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PixelCurve1D.h
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00001 //# PixelCurve1D.h: Arbitrary 1-dim curve in a lattice plane
00002 //# Copyright (C) 2003
00003 //# Associated Universities, Inc. Washington DC, USA.
00004 //#
00005 //# This library is free software; you can redistribute it and/or modify it
00006 //# under the terms of the GNU Library General Public License as published by
00007 //# the Free Software Foundation; either version 2 of the License, or (at your
00008 //# option) any later version.
00009 //#
00010 //# This library is distributed in the hope that it will be useful, but WITHOUT
00011 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00012 //# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
00013 //# License for more details.
00014 //#
00015 //# You should have receied a copy of the GNU Library General Public License
00016 //# along with this library; if not, write to the Free Software Foundation,
00017 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
00018 //#
00019 //# Correspondence concerning AIPS++ should be addressed as follows:
00020 //#        Internet email: aips2-request@nrao.edu.
00021 //#        Postal address: AIPS++ Project Office
00022 //#                        National Radio Astronomy Observatory
00023 //#                        520 Edgemont Road
00024 //#                        Charlottesville, VA 22903-2475 USA
00025 //#
00026 //# $Id: PixelCurve1D.h 18093 2004-11-30 17:51:10Z ddebonis $
00027 
00028 #ifndef LATTICES_PIXELCURVE1D_H
00029 #define LATTICES_PIXELCURVE1D_H
00030 
00031 
00032 //# Includes
00033 #include <scimath/Functionals/Function1D.h>
00034 #include <casa/Arrays/Vector.h>
00035 
00036 namespace casa { //# NAMESPACE CASA - BEGIN
00037 
00038 //# Forward Declarations
00039 
00040 
00041 // <summary>
00042 // Arbitrary 1-dim curve in a lattice plane.
00043 // </summary>
00044 
00045 // <use visibility=export>
00046 
00047 // <reviewed reviewer="" date="" tests="tPixelCurve1D.cc">
00048 // </reviewed>
00049 
00050 // <prerequisite>
00051 //# Classes you should understand before using this one.
00052 //   <li> <linkto class=Function1D>Function1D</linkto>
00053 //   <li> <linkto class=CurvedLattice2D>CurvedLattice2D</linkto>
00054 // </prerequisite>
00055 
00056 // <synopsis>
00057 // PixelCurve1D represents a 1-dim curve in a lattice plane to be
00058 // used by CurvedLattice2D.
00059 // The curve can be any function supported in the
00060 // <linkto module=Functionals>Functionals</linkto> module.
00061 // <br>A special constructor exists to define a straight line.
00062 // <br>Another special constructor exists for a polyline.
00063 //
00064 // The domain for which the curve is valid is given by the interval
00065 // [x1,x2]. The granularity of the domain is given by the number of
00066 // points. The number of points also define the length of the new axis
00067 // in the CurvedLattice2D object.
00068 // </synopsis>
00069 
00070 // <example>
00071 // <srcblock>
00072 //  // Use function y=cos(2*pi*x) on the interval [0,2] with 5 points.
00073 //  Sinusoid1D<float> fn;
00074 //  PixelCurve1D pcurve2(fn, 0., 2., 5);
00075 //  AlwaysAssertExit (pcurve2.npoints() == 5);
00076 //  pcurve2.getPixelCoord (x, y, 0, 4);
00077 //  cout << x << y << endl;
00078 // </srcblock>
00079 // The result of x is [0, 0.5, 1, 1.5, 2].
00080 // The result of y is [1, -1, 1, -1, 1]
00081 // </example>
00082 
00083 // <motivation>
00084 // The viewer must be able to show a crosscut through an image using
00085 // an arbitrary curve.
00086 // </motivation>
00087 
00088 // <todo asof=2003/10/23>
00089 //  <li> Maybe it is better to make itsNpoints part of CurvedLattice
00090 //  <li> If itsNpoint is still part of this class, it is possible to
00091 //       precompute all possible Y values in the constructors. This may
00092 //       speed things up for the polyline case.
00093 // </todo>
00094 
00095 class PixelCurve1D
00096 {
00097 public:
00098   // Define a straight line from (x1,y1) to (x2,y2).
00099   // The default number of points is the length of the line.
00100   explicit PixelCurve1D (double x1=0, double y1=0, double x2=1, double y2=1,
00101                          uInt npoints=0);
00102 
00103   // Define a curve with an arbitrary function from x1 to x2.
00104   // The default number of points is the length of the curve.
00105   // The length of the curve is determined numerically by integration
00106   // of sqrt(1+sqr(df/dx)).
00107   PixelCurve1D (const Function1D<float,float>&,
00108                 float x1, float x2, uInt npoints=0);
00109 
00110   // Define a curve from a polyline with the given points.
00111   // Both vectors have to be equally long and at least 2 long.
00112   // The argument <src>npoints</src> defines the number of points
00113   // (with regular steps) in which the curve is divided.
00114   // The default is the length of the polyline.
00115   PixelCurve1D (const Vector<Int>& x, const Vector<Int>& y,
00116                 uInt npoints=0);
00117   PixelCurve1D (const Vector<float>& x, const Vector<float>& y,
00118                 uInt npoints=0);
00119   PixelCurve1D (const Vector<double>& x, const Vector<double>& y,
00120                 uInt npoints=0);
00121 
00122   PixelCurve1D (const PixelCurve1D& that);
00123 
00124   ~PixelCurve1D();
00125 
00126   PixelCurve1D& operator= (const PixelCurve1D& that);
00127 
00128   uInt npoints() const
00129     { return itsNpoints; }
00130 
00131   // Get the pixel coordinates in the original lattice for point start
00132   // till end with given step.
00133   void getPixelCoord (Vector<float>& x, Vector<float>& y,
00134                       uInt start, uInt end, uInt incr=1) const;
00135 
00136 private:
00137   // Initialize the object.
00138   void init (const Vector<double>& x, const Vector<double>& y, uInt npoints);
00139 
00140   uInt           itsNpoints;
00141   Vector<double> itsX;
00142   Vector<double> itsY;
00143 };
00144 
00145 
00146 
00147 } //# NAMESPACE CASA - END
00148 
00149 #endif