Implement Harmony typography spec.

chrome/browser/ui/views/harmony/harmony_typography_provider.cc

+// Copyright 2017 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 "chrome/browser/ui/views/harmony/harmony_typography_provider.h"
+
+#include "chrome/browser/ui/views/harmony/chrome_typography.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/platform_font.h"
+
+const gfx::FontList& HarmonyTypographyProvider::GetFont(int text_context,
+                                                        int text_style) const {
+  // "Target" font size constants from the Harmony spec.
+  constexpr int kHeadlineSize = 20;
+  constexpr int kTitleSize = 15;
+  constexpr int kBodyTextLargeSize = 13;
+  constexpr int kDefaultSize = 12;
+
+#if defined(OS_WIN)
+  constexpr gfx::Font::Weight kButtonFontWeight = gfx::Font::Weight::BOLD;
+#else
+  constexpr gfx::Font::Weight kButtonFontWeight = gfx::Font::Weight::MEDIUM;
+#endif
+
+  int size_delta = kDefaultSize - gfx::PlatformFont::kDefaultBaseFontSize;
+  gfx::Font::Weight font_weight = gfx::Font::Weight::NORMAL;
+  switch (text_context) {
+    case CONTEXT_HEADLINE:
+      size_delta = kHeadlineSize - gfx::PlatformFont::kDefaultBaseFontSize;
+      break;
+    case views::style::CONTEXT_DIALOG_TITLE:
+      size_delta = kTitleSize - gfx::PlatformFont::kDefaultBaseFontSize;
+      break;
+    case CONTEXT_BODY_TEXT_LARGE:
+      size_delta = kBodyTextLargeSize - gfx::PlatformFont::kDefaultBaseFontSize;
+      break;
+    case views::style::CONTEXT_BUTTON:
+      font_weight = kButtonFontWeight;
+      break;
+    default:
+      break;
+  }
+
+  // Ignore |text_style| since it only affects color in the Harmony spec.
+  return ui::ResourceBundle::GetSharedInstance().GetFontListWithDelta(
+      size_delta, gfx::Font::NORMAL, font_weight);
+}
+
+SkColor HarmonyTypographyProvider::GetColor(int text_context,
+                                            int text_style) const {
+  // TODO(tapted): Look up colors from the spec.
+  return SK_ColorBLACK;
+}
+
+int HarmonyTypographyProvider::GetLineHeight(int text_context,
+                                             int text_style) const {
+  // "Target" line height constants from the Harmony spec. A default OS
+  // configuration should use these heights. However, if the user overrides OS
+  // defaults, then GetLineHeight() should return the height that would add the
+  // same extra space between lines as the default configuration would have.
+  constexpr int kHeadlineHeight = 32;
+  constexpr int kTitleHeight = 22;
+  constexpr int kBodyHeight = 20;  // For both large and small.
+
+  // Button text should always use the minimum line height for a font to avoid
+  // unnecessarily influencing the height of a button.
+  constexpr int kButtonAbsoluteHeight = 0;
+
+// The platform-specific heights (i.e. gfx::Font::GetHeight()) that result when
+// asking for the target size constants in HarmonyTypographyProvider::GetFont()
+// in a default OS configuration.
+// TODO(tapted): Update these with constants specific to an OS point version.
+#if defined(OS_MACOSX)
+  constexpr int kHeadlinePlatformHeight = 25;
+  constexpr int kTitlePlatformHeight = 19;
+  constexpr int kBodyTextLargePlatformHeight = 16;
+  constexpr int kBodyTextSmallPlatformHeight = 15;
+#elif defined(OS_WIN)
+  constexpr int kHeadlinePlatformHeight = 28;
+  constexpr int kTitlePlatformHeight = 20;
+  constexpr int kBodyTextLargePlatformHeight = 17;
+  constexpr int kBodyTextSmallPlatformHeight = 15;
+#else
+  constexpr int kHeadlinePlatformHeight = 24;
+  constexpr int kTitlePlatformHeight = 18;
+  constexpr int kBodyTextLargePlatformHeight = 17;
+  constexpr int kBodyTextSmallPlatformHeight = 15;
+#endif
+
+  // The style of the system font used to determine line heights.
+  constexpr int kTemplateStyle = views::style::STYLE_PRIMARY;
+
+  // TODO(tapted): These statics should be cleared out when something invokes
+  // ResourceBundle::ReloadFonts(). Currently that only happens on ChromeOS.
+  // See http://crbug.com/708943.
+  static const int headline_height =
+      GetFont(CONTEXT_HEADLINE, kTemplateStyle).GetHeight() -
+      kHeadlinePlatformHeight + kHeadlineHeight;
+  static const int title_height =
+      GetFont(views::style::CONTEXT_DIALOG_TITLE, kTemplateStyle).GetHeight() -
+      kTitlePlatformHeight + kTitleHeight;
+  static const int body_large_height =
+      GetFont(CONTEXT_BODY_TEXT_LARGE, kTemplateStyle).GetHeight() -
+      kBodyTextLargePlatformHeight + kBodyHeight;
+  static const int default_height =
+      GetFont(CONTEXT_BODY_TEXT_SMALL, kTemplateStyle).GetHeight() -
+      kBodyTextSmallPlatformHeight + kBodyHeight;
+
+  switch (text_context) {
+    case CONTEXT_HEADLINE:
+      return headline_height;
+    case views::style::CONTEXT_DIALOG_TITLE:
+      return title_height;
+    case CONTEXT_BODY_TEXT_LARGE:
+      return body_large_height;
+    case views::style::CONTEXT_BUTTON:
+      return kButtonAbsoluteHeight;
+    default:
+      return default_height;
+  }
+}