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);
+}
+
+// Create a tile logo from |icon_image|, and save it to |tile_path|.
+bool CreateLogoFromFavicon(const gfx::ImageSkia& icon_image,
+                           const FilePath& tile_path) {
+  static int kLogoWidth = 120;

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

you mean const int xxx = yy ?

[benwells, 2012/10/24 00:48:18]

Done.

+  static int kLogoHeight = 120;
+  static int kBoxWidth = 40;
+  static int kBoxHeight = 40;
+  static int kCaptionHeight = 20;
+  static double kBoxFade = 0.75;
+
+  // 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(*icon_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, 100, 665, sampler);

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

100 and 665 would be nice to have in constants above.

[benwells, 2012/10/24 00:48:18]

Done.

+  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 - icon_image.width()) / 2;
+  int top = (kLogoHeight - kCaptionHeight - icon_image.height()) / 2;
+  canvas.DrawImageInt(icon_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(tile_path,
+                              reinterpret_cast<char*>(&logo_png[0]),
+                              logo_png.size()) > 0;
+}
+
+// For the given |image| and |tile_id|, return the path to a tile image. This
+// will either generate a site specific logo or return a path to the backup tile
+// image.
+FilePath GetLogoPath(const gfx::ImageSkia& image,

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

seems the name could be better, like MakeLogo, as is seems just a path
construction.

[benwells, 2012/10/24 00:48:18]

Coming up with a name was hard as it did a variety of jobs. I've restructured a
bit which hopefully makes the flow more obvious (and the names more accurate).

+                     const string16& tile_id) {
+  FilePath logo_dir;
+  DCHECK(PathService::Get(chrome::DIR_USER_DATA, &logo_dir));
+  logo_dir = logo_dir.Append(L"TileImages");
+  if (!file_util::DirectoryExists(logo_dir) &&
+      !file_util::CreateDirectory(logo_dir))
+    return FilePath();
+
+  if (!image.isNull()) {
+    FilePath logo_path = logo_dir.Append(tile_id)
+                                 .ReplaceExtension(L".png");
+    if (CreateLogoFromFavicon(image, logo_path))
+      return logo_path;
+  }
+
+  // Use default tile image. If it doesn't exist, copy it 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.
+  static const wchar_t kDefaultLogoFileName[] = L"SecondaryTile.png";

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

don't need the static and its not used in most of our code.

[benwells, 2012/10/24 00:48:18]

Done.

+  FilePath logo_path = logo_dir.Append(kDefaultLogoFileName);
+  if (!file_util::PathExists(logo_path)) {
+    FilePath default_logo_path;
+    DCHECK(PathService::Get(base::DIR_MODULE, &default_logo_path));
+    default_logo_path = default_logo_path.Append(kDefaultLogoFileName);
+    if (!file_util::CopyFile(default_logo_path, logo_path))
+      return FilePath();

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

please extract 121-129 into a freestanding function.

[benwells, 2012/10/24 00:48:18]

Done.

+  }
+
+  return 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);
+};
+
+MetroPinTabHelper::TaskRunner::TaskRunner() {}
+
+MetroPinTabHelper::TaskRunner::~TaskRunner() {}
+

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

you can fold the do nothing funtions like 152 and 154 in the declaration, line
139.

+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_path = GetLogoPath(image, tile_id);
+  if (logo_path.empty()) {
+    LOG(ERROR) << "Count not create logo tile.";
+    return;
+  }
+
+  HMODULE metro_module = base::win::GetMetroModule();
+  if (metro_module) {
+    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()));

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

I don't know how cheap is to make a gfx::ImageSkia here or to deep copy one in
line 227, consider instead allocating it in the heap or passing NULL here.

I guess I don't know if the posttask ends up copying all those bits again. Can
you check?

[benwells, 2012/10/24 00:48:18]

As discussed over chat, ImageSkia is cheap. The ImageSkia does get copied over
properly, I checked it during development.

I think the deep copy is needed, it was suggested by sky@.

+}
+
+void MetroPinTabHelper::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& /*details*/,
+    const content::FrameNavigateParams& /*params*/) {
+  UpdatePinnedStateForCurrentURL();
+}
+
+void MetroPinTabHelper::UpdatePinnedStateForCurrentURL() {
+  HMODULE metro_module = base::win::GetMetroModule();
+  if (metro_module) {

[cpu_(ooo_6.6-7.5), 2012/10/23 20:17:01]

rather do
if (!metro_module)
  return;

To have less nested blocks.

[benwells, 2012/10/24 00:48:18]

Done.

+    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) {
+    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);
+  }
+}