wallpaper-webui: Make sure the wallpaper thumbnails are appropriately scaled.

chrome/browser/ui/webui/options2/chromeos/wallpaper_thumbnail_source.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/webui/options2/chromeos/wallpaper_thumbnail_source.h"
 
 #include "ash/desktop_background/desktop_background_resources.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/singleton.h"
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/synchronization/cancellation_flag.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/worker_pool.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/login/wallpaper_manager.h"
 #include "chrome/browser/io_thread.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
+#include "chrome/browser/ui/webui/web_ui_util.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/ui_resources.h"
 #include "net/base/mime_util.h"
 #include "ui/base/layout.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/codec/png_codec.h"
 
 namespace chromeos {
 namespace options2 {
 
 class WallpaperThumbnailSource::ThumbnailEncodingOperation
   : public base::RefCountedThreadSafe<
         WallpaperThumbnailSource::ThumbnailEncodingOperation> {
  public:
   ThumbnailEncodingOperation(int request_id,
                              const chromeos::User* user,
+                             ui::ScaleFactor scale_factor,
                              scoped_refptr<base::RefCountedBytes> data)
       : request_id_(request_id),
         user_(user),
+        scale_factor_(scale_factor),
         data_(data) {
   }
 
   int request_id() {
     return request_id_;
   }
 
   static void Run(scoped_refptr<ThumbnailEncodingOperation> teo) {
     teo->EncodeThumbnail();
   }
 
   void EncodeThumbnail() {
     if (cancel_flag_.IsSet())
       return;
+    gfx::ImageSkia image =
+        WallpaperManager::Get()->GetCustomWallpaperThumbnail(user_->email());
     gfx::PNGCodec::EncodeBGRASkBitmap(
-        WallpaperManager::Get()->GetCustomWallpaperThumbnail(user_->email()),
+        image.GetRepresentation(scale_factor_).sk_bitmap(),
         false, &data_->data());
   }
 
   void Cancel() {
     cancel_flag_.Set();
   }
 
  private:
   friend class base::RefCountedThreadSafe<
       WallpaperThumbnailSource::ThumbnailEncodingOperation>;
 
   ~ThumbnailEncodingOperation() {}
 
   base::CancellationFlag cancel_flag_;
 
   int request_id_;
 
   const chromeos::User* user_;
 
+  ui::ScaleFactor scale_factor_;
+
   scoped_refptr<base::RefCountedBytes> data_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailEncodingOperation);
 };
 
 namespace {
 
 const char kDefaultWallpaperPrefix[] = "default_";
 const char kCustomWallpaperPrefix[] = "custom_";
 
@@ skipping 51 matching lines @@
 
 WallpaperThumbnailSource::WallpaperThumbnailSource()
     : DataSource(chrome::kChromeUIWallpaperThumbnailHost, NULL),
       weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
 }
 
 std::string WallpaperThumbnailSource::GetMimeType(const std::string&) const {
   return "images/png";
 }
 
-void WallpaperThumbnailSource::StartDataRequest(const std::string& path,
+void WallpaperThumbnailSource::StartDataRequest(const std::string& full_path,
                                                 bool is_incognito,
                                                 int request_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  GURL url(chrome::kChromeUIWallpaperThumbnailURL + full_path);
+  std::string path;
+  ui::ScaleFactor scale_factor;

[Ivan Korotkov, 2012/08/15 20:36:03]

Does the URL ever include username@domain? In that case, any such occurrences
without trailing @<factor>x part will be parsed improperly.

[sadrul, 2012/08/15 20:53:28]

Good point! I discussed with bshe@, and username@domain indeed can be part of
the URL. However, the url is of the format
'chrome://.../custom_user@domain?id=...' etc., and it looks like the parsing
code will return NONE for the scale factor in this case (even if domain starts
with '1x' or '2x'), which is the current behaviour anyway. I think this is safe?

[sadrul, 2012/08/15 22:28:53]

I have also submitted http://codereview.chromium.org/10837270/ that should help
avoiding similar problem in the future.

[Ivan Korotkov, 2012/08/16 08:44:17]

Thanks! With CL 10837270 submitted it should be safe to use.  Prior to it,
|path| would only contain username, as @domain would be cut in absence of
@factor.

+  web_ui_util::ParsePathAndScale(url, &path, &scale_factor);
+
   CancelPendingCustomThumbnailEncodingOperation();
   content::BrowserThread::PostTask(
       content::BrowserThread::UI,
       FROM_HERE,
       base::Bind(&WallpaperThumbnailSource::GetCurrentUserThumbnail,
-                 this, path, request_id));
+                 this, path, scale_factor, request_id));
 }
 
 WallpaperThumbnailSource::~WallpaperThumbnailSource() {
 }
 
 void WallpaperThumbnailSource::GetCurrentUserThumbnail(
     const std::string& path,
+    ui::ScaleFactor scale_factor,
     int request_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   std::string email;
   if (IsCustomWallpaperPath(path, &email)) {
     const chromeos::User* user = chromeos::UserManager::Get()->FindUser(email);
     if (!user) {
       content::BrowserThread::PostTask(
           content::BrowserThread::IO,
           FROM_HERE,
           base::Bind(&WallpaperThumbnailSource::SendCurrentUserNullThumbnail,
                      this, request_id));
       return;
     }
     content::BrowserThread::PostTask(
         content::BrowserThread::IO,
         FROM_HERE,
         base::Bind(
             &WallpaperThumbnailSource::StartCustomThumbnailEncodingOperation,
-            this, user, request_id));
+            this, user, scale_factor, request_id));
     return;
   }
   content::BrowserThread::PostTask(
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(&WallpaperThumbnailSource::SendCurrentUserDefaultThumbnail,
-                 this, path, request_id));
+                 this, path, scale_factor, request_id));
 }
 
 void WallpaperThumbnailSource::StartCustomThumbnailEncodingOperation(
     const chromeos::User* user,
+    ui::ScaleFactor scale_factor,
     int request_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   CancelPendingCustomThumbnailEncodingOperation();
   scoped_refptr<base::RefCountedBytes> data = new base::RefCountedBytes();
   thumbnail_encoding_op_ = new ThumbnailEncodingOperation(request_id,
                                                           user,
+                                                          scale_factor,
                                                           data);
   base::WorkerPool::PostTaskAndReply(
       FROM_HERE,
       base::Bind(&ThumbnailEncodingOperation::Run, thumbnail_encoding_op_),
       base::Bind(&WallpaperThumbnailSource::SendCurrentUserCustomThumbnail,
                  weak_ptr_factory_.GetWeakPtr(), data, request_id),
       true /* task_is_slow */);
 }
 
 void WallpaperThumbnailSource::CancelPendingCustomThumbnailEncodingOperation() {
@@ skipping 12 matching lines @@
 
 void WallpaperThumbnailSource::SendCurrentUserCustomThumbnail(
   scoped_refptr<base::RefCountedBytes> data,
   int request_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   SendResponse(request_id, data);
 }
 
 void WallpaperThumbnailSource::SendCurrentUserDefaultThumbnail(
   const std::string& path,
+  ui::ScaleFactor scale_factor,
   int request_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   int idr = PathToIDR(path);
   if (idr == -1) {
     SendResponse(request_id, NULL);
     return;
   }
   const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   SendResponse(request_id,
-               rb.LoadDataResourceBytes(idr, ui::SCALE_FACTOR_100P));
+               rb.LoadDataResourceBytes(idr, scale_factor));
 }
 
 }  // namespace options2
 }  // namespace chromeos