1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "chrome/browser/thumbnails/thumbnail_tab_helper.h"
7 #include "chrome/browser/browser_process.h"
8 #include "chrome/browser/profiles/profile.h"
9 #include "chrome/browser/thumbnails/thumbnail_service.h"
10 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
11 #include "chrome/browser/thumbnails/thumbnailing_algorithm.h"
12 #include "chrome/browser/thumbnails/thumbnailing_context.h"
13 #include "content/public/browser/browser_thread.h"
14 #include "content/public/browser/notification_details.h"
15 #include "content/public/browser/notification_source.h"
16 #include "content/public/browser/notification_types.h"
17 #include "content/public/browser/render_view_host.h"
18 #include "content/public/browser/render_widget_host_view.h"
19 #include "ui/gfx/color_utils.h"
20 #include "ui/gfx/size_conversions.h"
21 #include "ui/gfx/screen.h"
22 #include "ui/gfx/scrollbar_size.h"
23 #include "ui/gfx/skbitmap_operations.h"
26 #include "base/win/windows_version.h"
29 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ThumbnailTabHelper);
35 // This class provides a service for updating thumbnails to be used in
36 // "Most visited" section of the new tab page. The service can be started
37 // by StartThumbnailing(). The current algorithm of the service is as
40 // When a renderer is about to be hidden (this usually occurs when the
41 // current tab is closed or another tab is clicked), update the
42 // thumbnail for the tab rendered by the renderer, if needed. The
43 // heuristics to judge whether or not to update the thumbnail is
44 // implemented in ShouldUpdateThumbnail().
46 using content::RenderViewHost;
47 using content::RenderWidgetHost;
48 using content::WebContents;
50 using thumbnails::ClipResult;
51 using thumbnails::ThumbnailingContext;
52 using thumbnails::ThumbnailingAlgorithm;
56 // Feed the constructed thumbnail to the thumbnail service.
57 void UpdateThumbnail(const ThumbnailingContext& context,
58 const SkBitmap& thumbnail) {
59 gfx::Image image = gfx::Image::CreateFrom1xBitmap(thumbnail);
60 context.service->SetPageThumbnail(context, image);
61 DVLOG(1) << "Thumbnail taken for " << context.url << ": "
62 << context.score.ToString();
65 void ProcessCapturedBitmap(scoped_refptr<ThumbnailingContext> context,
66 scoped_refptr<ThumbnailingAlgorithm> algorithm,
68 const SkBitmap& bitmap) {
72 // On success, we must be on the UI thread (on failure because of shutdown we
73 // are not on the UI thread).
74 DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
76 algorithm->ProcessBitmap(context, base::Bind(&UpdateThumbnail), bitmap);
79 void AsyncProcessThumbnail(content::WebContents* web_contents,
80 scoped_refptr<ThumbnailingContext> context,
81 scoped_refptr<ThumbnailingAlgorithm> algorithm) {
82 DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
83 RenderWidgetHost* render_widget_host = web_contents->GetRenderViewHost();
84 content::RenderWidgetHostView* view = render_widget_host->GetView();
87 if (!view->IsSurfaceAvailableForCopy())
90 gfx::Rect copy_rect = gfx::Rect(view->GetViewBounds().size());
91 // Clip the pixels that will commonly hold a scrollbar, which looks bad in
93 int scrollbar_size = gfx::scrollbar_size();
95 copy_rect.Inset(0, 0, scrollbar_size, scrollbar_size);
97 if (copy_rect.IsEmpty())
100 ui::ScaleFactor scale_factor =
101 ui::GetSupportedScaleFactor(
102 ui::GetScaleFactorForNativeView(view->GetNativeView()));
103 context->clip_result = algorithm->GetCanvasCopyInfo(
107 &context->requested_copy_size);
108 render_widget_host->CopyFromBackingStore(
110 context->requested_copy_size,
111 base::Bind(&ProcessCapturedBitmap, context, algorithm),
117 ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)
118 : content::WebContentsObserver(contents),
120 load_interrupted_(false) {
121 // Even though we deal in RenderWidgetHosts, we only care about its
122 // subclass, RenderViewHost when it is in a tab. We don't make thumbnails
123 // for RenderViewHosts that aren't in tabs, or RenderWidgetHosts that
124 // aren't views like select popups.
126 content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED,
127 content::Source<WebContents>(contents));
130 ThumbnailTabHelper::~ThumbnailTabHelper() {
133 void ThumbnailTabHelper::Observe(int type,
134 const content::NotificationSource& source,
135 const content::NotificationDetails& details) {
137 case content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED:
138 RenderViewHostCreated(content::Details<RenderViewHost>(details).ptr());
141 case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED:
142 if (!*content::Details<bool>(details).ptr())
143 WidgetHidden(content::Source<RenderWidgetHost>(source).ptr());
147 NOTREACHED() << "Unexpected notification type: " << type;
151 void ThumbnailTabHelper::RenderViewDeleted(
152 content::RenderViewHost* render_view_host) {
153 bool registered = registrar_.IsRegistered(
155 content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
156 content::Source<RenderWidgetHost>(render_view_host));
160 content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
161 content::Source<RenderWidgetHost>(render_view_host));
165 void ThumbnailTabHelper::DidStartLoading(
166 content::RenderViewHost* render_view_host) {
167 load_interrupted_ = false;
170 void ThumbnailTabHelper::NavigationStopped() {
171 // This function gets called when the page loading is interrupted by the
173 load_interrupted_ = true;
176 void ThumbnailTabHelper::UpdateThumbnailIfNecessary(
177 WebContents* web_contents) {
178 // Destroying a WebContents may trigger it to be hidden, prompting a snapshot
179 // which would be unwise to attempt <http://crbug.com/130097>. If the
180 // WebContents is in the middle of destruction, do not risk it.
181 if (!web_contents || web_contents->IsBeingDestroyed())
183 // Skip if a pending entry exists. WidgetHidden can be called while navigating
184 // pages and this is not a time when thumbnails should be generated.
185 if (web_contents->GetController().GetPendingEntry())
187 const GURL& url = web_contents->GetURL();
189 Profile::FromBrowserContext(web_contents->GetBrowserContext());
191 scoped_refptr<thumbnails::ThumbnailService> thumbnail_service =
192 ThumbnailServiceFactory::GetForProfile(profile);
194 // Skip if we don't need to update the thumbnail.
195 if (thumbnail_service.get() == NULL ||
196 !thumbnail_service->ShouldAcquirePageThumbnail(url)) {
200 scoped_refptr<thumbnails::ThumbnailingAlgorithm> algorithm(
201 thumbnail_service->GetThumbnailingAlgorithm());
203 scoped_refptr<ThumbnailingContext> context(new ThumbnailingContext(
204 web_contents, thumbnail_service.get(), load_interrupted_));
205 AsyncProcessThumbnail(web_contents, context, algorithm);
208 void ThumbnailTabHelper::RenderViewHostCreated(
209 content::RenderViewHost* renderer) {
210 // NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED is really a new
211 // RenderView, not RenderViewHost, and there is no good way to get
212 // notifications of RenderViewHosts. So just be tolerant of re-registrations.
213 bool registered = registrar_.IsRegistered(
215 content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
216 content::Source<RenderWidgetHost>(renderer));
220 content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
221 content::Source<RenderWidgetHost>(renderer));
225 void ThumbnailTabHelper::WidgetHidden(RenderWidgetHost* widget) {
228 UpdateThumbnailIfNecessary(web_contents());