Allow various font weights in gfx.

ui/gfx/font.h

 // 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.
 
 #ifndef UI_GFX_FONT_H_
 #define UI_GFX_FONT_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 14 matching lines @@
 //   +--------+-------------------+------------------+
 //   |        |                   | internal leading |
 //   |        | ascent (baseline) +------------------+
 //   | height |                   | cap height       |
 //   |        |-------------------+------------------+
 //   |        | descent (height - baseline)          |
 //   +--------+--------------------------------------+
 class GFX_EXPORT Font {
  public:
   // The following constants indicate the font style.
   enum FontStyle {

[Peter Kasting, 2016/03/26 00:56:51]

Didn't read previous conversations, so maybe you discussed this; should this
become "enum class Style" for parallel structure?  That would make some callers
read more clearly, since instead of:

gfx::Font::NORMAL, gfx::Font::Weight::BOLD

...as a parameter list, you get:

gfx::Font::Style::NORMAL, gfx::Font::Weight::BOLD

It may be that this would touch enough places that you'd want to do it
separately, but I raise it now in case you're already touching enough of those
places anyway to make this make sense.

[Mikus, 2016/03/29 10:55:38]

Yes, this was raised previously, we've decided to make this an enum class in a
follow-up patchset.

     NORMAL = 0,
-    BOLD = 1,
-    ITALIC = 2,
-    UNDERLINE = 4,
+    ITALIC = 1,
+    UNDERLINE = 2,
+  };
+
+  enum class Weight {
+    INVALID = -1,
+    THIN = 100,
+    EXTRA_LIGHT = 200,
+    LIGHT = 300,
+    NORMAL = 400,
+    MEDIUM = 500,
+    SEMIBOLD = 600,
+    BOLD = 700,
+    EXTRA_BOLD = 800,
+    BLACK = 900,
   };
 
   // Creates a font with the default name and style.
   Font();
 
   // Creates a font that is a clone of another font object.
   Font(const Font& other);
   Font& operator=(const Font& other);
 
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
   // Creates a font from the specified native font.
   explicit Font(NativeFont native_font);
 #endif
 
   // Constructs a Font object with the specified PlatformFont object. The Font
   // object takes ownership of the PlatformFont object.
   explicit Font(PlatformFont* platform_font);
 
   // Creates a font with the specified name in UTF-8 and size in pixels.
   Font(const std::string& font_name, int font_size);
 
   ~Font();
 
   // Returns a new Font derived from the existing font.
   // |size_delta| is the size in pixels to add to the current font. For example,
   // a value of 5 results in a font 5 pixels bigger than this font.
   // The style parameter specifies the new style for the font, and is a
-  // bitmask of the values: BOLD, ITALIC and UNDERLINE.
-  Font Derive(int size_delta, int style) const;
+  // bitmask of the values: ITALIC and UNDERLINE.
+  Font Derive(int size_delta, int style, gfx::Font::Weight weight) const;
 
   // Returns the number of vertical pixels needed to display characters from
   // the specified font.  This may include some leading, i.e. height may be
   // greater than just ascent + descent.  Specifically, the Windows and Mac
   // implementations include leading and the Linux one does not.  This may
   // need to be revisited in the future.
   int GetHeight() const;
 
+  // Returns the font weight.
+  gfx::Font::Weight GetWeight() const;
+
   // Returns the baseline, or ascent, of the font.
   int GetBaseline() const;
 
   // Returns the cap height of the font.
   int GetCapHeight() const;
 
   // Returns the expected number of horizontal pixels needed to display the
   // specified length of characters. Call gfx::GetStringWidth() to retrieve the
   // actual number.
   int GetExpectedTextWidth(int length) const;
@@ skipping 24 matching lines @@
 
   // Raw access to the underlying platform font implementation. Can be
   // static_cast to a known implementation type if needed.
   PlatformFont* platform_font() const { return platform_font_.get(); }
 
  private:
   // Wrapped platform font implementation.
   scoped_refptr<PlatformFont> platform_font_;
 };
 
+#ifndef NDEBUG
+GFX_EXPORT std::ostream& operator<<(std::ostream& stream,
+                                    const gfx::Font::Weight weight);
+#endif
+
 }  // namespace gfx
 
 #endif  // UI_GFX_FONT_H_