Copy the (early prototype of) remoting in Chrome into the public tree....

remoting/host/capturer.h

+// Copyright (c) 2010 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_CAPTURER_H_
+#define REMOTING_HOST_CAPTURER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/task.h"
+#include "gfx/rect.h"
+#include "remoting/base/protocol/chromotocol.pb.h"
+
+namespace remoting {
+
+typedef std::vector<gfx::Rect> DirtyRects;
+
+// A class to perform the task of capturing the image of a window.
+// The capture action is asynchronous to allow maximum throughput.
+//
+// Implementation has to ensure the following gurantees:
+// 1. Double buffering
+//    Since data can be read while another capture action is
+//    happening.
+class Capturer {
+ public:
+  Capturer();
+  virtual ~Capturer();
+
+  // Capture the full screen. When the action is completed |done_task|
+  // is called.
+  //
+  // It is OK to call this methods while another thread is reading
+  // data of the last capture.
+  // There can be at most one concurrent read going on when this
+  // methods is called.
+  virtual void CaptureFullScreen(Task* done_task) = 0;
+
+  // Capture the updated regions since last capture. If the last
+  // capture doesn't exist, the full window is captured.
+  //
+  // When complete |done_task| is called.
+  //
+  // It is OK to call this method while another thread is reading
+  // data of the last capture.
+  // There can be at most one concurrent read going on when this
+  // methods is called.
+  virtual void CaptureDirtyRects(Task* done_task) = 0;
+
+  // Capture the specified screen rect and call |done_task| when complete.
+  // Dirty or invalid regions are ignored and only the given |rect| area is
+  // captured.
+  //
+  // It is OK to call this method while another thread is reading
+  // data of the last capture.
+  // There can be at most one concurrent read going on when this
+  // methods is called.
+  virtual void CaptureRect(const gfx::Rect& rect, Task* done_task) = 0;
+
+  // Get the image data of the last capture. The pointers to data is
+  // written to |planes|. |planes| should be an array of 3 elements.
+  virtual void GetData(const uint8* planes[]) const = 0;
+
+  // Get the image data stride of the last capture. This size of strides
+  // is written to |strides|. |strides| should be array of 3 elements.
+  virtual void GetDataStride(int strides[]) const = 0;
+
+  // Get the list of updated rectangles in the last capture. The result is
+  // written into |rects|.
+  virtual void GetDirtyRects(DirtyRects* rects) const;
+
+  // Get the width of the image captured.
+  virtual int GetWidth() const;
+
+  // Get the height of the image captured.
+  virtual int GetHeight() const;
+
+  // Get the pixel format of the image captured.
+  virtual chromotocol_pb::PixelFormat GetPixelFormat() const;
+
+  // Invalidate the specified screen rect.
+  virtual void InvalidateRect(gfx::Rect dirty);
+
+ protected:
+  // Finish/cleanup capture task.
+  // This should be called at the end of each of the CaptureXxx() routines.
+  // This routine should (at least):
+  // (1) Call the |done_task| routine.
+  // (2) Select the next screen buffer.
+  //     Note that capturers are required to be double-buffered so that we can
+  //     read from one which capturing into another.
+  virtual void FinishCapture(Task* done_task);
+
+  // Number of screen buffers.
+  static const int kNumBuffers = 2;
+
+  // Capture screen dimensions.
+  int width_;
+  int height_;
+
+  // Format of pixels returned in buffer.
+  chromotocol_pb::PixelFormat pixel_format_;
+
+  // Information about screen.
+  int bytes_per_pixel_;
+  int bytes_per_row_;
+
+  // The current buffer with valid data for reading.
+  int current_buffer_;
+
+  // List of dirty rects.
+  // These are the rects that we send to the client to update.
+  DirtyRects dirty_rects_;
+
+  // Rects that have been manually invalidated (through InvalidateRect).
+  // These will be merged into |dirty_rects_| during the next capture.
+  DirtyRects inval_rects_;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_CAPTURER_H_