| // Copyright (c) 2013 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. |
| |
| #ifndef CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_ |
| #define CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_ |
| |
| #include "base/memory/ref_counted.h" |
| #include "chrome/browser/thumbnails/thumbnailing_context.h" |
| #include "ui/base/layout.h" |
| #include "ui/gfx/rect.h" |
| #include "ui/gfx/size.h" |
| |
| class SkBitmap; |
| |
| namespace thumbnails { |
| |
| // An interface abstracting thumbnailing algorithms. Instances are intended to |
| // be created by ThumbnailService's implementations and used by |
| // ThumbnailTabHelper as consumers of captured source images. |
| class ThumbnailingAlgorithm |
| : public base::RefCountedThreadSafe<ThumbnailingAlgorithm> { |
| public: |
| typedef base::Callback<void(const ThumbnailingContext&, const SkBitmap&)> |
| ConsumerCallback; |
| // Provides information necessary to crop-and-resize image data from a source |
| // canvas of |source_size|. Auxiliary |scale_factor| helps compute the target |
| // thumbnail size. Parameters of the required copy operation are assigned to |
| // |clipping_rect| (cropping rectangle for the source canvas) and |
| // |target_size| (the size of the target bitmap). |
| // The return value indicates the type of clipping that will be done. |
| virtual ClipResult GetCanvasCopyInfo(const gfx::Size& source_size, |
| ui::ScaleFactor scale_factor, |
| gfx::Rect* clipping_rect, |
| gfx::Size* target_size) const = 0; |
| |
| // Invoked to produce a thumbnail image from a |bitmap| extracted by the |
| // callee from source canvas according to instructions provided by a call |
| // to GetCanvasCopyInfo. |
| // Note that ProcessBitmap must be able to handle bitmaps which might have not |
| // been processed (scalled/cropped) as requested. |context| gives additional |
| // information on the source, including if and how it was clipped. |
| // The function shall invoke |callback| once done, passing in fully populated |
| // |context| along with resulting thumbnail bitmap. |
| virtual void ProcessBitmap(scoped_refptr<ThumbnailingContext> context, |
| const ConsumerCallback& callback, |
| const SkBitmap& bitmap) = 0; |
| |
| protected: |
| virtual ~ThumbnailingAlgorithm() {} |
| friend class base::RefCountedThreadSafe<ThumbnailingAlgorithm>; |
| }; |
| |
| } |
| |
| #endif // CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_ |