[Favicon] Add FallbackIconStyle and FallbackIconService.

components/favicon_base/fallback_icon_service.cc

+// Copyright 2015 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 "components/favicon_base/fallback_icon_service.h"
+
+#include <algorithm>
+
+#include "base/i18n/case_conversion.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/favicon_base/fallback_icon_style.h"
+#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/font_list.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
+#include "url/gurl.h"
+
+namespace favicon_base {
+
+namespace {
+
+const int kMaxFallbackFaviconSize = 288;

[stevenjb, 2015/02/11 18:04:37]

nit: document reason for '288'. "Arbitrary maximum icon size" is fine, but that
way in the future if there is reason to change this, the next dev will know if
it is OK (or not).

[huangs, 2015/02/11 20:28:38]

Done.

+
+// Returns a single character to represent a page URL. To do this we take the
+// first letter in a domain's name and make it upper case.
+// TODO(huangs): Handle non-ASCII ("xn--") domain names.
+base::string16 GetFallbackIconText(const GURL& url) {
+  std::string domain = net::registry_controlled_domains::GetDomainAndRegistry(
+        url, net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES);
+  return domain.empty() ? base::string16() :
+      base::i18n::ToUpper(base::ASCIIToUTF16(domain.substr(0, 1)));
+}
+
+}  // namespace
+
+FallbackIconService::FallbackIconService(
+    const std::vector<std::string>& font_list)
+  : font_list_(font_list) {
+}
+
+FallbackIconService::~FallbackIconService() {
+}
+
+std::vector<unsigned char> FallbackIconService::RenderFallbackIconBitmap(
+    const GURL& icon_url,
+    int size,
+    const FallbackIconStyle& style) {
+  int size_to_use = std::min(kMaxFallbackFaviconSize, size);
+  gfx::Canvas canvas(gfx::Size(size_to_use, size_to_use), 1.0f, false);
+  DrawFallbackIcon(icon_url, size_to_use, style, &canvas);
+
+  std::vector<unsigned char> bitmap_data;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(canvas.ExtractImageRep().sk_bitmap(),
+                                         false, &bitmap_data)) {
+    bitmap_data.clear();
+  }
+  return bitmap_data;
+}
+
+void FallbackIconService::DrawFallbackIcon(const GURL& icon_url,
+                                           int size,
+                                           const FallbackIconStyle& style,
+                                           gfx::Canvas* canvas) {
+  const int kOffsetX = 0;
+  const int kOffsetY = 0;
+  SkPaint paint;
+  paint.setStyle(SkPaint::kFill_Style);
+  paint.setAntiAlias(true);
+
+  // Draw a filled, colored rounded square.
+  paint.setColor(style.background_color);
+  int corner_radius = static_cast<int>(size * style.roundness * 0.5 + 0.5);
+  canvas->DrawRoundRect(
+      gfx::Rect(kOffsetX, kOffsetY, size, size), corner_radius, paint);
+
+  // Draw text.
+  base::string16 icon_text = GetFallbackIconText(icon_url);
+  if (!icon_text.empty()) {

[stevenjb, 2015/02/11 18:04:37]

nit: this could be an early exit

[huangs, 2015/02/11 20:28:38]

Done.

+    int font_size = static_cast<int>(size * style.font_size_ratio);
+    if (font_size > 0) {

[stevenjb, 2015/02/11 18:04:37]

nit: this too

[huangs, 2015/02/11 20:28:38]

Done.

+      // TODO(huangs): See how expensive gfx::FontList() is, and possibly cache.
+      canvas->DrawStringRectWithFlags(
+          icon_text,
+          gfx::FontList(font_list_, gfx::Font::NORMAL, font_size),
+          style.text_color,
+          gfx::Rect(kOffsetX, kOffsetY, size, size),
+          gfx::Canvas::TEXT_ALIGN_CENTER);
+    }
+  }
+}
+
+}  // namespace favicon_base