Rework gfx::Font by moving platform-specific code into inner classes....

gfx/font_gtk.cc

-// Copyright (c) 2006-2008 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 "gfx/font.h"
-
-#include <algorithm>
-#include <fontconfig/fontconfig.h>
-#include <gtk/gtk.h>
-
-#include "base/logging.h"
-#include "base/string_piece.h"
-#include "base/utf_string_conversions.h"
-#include "gfx/gtk_util.h"
-
-namespace gfx {
-
-Font* Font::default_font_ = NULL;
-
-// Find the best match font for |family_name| in the same way as Skia
-// to make sure CreateFont() successfully creates a default font.  In
-// Skia, it only checks the best match font.  If it failed to find
-// one, SkTypeface will be NULL for that font family.  It eventually
-// causes a segfault.  For example, family_name = "Sans" and system
-// may have various fonts.  The first font family in FcPattern will be
-// "DejaVu Sans" but a font family returned by FcFontMatch will be "VL
-// PGothic".  In this case, SkTypeface for "Sans" returns NULL even if
-// the system has a font for "Sans" font family.  See FontMatch() in
-// skia/ports/SkFontHost_fontconfig.cpp for more detail.
-static std::wstring FindBestMatchFontFamilyName(const char* family_name) {
-  FcPattern* pattern = FcPatternCreate();
-  FcValue fcvalue;
-  fcvalue.type = FcTypeString;
-  char* family_name_copy = strdup(family_name);
-  fcvalue.u.s = reinterpret_cast<FcChar8*>(family_name_copy);
-  FcPatternAdd(pattern, FC_FAMILY, fcvalue, 0);
-  FcConfigSubstitute(0, pattern, FcMatchPattern);
-  FcDefaultSubstitute(pattern);
-  FcResult result;
-  FcPattern* match = FcFontMatch(0, pattern, &result);
-  DCHECK(match) << "Could not find font: " << family_name;
-  FcChar8* match_family;
-  FcPatternGetString(match, FC_FAMILY, 0, &match_family);
-
-  std::wstring font_family = UTF8ToWide(
-      reinterpret_cast<char*>(match_family));
-  FcPatternDestroy(match);
-  FcPatternDestroy(pattern);
-  free(family_name_copy);
-  return font_family;
-}
-
-// Pango scales font sizes. This returns the scale factor. See
-// pango_cairo_context_set_resolution for details.
-// NOTE: this isn't entirely accurate, in that Pango also consults the
-// FC_PIXEL_SIZE first (see get_font_size in pangocairo-fcfont), but this
-// seems to give us the same sizes as used by Pango for all our fonts in both
-// English and Thai.
-float Font::GetPangoScaleFactor() {
-  static float scale_factor = gfx::GetPangoResolution();
-  static bool determined_scale = false;
-  if (!determined_scale) {
-    if (scale_factor <= 0)
-      scale_factor = 1;
-    else
-      scale_factor /= 72.0;
-    determined_scale = true;
-  }
-  return scale_factor;
-}
-
-// static
-Font Font::CreateFont(PangoFontDescription* desc) {
-  gint size = pango_font_description_get_size(desc);
-  const char* family_name = pango_font_description_get_family(desc);
-
-  // Find best match font for |family_name| to make sure we can get
-  // a SkTypeface for the default font.
-  // TODO(agl): remove this.
-  std::wstring font_family = FindBestMatchFontFamilyName(family_name);
-
-  Font font = CreateFont(font_family, size / PANGO_SCALE);
-  int style = 0;
-  if (pango_font_description_get_weight(desc) == PANGO_WEIGHT_BOLD) {
-    // TODO(davemoore) What should we do about other weights? We currently
-    // only support BOLD.
-    style |= BOLD;
-  }
-  if (pango_font_description_get_style(desc) == PANGO_STYLE_ITALIC) {
-    // TODO(davemoore) What about PANGO_STYLE_OBLIQUE?
-    style |= ITALIC;
-  }
-  if (style != 0) {
-    font = font.DeriveFont(0, style);
-  }
-  return Font(font);
-}
-
-// Get the default gtk system font (name and size).
-Font::Font() {
-  if (default_font_ == NULL) {
-    GtkSettings* settings = gtk_settings_get_default();
-
-    gchar* font_name = NULL;
-    g_object_get(settings, "gtk-font-name", &font_name, NULL);
-
-    // Temporary CHECK for helping track down
-    // http://code.google.com/p/chromium/issues/detail?id=12530
-    CHECK(font_name) << " Unable to get gtk-font-name for default font.";
-
-    PangoFontDescription* desc =
-        pango_font_description_from_string(font_name);
-    default_font_ = new Font(CreateFont(desc));
-    pango_font_description_free(desc);
-    g_free(font_name);
-
-    DCHECK(default_font_);
-  }
-
-  CopyFont(*default_font_);
-}
-
-// static
-PangoFontDescription* Font::PangoFontFromGfxFont(
-    const gfx::Font& gfx_font) {
-  gfx::Font font = gfx_font;  // Copy so we can call non-const methods.
-  PangoFontDescription* pfd = pango_font_description_new();
-  pango_font_description_set_family(pfd, WideToUTF8(font.FontName()).c_str());
-  // Set the absolute size to avoid overflowing UI elements.
-  pango_font_description_set_absolute_size(pfd,
-      font.FontSize() * PANGO_SCALE * Font::GetPangoScaleFactor());
-
-  switch (font.style()) {
-    case gfx::Font::NORMAL:
-      // Nothing to do, should already be PANGO_STYLE_NORMAL.
-      break;
-    case gfx::Font::BOLD:
-      pango_font_description_set_weight(pfd, PANGO_WEIGHT_BOLD);
-      break;
-    case gfx::Font::ITALIC:
-      pango_font_description_set_style(pfd, PANGO_STYLE_ITALIC);
-      break;
-    case gfx::Font::UNDERLINED:
-      // TODO(deanm): How to do underlined?  Where do we use it?  Probably have
-      // to paint it ourselves, see pango_font_metrics_get_underline_position.
-      break;
-  }
-
-  return pfd;
-}
-
-}  // namespace gfx