Add ability to defined ranges with different styles in StyledLabel

ui/views/controls/styled_label.cc

 // Copyright 2013 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/views/controls/styled_label.h"
 
 #include <vector>
 
 #include "base/string_util.h"
 #include "ui/base/text/text_elider.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/link.h"
 #include "ui/views/controls/styled_label_listener.h"
 
 namespace views {
 
 namespace {
 
 // Calculates the height of a line of text. Currently returns the height of
 // a label.
 int CalculateLineHeight() {
   Label label;
   return label.GetPreferredSize().height();
 }
 
+scoped_ptr<View> CreateLabelRange(const string16& text,
+                                  const StyledLabel::RangeStyleInfo& style_info,
+                                  views::LinkListener* link_listener) {
+  scoped_ptr<Label> result;
+
+  if (style_info.is_link) {
+    Link* link = new Link(text);
+    link->set_listener(link_listener);
+    link->SetUnderline(style_info.font_style & gfx::Font::UNDERLINE);
+    result.reset(link);
+  } else {
+    Label* label = new Label(text);
+    // Give the label a focus border so that its preferred size matches
+    // links' preferred sizes
+    label->SetHasFocusBorder(true);
+
+    result.reset(label);
+  }
+
+  if (!style_info.tooltip.empty())
+    result->SetTooltipText(style_info.tooltip);
+  if (style_info.font_style != gfx::Font::NORMAL)
+    result->SetFont(result->font().DeriveFont(0, style_info.font_style));
+
+  return scoped_ptr<View>(result.release());
+}
+
 }  // namespace
 
-bool StyledLabel::LinkRange::operator<(
-    const StyledLabel::LinkRange& other) const {
+
+StyledLabel::RangeStyleInfo::RangeStyleInfo()
+    : font_style(gfx::Font::NORMAL),
+      disable_line_wrapping(false),
+      is_link(false) {
+}
+
+StyledLabel::RangeStyleInfo::~RangeStyleInfo() {}
+
+// static
+StyledLabel::RangeStyleInfo StyledLabel::RangeStyleInfo::CreateForLink() {
+  RangeStyleInfo result;
+  result.disable_line_wrapping = true;
+  result.is_link = true;
+  result.font_style = gfx::Font::UNDERLINE;
+  return result;
+}
+
+bool StyledLabel::StyleRange::operator<(
+    const StyledLabel::StyleRange& other) const {
   // Intentionally reversed so the priority queue is sorted by smallest first.
   return range.start() > other.range.start();
 }
 
 StyledLabel::StyledLabel(const string16& text, StyledLabelListener* listener)
-    : text_(text),
-      listener_(listener) {}
+    : listener_(listener) {
+  TrimWhitespace(text, TRIM_TRAILING, &text_);
+}
 
 StyledLabel::~StyledLabel() {}
 
-void StyledLabel::AddLink(const ui::Range& range) {
+void StyledLabel::AddStyleRange(const ui::Range& range,
+                                const RangeStyleInfo& style_info) {
   DCHECK(!range.is_reversed());
   DCHECK(!range.is_empty());
   DCHECK(ui::Range(0, text_.size()).Contains(range));
-  link_ranges_.push(LinkRange(range));
+
+  style_ranges_.push(StyleRange(range, style_info));
+
   calculated_size_ = gfx::Size();
   InvalidateLayout();
 }
 
 gfx::Insets StyledLabel::GetInsets() const {
   gfx::Insets insets = View::GetInsets();
   const gfx::Insets focus_border_padding(1, 1, 1, 1);
   insets += focus_border_padding;
   return insets;
 }
@@ skipping 24 matching lines @@
     return 0;
 
   const int line_height = CalculateLineHeight();
   // The index of the line we're on.
   int line = 0;
   // The x position (in pixels) of the line we're on, relative to content
   // bounds.
   int x = 0;
 
   string16 remaining_string = text_;
-  std::priority_queue<LinkRange> link_ranges = link_ranges_;
+  std::priority_queue<StyleRange> style_ranges = style_ranges_;
 
   // Iterate over the text, creating a bunch of labels and links and laying them
   // out in the appropriate positions.
   while (!remaining_string.empty()) {
-    // Don't put whitespace at beginning of a line.
-    if (x == 0)
+    // Don't put whitespace at beginning of a line with an exception for the
+    // first line (so the text's leading whitespace is respected).
+    if (x == 0 && line > 0)

[Evan Stade, 2013/03/29 19:35:48]

I don't think you need to make this change. |position| is calculated in such a
way as to compensate for trimming leading whitespace no matter what line you're
on.

[tbarzic, 2013/03/29 20:00:57]

yeah, but this way we actually respect leading whitespace.

[Evan Stade, 2013/03/29 23:14:58]

ok, lgtm

       TrimWhitespace(remaining_string, TRIM_LEADING, &remaining_string);
 
     ui::Range range(ui::Range::InvalidRange());
-    if (!link_ranges.empty())
-      range = link_ranges.top().range;
+    if (!style_ranges.empty())
+      range = style_ranges.top().range;
+
+    const size_t position = text_.size() - remaining_string.size();
 
     const gfx::Rect chunk_bounds(x, 0, width - x, 2 * line_height);
     std::vector<string16> substrings;
+    gfx::Font text_font;
+    // If the start of the remaining text is inside a styled range, the font
+    // style may differ from the base font. The font specified by the range
+    // should be used when eliding text.
+    if (position >= range.start()) {
+      text_font =
+          text_font.DeriveFont(0, style_ranges.top().style_info.font_style);
+    }
     ui::ElideRectangleText(remaining_string,
-                           gfx::Font(),
+                           text_font,
                            chunk_bounds.width(),
                            chunk_bounds.height(),
                            ui::IGNORE_LONG_WORDS,
                            &substrings);
 
+    DCHECK(!substrings.empty());
     string16 chunk = substrings[0];
     if (chunk.empty()) {
-      // Nothing fit on this line. Start a new line. If x is 0, there's no room
-      // for anything. Just abort.
-      if (x == 0)
+      // Nothing fits on this line. Start a new line.
+      // If x is 0, first line may have leading whitespace that doesn't fit in a
+      // single line, so try trimming those. Otherwise there is no room for
+      // anything; abort.
+      if (x == 0) {
+        if (line == 0) {
+          TrimWhitespace(remaining_string, TRIM_LEADING, &remaining_string);
+          continue;
+        }
         break;
+      }
 
       x = 0;
       line++;
       continue;
     }
 
     scoped_ptr<View> view;
-    const size_t position = text_.size() - remaining_string.size();
     if (position >= range.start()) {
-      // This chunk is a link.
-      if (chunk.size() < range.length() && x != 0) {
-        // Don't wrap links. Try to fit them entirely on one line.
+      const RangeStyleInfo& style_info = style_ranges.top().style_info;
+
+      if (style_info.disable_line_wrapping && chunk.size() < range.length() &&
+          position == range.start() && x != 0) {
+        // If the chunk should not be wrapped, try to fit it entirely on the
+        // next line.
         x = 0;
         line++;
         continue;
       }
 
-      chunk = chunk.substr(0, range.length());
-      Link* link = new Link(chunk);
-      link->set_listener(this);
-      if (!dry_run)
-        link_targets_[link] = range;
-      view.reset(link);
-      link_ranges.pop();
+      chunk = chunk.substr(0, std::min(chunk.size(), range.end() - position));
+
+      view = CreateLabelRange(chunk, style_info, this);
+
+      if (style_info.is_link && !dry_run)
+        link_targets_[view.get()] = range;
+
+      if (position + chunk.size() >= range.end())
+        style_ranges.pop();
     } else {
       // This chunk is normal text.
       if (position + chunk.size() > range.start())
         chunk = chunk.substr(0, range.start() - position);
-
-      Label* label = new Label(chunk);
-      // Give the label a focus border so that its preferred size matches
-      // links' preferred sizes.
-      label->SetHasFocusBorder(true);
-      view.reset(label);
+      view = CreateLabelRange(chunk, RangeStyleInfo(), this);
     }
 
     // Lay out the views to overlap by 1 pixel to compensate for their border
     // spacing. Otherwise, "<a>link</a>," will render as "link ,".
     const int overlap = 1;
     const gfx::Size view_size = view->GetPreferredSize();
     DCHECK_EQ(line_height, view_size.height() - 2 * overlap);
     if (!dry_run) {
       view->SetBoundsRect(gfx::Rect(
           gfx::Point(GetInsets().left() + x - overlap,
                      GetInsets().top() + line * line_height - overlap),
           view_size));
       AddChildView(view.release());
     }
     x += view_size.width() - 2 * overlap;
 
     remaining_string = remaining_string.substr(chunk.size());
   }
 
   return (line + 1) * line_height + GetInsets().height();
 }
 
 }  // namespace views