Add chrome to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 92 insertions, 0 deletions

diff --git a/chrome/common/thumbnail_score.h b/chrome/common/thumbnail_score.h
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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CHROME_BROWSER_COMMON_THUMBNAIL_SCORE_H__
+#define CHROME_BROWSER_COMMON_THUMBNAIL_SCORE_H__
+
+#include "base/time.h"
+
+// A set of metadata about a Thumbnail.
+struct ThumbnailScore {
+  // Initializes the ThumbnailScore to the absolute worst possible
+  // values except for time, which is set to Now().
+  ThumbnailScore();
+
+  // Builds a ThumbnailScore with the passed in values, and sets the
+  // thumbnail generation time to Now().
+  ThumbnailScore(double score, bool clipping, bool top);
+
+  // Builds a ThumbnailScore with the passed in values.
+  ThumbnailScore(double score, bool clipping, bool top,
+                 const Time& time);
+  ~ThumbnailScore();
+
+  // Tests for equivalence between two ThumbnailScore objects.
+  bool Equals(const ThumbnailScore& rhs) const;
+
+  // How "boring" a thumbnail is. The boring score is the 0,1 ranged
+  // percentage of pixels that are the most common luma. Higher boring
+  // scores indicate that a higher percentage of a bitmap are all the
+  // same brightness (most likely the same color).
+  double boring_score;
+
+  // Whether the thumbnail was taken with height greater then
+  // width. In cases where we don't have |good_clipping|, the
+  // thumbnails are either clipped from the horizontal center of the
+  // window, or are otherwise weirdly stretched.
+  bool good_clipping;
+
+  // Whether this thumbnail was taken while the renderer was
+  // displaying the top of the page. Most pages are more recognizable
+  // by their headers then by a set of random text half way down the
+  // page; i.e. most MediaWiki sites would be indistinguishable by
+  // thumbnails with |at_top| set to false.
+  bool at_top;
+
+  // Record the time when a thumbnail was taken. This is used to make
+  // sure thumbnails are kept fresh.
+  Time time_at_snapshot;
+
+  // How bad a thumbnail needs to be before we completely ignore it.
+  static const double kThumbnailMaximumBoringness;
+
+  // Time before we take a worse thumbnail (subject to
+  // kThumbnailMaximumBoringness) over what's currently in the database
+  // for freshness.
+  static const TimeDelta kUpdateThumbnailTime;
+
+  // Penalty of how much more boring a thumbnail should be per hour.
+  static const double kThumbnailDegradePerHour;
+};
+
+// Checks whether we should replace one thumbnail with another.
+bool ShouldReplaceThumbnailWith(const ThumbnailScore& current,
+                                const ThumbnailScore& replacement);
+
+#endif  // CHROME_BROWSER_COMMON_THUMBNAIL_SCORE_H__