Windows implementation of multiline RenderText

ui/gfx/render_text.cc

 // Copyright (c) 2012 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.h"
 
 #include <algorithm>
 
 #include "base/i18n/break_iterator.h"
 #include "base/logging.h"
@@ skipping 283 matching lines @@
     range = range.Intersect(styles_[i].GetRange(style_[i]));
   return range;
 }
 
 void StyleIterator::UpdatePosition(size_t position) {
   color_ = colors_.GetBreak(position);
   for (size_t i = 0; i < NUM_TEXT_STYLES; ++i)
     style_[i] = styles_[i].GetBreak(position);
 }
 
+LineSegment::LineSegment() : run(0) {}
+
+Line::Line() : preceding_heights(0), baseline(0) {}
+
 }  // namespace internal
 
 RenderText::~RenderText() {
 }
 
 void RenderText::SetText(const base::string16& text) {
   DCHECK(!composition_range_.IsValid());
+  if (text_ == text)
+    return;
   text_ = text;
 
   // Adjust ranged styles and colors to accommodate a new text length.
   const size_t text_length = text_.length();
   colors_.SetMax(text_length);
   for (size_t style = 0; style < NUM_TEXT_STYLES; ++style)
     styles_[style].SetMax(text_length);
   cached_bounds_and_offset_valid_ = false;
 
   // Reset selection model. SetText should always followed by SetSelectionModel
@@ skipping 66 matching lines @@
 void RenderText::SetObscuredRevealIndex(int index) {
   if (obscured_reveal_index_ == index)
     return;
 
   obscured_reveal_index_ = index;
   cached_bounds_and_offset_valid_ = false;
   UpdateLayoutText();
   ResetLayout();
 }
 
+void RenderText::SetMultiline(bool multiline) {
+  if (multiline != multiline_) {
+    multiline_ = multiline;
+    cached_bounds_and_offset_valid_ = false;
+    lines_.clear();
+  }
+}
+
 void RenderText::SetDisplayRect(const Rect& r) {
   display_rect_ = r;
   cached_bounds_and_offset_valid_ = false;
+  lines_.clear();
 }
 
 void RenderText::SetCursorPosition(size_t position) {
   MoveCursorTo(position, false);
 }
 
 void RenderText::MoveCursor(BreakType break_type,
                             VisualCursorDirection direction,
                             bool select) {
   SelectionModel position(cursor_position(), selection_model_.caret_affinity());
@@ skipping 267 matching lines @@
     canvas->ClipRect(sel[i]);
     DrawVisualText(canvas);
     canvas->Restore();
   }
 
   // Restore saved transparency and selection color.
   set_selection_color(saved_selection_color);
   set_background_is_transparent(saved_background_is_transparent);
 }
 
+// TODO(ckocagil): Support multi-line. This function should return the height of

[msw, 2013/09/06 23:47:45]

nit: move this comment inside the function or to the header's function decl.

[ckocagil, 2013/09/11 14:59:49]

Done, moved inside the function.

+//                 the line the cursor is on. |GetStringSize()| now returns the
+//                 multi-line size, eliminate its use here.
 Rect RenderText::GetCursorBounds(const SelectionModel& caret,
                                  bool insert_mode) {
   EnsureLayout();
 
   size_t caret_pos = caret.caret_pos();
   DCHECK(IsCursorablePosition(caret_pos));
   // In overtype mode, ignore the affinity and always indicate that we will
   // overtype the next character.
   LogicalCursorDirection caret_affinity =
       insert_mode ? caret.caret_affinity() : CURSOR_FORWARD;
@@ skipping 71 matching lines @@
       selection_color_(kDefaultColor),
       selection_background_focused_color_(kDefaultSelectionBackgroundColor),
       focused_(false),
       composition_range_(ui::Range::InvalidRange()),
       colors_(kDefaultColor),
       styles_(NUM_TEXT_STYLES),
       composition_and_selection_styles_applied_(false),
       obscured_(false),
       obscured_reveal_index_(-1),
       truncate_length_(0),
+      multiline_(false),
       fade_head_(false),
       fade_tail_(false),
       background_is_transparent_(false),
       clip_to_display_rect_(true),
       cached_bounds_and_offset_valid_(false) {
 }
 
 const Vector2d& RenderText::GetUpdatedDisplayOffset() {
   UpdateCachedBoundsAndOffset();
   return display_offset_;
@@ skipping 23 matching lines @@
 void RenderText::SetSelectionModel(const SelectionModel& model) {
   DCHECK_LE(model.selection().GetMax(), text().length());
   selection_model_ = model;
   cached_bounds_and_offset_valid_ = false;
 }
 
 const base::string16& RenderText::GetLayoutText() const {
   return layout_text_.empty() ? text_ : layout_text_;
 }
 
+const BreakList<size_t>& RenderText::GetLineBreaks() {
+  if (line_breaks_.max() != 0)
+    return line_breaks_;
+
+  const string16& layout_text = GetLayoutText();
+  const size_t text_length = layout_text.length();
+  line_breaks_.SetValue(0);
+  line_breaks_.SetMax(text_length);
+  base::i18n::BreakIterator iter(layout_text,
+                                  base::i18n::BreakIterator::BREAK_LINE);

[msw, 2013/09/06 23:47:45]

nit: out-dent one space.

[ckocagil, 2013/09/11 14:59:49]

Done.

+  bool success = iter.Init();

[msw, 2013/09/06 23:47:45]

nit: const.

[ckocagil, 2013/09/11 14:59:49]

Done.

+  DCHECK(success);
+  if (success) {

[msw, 2013/09/06 23:47:45]

optional: I think the first break would always be 0, so you could just do:
while (success && iter.Advance())
  line_breaks_.ApplyValue(iter.pos(), ui::Range(iter.pos(), text_length));
But that's a little non-obvious, so it's entirely optional.

[ckocagil, 2013/09/11 14:59:49]

I would rather keep the explicit if block.

+    do {
+      line_breaks_.ApplyValue(iter.pos(), ui::Range(iter.pos(), text_length));
+    } while (iter.Advance());
+  }
+  return line_breaks_;
+}
+
 void RenderText::ApplyCompositionAndSelectionStyles() {
   // Save the underline and color breaks to undo the temporary styles later.
   DCHECK(!composition_and_selection_styles_applied_);
   saved_colors_ = colors_;
   saved_underlines_ = styles_[UNDERLINE];
 
   // Apply an underline to the composition range in |underlines|.
   if (composition_range_.IsValid() && !composition_range_.is_empty())
     styles_[UNDERLINE].ApplyValue(true, composition_range_);
 
   // Apply the selected text color to the [un-reversed] selection range.
   if (!selection().is_empty()) {
     const ui::Range range(selection().GetMin(), selection().GetMax());
     colors_.ApplyValue(selection_color_, range);
   }
   composition_and_selection_styles_applied_ = true;
 }
 
 void RenderText::UndoCompositionAndSelectionStyles() {
   // Restore the underline and color breaks to undo the temporary styles.
   DCHECK(composition_and_selection_styles_applied_);
   colors_ = saved_colors_;
   styles_[UNDERLINE] = saved_underlines_;
   composition_and_selection_styles_applied_ = false;
 }
 
-Vector2d RenderText::GetTextOffset() {
+Vector2d RenderText::GetLineOffset(size_t line_number) {
   Vector2d offset = display_rect().OffsetFromOrigin();
-  offset.Add(GetUpdatedDisplayOffset());
-  offset.Add(GetAlignmentOffset());
+  if (!multiline())
+    offset.Add(GetUpdatedDisplayOffset());

[msw, 2013/09/06 23:47:45]

Shouldn't it be okay to add the display offset even in multiline?
I think that'd give us horizontal scrolling of multiline text for free.
Otherwise, add a TODO here like the one in UpdateCachedBoundsAndOffset.
// TODO(ckocagil): Implement multiline text scrolling.

[ckocagil, 2013/09/11 14:59:49]

I'm disabling it in multiline because I need to test it with many cases to see
whether it currently works or not, which would probably be better done in a
followup CL. I have a TODO in UpdateCachedBoundsAndOffset() about this, should I
move it here?

[msw, 2013/09/11 17:32:37]

I think an additional TODO here would help call out this part of that change.
// TODO(ckocagil): Apply the display offset for multiline scrolling.

[ckocagil, 2013/09/11 20:31:15]

Done.

+  else
+    offset.Add(Vector2d(0, lines_[line_number].preceding_heights));
+  offset.Add(GetAlignmentOffset(line_number));
   return offset;
 }
 
 Point RenderText::ToTextPoint(const Point& point) {
-  return point - GetTextOffset();
+  return point - GetLineOffset(0);
+  // TODO(ckocagil): implement multiline.

[msw, 2013/09/06 23:47:45]

nit: capitalize "Implement", consider expanding the TODO:
// TODO(ckocagil): Convert multi-line view space points to text space.

[ckocagil, 2013/09/11 14:59:49]

Done.

 }
 
 Point RenderText::ToViewPoint(const Point& point) {
-  return point + GetTextOffset();
+  if (!multiline())
+    return point + GetLineOffset(0);
+
+  // TODO(ckocagil): refactor this to traverse all line segments to support rtl.

[msw, 2013/09/06 23:47:45]

nit: capitalize 'Refactor' and 'RTL'; consider:
// TODO(ckocagil): Traverse individual line segments for RTL support.

[ckocagil, 2013/09/11 14:59:49]

Done.

+  DCHECK(!lines_.empty());
+  int x = point.x();
+  size_t line = 0;
+  while (line < lines_.size() && x > lines_[line].size.width()) {

[msw, 2013/09/06 23:47:45]

Optionally, you could do:
for (line = 0; line < lines_.size() && x > lines_[line].size.width(); ++line)
  x -= lines_[line].size.width();

[ckocagil, 2013/09/11 14:59:49]

Done.

+    x -= lines_[line].size.width();
+    ++line;
+  }
+  return Point(x, point.y()) + GetLineOffset(line);
 }
 
-Vector2d RenderText::GetAlignmentOffset() {
+std::vector<Rect> RenderText::TextBoundsToViewBounds(const ui::Range& x) {
+  std::vector<Rect> rects;
+
+  if (!multiline()) {
+    rects.push_back(Rect(ToViewPoint(Point(x.GetMin(), 0)),
+                         Size(x.length(), GetStringSize().height())));
+    return rects;
+  }
+
+  EnsureLayout();
+
+  // Each line segment keeps its position in text coordinates. Traverse all line
+  // segments and if the segment intersects with the given range, add the view
+  // rect corresponding to the intersection to |rects|.
+  for (size_t line = 0; line < lines_.size(); ++line) {
+    int line_x = 0;
+    Vector2d offset = GetLineOffset(line);

[msw, 2013/09/06 23:47:45]

nit: const

[ckocagil, 2013/09/11 14:59:49]

Done.

+    for (size_t i = 0; i < lines_[line].segments.size(); ++i) {
+      const internal::LineSegment* segment = &lines_[line].segments[i];
+      const ui::Range intersection = segment->x_range.Intersect(x);
+      if (!intersection.is_empty()) {
+        Rect rect(line_x + intersection.start() - segment->x_range.start(),
+                  0, intersection.length(), lines_[line].size.height());
+        rects.push_back(rect + offset);
+      }
+      line_x += segment->x_range.length();
+    }
+  }
+
+  return rects;
+}
+
+Vector2d RenderText::GetAlignmentOffset(size_t line_number) {
+  DCHECK_LT(line_number, lines_.size());
   Vector2d offset;
   if (horizontal_alignment_ != ALIGN_LEFT) {
-    offset.set_x(display_rect().width() - GetContentWidth());
+    const int width = lines_[line_number].size.width() +
+        (cursor_enabled_ ? 1 : 0);
+    offset.set_x(display_rect().width() - width);
     if (horizontal_alignment_ == ALIGN_CENTER)
       offset.set_x(offset.x() / 2);
   }
   if (vertical_alignment_ != ALIGN_TOP) {
     offset.set_y(display_rect().height() - GetStringSize().height());
     if (vertical_alignment_ == ALIGN_VCENTER)
       offset.set_y(offset.y() / 2);
   }
   return offset;
 }
 
 void RenderText::ApplyFadeEffects(internal::SkiaTextRenderer* renderer) {
-  if (!fade_head() && !fade_tail())
+  if (multiline() || !fade_head() && !fade_tail())
     return;
 
-  const int text_width = GetStringSize().width();
   const int display_width = display_rect().width();
 
   // If the text fits as-is, no need to fade.
-  if (text_width <= display_width)
+  if (GetStringSize().width() <= display_width)
     return;
 
   int gradient_width = CalculateFadeGradientWidth(GetPrimaryFont(),
                                                   display_width);
   if (gradient_width == 0)
     return;
 
   bool fade_left = fade_head();
   bool fade_right = fade_tail();
   // Under RTL, |fade_right| == |fade_head|.
@@ skipping 11 matching lines @@
     left_part.Inset(0, 0, solid_part.width() - gradient_width, 0);
     solid_part.Inset(gradient_width, 0, 0, 0);
   }
   if (fade_right) {
     right_part = solid_part;
     right_part.Inset(solid_part.width() - gradient_width, 0, 0, 0);
     solid_part.Inset(0, 0, gradient_width, 0);
   }
 
   Rect text_rect = display_rect();
-  text_rect.Inset(GetAlignmentOffset().x(), 0, 0, 0);
+  text_rect.Inset(GetAlignmentOffset(0).x(), 0, 0, 0);
 
   // TODO(msw): Use the actual text colors corresponding to each faded part.
   skia::RefPtr<SkShader> shader = CreateFadeShader(
       text_rect, left_part, right_part, colors_.breaks().front().second);
   if (shader)
     renderer->SetShader(shader.get(), display_rect());
 }
 
 void RenderText::ApplyTextShadows(internal::SkiaTextRenderer* renderer) {
   skia::RefPtr<SkDrawLooper> looper = CreateShadowDrawLooper(text_shadows_);
@@ skipping 13 matching lines @@
 void RenderText::MoveCursorTo(size_t position, bool select) {
   size_t cursor = std::min(position, text().length());
   if (IsCursorablePosition(cursor))
     SetSelectionModel(SelectionModel(
         ui::Range(select ? selection().start() : cursor, cursor),
         (cursor == 0) ? CURSOR_FORWARD : CURSOR_BACKWARD));
 }
 
 void RenderText::UpdateLayoutText() {
   layout_text_.clear();
+  line_breaks_.SetMax(0);
 
   if (obscured_) {
     size_t obscured_text_length =
         static_cast<size_t>(ui::UTF16IndexToOffset(text_, 0, text_.length()));
     layout_text_.assign(obscured_text_length, kPasswordReplacementChar);
 
     if (obscured_reveal_index_ >= 0 &&
         obscured_reveal_index_ < static_cast<int>(text_.length())) {
       // Gets the index range in |text_| to be revealed.
       size_t start = obscured_reveal_index_;
@@ skipping 16 matching lines @@
     icu::StringCharacterIterator iter(text.c_str());
     iter.setIndex32(truncate_length_ - 1);
     layout_text_.assign(text.substr(0, iter.getIndex()) + ui::kEllipsisUTF16);
   }
 }
 
 void RenderText::UpdateCachedBoundsAndOffset() {
   if (cached_bounds_and_offset_valid_)
     return;
 
+  // TODO(ckocagil): Add vertical offset support for scrolling multi-line text.

[msw, 2013/09/06 23:47:45]

nit: Address my GetLineOffset comment or remove "Vertical". Multi-line doesn't
use the display offset and thus doesn't support horizontal scrolling either.

[ckocagil, 2013/09/11 14:59:49]

Done, removed "vertical".

+
   // First, set the valid flag true to calculate the current cursor bounds using
   // the stale |display_offset_|. Applying |delta_offset| at the end of this
   // function will set |cursor_bounds_| and |display_offset_| to correct values.
   cached_bounds_and_offset_valid_ = true;
   cursor_bounds_ = GetCursorBounds(selection_model_, insert_mode_);
 
   // Update |display_offset_| to ensure the current cursor is visible.
   const int display_width = display_rect_.width();
   const int content_width = GetContentWidth();
 
@@ skipping 30 matching lines @@
   cursor_bounds_ += delta_offset;
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   const std::vector<Rect> sel = GetSubstringBounds(selection());
   for (std::vector<Rect>::const_iterator i = sel.begin(); i < sel.end(); ++i)
     canvas->FillRect(*i, selection_background_focused_color_);
 }
 
 }  // namespace gfx