModel::TRAILING);
-  SetSelectionModel(sel);
+void RenderText::SetCursorPosition(size_t position) {
+  MoveCursorTo(position, false);
 }
 
 void RenderText::MoveCursorLeft(BreakType break_type, bool select) {
@@ -237,9 +226,26 @@ void RenderText::MoveCursorRight(BreakType break_type, bool select) {
   MoveCursorTo(position);
 }
 
-bool RenderText::MoveCursorTo(const SelectionModel& selection) {
-  bool changed = !selection.Equals(selection_model_);
-  SetSelectionModel(selection);
+bool RenderText::MoveCursorTo(const SelectionModel& selection_model) {
+  SelectionModel sel(selection_model);
+  size_t text_length = text().length();
+  // Enforce valid selection model components.
+  if (sel.selection_start() > text_length)
+    sel.set_selection_start(text_length);
+  if (sel.selection_end() > text_length)
+    sel.set_selection_end(text_length);
+  // The current model only supports caret positions at valid character indices.
+  if (text_length == 0) {
+    sel.set_caret_pos(0);
+    sel.set_caret_placement(SelectionModel::LEADING);
+  } else if (sel.caret_pos() >= text_length) {
+    SelectionModel end = GetTextDirection() == base::i18n::RIGHT_TO_LEFT ?
+        LeftEndSelectionModel() : RightEndSelectionModel();
+    sel.set_caret_pos(end.caret_pos());
+    sel.set_caret_placement(end.caret_placement());
+  }
+  bool changed = !sel.Equals(selection_model_);
+  SetSelectionModel(sel);
   return changed;
 }
 
@@ -251,6 +257,8 @@ bool RenderText::MoveCursorTo(const Point& point, bool select) {
 }
 
 bool RenderText::IsPointInSelection(const Point& point) {
+  if (EmptySelection())
+    return false;
   // TODO(xji): should this check whether the point is inside the visual
   // selection bounds? In case of "abcFED", if "ED" is selected, |point| points
   // to the right half of 'c', is the point in selection?
@@ -265,8 +273,8 @@ void RenderText::ClearSelection() {
 }
 
 void RenderText::SelectAll() {
-  SelectionModel sel(0, text().length(),
-                     text().length(), SelectionModel::LEADING);
+  SelectionModel sel(RightEndSelectionModel());
+  sel.set_selection_start(LeftEndSelectionModel().selection_start());
   SetSelectionModel(sel);
 }
 
@@ -308,12 +316,8 @@ void RenderText::SelectWord() {
       break;
   }
 
-  SelectionModel sel(selection_model());
-  sel.set_selection_start(selection_start);
-  sel.set_selection_end(cursor_position);
-  sel.set_caret_pos(GetIndexOfPreviousGrapheme(cursor_position));
-  sel.set_caret_placement(SelectionModel::TRAILING);
-  SetSelectionModel(sel);
+  MoveCursorTo(selection_start, false);
+  MoveCursorTo(cursor_position, true);
 }
 
 const ui::Range& RenderText::GetCompositionRange() const {
@@ -350,8 +354,8 @@ void RenderText::ApplyDefaultStyle() {
 }
 
 base::i18n::TextDirection RenderText::GetTextDirection() const {
-  // TODO(msw): Bidi implementation, intended to replace the functionality added
-  //  in crrev.com/91881 (discussed in codereview.chromium.org/7324011).
+  if (base::i18n::IsRTL())
+    return base::i18n::RIGHT_TO_LEFT;
   return base::i18n::LEFT_TO_RIGHT;
 }
 
@@ -443,20 +447,6 @@ SelectionModel RenderText::FindCursorPosition(const Point& point) {
   return SelectionModel(left_pos);
 }
 
-std::vector<Rect> RenderText::GetSubstringBounds(size_t from, size_t to) {
-  size_t start = std::min(from, to);
-  size_t end = std::max(from, to);
-  const Font& font = default_style_.font;
-  int start_x = font.GetStringWidth(text().substr(0, start));
-  int end_x = font.GetStringWidth(text().substr(0, end));
-  Rect rect(start_x, 0, end_x - start_x, font.GetHeight());
-  rect.Offset(display_rect_.origin());
-  rect.Offset(GetUpdatedDisplayOffset());
-  // Center the rect vertically in |display_rect_|.
-  rect.Offset(Point(0, (display_rect_.height() - rect.height()) / 2));
-  return std::vector<Rect>(1, rect);
-}
-
 Rect RenderText::GetCursorBounds(const SelectionModel& selection,
                                  bool insert_mode) {
   size_t from = selection.selection_end();
@@ -549,9 +539,35 @@ SelectionModel RenderText::GetRightSelectionModel(const SelectionModel& current,
   return SelectionModel(pos, pos, SelectionModel::LEADING);
 }
 
+SelectionModel RenderText::LeftEndSelectionModel() {
+  return SelectionModel(0, 0, SelectionModel::LEADING);
+}
+
+SelectionModel RenderText::RightEndSelectionModel() {
+  size_t cursor = text().length();
+  size_t caret_pos = GetIndexOfPreviousGrapheme(cursor);
+  SelectionModel::CaretPlacement placement = (caret_pos == cursor) ?
+      SelectionModel::LEADING : SelectionModel::TRAILING;
+  return SelectionModel(cursor, caret_pos, placement);
+}
+
 size_t RenderText::GetIndexOfPreviousGrapheme(size_t position) {
   // TODO(msw): Handle complex script.
-  return std::max(static_cast<int>(position - 1), static_cast<int>(0));
+  return std::max(static_cast<long>(position - 1), static_cast<long>(0));
+}
+
+std::vector<Rect> RenderText::GetSubstringBounds(size_t from, size_t to) {
+  size_t start = std::min(from, to);
+  size_t end = std::max(from, to);
+  const Font& font = default_style_.font;
+  int start_x = font.GetStringWidth(text().substr(0, start));
+  int end_x = font.GetStringWidth(text().substr(0, end));
+  Rect rect(start_x, 0, end_x - start_x, font.GetHeight());
+  rect.Offset(display_rect_.origin());
+  rect.Offset(GetUpdatedDisplayOffset());
+  // Center the rect vertically in |display_rect_|.
+  rect.Offset(Point(0, (display_rect_.height() - rect.height()) / 2));
+  return std::vector<Rect>(1, rect);
 }
 
 void RenderText::ApplyCompositionAndSelectionStyles(
@@ -576,6 +592,45 @@ void RenderText::ApplyCompositionAndSelectionStyles(
   }
 }
 
+Point RenderText::ToTextPoint(const Point& point) {
+  Point p(point.Subtract(display_rect().origin()));
+  p = p.Subtract(GetUpdatedDisplayOffset());
+  if (base::i18n::IsRTL())
+    p.Offset(GetStringWidth() - display_rect().width() + 1, 0);
+  return p;
+}
+
+Point RenderText::ToViewPoint(const Point& point) {
+  Point p(point.Add(display_rect().origin()));
+  p = p.Add(GetUpdatedDisplayOffset());
+  if (base::i18n::IsRTL())
+    p.Offset(display_rect().width() - GetStringWidth() - 1, 0);
+  return p;
+}
+
+void RenderText::SetSelectionModel(const SelectionModel& selection_model) {
+  DCHECK_LE(selection_model.selection_start(), text().length());
+  selection_model_.set_selection_start(selection_model.selection_start());
+  DCHECK_LE(selection_model.selection_end(), text().length());
+  selection_model_.set_selection_end(selection_model.selection_end());
+  DCHECK_LT(selection_model.caret_pos(),
+            std::max(text().length(), static_cast<size_t>(1)));
+  selection_model_.set_caret_pos(selection_model.caret_pos());
+  selection_model_.set_caret_placement(selection_model.caret_placement());
+
+  cached_bounds_and_offset_valid_ = false;
+}
+
+void RenderText::MoveCursorTo(size_t position, bool select) {
+  size_t cursor = std::min(position, text().length());
+  size_t caret_pos = GetIndexOfPreviousGrapheme(cursor);
+  SelectionModel::CaretPlacement placement = (caret_pos == cursor) ?
+      SelectionModel::LEADING : SelectionModel::TRAILING;
+  size_t selection_start = select ? GetSelectionStart() : cursor;
+  SelectionModel sel(selection_start, cursor, caret_pos, placement);
+  SetSelectionModel(sel);
+}
+
 bool RenderText::IsPositionAtWordSelectionBoundary(size_t pos) {
   return pos == 0 || (u_isalnum(text()[pos - 1]) && !u_isalnum(text()[pos])) ||
       (!u_isalnum(text()[pos - 1]) && u_isalnum(text()[pos]));
@@ -589,7 +644,6 @@ void RenderText::UpdateCachedBoundsAndOffset() {
   // function will set |cursor_bounds_| and |display_offset_| to correct values.
   cached_bounds_and_offset_valid_ = true;
   cursor_bounds_ = GetCursorBounds(selection_model_, insert_mode_);
-  cursor_bounds_.set_width(std::max(cursor_bounds_.width(), 1));
   // Update |display_offset_| to ensure the current cursor is visible.
   int display_width = display_rect_.width();
   int string_width = GetStringWidth();