common/rfb/UpdateTracker.h

/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
 * 
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this software; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 * USA.
 */

#ifndef __RFB_UPDATETRACKER_INCLUDED__
#define __RFB_UPDATETRACKER_INCLUDED__

#include <rfb/Rect.h>
#include <rfb/Region.h>
#include <rfb/PixelBuffer.h>

namespace rfb {

  class UpdateInfo {
  public:
    Region changed;
    Region copied;
    Point copy_delta;
    Rect video_area;
    bool is_empty() const {
      return copied.is_empty() && changed.is_empty() && video_area.is_empty();
    }
    // NOTE: We do not ever use UpdateInfo::numRects(), because Tight encoding
    //       complicates computing the number of rectangles.
    /*
    int numRects() const {
      return copied.numRects() + changed.numRects() + !video_area.is_empty();
    }
    */
  };

  class UpdateTracker {
  public:
    UpdateTracker() {};
    virtual ~UpdateTracker() {};

    virtual void add_changed(const Region &region) = 0;
    virtual void add_copied(const Region &dest, const Point &delta) = 0;
    virtual void set_video_area(const Rect &rect) = 0;
  };

  class ClippingUpdateTracker : public UpdateTracker {
  public:
    ClippingUpdateTracker() : ut(0) {}
    ClippingUpdateTracker(UpdateTracker* ut_, const Rect& r=Rect()) : ut(ut_), clipRect(r) {}
    
    void setUpdateTracker(UpdateTracker* ut_) {ut = ut_;}
    void setClipRect(const Rect& cr) {clipRect = cr;}

    virtual void add_changed(const Region &region);
    virtual void add_copied(const Region &dest, const Point &delta);
    virtual void set_video_area(const Rect &rect);
  protected:
    UpdateTracker* ut;
    Rect clipRect;
  };

  class SimpleUpdateTracker : public UpdateTracker {
  public:
    SimpleUpdateTracker(bool use_copyrect=true);
    virtual ~SimpleUpdateTracker();

    virtual void enable_copyrect(bool enable);

    virtual void add_changed(const Region &region);
    virtual void add_copied(const Region &dest, const Point &delta);
    virtual void set_video_area(const Rect &rect);
    virtual void subtract(const Region& region);

    // Fill the supplied UpdateInfo structure with update information
    // FIXME: Provide getUpdateInfo() with no clipping, for better efficiency.
    virtual void getUpdateInfo(UpdateInfo* info, const Region& cliprgn);

    // Get coordinates of the video rectangle
    virtual const Rect& getVideoArea() const {
      return video_area;
    }

    // Copy the contained updates to another tracker
    virtual void copyTo(UpdateTracker* to) const;

    // Move the entire update region by an offset
    void translate(const Point& p) {
      changed.translate(p);
      copied.translate(p);
      video_area.translate(p);
    }

    virtual bool is_empty() const {
      return changed.is_empty() && copied.is_empty() && video_area.is_empty();
    }

    // NOTE: We do not clear video_area intentionally.
    virtual void clear() {
      changed.clear();
      copied.clear();
    }

  protected:
    Region changed;
    Region copied;
    Point copy_delta;
    bool copy_enabled;

    // We can track one rectangle on the screen as a "video area". We assume
    // it is changing continuously, in whole. Thus, we don't need to detect
    // and track individual changes in the video area -- we can assume it's
    // always in the changed state.
    Rect video_area;
  };

}

#endif // __RFB_UPDATETRACKER_INCLUDED__