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// Copyright (c) 2011 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 REMOTING_HOST_DIFFER_H_
#define REMOTING_HOST_DIFFER_H_
#include <vector>
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "third_party/skia/include/core/SkRegion.h"
namespace remoting {
typedef uint8 DiffInfo;
// TODO: Simplify differ now that we are working with SkRegions.
// diff_info_ should no longer be needed, as we can put our data directly into
// the region that we are calculating.
// http://crbug.com/92379
class Differ {
public:
// Create a differ that operates on bitmaps with the specified width, height
// and bytes_per_pixel.
Differ(int width, int height, int bytes_per_pixel, int stride);
~Differ();
int width() { return width_; }
int height() { return height_; }
int bytes_per_pixel() { return bytes_per_pixel_; }
int bytes_per_row() { return bytes_per_row_; }
// Given the previous and current screen buffer, calculate the dirty region
// that encloses all of the changed pixels in the new screen.
void CalcDirtyRegion(const void* prev_buffer, const void* curr_buffer,
SkRegion* region);
private:
// Allow tests to access our private parts.
friend class DifferTest;
// Identify all of the blocks that contain changed pixels.
void MarkDirtyBlocks(const void* prev_buffer, const void* curr_buffer);
// After the dirty blocks have been identified, this routine merges adjacent
// blocks into a region.
// The goal is to minimize the region that covers the dirty blocks.
void MergeBlocks(SkRegion* region);
// Check for diffs in upper-left portion of the block. The size of the portion
// to check is specified by the |width| and |height| values.
// Note that if we force the capturer to always return images whose width and
// height are multiples of kBlockSize, then this will never be called.
DiffInfo DiffPartialBlock(const uint8* prev_buffer, const uint8* curr_buffer,
int stride, int width, int height);
// Dimensions of screen.
int width_;
int height_;
// Number of bytes for each pixel in source and dest bitmap.
// (Yes, they must match.)
int bytes_per_pixel_;
// Number of bytes in each row of the image (AKA: stride).
int bytes_per_row_;
// Diff information for each block in the image.
scoped_array<DiffInfo> diff_info_;
// Dimensions and total size of diff info array.
int diff_info_width_;
int diff_info_height_;
int diff_info_size_;
DISALLOW_COPY_AND_ASSIGN(Differ);
};
} // namespace remoting
#endif // REMOTING_HOST_DIFFER_H_
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