Implement Pango RenderText for Linux.

ui/gfx/render_text.cc

Index: ui/gfx/render_text.cc
===================================================================
--- ui/gfx/render_text.cc	(revision 97029)
+++ ui/gfx/render_text.cc	(working copy)
@@ -184,13 +184,8 @@
   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) {
@@ -199,8 +194,7 @@
   // Cancelling a selection moves to the edge of the selection.
   if (break_type != LINE_BREAK && !EmptySelection() && !select) {
     // Use the selection start if it is left of the selection end.
-    SelectionModel selection_start(GetSelectionStart(), GetSelectionStart(),
-                                   SelectionModel::LEADING);
+    SelectionModel selection_start =  GetSelectionModelForSelectionStart();

[msw, 2011/08/23 08:01:01]

Remove the extra space after '='.

[xji, 2011/08/23 23:52:52]

Done.

     if (GetCursorBounds(selection_start, false).x() <
         GetCursorBounds(position, false).x())
       position = selection_start;
@@ -221,8 +215,7 @@
   // Cancelling a selection moves to the edge of the selection.
   if (break_type != LINE_BREAK && !EmptySelection() && !select) {
     // Use the selection start if it is right of the selection end.
-    SelectionModel selection_start(GetSelectionStart(), GetSelectionStart(),
-                                   SelectionModel::LEADING);
+    SelectionModel selection_start = GetSelectionModelForSelectionStart();
     if (GetCursorBounds(selection_start, false).x() >
         GetCursorBounds(position, false).x())
       position = selection_start;
@@ -349,9 +342,11 @@
   cached_bounds_and_offset_valid_ = false;
 }
 
-base::i18n::TextDirection RenderText::GetTextDirection() const {
+base::i18n::TextDirection RenderText::GetTextDirection() {
   // 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;
 }
 
@@ -576,6 +571,31 @@
   }
 }
 
+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::MoveCursorTo(size_t position, bool select) {
+  size_t caret_pos = GetIndexOfPreviousGrapheme(position);
+  SelectionModel::CaretPlacement placement = (caret_pos == position) ?
+      SelectionModel::LEADING : SelectionModel::TRAILING;
+  size_t selection_start = select ? GetSelectionStart() : position;
+  SelectionModel sel(selection_start, position, 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]));
@@ -598,9 +618,17 @@
     // Show all text whenever the text fits to the size.
     delta_offset = -display_offset_.x();
   } else if (cursor_bounds_.right() > display_rect_.right()) {
+    // TODO(xji): when the character overflow is a RTL character, currently, if
+    // we pan cursor at the rightmost position, the entered RTL character is not
+    // displayed. Should pan cursor to show the last logical characters.
+    // BTW, Firefox has the same issue.

[msw, 2011/08/23 08:01:01]

No need to call out Firefox here, we can alert them if they have a similar bug.

[xji, 2011/08/23 23:52:52]

Ah, you absolutely right. removed.

+    //
     // Pan to show the cursor when it overflows to the right,
     delta_offset = display_rect_.right() - cursor_bounds_.right();
   } else if (cursor_bounds_.x() < display_rect_.x()) {
+    // TODO(xji): have similar problem as above when overflow character is a
+    // LTR character.
+    //
     // Pan to show the cursor when it overflows to the left.
     delta_offset = display_rect_.x() - cursor_bounds_.x();
   }
@@ -608,4 +636,14 @@
   cursor_bounds_.Offset(delta_offset, 0);
 }
 
+SelectionModel RenderText::GetSelectionModelForSelectionStart() {
+  if (GetSelectionStart() < GetCursorPosition())
+    return SelectionModel(GetSelectionStart(),
+                          GetSelectionStart(),
+                          SelectionModel::LEADING);
+  return SelectionModel(GetSelectionStart(),
+                        GetIndexOfPreviousGrapheme(GetSelectionStart()),

[msw, 2011/08/23 08:01:01]

What if the selection start is 0 and there is not previous grapheme?

[xji, 2011/08/23 23:52:52]

this is called when selection is not empty and selection_start > cursor_pos, so
selection_start should not be 0.
I added comments in header file.

+                        SelectionModel::TRAILING);
+}
+
 }  // namespace gfx