Use RenderText directly to draw tooltip

ui/views/corewm/tooltip_aura.cc

Index: ui/views/corewm/tooltip_aura.cc
diff --git a/ui/views/corewm/tooltip_aura.cc b/ui/views/corewm/tooltip_aura.cc
index 3e98cf16440855cd1adea7d6262603c79957c8a8..c0d369149afb1082c4b273ac6b8db79d2b9970f4 100644
--- a/ui/views/corewm/tooltip_aura.cc
+++ b/ui/views/corewm/tooltip_aura.cc
@@ -5,14 +5,18 @@
 #include "ui/views/corewm/tooltip_aura.h"
 
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/render_text.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/text_elider.h"
 #include "ui/gfx/text_utils.h"
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
+#include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
@@ -21,8 +25,6 @@ namespace {
 // be wrapped.
 const int kTooltipMaxWidthPixels = 400;
 
-const size_t kMaxLines = 10;
-
 // FIXME: get cursor offset from actual cursor size.
 const int kCursorOffsetX = 10;
 const int kCursorOffsetY = 15;
@@ -47,16 +49,68 @@ views::Widget* CreateTooltipWidget(aura::Window* tooltip_window) {
 namespace views {
 namespace corewm {
 
+// TODO(oshima): Consider to use views::Label.
+class TooltipAura::TooltipView : public views::View {
+ public:
+  TooltipView()
+      : render_text_(gfx::RenderText::CreateInstance()),
+        max_width_(0) {
+    set_owned_by_client();
+    render_text_->SetMultiline(true);
+    ResetDisplayRect();
+  }
+
+  ~TooltipView() override {}
+
+  // views:View:
+  void OnPaint(gfx::Canvas* canvas) override {
+    OnPaintBackground(canvas);
+    render_text_->SetDisplayRect(gfx::Rect(size()));
+    render_text_->Draw(canvas);
+    OnPaintBorder(canvas);
+  }
+
+  gfx::Size GetPreferredSize() const override {
+    return render_text_->GetStringSize();
+  }
+
+  const char* GetClassName() const override {
+    return "TooltipView";
+  }
+
+  void SetText(const base::string16& text) {
+    render_text_->SetHorizontalAlignment(gfx::ALIGN_TO_HEAD);
+    render_text_->SetText(text);
+  }
+
+  void SetForegroundColor(SkColor color) {
+    render_text_->SetColor(color);
+  }
+
+  void SetMaxWidth(int width) {
+    max_width_ = width;
+    ResetDisplayRect();
+  }
+
+ private:
+  void ResetDisplayRect() {
+    render_text_->SetDisplayRect(gfx::Rect(0, 0, max_width_, 100000));
+  }
+
+  scoped_ptr<gfx::RenderText> render_text_;
+  int max_width_;
+
+  DISALLOW_COPY_AND_ASSIGN(TooltipView);
+};
+
 TooltipAura::TooltipAura()
-    : widget_(NULL),
+    : tooltip_view_(new TooltipView),
+      widget_(NULL),
       tooltip_window_(NULL) {
-  label_.set_owned_by_client();
-  label_.SetMultiLine(true);
-  label_.SetHorizontalAlignment(gfx::ALIGN_TO_HEAD);
 
   const int kHorizontalPadding = 3;
   const int kVerticalPadding = 2;
-  label_.SetBorder(Border::CreateEmptyBorder(
+  tooltip_view_->SetBorder(Border::CreateEmptyBorder(
       kVerticalPadding, kHorizontalPadding,
       kVerticalPadding, kHorizontalPadding));
 }
@@ -65,82 +119,6 @@ TooltipAura::~TooltipAura() {
   DestroyWidget();
 }
 
-// static
-void TooltipAura::TrimTooltipToFit(const gfx::FontList& font_list,
-                                   int max_width,
-                                   base::string16* text,
-                                   int* width,
-                                   int* line_count) {
-  *width = 0;
-  *line_count = 0;
-
-  // Determine the available width for the tooltip.
-  int available_width = std::min(kTooltipMaxWidthPixels, max_width);
-
-  std::vector<base::string16> lines;
-  base::SplitString(*text, '\n', &lines);
-  std::vector<base::string16> result_lines;
-
-  // Format each line to fit.
-  for (std::vector<base::string16>::iterator l = lines.begin();
-       l != lines.end(); ++l) {
-    // We break the line at word boundaries, then stuff as many words as we can
-    // in the available width to the current line, and move the remaining words
-    // to a new line.
-    std::vector<base::string16> words;
-    base::SplitStringDontTrim(*l, ' ', &words);
-    int current_width = 0;
-    base::string16 line;
-    for (std::vector<base::string16>::iterator w = words.begin();
-         w != words.end(); ++w) {
-      base::string16 word = *w;
-      if (w + 1 != words.end())
-        word.push_back(' ');
-      int word_width = gfx::GetStringWidth(word, font_list);
-      if (current_width + word_width > available_width) {
-        // Current width will exceed the available width. Must start a new line.
-        if (!line.empty())
-          result_lines.push_back(line);
-        current_width = 0;
-        line.clear();
-      }
-      current_width += word_width;
-      line.append(word);
-    }
-    result_lines.push_back(line);
-  }
-
-  // Clamp number of lines to |kMaxLines|.
-  if (result_lines.size() > kMaxLines) {
-    result_lines.resize(kMaxLines);
-    // Add ellipses character to last line.
-    result_lines[kMaxLines - 1] = gfx::TruncateString(
-        result_lines.back(), result_lines.back().length() - 1, gfx::WORD_BREAK);
-  }
-  *line_count = result_lines.size();
-
-  // Flatten the result.
-  base::string16 result;
-  for (std::vector<base::string16>::iterator l = result_lines.begin();
-      l != result_lines.end(); ++l) {
-    if (!result.empty())
-      result.push_back('\n');
-    int line_width = gfx::GetStringWidth(*l, font_list);
-    // Since we only break at word boundaries, it could happen that due to some
-    // very long word, line_width is greater than the available_width. In such
-    // case, we simply truncate at available_width and add ellipses at the end.
-    if (line_width > available_width) {
-      *width = available_width;
-      result.append(gfx::ElideText(*l, font_list, available_width,
-                                   gfx::ELIDE_TAIL));
-    } else {
-      *width = std::max(*width, line_width);
-      result.append(*l);
-    }
-  }
-  *text = result;
-}
-
 void TooltipAura::SetTooltipBounds(const gfx::Point& mouse_pos,
                                    const gfx::Size& tooltip_size) {
   gfx::Rect tooltip_rect(mouse_pos, tooltip_size);
@@ -183,30 +161,23 @@ void TooltipAura::SetText(aura::Window* window,
                           const base::string16& tooltip_text,
                           const gfx::Point& location) {
   tooltip_window_ = window;
-  int max_width = 0;
-  int line_count = 0;
-  base::string16 trimmed_text(tooltip_text);
-  TrimTooltipToFit(label_.font_list(), GetMaxWidth(location, window),
-                   &trimmed_text, &max_width, &line_count);
-  label_.SetText(trimmed_text);
+  tooltip_view_->SetMaxWidth(GetMaxWidth(location, window));
+  tooltip_view_->SetText(tooltip_text);
 
   if (!widget_) {
     widget_ = CreateTooltipWidget(tooltip_window_);
-    widget_->SetContentsView(&label_);
+    widget_->SetContentsView(tooltip_view_.get());
     widget_->AddObserver(this);
   }
 
-  label_.SizeToFit(max_width + label_.GetInsets().width());
-  SetTooltipBounds(location, label_.size());
+  SetTooltipBounds(location, tooltip_view_->GetPreferredSize());
 
   ui::NativeTheme* native_theme = widget_->GetNativeTheme();
-  label_.set_background(
+  tooltip_view_->set_background(
       views::Background::CreateSolidBackground(
           native_theme->GetSystemColor(
               ui::NativeTheme::kColorId_TooltipBackground)));
-
-  label_.SetAutoColorReadabilityEnabled(false);
-  label_.SetEnabledColor(native_theme->GetSystemColor(
+  tooltip_view_->SetForegroundColor(native_theme->GetSystemColor(
       ui::NativeTheme::kColorId_TooltipText));
 }