| // 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_CONTENT_ANALYSIS_H_ |
| #define CHROME_BROWSER_THUMBNAILS_CONTENT_ANALYSIS_H_ |
| |
| #include <vector> |
| |
| #include "base/basictypes.h" |
| #include "third_party/skia/include/core/SkColor.h" |
| #include "ui/gfx/rect.h" |
| #include "ui/gfx/size.h" |
| |
| class SkBitmap; |
| |
| namespace thumbnailing_utils { |
| |
| // Compute in-place gaussian gradient magnitude of |input_bitmap| with sigma |
| // |kernel_sigma|. |input_bitmap| is requried to be of SkBitmap::kA8_Config |
| // type. The routine computes first-order gaussian derivative on a |
| // gaussian-smoothed image. Beware, this is fairly slow since kernel size is |
| // 4 * kernel_sigma + 1. |
| void ApplyGaussianGradientMagnitudeFilter(SkBitmap* input_bitmap, |
| float kernel_sigma); |
| |
| // Accumulates vertical and horizontal sum of pixel values from a subsection of |
| // |input_bitmap| defined by |image_area|. The image is required to be of |
| // SkBitmap::kA8_Config type. |
| // If non-empty |target_size| is given, the routine will use it to process the |
| // profiles with closing operator sized to eliminate gaps which would be smaller |
| // than 1 pixel after rescaling to |target_size|. |
| // If |apply_log| is true, logarithm of counts are used for morhology (and |
| // returned). |
| void ExtractImageProfileInformation(const SkBitmap& input_bitmap, |
| const gfx::Rect& image_area, |
| const gfx::Size& target_size, |
| bool apply_log, |
| std::vector<float>* rows, |
| std::vector<float>* columns); |
| |
| // Compute a threshold value separating background (low) from signal (high) |
| // areas in the |input| profile. |
| float AutoSegmentPeaks(const std::vector<float>& input); |
| |
| // Compute and return a workable (not too distorted, not bigger than the image) |
| // target size for retargeting in ConstrainedProfileSegmentation. |target_size| |
| // is the desired image size (defines aspect ratio and minimal image size) while |
| // |computed_size| is the size of a result of unconstrained segmentation. |
| // This routine makes very little sense outside ConstrainedProfileSegmentation |
| // and is exposed only for unit tests (it is somehow complicated). |
| gfx::Size AdjustClippingSizeToAspectRatio(const gfx::Size& target_size, |
| const gfx::Size& image_size, |
| const gfx::Size& computed_size); |
| |
| // Compute thresholding guides |included_rows| and |included_columns| by |
| // segmenting 1-d profiles |row_profile| and |column_profile|. The routine will |
| // attempt to keep the image which would result from using these guides as close |
| // to the desired aspect ratio (given by |target_size|) as reasonable. |
| void ConstrainedProfileSegmentation(const std::vector<float>& row_profile, |
| const std::vector<float>& column_profile, |
| const gfx::Size& target_size, |
| std::vector<bool>* included_rows, |
| std::vector<bool>* included_columns); |
| |
| // Shrinks the source |bitmap| by removing rows and columns where |rows| and |
| // |columns| are false, respectively. The function returns a new bitmap if the |
| // shrinking can be performed and an empty instance otherwise. |
| SkBitmap ComputeDecimatedImage(const SkBitmap& bitmap, |
| const std::vector<bool>& rows, |
| const std::vector<bool>& columns); |
| |
| // Creates a new bitmap which contains only 'interesting' areas of |
| // |source_bitmap|. The |target_size| is used to estimate some computation |
| // parameters, but the resulting bitmap will not necessarily be of that size. |
| // |kernel_sigma| defines the degree of image smoothing in gradient computation. |
| // For a natural-sized (not shrunk) screenshot at 96 DPI and regular font size |
| // 5.0 was determined to be a good value. |
| SkBitmap CreateRetargetedThumbnailImage(const SkBitmap& source_bitmap, |
| const gfx::Size& target_size, |
| float kernel_sigma); |
| |
| } // namespace thumbnailing_utils |
| |
| #endif // CHROME_BROWSER_THUMBNAILS_CONTENT_ANALYSIS_H_ |