Elide long emails in the wrench and profile menus.

ui/base/text/text_elider.cc

Index: ui/base/text/text_elider.cc
diff --git a/ui/base/text/text_elider.cc b/ui/base/text/text_elider.cc
index 525cea0df61eb373507b91372f144dbf327cf419..9bff2a11110c3b28fe931e49747b6a3879f2db8a 100644
--- a/ui/base/text/text_elider.cc
+++ b/ui/base/text/text_elider.cc
@@ -149,12 +149,56 @@ string16 ElideComponentizedPath(const string16& url_path_prefix,
 
 }  // namespace
 
-// This function takes a GURL object and elides it. It returns a string
-// which composed of parts from subdomain, domain, path, filename and query.
-// A "..." is added automatically at the end if the elided string is bigger
-// than the available pixel width. For available pixel width = 0, a formatted,
-// but un-elided, string is returned.
-//
+string16 ElideEmail(const string16& email,
+                    const gfx::Font& font,
+                    int available_pixel_width) {
+  if (font.GetStringWidth(email) <= available_pixel_width)
+    return email;
+
+  std::vector<string16> email_split;
+  base::SplitString(email, '@', &email_split);
+  DCHECK_EQ(email_split.size(), 2U);
+  string16 username = email_split.front();
+  string16 domain = email_split.back();
+
+  const string16 kEllipsisUTF16 = UTF8ToUTF16(kEllipsis);
+
+  // Subtract the @ symbol from the available width as it is mandatory.
+  const string16 kAtSignUTF16 = ASCIIToUTF16("@");
+  available_pixel_width -= font.GetStringWidth(kAtSignUTF16);
+
+  // Check whether eliding the domain is necessary: if eliding the username
+  // is sufficient, the domain will not be elided.
+  const int available_domain_width =
+      available_pixel_width -
+      font.GetStringWidth(username.substr(0, 1) + kEllipsisUTF16);
+  const int full_username_width = font.GetStringWidth(username);
+  if (font.GetStringWidth(domain) > available_domain_width) {
+    // Elide the domain so that it only takes half of the available width.
+    // Should the username not need all the width available in its half, the
+    // domain will occupy the leftover width.
+    const int desired_domain_width =
+        std::max(available_pixel_width - full_username_width,
+                 available_pixel_width / 2);

[Alexei Svitkine (slow), 2012/03/02 20:20:44]

I think the "available_pixel_width / 2" is not strictly correct here. You're
trying to elide the domain to satisfy the if statement condition, such as the
post condition should be that font.GetStringWidth(domain) <=
available_domain_width.

Suppose the username is long. so available_pixel_width - full_username_width is
e.g. 0 or negative. Then domain will be elided to available_pixel_width/2.

Now, suppose that available_pixel_width/2 is >= available_domain_width. This
would only happen if available_pixel_width is enough to fit only a few
characters or so, so granted it's unlikely. Still, in that case you might elide
domain to a width that won't fit the "r..." name.

I think you can fix this by adding a std::min(available_domain_width,
available_pixel_width / 2) here (while still keeping the outer std::max()).

[gab, 2012/03/02 21:57:37]

Actually, if available_pixel_width/2 > available_domain_width (note: == is
fine), then later the username will elide to "..." which will cause "..." to be
returned as a whole (as specified by the spec which doesn't allow either side to
be "character-less").

[asvitkine_google, 2012/03/02 22:08:41]

Okay. Please add a comment here explaining this.

+    domain = ElideText(domain, font, desired_domain_width, ELIDE_IN_MIDDLE);
+    if (domain.length() <= 1U)
+      return kEllipsisUTF16;
+  }
+
+  // Fit the username in the remaining width.
+  available_pixel_width -= font.GetStringWidth(domain);
+  if (full_username_width > available_pixel_width) {
+    username = ElideText(username,

[Alexei Svitkine (slow), 2012/03/02 20:20:44]

I think this can fit on one line now.

[gab, 2012/03/02 21:57:37]

Yay :)!

+                         font,
+                         available_pixel_width,
+                         ELIDE_AT_END);
+    if (username.length() <= 1U)
+      return kEllipsisUTF16;
+  }
+
+  return username + kAtSignUTF16 + domain;
+}
+
 // TODO(pkasting): http://crbug.com/77883 This whole function gets
 // kerning/ligatures/etc. issues potentially wrong by assuming that the width of
 // a rendered string is always the sum of the widths of its substrings.  Also I
@@ -393,8 +437,6 @@ string16 ElideFilename(const FilePath& filename,
   return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
 }
 
-// This function adds an ellipsis at the end of the text if the text
-// does not fit the given pixel width.
 string16 ElideText(const string16& text,
                    const gfx::Font& font,
                    int available_pixel_width,