1// Copyright (c) 2013 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. 4 5#ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_SCREENSHOT_MANAGER_H_ 6#define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_SCREENSHOT_MANAGER_H_ 7 8#include "base/compiler_specific.h" 9#include "base/memory/weak_ptr.h" 10#include "base/time/time.h" 11#include "content/common/content_export.h" 12 13class SkBitmap; 14 15namespace content { 16 17class NavigationControllerImpl; 18class NavigationEntryImpl; 19class RenderViewHost; 20class ScreenshotData; 21 22// WebContentsScreenshotManager takes care of taking image-captures for the 23// current navigation entry of a NavigationControllerImpl, and managing these 24// captured images. These image-captures are used for history navigation using 25// overscroll gestures. 26class CONTENT_EXPORT WebContentsScreenshotManager { 27 public: 28 explicit WebContentsScreenshotManager(NavigationControllerImpl* controller); 29 virtual ~WebContentsScreenshotManager(); 30 31 // Takes a screenshot of the last-committed entry of the controller. 32 void TakeScreenshot(); 33 34 // Clears screenshots of all navigation entries. 35 void ClearAllScreenshots(); 36 37 protected: 38 virtual void TakeScreenshotImpl(RenderViewHost* host, 39 NavigationEntryImpl* entry); 40 41 // Called after a screenshot has been set on an NavigationEntryImpl. 42 // Overridden in tests to get notified of when a screenshot is set. 43 virtual void OnScreenshotSet(NavigationEntryImpl* entry); 44 45 NavigationControllerImpl* owner() { return owner_; } 46 47 void SetMinScreenshotIntervalMS(int interval_ms); 48 49 // The callback invoked when taking the screenshot of the page is complete. 50 // This sets the screenshot on the navigation entry. 51 void OnScreenshotTaken(int unique_id, 52 bool success, 53 const SkBitmap& bitmap); 54 55 // Returns the number of entries with screenshots. 56 int GetScreenshotCount() const; 57 58 private: 59 // This is called when the screenshot data has beene encoded to PNG in a 60 // worker thread. 61 void OnScreenshotEncodeComplete(int unique_id, 62 scoped_refptr<ScreenshotData> data); 63 64 // Removes the screenshot for the entry, returning true if the entry had a 65 // screenshot. 66 bool ClearScreenshot(NavigationEntryImpl* entry); 67 68 // The screenshots in the NavigationEntryImpls can accumulate and consume a 69 // large amount of memory. This function makes sure that the memory 70 // consumption is within a certain limit. 71 void PurgeScreenshotsIfNecessary(); 72 73 // The navigation controller that owns this screenshot-manager. 74 NavigationControllerImpl* owner_; 75 76 // Taking a screenshot and encoding them can be async. So use a weakptr for 77 // the callback to make sure that the screenshot/encoding completion callback 78 // does not trigger on a destroyed WebContentsScreenshotManager. 79 base::WeakPtrFactory<WebContentsScreenshotManager> screenshot_factory_; 80 81 base::Time last_screenshot_time_; 82 int min_screenshot_interval_ms_; 83 84 DISALLOW_COPY_AND_ASSIGN(WebContentsScreenshotManager); 85}; 86 87} // namespace content 88 89#endif // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_SCREENSHOT_MANAGER_H_ 90