DSArrow.h

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//# DSArrow.h: Arrow implementation for "DisplayShapes"
//# Copyright (C) 1998,1999,2000,2001,2002
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library 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 Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: aips2-request@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
//#
//# $Id:

#ifndef TRIALDISPLAY_DSARROW_H
#define TRIALDISPLAY_DSARROW_H

#include <casa/aips.h>

#include <display/DisplayShapes/DSLine.h>
#include <display/DisplayShapes/DSPoly.h>

#include <casa/Arrays/Matrix.h>
#include <casa/Arrays/Vector.h>

namespace casa { //# NAMESPACE CASA - BEGIN

        class PixelCanvas;
        template <class T> class DParameterRange;

// <summary>
// Arrow implementation;adds a polygon to a DSLine to represent the arrow head
// </summary>
//
// <prerequisite>
// <li> <linkto class="DSLine">DSLine</linkto>
// <li> <linkto class="DSPoly">DSPoly</linkto>
// <li> <linkto class="DisplayShape">DisplayShape</linkto>
// </prerequisite>
//
// <etymology>
// DSArrow is a method of managing the drawing of a line and polygon onto a
// PixelCanvas.
// </etymology>
//
// <synopsis>
// DSArrow simply extends from DSLine, and adds the management of a polygon
// to it. The polygon is used to represent the arrow head, and various options
// regarding its apppearance can be changed.
//
// There are generally two ways to make DisplayShape(s); To create them in
// "one hit" by providing arguments to the constructor, or by using the
// default constructor and then the "setOptions" method. A simple interface
// for all classes inheriting from the
// <linkto class="DisplayShape">DisplayShape</linkto> class is provided by
// <linkto class="DisplayShapeInterface">DisplayShapeInterface</linkto>.
// </synopsis>
//
// <motivation>
// It was thought, especially in an annotations context, that an Arrow would be
// a usefull drawing tool.
// </motivation>
//
// <example>
// <srcblock>
// Vector<Float> startPoint(2); startPoint[0] = 100; startPoint[1] = 100;
// Vector<Float> endPoint(2);   endPoint[0] = 200;   endPoint[1] = 200;
//
// DSArrow* myArrow =
// new DSArrow(startPoint, endPoint, DSArrow::Filled_Triangle, 10);
//
// myArrow->move(10,10);
//
// Vector<Float> newStart(2); newStart[0] = 50; newStart[1] = 50;
// myArrow->setStartPoint(newStart);
//
// Record newArrow;
// newArrow.define("arrowheadsize", 6);
//
// myArrow->setOptions(newArrow);
// myArrow->draw(myPixelCanvas);
// etc..
// </srcblock>
// </example>

        class DSArrow : public DSLine {

        public:

                // Supported arrow head types
                enum ArrowHead { Open_Triangle, Filled_Triangle , Cool_Triangle};

                // For checking setoptions(arrowheadstyle = ?)
                static const int numArrowHeads = 3;


                // Default constructor. In order to make the arrow "valid", it must
                // be supplied with a valid start and end point.
                DSArrow();

                // The start and end point are in pixel co-ordinates.
                DSArrow(const Vector<Float> &startPoint, const Vector<Float> &endPoint,
                        DSArrow::ArrowHead style = DSArrow::Cool_Triangle,
                        const Int arrowHeadSize = 8);

                // Copy constructor
                DSArrow(const DSArrow& other);

                // Destructor
                virtual ~DSArrow();

                // Standard Display Shape functions
                // <group>
                virtual void draw(PixelCanvas *pc);
                virtual void move(const Float& dX, const Float& dY);
                virtual void rotate(const Float& angle);
                virtual void scale(const Float& scaleFactor);
                virtual void setCenter(const Float& xPos, const Float& yPos);
                // </group>

                // Does nothing currently
                virtual void rotateAbout(const Float& angle, const Float& aboutX,
                                         const Float& aboutY);

                // Standard (changePoint) and specific funtions for altering the arrow. the
                // changePoint method with only one argument will move the closest point to
                // the specified new point. When speciffyin 'n', in this case only 0 or
                // 1 are valid. The 'startpoint' is the one with the arrow head on it.
                // <group>
                virtual void setStartPoint(const Vector<Float>& startPoint);
                virtual void setEndPoint(const Vector<Float>& endPoint);
                virtual void changePoint(const Vector<Float>&pos, const Int n);
                virtual void changePoint(const Vector<Float>& pos);
                // </group>

                // These are to enable the use of arrows more easily in vector plots
                // <group>
                virtual void setLength(const Float& pixelLength);
                virtual void setAngle(const Float& angle);
                // </group>

                // Return an option record describing the shape
                virtual Record getOptions();

                // Set options.
                virtual Bool setOptions(const Record& newSettings);

        protected:

        private:
                // If someone calls "setLength" before "setCenter", we can store our
                // length until they DO call setLength;
                Float itsLength;

                // Make a new arrow head (which is simply a DSPoly)
                virtual void buildArrowHead();

                // Caluclate angle etc.
                virtual void updateArrowHead();

                // Set default options
                virtual void setDefaultOptions();

                // Construct the line segment of the arrow when we have
                // valid start / end points
                virtual void make();

                DParameterRange<Int>* itsHeadSize;

                DSPoly* itsArrowHead;

                // Temp storage while I am being set up
                // <group>
                Vector<Float> itsStartPoint;
                Vector<Float> itsEndPoint;
                // </group>

                // A Matrix of the unRotated arrow head
                Matrix<Float> itsUnrotatedHead;

                // Offset needed to make sure the tip of the arrow is at the end of
                // the line.
                Float itsOffset;

                // Style of arrow head
                DSArrow::ArrowHead itsArrowHeadStyle;

                // Have I been supplied with valid points yet
                Bool itsValidStart,itsValidEnd;
        };


} //# NAMESPACE CASA - END

#endif