Implement Pango RenderText for Linux.

ui/gfx/render_text_linux.cc

 // 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.
 
 #include "ui/gfx/render_text_linux.h"
 
+#include <pango/pangocairo.h>
+#include <algorithm>
+
+#include "base/logging.h"
+#include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/gtk_util.h"
+#include "unicode/uchar.h"
+
+#define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)
+#define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)

[oshima, 2011/08/19 18:44:07]

space around operators

[xji, 2011/08/20 00:53:05]

these are actually not needed. defined in include files included in uchar.h

+// TODO(xji): massage ARGB to RGB.
+#define COLOR_16_TO_32_BIT(c) ((c)/0xff * 0xffff)

[oshima, 2011/08/19 18:44:07]

If this is to convert ARGB to RGB, please name accordingly. (ARGB_TO_RGB,
ARGB2RGB etc)

[xji, 2011/08/20 00:53:05]

It is just convert R/G/B from 16 bit to 32 bit.
but since we are useing ARGB, but pango uses only RGB, we should do A massage to
be more accurate.

Changed the description of TODO.

+
+// TODO(xji): index saved in upper layer are utf16 index. Pango uses utf8 index.
+// Since caret_pos is used internally, we could save utf8 index for caret_pos
+// to avoid conversion.
+
 namespace gfx {
 
 RenderTextLinux::RenderTextLinux()
-    : RenderText() {
+    : layout_(NULL),
+      layout_line_(NULL) {
 }
 
 RenderTextLinux::~RenderTextLinux() {
+  ResetLayout();
 }
 
 RenderText* RenderText::CreateRenderText() {
   return new RenderTextLinux;
 }
 
+int RenderTextLinux::GetStringWidth() {
+  PangoLayout* layout = EnsureLayout();
+  int width, height;
+  pango_layout_get_pixel_size(layout, &width, &height);
+  return width;
+}
+
+void RenderTextLinux::Draw(Canvas* canvas) {
+  PangoLayout* layout = EnsureLayout();
+  Rect bounds(display_rect());
+
+  // Clip the canvas to the text display area.
+  CanvasSkia* canvas_skia = static_cast<CanvasSkia*>(canvas);

[oshima, 2011/08/19 18:44:07]

canvas->AsCanvasSkia()

[xji, 2011/08/20 00:53:05]

Done.

+  canvas_skia->ClipRectInt(
+      bounds.x(), bounds.y(), bounds.width(), bounds.height());
+
+  // TODO(xji): is this Begin/EndPlatformPaint correct? How about performance?

[oshima, 2011/08/19 18:44:07]

This seems to be fine (assuming this class replaces DrawStringContet)

[xji, 2011/08/20 00:53:05]

comments removed.

+  cairo_t* cr = skia::BeginPlatformPaint(canvas_skia);
+  cairo_save(cr);
+  cairo_rectangle(cr, bounds.x(), bounds.y(), bounds.width(), bounds.height());
+  cairo_clip(cr);
+
+  int text_width, text_height;
+  pango_layout_get_pixel_size(layout, &text_width, &text_height);
+  // Vertically centered.
+  int text_y = bounds.y() + ((bounds.height() - text_height) / 2);
+  int text_x = bounds.x() + GetUpdatedDisplayOffset().x();
+  cairo_move_to(cr, text_x, text_y);
+  pango_cairo_show_layout(cr, layout);
+
+  // Destructor.
+  cairo_restore(cr);
+  skia::EndPlatformPaint(canvas_skia);
+
+  // Paint cursor.
+  bounds = GetUpdatedCursorBounds();
+  if (cursor_visible() && focused() && !bounds.IsEmpty()) {
+    if (!bounds.IsEmpty())
+       canvas->DrawRectInt(kCursorColor,
+                          bounds.x(),
+                          bounds.y(),
+                          bounds.width(),
+                          bounds.height());
+  }
+}
+
+SelectionModel RenderTextLinux::FindCursorPosition(const Point& point) {
+  // TODO(xji): when points outside of text, return HOME/END position.
+  PangoLayout* layout = EnsureLayout();
+
+  if (text().length() == 0)
+    return SelectionModel(0, 0, SelectionModel::LEADING);
+
+  int adjusted_x =
+      point.x() - display_rect().x() - GetUpdatedDisplayOffset().x();
+  int caret_pos, trailing;
+  pango_layout_xy_to_index(layout,
+                           adjusted_x * PANGO_SCALE,
+                           point.y() * PANGO_SCALE,
+                           &caret_pos,
+                           &trailing);
+
+  size_t selection_end = caret_pos;
+  if (trailing > 0) {
+    const char* layout_text = pango_layout_get_text(layout);
+    selection_end = g_utf8_offset_to_pointer(layout_text + caret_pos, trailing)
+        - layout_text;
+  }
+
+  return SelectionModel(
+      Utf8IndexToUtf16Index(text(), selection_end),
+      Utf8IndexToUtf16Index(text(), caret_pos),
+      trailing > 0 ? SelectionModel::TRAILING : SelectionModel::LEADING);
+}
+
+Rect RenderTextLinux::GetCursorBounds(const SelectionModel& selection,
+                                      bool insert_mode) {
+  PangoLayout* layout = EnsureLayout();
+
+  PangoRectangle pos;
+  pango_layout_index_to_pos(
+      layout, Utf16IndexToUtf8Index(text(), selection.caret_pos()), &pos);
+
+  int x;
+  SelectionModel::CaretPlacement caret_placement = selection.caret_placement();
+  if (caret_placement == SelectionModel::TRAILING)
+    x = (pos.x + pos.width) / PANGO_SCALE;
+  else
+    x = pos.x / PANGO_SCALE;
+  x += display_rect().x() + GetUpdatedDisplayOffset().x();

[oshima, 2011/08/19 18:44:07]

these can be

int x = (caret_placement == SelectionModel::TRAILING ? ... : ...) +
display_rect().x() + GetUpdatedDisplayOffset().x()

[xji, 2011/08/20 00:53:05]

I'd prefer the old way.
moderate use of tertiary is ok. but mixed with other operation makes the code
not much readable.

Also, this piece code changed by taking care of RTL locale and non-insert-mode
(but still in simple assignment)

+
+  const Font& font = default_style().font;
+  int h = std::min(display_rect().height(), font.GetHeight());
+  Rect bounds(x, (display_rect().height() - h) / 2, 1, h);
+
+  size_t position = selection.selection_end();
+  if (!insert_mode && text().length() != position)
+    AdjustBoundsForNonInsertMode(selection, pos, &bounds);
+
+  return bounds;
+}
+
+SelectionModel RenderTextLinux::GetLeftSelectionModel(
+    const SelectionModel& current, BreakType break_type) {
+  EnsureLayout();
+
+  if (break_type == LINE_BREAK)
+     return GetSelectionModelForVisualLeftmost();

[oshima, 2011/08/19 18:44:07]

indent

[xji, 2011/08/20 00:53:05]

Done.

+  if (break_type == CHARACTER_BREAK)
+    return GetLeftSelectionModelByGrapheme(current);
+  // TODO(xji): implementation.
+  return RenderText::GetLeftSelectionModel(current, break_type);
+}
+
+SelectionModel RenderTextLinux::GetRightSelectionModel(
+    const SelectionModel& current, BreakType break_type) {
+  EnsureLayout();
+
+  if (break_type == LINE_BREAK) {
+    const char* layout_text = pango_layout_get_text(layout_);
+    PangoDirection base_dir =
+        pango_find_base_dir(layout_text, strlen(layout_text));
+    if (base_dir == PANGO_DIRECTION_RTL ||
+        base_dir == PANGO_DIRECTION_WEAK_RTL)
+      return SelectionModel(0, 0, SelectionModel::LEADING);
+    return SelectionModel(
+        text().length(), text().length(), SelectionModel::LEADING);
+  }
+  if (break_type == CHARACTER_BREAK)
+    return GetRightSelectionModelByGrapheme(current);
+  // TODO(xji): implementation.

[oshima, 2011/08/19 18:44:07]

can you update the comment to be more descriptive?

[xji, 2011/08/20 00:53:05]

changed to "not implemented yet".

+  return RenderText::GetRightSelectionModel(current, break_type);
+}
+
+size_t RenderTextLinux::GetIndexOfPreviousGrapheme(size_t position) {
+  EnsureLayout();
+  return Utf16IndexOfAdjacentGrapheme(position, PREVIOUS);
+}
+
+SelectionModel RenderTextLinux::GetSelectionModelForVisualLeftmost() const {
+  const char* layout_text = pango_layout_get_text(layout_);
+  PangoDirection base_dir =
+      pango_find_base_dir(layout_text, strlen(layout_text));
+
+  if (base_dir == PANGO_DIRECTION_RTL || base_dir == PANGO_DIRECTION_WEAK_RTL) {
+    GSList* first_visual_run = layout_line_->runs;
+    if (first_visual_run) {
+      PangoItem* item =
+          reinterpret_cast<PangoLayoutRun*>(first_visual_run->data)->item;
+      if (item->analysis.level % 2 == 0) {  // LTR.
+        size_t utf16_index = Utf8IndexToUtf16Index(text(), item->offset);
+        return SelectionModel(
+            text().length(), utf16_index, SelectionModel::LEADING);
+      } else {  // RTL.
+        size_t utf16_index = Utf8IndexToUtf16Index(
+            text(), item->offset + item->length);
+        utf16_index = Utf16IndexOfAdjacentGrapheme(utf16_index, PREVIOUS);
+        return SelectionModel(
+            text().length(), utf16_index, SelectionModel::TRAILING);
+      }
+    }
+  }
+  return SelectionModel(0, 0, SelectionModel::LEADING);
+}
+
+GSList* RenderTextLinux::GetRunContainsCaretPos(const SelectionModel& current,
+                                                CursorMovementDirection dir,
+                                                bool* at_boundary) const {
+  GSList* run_contains_caret_pos = NULL;
+  *at_boundary = false;
+
+  GSList* run = layout_line_->runs;
+  while (run) {
+    PangoItem* pango_item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
+    size_t caret_pos = current.caret_pos();
+    size_t run_end_utf16_index =
+        Utf8IndexToUtf16Index(text(), pango_item->offset + pango_item->length);
+    size_t run_start_utf16_index =
+        Utf8IndexToUtf16Index(text(), pango_item->offset);
+
+    if (caret_pos >= run_start_utf16_index && caret_pos < run_end_utf16_index) {
+      run_contains_caret_pos = run;
+
+      size_t selection_end = current.selection_end();
+      SelectionModel::CaretPlacement caret_placement =
+          current.caret_placement();
+
+      if (caret_placement == SelectionModel::LEADING &&
+          caret_pos == run_start_utf16_index) {
+        *at_boundary = (dir == RIGHT && pango_item->analysis.level % 2) ||
+                       (dir == LEFT && pango_item->analysis.level % 2 == 0);
+      } else if (caret_placement == SelectionModel::TRAILING &&
+                 selection_end == run_end_utf16_index) {
+        *at_boundary = (dir == RIGHT && pango_item->analysis.level % 2 == 0) ||
+                       (dir == LEFT && pango_item->analysis.level % 2);
+      }
+      break;
+    }
+    run = run->next;
+  }
+  return run_contains_caret_pos;
+}
+
+size_t RenderTextLinux::Utf8IndexOfAdjacentGrapheme(
+    size_t utf16_index_of_current_grapheme, RelativeLogicalPosition pos) const {
+  PangoLogAttr* log_attrs;
+  gint n_attrs;
+  pango_layout_get_log_attrs(layout_, &log_attrs, &n_attrs);
+
+  const char* layout_text = pango_layout_get_text(layout_);
+  const char* ch = layout_text +
+      Utf16IndexToUtf8Index(text(), utf16_index_of_current_grapheme);
+  int char_offset = static_cast<int>(g_utf8_pointer_to_offset(layout_text, ch));
+
+  if (pos == PREVIOUS) {
+    if (ch > layout_text) {
+      do {
+        ch = g_utf8_find_prev_char(layout_text, ch);
+        --char_offset;
+      } while (ch && *ch && !log_attrs[char_offset].is_cursor_position);
+      if (!ch)
+        ch = layout_text;
+    }
+  } else {
+    if (ch < layout_text + strlen(layout_text)) {
+      do {
+        ch = g_utf8_find_next_char(ch, NULL);
+        ++char_offset;
+      } while (ch && *ch && !log_attrs[char_offset].is_cursor_position);
+      if (ch >= layout_text + strlen(layout_text))
+        ch = layout_text + strlen(layout_text);
+    }
+  }
+
+  size_t utf8_index = static_cast<size_t>(ch - layout_text);
+  // TODO(xji): how costly those g_free is?

[oshima, 2011/08/19 18:44:07]

negligible compared to other stuff we're doing.

[xji, 2011/08/20 00:53:05]

comment removed.

+  g_free(log_attrs);
+  return utf8_index;
+}
+
+size_t RenderTextLinux::Utf16IndexOfAdjacentGrapheme(
+    size_t utf16_index_of_current_grapheme, RelativeLogicalPosition pos) const {
+  size_t utf8_index = Utf8IndexOfAdjacentGrapheme(
+      utf16_index_of_current_grapheme, pos);
+  return Utf8IndexToUtf16Index(text(), utf8_index);
+}
+
+SelectionModel RenderTextLinux::FirstSelectionModelInsideRun(
+    const PangoItem* run) const {
+    size_t utf16_index = Utf8IndexToUtf16Index(text(), run->offset);

[oshima, 2011/08/19 18:44:07]

indnet

[xji, 2011/08/20 00:53:05]

Done.

+    return SelectionModel(Utf16IndexOfAdjacentGrapheme(utf16_index, NEXT),
+                          utf16_index,
+                          SelectionModel::TRAILING);
+}
+
+SelectionModel RenderTextLinux::LastSelectionModelInsideRun(
+    const PangoItem* run) const {
+    size_t utf16_index = Utf8IndexToUtf16Index(
+        text(), run->offset + run->length);

[oshima, 2011/08/19 18:44:07]

ditto

[xji, 2011/08/20 00:53:05]

Done.

+    utf16_index = Utf16IndexOfAdjacentGrapheme(utf16_index, PREVIOUS);
+    return SelectionModel(utf16_index, utf16_index, SelectionModel::LEADING);
+}
+
+SelectionModel RenderTextLinux::LeftmostSelectionModelInsideRun(
+    const PangoItem* run) const {
+  if (run->analysis.level % 2 == 0)
+    return FirstSelectionModelInsideRun(run);
+  return LastSelectionModelInsideRun(run);

[oshima, 2011/08/19 18:44:07]

can these be
return run->analysis.level % 2 == 0 ? .. : ..;

[xji, 2011/08/20 00:53:05]

Done.

+}
+
+SelectionModel RenderTextLinux::RightmostSelectionModelInsideRun(
+    const PangoItem* run) const {
+  if (run->analysis.level % 2)
+    return FirstSelectionModelInsideRun(run);
+  return LastSelectionModelInsideRun(run);
+}
+
+bool RenderTextLinux::GetVisuallyAdjacentCursorPositionForEnd(
+      const SelectionModel& current,
+      CursorMovementDirection dir,
+      SelectionModel* adjacent) const {
+  size_t text_length = text().length();
+  if (current.selection_end() == text_length &&
+      current.caret_pos() == text_length &&
+      current.caret_placement() == SelectionModel::LEADING) {
+    // Visually rightmost END position.
+    if (dir == LEFT) {
+      GSList* last_run = GetLastRun();
+      if (last_run) {
+        *adjacent = RightmostSelectionModelInsideRun(
+            reinterpret_cast<PangoLayoutRun*>(last_run->data)->item);
+      }
+    }
+    adjacent->set_selection_start(adjacent->selection_end());
+    return true;
+  }
+  return false;
+}
+
+// Assume caret_pos in |current| is n, 'l' represents leading in
+// caret_placement and 't' represents trailing in caret_placement. Following
+// is the calculation from (caret_pos, caret_placement) in |current| to
+// (caret_pos, caret_placement, selection_end) when moving cursor left by
+// one grapheme (for simplilcity, assume each grapheme is one character).
+// If n is in LTR run,
+// (n, t) ---> (n, l, n)
+// (n, l) ---> (n-1, l, n-1) if n is inside run (not at boundary).
+// (n, l) ---> goto across run case if n is at run boundary;
+// If n is in RTL run,
+// (n, l) --> (n, t, n+1);
+// (n, t) --> (n+1, t n+2) if n is inside run;
+// (n, t) --> goto across run case if n is at run boundar;
+// If n is at run boudary, get its visually left run,
+// if left run is LTR run,
+// (n, t) --> (left run's end, l, left run's end);
+// If rght run is RTL run,
+// (n, t) --> (left run's begin, t, left run's begin + 1);
+//
+// TODO(xji): duplication with GetRightSelectionModelByGrapheme.

[oshima, 2011/08/19 18:44:07]

do you mean you will consolidate two?

[xji, 2011/08/20 00:53:05]

I am not sure whether to consolidate them. Although the code is duplicated. but
consolidate will introduce several small function calls or make the code not
very readable.

+SelectionModel RenderTextLinux::GetLeftSelectionModelByGrapheme(
+    const SelectionModel& current) const {
+  SelectionModel left(current);
+  if (GetVisuallyAdjacentCursorPositionForEnd(current, LEFT, &left))
+    return left;
+
+  bool at_run_boundary = false;
+  GSList* run = GetRunContainsCaretPos(current, LEFT, &at_run_boundary);
+  if (run == NULL) {
+    left.set_selection_start(left.selection_end());
+    return left;
+  }
+
+  PangoItem* box = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
+  if (box->analysis.level % 2 == 0) {  // LTR box.
+    if (current.caret_placement() == SelectionModel::TRAILING) {
+      left.set_caret_placement(SelectionModel::LEADING);
+      left.set_selection_end(left.caret_pos());
+    } else {  // caret_placement == TRAILING.
+      if (at_run_boundary) {
+        GSList* prev_run = GetPreviousRun(run);
+        if (prev_run) {
+          return RightmostSelectionModelInsideRun(
+              reinterpret_cast<PangoLayoutRun*>(prev_run->data)->item);
+        }

[oshima, 2011/08/19 18:44:07]

nuke {}

[xji, 2011/08/20 00:53:05]

Done.

+      } else {  // !at_run_boundary.
+        size_t prev = Utf16IndexOfAdjacentGrapheme(left.caret_pos(), PREVIOUS);
+        left.set_caret_pos(prev);
+        left.set_selection_end(prev);
+      }
+    }
+  } else {  // RTL box.
+    if (current.caret_placement() == SelectionModel::LEADING) {
+      left.set_caret_placement(SelectionModel::TRAILING);
+      left.set_selection_end(
+          Utf16IndexOfAdjacentGrapheme(current.caret_pos(), NEXT));
+    } else {  // caret_placement == LEADING
+      if (at_run_boundary) {
+        GSList* prev_run = GetPreviousRun(run);
+        if (prev_run) {
+          return RightmostSelectionModelInsideRun(
+              reinterpret_cast<PangoLayoutRun*>(prev_run->data)->item);
+        }

[oshima, 2011/08/19 18:44:07]

ditto

[xji, 2011/08/20 00:53:05]

Done.

+      } else {  // !at_run_boundary
+        // current.seletion_end - current.caret_pos
+        // == NumOfCharsInGrapheme(caret_pos);

[oshima, 2011/08/19 18:44:07]

is this comment or dead code?

[xji, 2011/08/20 00:53:05]

it is comment, changed "==" to "equals to"

+        left.set_caret_pos(current.selection_end());
+        left.set_selection_end(
+            Utf16IndexOfAdjacentGrapheme(left.caret_pos(), NEXT));
+      }
+    }
+  }
+
+  left.set_selection_start(left.selection_end());
+  return left;
+}
+
+// Assume caret_pos in |current| is n, 'l' represents leading in
+// caret_placement and 't' represents trailing in caret_placement. Following
+// is the calculation from (caret_pos, caret_placement) in |current| to
+// (caret_pos, caret_placement, selection_end) when moving cursor right by
+// one grapheme (for simplilcity, assume each grapheme is one character).
+// If n is in LTR run,
+// (n, l) ---> (n, t, n+1)
+// (n, t) ---> (n+1, t, n+2) if n is inside run (not at boundary).
+// (n, t) ---> goto across run case if n is at run boundary;
+// If n is in RTL run,
+// (n, t) --> (n, l, n);
+// (n, l) --> (n-1, l, n-1) if n is inside run;
+// (n, l) --> goto across run case if n is at run boundar;
+// If n is at run boudary, get its visually right run,
+// if right run is LTR run,
+// (n, t) --> (right run's begin, t, right run's begin + 1);
+// If rght run is RTL run,
+// (n, t) --> (right run's end, l, right run's end);
+SelectionModel RenderTextLinux::GetRightSelectionModelByGrapheme(
+    const SelectionModel& current) const {
+  SelectionModel right(current);
+  if (GetVisuallyAdjacentCursorPositionForEnd(current, RIGHT, &right))
+    return right;
+
+  bool at_run_boundary = false;
+  GSList* run = GetRunContainsCaretPos(current, RIGHT, &at_run_boundary);
+  if (run == NULL) {
+    right.set_selection_start(right.selection_end());
+    return right;
+  }
+
+  PangoItem* box = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
+  if (box->analysis.level % 2 == 0) {  // LTR box.
+    if (current.caret_placement() == SelectionModel::LEADING) {
+      right.set_caret_placement(SelectionModel::TRAILING);
+      right.set_selection_end(
+          Utf16IndexOfAdjacentGrapheme(current.caret_pos(), NEXT));
+    } else {  // caret_placement == TRAILING.
+      if (at_run_boundary) {
+        if (run->next) {
+          return LeftmostSelectionModelInsideRun(
+              reinterpret_cast<PangoLayoutRun*>(run->next->data)->item);
+        }
+      } else {  // !at_run_boundary.
+        // current.seletion_end - current.caret_pos
+        // == NumOfCharsInGrapheme(caret_pos);
+        right.set_caret_pos(current.selection_end());
+        right.set_selection_end(
+            Utf16IndexOfAdjacentGrapheme(right.caret_pos(), NEXT));
+      }
+    }
+  } else {  // RTL box.
+    if (current.caret_placement() == SelectionModel::TRAILING) {
+      right.set_caret_placement(SelectionModel::LEADING);
+      right.set_selection_end(right.caret_pos());
+    } else {  // caret_placement == LEADING
+      if (at_run_boundary) {
+        if (run->next) {
+          return LeftmostSelectionModelInsideRun(
+              reinterpret_cast<PangoLayoutRun*>(run->next->data)->item);
+        }
+      } else {  // !at_run_boundary
+        // current.seletion_end - current.caret_pos
+        // == NumOfCharsInGrapheme(caret_pos);
+        size_t prev = Utf16IndexOfAdjacentGrapheme(right.caret_pos(), PREVIOUS);
+        right.set_caret_pos(prev);
+        right.set_selection_end(prev);
+      }
+    }
+  }
+
+  right.set_selection_start(right.selection_end());
+  return right;
+}
+
+PangoLayout* RenderTextLinux::EnsureLayout() {
+  if (layout_ == NULL) {
+    CanvasSkia canvas(display_rect().width(), display_rect().height(), false);
+    // TODO(xji): how costly is the Begin/EndPlatformPaint? Can I get cairo
+    // context in another way?
+    cairo_t* cr = skia::BeginPlatformPaint(&canvas);
+
+    layout_ = pango_cairo_create_layout(cr);
+    SetupPangoLayout(layout_, text(), default_style().font,
+        display_rect().width(), GetTextDirection(),
+        CanvasSkia::DefaultCanvasTextAlignment());
+    pango_layout_set_height(layout_, display_rect().height() * PANGO_SCALE);
+    SetupPangoAttributes(layout_);
+
+    skia::EndPlatformPaint(&canvas);
+
+    layout_line_ = pango_layout_get_line_readonly(layout_, 0);
+  }
+  return layout_;
+}
+
+void RenderTextLinux::ResetLayout() {
+  // set_cached_bounds_and_offset_valid(false) is done in RenderText for every
+  // operation that trigger ResetLayout().
+  if (layout_) {
+    g_object_unref(layout_);
+    layout_ = NULL;
+  }
+  if (layout_line_) {
+    // TODO(xji): do I need ref/unref?
+    // pango_layout_line_unref(layout_line_);

[oshima, 2011/08/19 18:44:07]

you may want to run test with valgrind bots. (linux_chromeos_valgrind)

[xji, 2011/08/20 00:53:05]

submitted.

+    layout_line_ = NULL;
+  }
+}
+
+void RenderTextLinux::SetupPangoAttributes(PangoLayout* layout) {
+  PangoAttrList* attrs = pango_attr_list_new();
+  // Set selection background color.
+  SkColor selection_color =
+      focused() ? kFocusedSelectionColor : kUnfocusedSelectionColor;
+  PangoAttribute* pango_attr = pango_attr_background_new(
+      COLOR_16_TO_32_BIT(SkColorGetR(selection_color)),
+      COLOR_16_TO_32_BIT(SkColorGetG(selection_color)),
+      COLOR_16_TO_32_BIT(SkColorGetB(selection_color)));
+  AppendPangoAttribute(MinOfSelection(), MaxOfSelection(),
+                       pango_attr, attrs);
+
+  StyleRanges ranges_of_style(style_ranges());
+  ApplyCompositionAndSelectionStyles(&ranges_of_style);
+
+  for (StyleRanges::const_iterator i = ranges_of_style.begin();
+       i < ranges_of_style.end(); ++i) {
+    const Font& font = !i->underline ? i->font :
+        i->font.DeriveFont(0, i->font.GetStyle() | Font::UNDERLINED);
+    pango_attr = pango_attr_font_desc_new(
+        reinterpret_cast<PangoFontDescription*>(font.GetNativeFont()));
+    AppendPangoAttribute(i->range.start(), i->range.end(), pango_attr, attrs);
+
+    SkColor foreground = i->foreground;
+    pango_attr = pango_attr_foreground_new(
+        COLOR_16_TO_32_BIT(SkColorGetR(foreground)),
+        COLOR_16_TO_32_BIT(SkColorGetG(foreground)),
+        COLOR_16_TO_32_BIT(SkColorGetB(foreground)));
+    AppendPangoAttribute(i->range.start(), i->range.end(), pango_attr, attrs);
+
+    if (i->strike) {
+      pango_attr = pango_attr_strikethrough_new(true);
+      AppendPangoAttribute(i->range.start(), i->range.end(), pango_attr, attrs);
+    }
+  }
+
+  pango_layout_set_attributes(layout, attrs);
+  pango_attr_list_unref(attrs);
+}
+
+void RenderTextLinux::AppendPangoAttribute(size_t start,
+                                           size_t end,
+                                           PangoAttribute* pango_attr,
+                                           PangoAttrList* attrs) {
+  pango_attr->start_index = Utf16IndexToUtf8Index(text(), start);
+  pango_attr->end_index = Utf16IndexToUtf8Index(text(), end);
+  pango_attr_list_insert(attrs, pango_attr);
+}
+
+GSList* RenderTextLinux::GetPreviousRun(GSList* run) const {
+  GSList* current = layout_line_->runs;
+  GSList* prev = NULL;
+  while (current) {
+    if (current == run)
+      return prev;
+    prev = current;
+    current = current->next;
+  }
+  return NULL;
+}
+
+GSList* RenderTextLinux::GetLastRun() const {
+  GSList* current = layout_line_->runs;
+  while (current && current->next) {
+    current = current->next;
+  }
+  return current;
+}
+
+size_t RenderTextLinux::Utf16IndexToUtf8Index(const string16& text,
+                                              size_t index) const {

[oshima, 2011/08/19 18:44:07]

so there is no library which does this?

[xji, 2011/08/20 00:53:05]

there is no ICU library does that directly without doing the actual conversion.

+  int utf8_index = 0;
+  for (size_t i = 0; i < index; ++i) {
+    if (text[i] < 0x80) {
+      ++utf8_index;
+    } else if (text[i] < 0x800) {
+      utf8_index += 2;
+    } else {
+      if ((U16_IS_LEAD(text[i]))) {
+        if (i + 1 < index) {
+          if (U16_IS_TRAIL(text[i + 1])) {
+            // A surrogate pair.
+            utf8_index += 4;
+            ++i;
+            continue;
+          }
+        } else if (i + 1 < text.length() && U16_IS_TRAIL(text[i + 1])) {
+          // A split surrogate pair, stop at the leading.
+          break;
+        }
+      }
+      utf8_index += 3;
+    }
+  }
+  return utf8_index;
+}
+
+
+size_t RenderTextLinux::Utf8IndexToUtf16Index(const string16& text,
+                                              size_t index) const {
+  // TODO(xji): DUP with utf16IndexToUtf8Index.
+  size_t utf8_index = 0;
+  size_t utf16_index = 0;
+  for (; utf16_index < text.length(); ++utf16_index) {
+    if (text[utf16_index] < 0x80) {
+      ++utf8_index;
+    } else if (text[utf16_index] < 0x800) {
+      utf8_index += 2;
+    } else {
+      if ((U16_IS_LEAD(text[utf16_index]))) {
+        if (utf16_index + 1 < text.length()) {
+          if (U16_IS_TRAIL(text[utf16_index + 1])) {
+            // A surrogate pair.
+            utf8_index += 4;
+            if (utf8_index >= index)
+              break;
+            ++utf16_index;
+            continue;
+          }
+        }
+      }
+      utf8_index += 3;
+    }
+    if (utf8_index > index)
+      break;
+  }
+  return utf16_index;
+}
+
+void RenderTextLinux::AdjustBoundsForNonInsertMode(
+    const SelectionModel& selection,
+    const PangoRectangle& pos,
+    Rect* bounds) const {
+  SelectionModel::CaretPlacement caret_placement = selection.caret_placement();
+  if (caret_placement == SelectionModel::LEADING) {
+    if (pos.width > 0) {
+      bounds->set_width(pos.width);
+    } else {
+      bounds->set_x(pos.x + pos.width);
+      bounds->set_width(-pos.width);
+    }
+  } else {
+    // TODO(xji): what is the expected behavior? For example, "abcFED",
+    // when |selection| == SelectionModel(3, 2, TRAILING), in insert-mode,
+    // cursor is at right of 'c'. In non-insert-mode, is the bounds around 'D'?
+  }
+}
+
 }  // namespace gfx