Uses and returns the fractional width in text eliding

ui/views/controls/label.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/views/controls/label.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <vector>
@@ skipping 171 matching lines @@
 
 void Label::SizeToFit(int max_width) {
   DCHECK(is_multi_line_);
 
   std::vector<string16> lines;
   base::SplitString(text_, '\n', &lines);
 
   int label_width = 0;
   for (std::vector<string16>::const_iterator iter = lines.begin();
        iter != lines.end(); ++iter) {
-    label_width = std::max(label_width, gfx::GetStringWidth(*iter, font_list_));
+    label_width = std::max(
+        label_width,
+        static_cast<int>(gfx::GetStringWidth(*iter, font_list_)));

[msw, 2013/09/27 21:54:48]

Shouldn't this retain the floating point value? Either way, use
std::max<int|float> instead of static casting an arg, if possible.

[jianli, 2013/10/01 00:32:58]

I do not think fractional width will be needed for those platforms that use
views. Changed to use std::max<int>.

   }
 
   label_width += GetInsets().width();
 
   if (max_width > 0)
     label_width = std::min(label_width, max_width);
 
   SetBounds(x(), y(), label_width, 0);
   SizeToPreferredSize();
 }
@@ skipping 39 matching lines @@
     return View::GetHeightForWidth(w);
 
   w = std::max(0, w - GetInsets().width());
 
   for (size_t i = 0; i < cached_heights_.size(); ++i) {
     const gfx::Size& s = cached_heights_[i];
     if (s.width() == w)
       return s.height() + GetInsets().height();
   }
 
-  int cache_width = w;
-
-  int h = font_list_.GetHeight();
+  float fw = w;

[msw, 2013/09/27 21:54:48]

|fw| isn't really used after its value is updated below, because you changed
line 258 to use |w| instead of |fw|/|cache_width|. Can you clean this code up?

[jianli, 2013/10/01 00:32:58]

Though |fw| is not used  after its value is updated, we still need it since
Canvas::SizeStringToFit needs a float parameter to pass. I changed to use w
instead of cache_width since we do not need to introduce another variable to
cache the old value.

[msw, 2013/10/01 02:42:48]

Ah, now I understand; this code was already caching the argument width instead
of the width value that was potentially increased by SizeStringToFit... this
change is okay since you're retaining the original behavior.

+  float h = font_list_.GetHeight();
   const int flags = ComputeDrawStringFlags();
-  gfx::Canvas::SizeStringInt(text_, font_list_, &w, &h, line_height_, flags);
-  cached_heights_[cached_heights_cursor_] = gfx::Size(cache_width, h);
+  gfx::Canvas::SizeStringInt(text_, font_list_, &fw, &h, line_height_, flags);
+  cached_heights_[cached_heights_cursor_] = gfx::Size(w, h);
   cached_heights_cursor_ = (cached_heights_cursor_ + 1) % kCachedSizeLimit;
   return h + GetInsets().height();
 }
 
 const char* Label::GetClassName() const {
   return kViewClassName;
 }
 
 View* Label::GetTooltipHandlerForPoint(const gfx::Point& point) {
   // Bail out if the label does not contain the point.
@@ skipping 56 matching lines @@
     canvas->DrawFocusRect(focus_bounds);
   }
 }
 
 gfx::Size Label::GetTextSize() const {
   if (!text_size_valid_) {
     // For single-line strings, we supply the largest possible width, because
     // while adding NO_ELLIPSIS to the flags works on Windows for forcing
     // SizeStringInt() to calculate the desired width, it doesn't seem to work
     // on Linux.
-    int w = is_multi_line_ ?
+    float w = is_multi_line_ ?
         GetAvailableRect().width() : std::numeric_limits<int>::max();
-    int h = font_list_.GetHeight();
+    float h = font_list_.GetHeight();
     // For single-line strings, ignore the available width and calculate how
     // wide the text wants to be.
     int flags = ComputeDrawStringFlags();
     if (!is_multi_line_)
       flags |= gfx::Canvas::NO_ELLIPSIS;
     gfx::Canvas::SizeStringInt(text_, font_list_, &w, &h, line_height_, flags);
     text_size_.SetSize(w, h);
     text_size_valid_ = true;
   }
 
@@ skipping 187 matching lines @@
   for (int i = 0; i < kCachedSizeLimit; ++i)
     cached_heights_[i] = gfx::Size();
 }
 
 bool Label::ShouldShowDefaultTooltip() const {
   return !is_multi_line_ &&
       gfx::GetStringWidth(text_, font_list_) > GetAvailableRect().width();
 }
 
 }  // namespace views