Zoom Extension API (chrome)

chrome/browser/ui/zoom/zoom_controller.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/zoom/zoom_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/extensions/api/tabs/tabs_event_router.h"
+#include "chrome/browser/extensions/api/tabs/tabs_windows_api.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/zoom/zoom_event_manager.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_zoom.h"
+#include "extensions/common/extension.h"
 #include "grit/theme_resources.h"
 #include "net/base/net_util.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ZoomController);
 
 ZoomController::ZoomController(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
-      zoom_percent_(100),
-      observer_(NULL),
+      zoom_mode_(ZOOM_MODE_DEFAULT),
+      zoom_level_(1.0),
       browser_context_(web_contents->GetBrowserContext()) {
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
-  default_zoom_level_.Init(prefs::kDefaultZoomLevel, profile->GetPrefs(),
-                           base::Bind(&ZoomController::UpdateState,
-                                      base::Unretained(this),
-                                      std::string()));
+  default_zoom_level_.Init(
+      prefs::kDefaultZoomLevel,
+      profile->GetPrefs(),
+      base::Bind(
+          &ZoomController::UpdateState, base::Unretained(this), std::string()));
+  zoom_level_ = default_zoom_level_.GetValue();
 
   zoom_subscription_ = content::HostZoomMap::GetForBrowserContext(
       browser_context_)->AddZoomLevelChangedCallback(
           base::Bind(&ZoomController::OnZoomLevelChanged,
                      base::Unretained(this)));
 
   UpdateState(std::string());
 }
 
 ZoomController::~ZoomController() {}
 
 bool ZoomController::IsAtDefaultZoom() const {
-  return content::ZoomValuesEqual(
-      content::HostZoomMap::GetZoomLevel(web_contents()),
-      default_zoom_level_.GetValue());
+  return content::ZoomValuesEqual(GetZoomLevel(),
+                                  default_zoom_level_.GetValue());
 }
 
 int ZoomController::GetResourceForZoomLevel() const {
   if (IsAtDefaultZoom())
     return IDR_ZOOM_NORMAL;
-  double zoom = content::HostZoomMap::GetZoomLevel(web_contents());
-  return zoom > default_zoom_level_.GetValue() ? IDR_ZOOM_PLUS : IDR_ZOOM_MINUS;
+  return GetZoomLevel() > default_zoom_level_.GetValue() ? IDR_ZOOM_PLUS
+                                                         : IDR_ZOOM_MINUS;
+}
+
+void ZoomController::AddObserver(ZoomObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void ZoomController::RemoveObserver(ZoomObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+double ZoomController::GetZoomLevel() const {
+  return zoom_mode_ == ZOOM_MODE_MANUAL
+             ? zoom_level_
+             : content::HostZoomMap::GetZoomLevel(web_contents());

[Dan Beam, 2014/06/26 03:40:02]

return zoom_mode_ == ZOOM_MODE_MANUAL ?
    zoom_level_ : content::HostZoomMap::GetZoomLevel(web_contents());

?/: (operators) at the end

[wjmaclean, 2014/06/26 15:30:30]

Dang Clang formatter ... done.

+}
+
+int ZoomController::GetZoomPercent() const {
+  double zoom_factor = content::ZoomLevelToZoomFactor(GetZoomLevel());
+  return static_cast<int>(zoom_factor * 100 + 0.5);

[Dan Beam, 2014/06/26 03:40:02]

nit: mention in a comment that this is rounding

[wjmaclean, 2014/06/26 15:30:31]

Done.

+}
+
+bool ZoomController::SetZoomLevel(double zoom_level) {
+  // An extension did not initiate this zoom change.
+  return SetZoomLevelByExtension(zoom_level,
+                                 scoped_refptr<const extensions::Extension>());

[Dan Beam, 2014/06/26 03:40:02]

can you use NULL instead of scoped_refptr<const extensions::Extension>()?

[wjmaclean, 2014/06/26 15:30:30]

Done. The current form was requested in a previous review round.

+}
+
+bool ZoomController::SetZoomLevelByExtension(
+    double zoom_level,
+    scoped_refptr<const extensions::Extension> extension) {

[Dan Beam, 2014/06/26 03:40:02]

nit: const-ref if possible/cheaper

[wjmaclean, 2014/06/26 15:30:31]

Done.

+  // Cannot zoom in disabled mode.
+  if (zoom_mode_ == ZOOM_MODE_DISABLED)
+    return false;
+
+  // Store extension data so that |extension| can be attributed when the zoom
+  // change completes. We expect that by the time this function returns that
+  // any observers that require this information will have requested it.
+  last_extension_ = extension;
+
+  if (zoom_mode_ == ZOOM_MODE_MANUAL) {
+    double old_zoom_level = zoom_level_;
+    zoom_level_ = zoom_level;
+
+    // TODO(wjmaclean) Do we care about filling in host/scheme here?
+    content::HostZoomMap::ZoomLevelChange change;
+    change.mode = content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM;
+    change.zoom_level = zoom_level;
+    ZoomEventManager::GetForBrowserContext(browser_context_)
+        ->OnZoomLevelChanged(change);
+
+    FOR_EACH_OBSERVER(
+        ZoomObserver,
+        observers_,
+        OnZoomChanged(web_contents(), true /* can_show_bubble */));
+    FOR_EACH_OBSERVER(
+        ZoomObserver,
+        observers_,
+        OnZoomChangeInitiated(
+            web_contents(), old_zoom_level, zoom_level, zoom_mode_));
+
+    last_extension_ = NULL;
+    return true;
+  }
+
+  // Do not actually rescale the page in manual mode.
+  content::HostZoomMap* zoom_map =
+      content::HostZoomMap::GetForBrowserContext(browser_context_);
+  DCHECK(zoom_map);
+  double old_zoom_level = GetZoomLevel();
+  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
+  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
+  if (zoom_mode_ == ZOOM_MODE_ISOLATED ||
+      zoom_map->UsesTemporaryZoomLevel(render_process_id, render_view_id)) {
+    zoom_map->SetTemporaryZoomLevel(
+        render_process_id, render_view_id, zoom_level);
+  } else {
+    content::NavigationEntry* entry =
+        web_contents()->GetController().GetLastCommittedEntry();
+    // We allow empty |host| values for data urls.
+    std::string host =
+        net::GetHostOrSpecFromURL(entry ? entry->GetURL() : GURL::EmptyGURL());
+    zoom_map->SetZoomLevelForHost(host, zoom_level);
+  }
+  FOR_EACH_OBSERVER(
+      ZoomObserver,
+      observers_,
+      OnZoomChangeInitiated(
+          web_contents(), old_zoom_level, zoom_level, zoom_mode_));
+
+  last_extension_ = NULL;
+  return true;
+}
+
+void ZoomController::SetZoomMode(ZoomMode new_mode) {
+  if (new_mode == zoom_mode_)
+    return;
+
+  content::HostZoomMap* zoom_map =
+      content::HostZoomMap::GetForBrowserContext(browser_context_);
+  DCHECK(zoom_map);
+  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
+  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
+  double original_zoom_level = GetZoomLevel();
+
+  switch (new_mode) {
+    case ZOOM_MODE_DEFAULT: {
+      content::NavigationEntry* entry =
+          web_contents()->GetController().GetLastCommittedEntry();
+      GURL url;
+      if (entry)
+        url = entry->GetURL();
+      std::string host = net::GetHostOrSpecFromURL(url);
+
+      if (zoom_map->HasZoomLevel(url.scheme(), host)) {
+        // If there are other tabs with the same origin, then set this tab's
+        // zoom level to match theirs. The temporary zoom level will be cleared
+        // below, but this call will make sure this tab re-draws at the correct
+        // zoom level.
+        double origin_zoom_level =
+            zoom_map->GetZoomLevelForHostAndScheme(url.scheme(), host);
+        zoom_map->SetTemporaryZoomLevel(
+            render_process_id, render_view_id, origin_zoom_level);
+      } else {
+        // The host will need a level prior to removing the temporary level.
+        // We don't want the zoom level to change just because we entered
+        // default mode.
+        zoom_map->SetZoomLevelForHost(host, original_zoom_level);
+      }
+      // Remove per-tab zoom data for this tab.
+      zoom_map->ClearTemporaryZoomLevel(render_process_id, render_view_id);

[Dan Beam, 2014/06/26 03:40:02]

i'm confused, why are you settings the temporary zoom then clearing it right
after?

[wjmaclean, 2014/06/26 15:30:30]

The call to SetTemporaryZoomLevel is required to force the render view to
actually re-paint at the zoom level specified for the content's origin, prior to
clearing the temporary level.

+      break;
+    }
+    case ZOOM_MODE_ISOLATED: {
+      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
+      // page needs an initial isolated zoom back to the same level it was at
+      // in the other mode.

[Dan Beam, 2014/06/26 03:40:02]

can you give an example of when this ^ would happen?

[wjmaclean, 2014/06/26 15:30:30]

This will happen when going from default mode to isolated? In the transition
Disabled->Isolated, we know the page is already at the default zoom level.

[Dan Beam, 2014/06/26 22:16:37]

I mean, what can a user do to trigger this?  Put it in a comment.

+      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
+        zoom_map->SetTemporaryZoomLevel(
+            render_process_id, render_view_id, original_zoom_level);
+      }
+      break;
+    }
+    case ZOOM_MODE_MANUAL: {
+      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
+      // page needs to be resized to the default zoom before calling
+      // SetZoomLevel() so that the page can be resized manually to the same
+      // zoom as before.

[Dan Beam, 2014/06/26 03:40:02]

i'm confused, is there any other way you can put this?

[wjmaclean, 2014/06/26 15:30:30]

Done.

+      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
+        zoom_map->SetTemporaryZoomLevel(render_process_id, render_view_id, 0);
+        zoom_level_ = original_zoom_level;
+      }
+      break;
+    }
+    case ZOOM_MODE_DISABLED: {
+      // The page needs to be zoomed back to default before disabling the zoom
+      zoom_map->SetTemporaryZoomLevel(render_process_id, render_view_id, 0);
+      break;
+    }
+  }
+
+  zoom_mode_ = new_mode;
 }
 
 void ZoomController::DidNavigateMainFrame(
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
   // If the main frame's content has changed, the new page may have a different
   // zoom level from the old one.
   UpdateState(std::string());
 }
 
 void ZoomController::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
-  UpdateState(change.host);
+  UpdateStateIncludingTemporary(
+      change.host,
+      change.mode == content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM);
 }
 
 void ZoomController::UpdateState(const std::string& host) {
+  UpdateStateIncludingTemporary(host, false);
+}
+
+void ZoomController::UpdateStateIncludingTemporary(const std::string& host,
+                                                   bool is_temporary_zoom) {
   // If |host| is empty, all observers should be updated.
   if (!host.empty()) {
     // Use the navigation entry's URL instead of the WebContents' so virtual
     // URLs work (e.g. chrome://settings). http://crbug.com/153950
     content::NavigationEntry* entry =
         web_contents()->GetController().GetLastCommittedEntry();
     if (!entry ||
         host != net::GetHostOrSpecFromURL(entry->GetURL())) {
       return;
     }
   }
 
-  bool dummy;
-  zoom_percent_ = web_contents()->GetZoomPercent(&dummy, &dummy);
-
-  if (observer_)
-    observer_->OnZoomChanged(web_contents(), !host.empty());
+  // The zoom bubble can be shown for all normal, per-origin zoom changes
+  // (where the host will not be empty and the zoom is not temporary), or any
+  // special zoom changes (where the zoom mode will not be "default").
+  bool can_show_bubble =
+      zoom_mode_ != ZOOM_MODE_DEFAULT || (!host.empty() && !is_temporary_zoom);
+  FOR_EACH_OBSERVER(ZoomObserver,
+                    observers_,
+                    OnZoomChanged(web_contents(), can_show_bubble));
 }