Site specific secondary tiles for Windows 8.

chrome/browser/ui/metro_pin_tab_helper_win.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 "chrome/browser/ui/metro_pin_tab_helper_win.h"
+
+#include "base/base_paths.h"
+#include "base/bind.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/path_service.h"
+#include "base/string_number_conversions.h"
+#include "base/utf_string_conversions.h"
+#include "base/win/metro.h"
+#include "chrome/browser/favicon/favicon_tab_helper.h"
+#include "chrome/browser/ui/tab_contents/tab_contents.h"
+#include "chrome/common/chrome_paths.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
+#include "crypto/sha2.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/color_analysis.h"
+#include "ui/gfx/color_utils.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/size.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(MetroPinTabHelper)
+
+namespace {
+
+// Generate an ID for the tile based on |url_str|. The ID is simply a hash of
+// the URL.
+string16 GenerateTileId(const string16& url_str) {
+  uint8 hash[crypto::kSHA256Length];
+  crypto::SHA256HashString(UTF16ToUTF8(url_str), hash, sizeof(hash));
+  std::string hash_str = base::HexEncode(hash, sizeof(hash));
+  return UTF8ToUTF16(hash_str);
+}
+
+// Get the path of the directory to store the tile logos in.
+FilePath GetTileImagesDir() {
+  FilePath time_images_dir;
+  DCHECK(PathService::Get(chrome::DIR_USER_DATA, &time_images_dir));
+  time_images_dir = time_images_dir.Append(L"TileImages");
+  if (!file_util::DirectoryExists(time_images_dir) &&
+      !file_util::CreateDirectory(time_images_dir))
+    return FilePath();
+
+  return time_images_dir;
+}
+
+// For the given |image| and |tile_id|, try to create a site specific logo in
+// |logo_dir|. The path of any created logo is returned in |logo_path|. Return
+// value indicates whether a site specific logo was created.
+bool CreateSiteSpecificLogo(const gfx::ImageSkia& image,
+                            const string16& tile_id,
+                            const FilePath& logo_dir,
+                            FilePath* logo_path) {
+  const int kLogoWidth = 120;
+  const int kLogoHeight = 120;
+  const int kBoxWidth = 40;
+  const int kBoxHeight = 40;
+  const int kCaptionHeight = 20;
+  const double kBoxFade = 0.75;
+  const int kColorMeanDarknessLimit = 100;
+  const int kColorMeanLightnessLimit = 100;
+
+  if (image.isNull())
+    return false;
+
+  *logo_path = logo_dir.Append(tile_id).ReplaceExtension(L".png");
+
+  // Use a canvas to paint the tile logo.
+  gfx::Canvas canvas(gfx::Size(kLogoWidth, kLogoHeight), ui::SCALE_FACTOR_100P,
+                     true);
+
+  // Fill the tile logo with the average color from bitmap. To do this we need
+  // to work out the 'average color' which is calculated using PNG encoded data
+  // of the bitmap.
+  SkPaint paint;
+  std::vector<unsigned char> icon_png;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(*image.bitmap(), true, &icon_png))
+    return false;
+
+  scoped_refptr<base::RefCountedStaticMemory> icon_mem(
+      new base::RefCountedStaticMemory(&icon_png.front(), icon_png.size()));
+  color_utils::GridSampler sampler;
+  SkColor mean_color = color_utils::CalculateKMeanColorOfPNG(
+      icon_mem, kColorMeanDarknessLimit, kColorMeanLightnessLimit, sampler);
+  paint.setColor(mean_color);
+  canvas.DrawRect(gfx::Rect(0, 0, kLogoWidth, kLogoHeight), paint);
+
+  // Now paint a faded square for the favicon to go in.
+  color_utils::HSL shift = {-1, -1, kBoxFade};
+  paint.setColor(color_utils::HSLShift(mean_color, shift));
+  int box_left = (kLogoWidth - kBoxWidth) / 2;
+  int box_top = (kLogoHeight - kCaptionHeight - kBoxHeight) / 2;
+  canvas.DrawRect(gfx::Rect(box_left, box_top, kBoxWidth, kBoxHeight), paint);
+
+  // Now paint the favicon into the tile, leaving some room at the bottom for
+  // the caption.
+  int left = (kLogoWidth - image.width()) / 2;
+  int top = (kLogoHeight - kCaptionHeight - image.height()) / 2;
+  canvas.DrawImageInt(image, left, top);
+
+  SkBitmap logo_bitmap = canvas.ExtractImageRep().sk_bitmap();
+  std::vector<unsigned char> logo_png;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(logo_bitmap, true, &logo_png))
+    return false;
+
+  return file_util::WriteFile(*logo_path,
+                              reinterpret_cast<char*>(&logo_png[0]),
+                              logo_png.size()) > 0;
+}
+
+// Get the path to the backup logo. If the backup logo already exists in
+// |logo_dir|, it will be used, otherwise it will be copied out of the install
+// folder. (The version in the install folder is not used as it may disappear
+// after an upgrade, causing tiles to lose their images if Windows rebuilds
+// its tile image cache.)
+// The path to the logo is returned in |logo_path|, with the return value
+// indicating success.
+bool GetPathToBackupLogo(const FilePath& logo_dir,
+                         FilePath* logo_path) {
+  const wchar_t kDefaultLogoFileName[] = L"SecondaryTile.png";
+  *logo_path = logo_dir.Append(kDefaultLogoFileName);
+  if (file_util::PathExists(*logo_path))
+    return true;
+
+  FilePath default_logo_path;
+  DCHECK(PathService::Get(base::DIR_MODULE, &default_logo_path));
+  default_logo_path = default_logo_path.Append(kDefaultLogoFileName);
+  return file_util::CopyFile(default_logo_path, *logo_path);
+}
+
+}  // namespace
+
+class MetroPinTabHelper::TaskRunner
+    : public base::RefCountedThreadSafe<TaskRunner> {
+ public:
+  TaskRunner() {}
+
+  void PinPageToStartScreen(const string16& title,
+                            const string16& url,
+                            const gfx::ImageSkia& image);
+
+ private:
+  ~TaskRunner() {}
+
+  friend class base::RefCountedThreadSafe<TaskRunner>;
+  DISALLOW_COPY_AND_ASSIGN(TaskRunner);
+};
+
+void MetroPinTabHelper::TaskRunner::PinPageToStartScreen(
+    const string16& title,
+    const string16& url,
+    const gfx::ImageSkia& image) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+
+  string16 tile_id = GenerateTileId(url);
+  FilePath logo_dir = GetTileImagesDir();
+  if (logo_dir.empty()) {
+    LOG(ERROR) << "Could not create directory to store tile image.";
+    return;
+  }
+
+  FilePath logo_path;
+  if (!CreateSiteSpecificLogo(image, tile_id, logo_dir, &logo_path) &&
+      !GetPathToBackupLogo(logo_dir, &logo_path)) {
+    LOG(ERROR) << "Count not get path to logo tile.";
+    return;
+  }
+
+  HMODULE metro_module = base::win::GetMetroModule();
+  if (!metro_module)
+    return;
+
+  typedef void (*MetroPinToStartScreen)(const string16&, const string16&,
+      const string16&, const FilePath&);
+  MetroPinToStartScreen metro_pin_to_start_screen =
+      reinterpret_cast<MetroPinToStartScreen>(
+          ::GetProcAddress(metro_module, "MetroPinToStartScreen"));
+  if (!metro_pin_to_start_screen) {
+    NOTREACHED();
+    return;
+  }
+
+  VLOG(1) << __FUNCTION__ << " calling pin with title: " << title
+          << " and url: " << url;
+  metro_pin_to_start_screen(tile_id, title, url, logo_path);
+}
+
+MetroPinTabHelper::MetroPinTabHelper(content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents),
+      is_pinned_(false),
+      task_runner_(new TaskRunner) {}
+
+MetroPinTabHelper::~MetroPinTabHelper() {}
+
+void MetroPinTabHelper::TogglePinnedToStartScreen() {
+  UpdatePinnedStateForCurrentURL();
+  bool was_pinned = is_pinned_;
+
+  // TODO(benwells): This will update the state incorrectly if the user
+  // cancels. To fix this some sort of callback needs to be introduced as
+  // the pinning happens on another thread.
+  is_pinned_ = !is_pinned_;
+
+  if (was_pinned) {
+    UnPinPageFromStartScreen();
+    return;
+  }
+
+  // TODO(benwells): Handle downloading a larger favicon if there is one.
+  GURL url = web_contents()->GetURL();
+  string16 url_str = UTF8ToUTF16(url.spec());
+  string16 title = web_contents()->GetTitle();
+  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
+  DCHECK(tab_contents);
+  FaviconTabHelper* favicon_tab_helper = FaviconTabHelper::FromWebContents(
+      tab_contents->web_contents());
+  if (favicon_tab_helper->FaviconIsValid()) {
+    gfx::Image favicon = favicon_tab_helper->GetFavicon();
+    gfx::ImageSkia favicon_skia = favicon.AsImageSkia().DeepCopy();
+    content::BrowserThread::PostTask(
+        content::BrowserThread::FILE,
+        FROM_HERE,
+        base::Bind(&TaskRunner::PinPageToStartScreen,
+                   task_runner_,
+                   title,
+                   url_str,
+                   favicon_skia));
+    return;
+  }
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&TaskRunner::PinPageToStartScreen,
+                 task_runner_,
+                 title,
+                 url_str,
+                 gfx::ImageSkia()));
+}
+
+void MetroPinTabHelper::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& /*details*/,
+    const content::FrameNavigateParams& /*params*/) {
+  UpdatePinnedStateForCurrentURL();
+}
+
+void MetroPinTabHelper::UpdatePinnedStateForCurrentURL() {
+  HMODULE metro_module = base::win::GetMetroModule();
+  if (!metro_module)
+    return;
+
+  typedef BOOL (*MetroIsPinnedToStartScreen)(const string16&);
+  MetroIsPinnedToStartScreen metro_is_pinned_to_start_screen =
+      reinterpret_cast<MetroIsPinnedToStartScreen>(
+          ::GetProcAddress(metro_module, "MetroIsPinnedToStartScreen"));
+  if (!metro_is_pinned_to_start_screen) {
+    NOTREACHED();
+    return;
+  }
+
+  GURL url = web_contents()->GetURL();
+  string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
+  is_pinned_ = metro_is_pinned_to_start_screen(tile_id) != 0;
+  VLOG(1) << __FUNCTION__ << " with url " << UTF8ToUTF16(url.spec())
+          << " result: " << is_pinned_;
+}
+
+void MetroPinTabHelper::UnPinPageFromStartScreen() {
+  HMODULE metro_module = base::win::GetMetroModule();
+  if (!metro_module)
+    return;
+
+  typedef void (*MetroUnPinFromStartScreen)(const string16&);
+  MetroUnPinFromStartScreen metro_un_pin_from_start_screen =
+      reinterpret_cast<MetroUnPinFromStartScreen>(
+          ::GetProcAddress(metro_module, "MetroUnPinFromStartScreen"));
+  if (!metro_un_pin_from_start_screen) {
+    NOTREACHED();
+    return;
+  }
+
+  GURL url = web_contents()->GetURL();
+  VLOG(1) << __FUNCTION__ << " calling unpin with url: "
+          << UTF8ToUTF16(url.spec());
+  string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
+  metro_un_pin_from_start_screen(tile_id);
+}