/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file pgVirtualFrame.h
 * @author drose
 * @date 2005-08-17
 */

#ifndef PGVIRTUALFRAME_H
#define PGVIRTUALFRAME_H

#include "pandabase.h"

#include "pgItem.h"
#include "modelNode.h"

class TransformState;

/**
 * This represents a frame that is rendered as a window onto another (possibly
 * much larger) canvas.  You can only see the portion of the canvas that is
 * below the window at any given time.
 *
 * This works simply by automatically defining a scissor effect to be applied
 * to a special child node, called the canvas_node, of the PGVirtualFrame
 * node.  Every object that is parented to the canvas_node will be clipped by
 * the scissor effect.  Also, you can modify the canvas_transform through
 * convenience methods here, which actually modifies the transform on the
 * canvas_node.
 *
 * The net effect is that the virtual canvas is arbitrarily large, and we can
 * peek at it through the scissor region, and scroll through different parts
 * of it by modifying the canvas_transform.
 *
 * See PGScrollFrame for a specialization of this class that handles the
 * traditional scrolling canvas, with scroll bars.
 */
class EXPCL_PANDA_PGUI PGVirtualFrame : public PGItem {
PUBLISHED:
  explicit PGVirtualFrame(const std::string &name = "");
  virtual ~PGVirtualFrame();

protected:
  PGVirtualFrame(const PGVirtualFrame &copy);
  virtual PandaNode *make_copy() const;
  virtual void r_copy_children(const PandaNode *from, InstanceMap &inst_map,
                               Thread *current_thread);

PUBLISHED:
  void setup(PN_stdfloat width, PN_stdfloat height);

  INLINE void set_clip_frame(PN_stdfloat left, PN_stdfloat right, PN_stdfloat bottom, PN_stdfloat top);
  void set_clip_frame(const LVecBase4 &clip_frame);
  INLINE const LVecBase4 &get_clip_frame() const;
  INLINE bool has_clip_frame() const;
  void clear_clip_frame();

  INLINE void set_canvas_transform(const TransformState *transform);
  INLINE const TransformState *get_canvas_transform() const;

  INLINE PandaNode *get_canvas_node() const;
  INLINE PandaNode *get_canvas_parent() const;

protected:
  virtual void clip_frame_changed();

private:
  void setup_child_nodes();

protected:
  bool _has_clip_frame;
  LVecBase4 _clip_frame;

  PT(ModelNode) _canvas_node;
  PT(ModelNode) _canvas_parent;

public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    PGItem::init_type();
    register_type(_type_handle, "PGVirtualFrame",
                  PGItem::get_class_type());
  }
  virtual TypeHandle get_type() const {
    return get_class_type();
  }
  virtual TypeHandle force_init_type() {init_type(); return get_class_type();}

private:
  static TypeHandle _type_handle;
};

#include "pgVirtualFrame.I"

#endif