Implement all resolution change policies for desktop and tab capture.

media/base/video_util.h

 // Copyright (c) 2012 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 MEDIA_BASE_VIDEO_UTIL_H_
 #define MEDIA_BASE_VIDEO_UTIL_H_
 
 #include "base/basictypes.h"
 #include "media/base/media_export.h"
 #include "ui/gfx/geometry/rect.h"
@@ skipping 66 matching lines @@
     int rotation,  // Clockwise.
     bool flip_vert,
     bool flip_horiz);
 
 // Return the largest centered rectangle with the same aspect ratio of |content|
 // that fits entirely inside of |bounds|.  If |content| is empty, its aspect
 // ratio would be undefined; and in this case an empty Rect would be returned.
 MEDIA_EXPORT gfx::Rect ComputeLetterboxRegion(const gfx::Rect& bounds,
                                               const gfx::Size& content);
 
+// Return a scaled |size| whose area is less than or equal to |target|, where
+// one of its dimensions is equal to |target|'s.  The aspect ratio of |size| is
+// preserved as closely as possible.  If |size| is empty, the result will be
+// empty.
+MEDIA_EXPORT gfx::Size ScaleSizeToFitWithinTarget(const gfx::Size& size,
+                                                  const gfx::Size& target);
+
+// Return a scaled |size| whose area is greater than or equal to |target|, where
+// one of its dimensions is equal to |target|'s.  The aspect ratio of |size| is
+// preserved as closely as possible.  If |size| is empty, the result will be
+// empty.
+MEDIA_EXPORT gfx::Size ScaleSizeToEncompassTarget(const gfx::Size& size,
+                                                  const gfx::Size& target);
+
+// Returns |size| with only one of its dimensions increased such that the result
+// matches the aspect ratio of |target|.  This is different from
+// ScaleSizeToEncompassTarget() in two ways: 1) The goal is to match the aspect
+// ratio of |target| rather than that of |size|.  2) Only one of the dimensions
+// of |size| may change, and it may only be increased (padded).  If either
+// |size| or |target| is empty, the result will be empty.
+MEDIA_EXPORT gfx::Size PadToMatchAspectRatio(const gfx::Size& size,
+                                             const gfx::Size& target);
+
 // Copy an RGB bitmap into the specified |region_in_frame| of a YUV video frame.
 // Fills the regions outside |region_in_frame| with black.
 MEDIA_EXPORT void CopyRGBToVideoFrame(const uint8* source,
                                       int stride,
                                       const gfx::Rect& region_in_frame,
                                       VideoFrame* frame);
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_UTIL_H_