components/zoom/zoom_controller.h - chromium/src - Git at Google

 // Copyright 2012 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_
 #define COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_

 #include <memory>
 #include <optional>

 #include "base/compiler_specific.h"
 #include "base/memory/raw_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "components/prefs/pref_member.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"

 class ZoomControllerTest;

 namespace content {
 class WebContents;
 }

 namespace zoom {
 class ZoomObserver;

 class ZoomRequestClient : public base::RefCounted<ZoomRequestClient> {
  public:
   ZoomRequestClient() {}

   ZoomRequestClient(const ZoomRequestClient&) = delete;
   ZoomRequestClient& operator=(const ZoomRequestClient&) = delete;

   virtual bool ShouldSuppressBubble() const = 0;

  protected:
   virtual ~ZoomRequestClient() {}

  private:
   friend class base::RefCounted<ZoomRequestClient>;
 };

 // Per-tab class to manage zoom changes and the Omnibox zoom icon. Lives on the
 // UI thread.
 class ZoomController : public content::WebContentsObserver,
                        public content::WebContentsUserData<ZoomController> {
  public:
   // Defines how zoom changes are handled.
   enum ZoomMode {
     // Results in default zoom behavior, i.e. zoom changes are handled
     // automatically and on a per-origin basis, meaning that other tabs
     // navigated to the same origin will also zoom.
     ZOOM_MODE_DEFAULT,
     // Results in zoom changes being handled automatically, but on a per-tab
     // basis. Tabs in this zoom mode will not be affected by zoom changes in
     // other tabs, and vice versa.
     ZOOM_MODE_ISOLATED,
     // Overrides the automatic handling of zoom changes. The |onZoomChange|
     // event will still be dispatched, but the page will not actually be zoomed.
     // These zoom changes can be handled manually by listening for the
     // |onZoomChange| event. Zooming in this mode is also on a per-tab basis.
     ZOOM_MODE_MANUAL,
     // Disables all zooming in this tab. The tab will revert to the default
     // zoom level, and all attempted zoom changes will be ignored.
     ZOOM_MODE_DISABLED,
   };

   enum RelativeZoom {
     ZOOM_BELOW_DEFAULT_ZOOM,
     ZOOM_AT_DEFAULT_ZOOM,
     ZOOM_ABOVE_DEFAULT_ZOOM
   };

   struct ZoomChangedEventData {
     ZoomChangedEventData(content::WebContents* web_contents,
                          double old_zoom_level,
                          double new_zoom_level,
                          ZoomController::ZoomMode zoom_mode,
                          bool can_show_bubble)
         : web_contents(web_contents),
           old_zoom_level(old_zoom_level),
           new_zoom_level(new_zoom_level),
           zoom_mode(zoom_mode),
           can_show_bubble(can_show_bubble) {}
     raw_ptr<content::WebContents> web_contents;
     double old_zoom_level;
     double new_zoom_level;
     ZoomController::ZoomMode zoom_mode;
     bool can_show_bubble;
   };

   // Since it's possible for a WebContents to not have a ZoomController, provide
   // a simple, safe and reliable method to find the current zoom level for a
   // given WebContents*.
   static double GetZoomLevelForWebContents(content::WebContents* web_contents);

   ZoomController(const ZoomController&) = delete;
   ZoomController& operator=(const ZoomController&) = delete;

   ~ZoomController() override;

   ZoomMode zoom_mode() const { return zoom_mode_; }

   // Convenience method to get default zoom level. Implemented here for
   // inlining.
   double GetDefaultZoomLevel() const {
     return content::HostZoomMap::GetForWebContents(web_contents())
         ->GetDefaultZoomLevel();
   }

   // Convenience method to quickly check if the tab's at default zoom.
   // Virtual for testing.
   virtual bool IsAtDefaultZoom() const;

   // Returns which image should be loaded for the current zoom level.
   RelativeZoom GetZoomRelativeToDefault() const;

   const ZoomRequestClient* last_client() const { return last_client_.get(); }

   void AddObserver(ZoomObserver* observer);
   void RemoveObserver(ZoomObserver* observer);

   // Used to set whether the zoom notification bubble can be shown when the
   // zoom level is changed for this controller. Default behavior is to show
   // the bubble.
   void SetShowsNotificationBubble(bool can_show_bubble) {
     can_show_bubble_ = can_show_bubble;
   }

   // Gets the current zoom level by querying HostZoomMap (if not in manual zoom
   // mode) or from the ZoomController local value otherwise.
   double GetZoomLevel() const;
   // Calls GetZoomLevel() then converts the returned value to a percentage
   // zoom factor.
   // Virtual for testing.
   virtual int GetZoomPercent() const;

   // Sets the zoom level through HostZoomMap.
   // Returns true on success.
   bool SetZoomLevel(double zoom_level);

   // Sets the zoom level via HostZoomMap (or stores it locally if in manual zoom
   // mode), and attributes the zoom to |client|. Returns true on success.
   bool SetZoomLevelByClient(
       double zoom_level,
       const scoped_refptr<const ZoomRequestClient>& client);

   // Sets the zoom mode, which defines zoom behavior (see enum ZoomMode).
   void SetZoomMode(ZoomMode zoom_mode);

   // Set and query whether or not the page scale factor is one.
   void SetPageScaleFactorIsOneForTesting(bool is_one);
   bool PageScaleFactorIsOne() const;

   // content::WebContentsObserver overrides:
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
   void WebContentsDestroyed() override;
   void RenderFrameHostChanged(content::RenderFrameHost* old_host,
                               content::RenderFrameHost* new_host) override;
   void OnPageScaleFactorChanged(float page_scale_factor) override;

  protected:
   // Protected for testing.
   explicit ZoomController(content::WebContents* web_contents);

  private:
   friend class content::WebContentsUserData<ZoomController>;
   friend class ::ZoomControllerTest;

   void ResetZoomModeOnNavigationIfNeeded(const GURL& url);
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);

   // Updates the zoom icon and zoom percentage based on current values and
   // notifies the observer if changes have occurred. |host| may be empty,
   // meaning the change should apply to ~all sites. If it is not empty, the
   // change only affects sites with the given host.
   void UpdateState(const std::string& host);

   // True if changes to zoom level can trigger the zoom notification bubble.
   bool can_show_bubble_ = true;

   // The current zoom mode.
   ZoomMode zoom_mode_ = ZOOM_MODE_DEFAULT;

   // Current zoom level.
   double zoom_level_;

   std::unique_ptr<ZoomChangedEventData> event_data_;

   // Keeps track of the extension (if any) that initiated the last zoom change
   // that took effect.
   scoped_refptr<const ZoomRequestClient> last_client_;

   // Observer receiving notifications on state changes.
   base::ObserverList<ZoomObserver> observers_;

   raw_ptr<content::BrowserContext> browser_context_;
   // Keep track of the HostZoomMap we're currently subscribed to.
   raw_ptr<content::HostZoomMap> host_zoom_map_;

   base::CallbackListSubscription zoom_subscription_;

   // Whether the page scale factor was one the last time we notified our
   // observers of a change to PageScaleFactorIsOne.
   bool last_page_scale_factor_was_one_ = true;

   // If set, this value is returned in PageScaleFactorIsOne.
   std::optional<bool> page_scale_factor_is_one_for_testing_;

   WEB_CONTENTS_USER_DATA_KEY_DECL();
 };

 }  // namespace zoom

 #endif  // COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_
	// Copyright 2012 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_
	#define COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_

	#include <memory>
	#include <optional>

	#include "base/compiler_specific.h"
	#include "base/memory/raw_ptr.h"
	#include "base/memory/ref_counted.h"
	#include "base/observer_list.h"
	#include "components/prefs/pref_member.h"
	#include "content/public/browser/host_zoom_map.h"
	#include "content/public/browser/web_contents_observer.h"
	#include "content/public/browser/web_contents_user_data.h"

	class ZoomControllerTest;

	namespace content {
	class WebContents;
	}

	namespace zoom {
	class ZoomObserver;

	class ZoomRequestClient : public base::RefCounted<ZoomRequestClient> {
	public:
	ZoomRequestClient() {}

	ZoomRequestClient(const ZoomRequestClient&) = delete;
	ZoomRequestClient& operator=(const ZoomRequestClient&) = delete;

	virtual bool ShouldSuppressBubble() const = 0;

	protected:
	virtual ~ZoomRequestClient() {}

	private:
	friend class base::RefCounted<ZoomRequestClient>;
	};

	// Per-tab class to manage zoom changes and the Omnibox zoom icon. Lives on the
	// UI thread.
	class ZoomController : public content::WebContentsObserver,
	public content::WebContentsUserData<ZoomController> {
	public:
	// Defines how zoom changes are handled.
	enum ZoomMode {
	// Results in default zoom behavior, i.e. zoom changes are handled
	// automatically and on a per-origin basis, meaning that other tabs
	// navigated to the same origin will also zoom.
	ZOOM_MODE_DEFAULT,
	// Results in zoom changes being handled automatically, but on a per-tab
	// basis. Tabs in this zoom mode will not be affected by zoom changes in
	// other tabs, and vice versa.
	ZOOM_MODE_ISOLATED,
	// Overrides the automatic handling of zoom changes. The \|onZoomChange\|
	// event will still be dispatched, but the page will not actually be zoomed.
	// These zoom changes can be handled manually by listening for the
	// \|onZoomChange\| event. Zooming in this mode is also on a per-tab basis.
	ZOOM_MODE_MANUAL,
	// Disables all zooming in this tab. The tab will revert to the default
	// zoom level, and all attempted zoom changes will be ignored.
	ZOOM_MODE_DISABLED,
	};

	enum RelativeZoom {
	ZOOM_BELOW_DEFAULT_ZOOM,
	ZOOM_AT_DEFAULT_ZOOM,
	ZOOM_ABOVE_DEFAULT_ZOOM
	};

	struct ZoomChangedEventData {
	ZoomChangedEventData(content::WebContents* web_contents,
	double old_zoom_level,
	double new_zoom_level,
	ZoomController::ZoomMode zoom_mode,
	bool can_show_bubble)
	: web_contents(web_contents),
	old_zoom_level(old_zoom_level),
	new_zoom_level(new_zoom_level),
	zoom_mode(zoom_mode),
	can_show_bubble(can_show_bubble) {}
	raw_ptr<content::WebContents> web_contents;
	double old_zoom_level;
	double new_zoom_level;
	ZoomController::ZoomMode zoom_mode;
	bool can_show_bubble;
	};

	// Since it's possible for a WebContents to not have a ZoomController, provide
	// a simple, safe and reliable method to find the current zoom level for a
	// given WebContents*.
	static double GetZoomLevelForWebContents(content::WebContents* web_contents);

	ZoomController(const ZoomController&) = delete;
	ZoomController& operator=(const ZoomController&) = delete;

	~ZoomController() override;

	ZoomMode zoom_mode() const { return zoom_mode_; }

	// Convenience method to get default zoom level. Implemented here for
	// inlining.
	double GetDefaultZoomLevel() const {
	return content::HostZoomMap::GetForWebContents(web_contents())
	->GetDefaultZoomLevel();
	}

	// Convenience method to quickly check if the tab's at default zoom.
	// Virtual for testing.
	virtual bool IsAtDefaultZoom() const;

	// Returns which image should be loaded for the current zoom level.
	RelativeZoom GetZoomRelativeToDefault() const;

	const ZoomRequestClient* last_client() const { return last_client_.get(); }

	void AddObserver(ZoomObserver* observer);
	void RemoveObserver(ZoomObserver* observer);

	// Used to set whether the zoom notification bubble can be shown when the
	// zoom level is changed for this controller. Default behavior is to show
	// the bubble.
	void SetShowsNotificationBubble(bool can_show_bubble) {
	can_show_bubble_ = can_show_bubble;
	}

	// Gets the current zoom level by querying HostZoomMap (if not in manual zoom
	// mode) or from the ZoomController local value otherwise.
	double GetZoomLevel() const;
	// Calls GetZoomLevel() then converts the returned value to a percentage
	// zoom factor.
	// Virtual for testing.
	virtual int GetZoomPercent() const;

	// Sets the zoom level through HostZoomMap.
	// Returns true on success.
	bool SetZoomLevel(double zoom_level);

	// Sets the zoom level via HostZoomMap (or stores it locally if in manual zoom
	// mode), and attributes the zoom to \|client\|. Returns true on success.
	bool SetZoomLevelByClient(
	double zoom_level,
	const scoped_refptr<const ZoomRequestClient>& client);

	// Sets the zoom mode, which defines zoom behavior (see enum ZoomMode).
	void SetZoomMode(ZoomMode zoom_mode);

	// Set and query whether or not the page scale factor is one.
	void SetPageScaleFactorIsOneForTesting(bool is_one);
	bool PageScaleFactorIsOne() const;

	// content::WebContentsObserver overrides:
	void DidFinishNavigation(
	content::NavigationHandle* navigation_handle) override;
	void WebContentsDestroyed() override;
	void RenderFrameHostChanged(content::RenderFrameHost* old_host,
	content::RenderFrameHost* new_host) override;
	void OnPageScaleFactorChanged(float page_scale_factor) override;

	protected:
	// Protected for testing.
	explicit ZoomController(content::WebContents* web_contents);

	private:
	friend class content::WebContentsUserData<ZoomController>;
	friend class ::ZoomControllerTest;

	void ResetZoomModeOnNavigationIfNeeded(const GURL& url);
	void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);

	// Updates the zoom icon and zoom percentage based on current values and
	// notifies the observer if changes have occurred. \|host\| may be empty,
	// meaning the change should apply to ~all sites. If it is not empty, the
	// change only affects sites with the given host.
	void UpdateState(const std::string& host);

	// True if changes to zoom level can trigger the zoom notification bubble.
	bool can_show_bubble_ = true;

	// The current zoom mode.
	ZoomMode zoom_mode_ = ZOOM_MODE_DEFAULT;

	// Current zoom level.
	double zoom_level_;

	std::unique_ptr<ZoomChangedEventData> event_data_;

	// Keeps track of the extension (if any) that initiated the last zoom change
	// that took effect.
	scoped_refptr<const ZoomRequestClient> last_client_;

	// Observer receiving notifications on state changes.
	base::ObserverList<ZoomObserver> observers_;

	raw_ptr<content::BrowserContext> browser_context_;
	// Keep track of the HostZoomMap we're currently subscribed to.
	raw_ptr<content::HostZoomMap> host_zoom_map_;

	base::CallbackListSubscription zoom_subscription_;

	// Whether the page scale factor was one the last time we notified our
	// observers of a change to PageScaleFactorIsOne.
	bool last_page_scale_factor_was_one_ = true;

	// If set, this value is returned in PageScaleFactorIsOne.
	std::optional<bool> page_scale_factor_is_one_for_testing_;

	WEB_CONTENTS_USER_DATA_KEY_DECL();
	};

	} // namespace zoom

	#endif // COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_