
plimagefr: Plot a 2D matrix using cmap1 

DESCRIPTION:

    This function is used in example 20. 

SYNOPSIS:

plimagefr(idata, nx, ny, xmin, xmax, ymin, ymax, zmin, zmax, valuemin, valuemax, pltr, pltr_data)

ARGUMENTS:

    idata (const PLFLT * const *, input) :    A 2D array of values
    (intensities) to plot.    Should have dimensions idata[nx][ny]. 

    nx, ny (PLINT, input) :    Dimensions of idata 

    xmin, xmax, ymin, ymax (PLFLT, input) :    Stretch image data to these
    Plot coordinates.  idata[0][0] corresponds to (xmin, ymin) and
    idata[nx - 1][ny - 1] corresponds to (xmax, ymax). 

    zmin, zmax (PLFLT, input) :    Only data between zmin and zmax
    (inclusive) will be plotted. 

    valuemin, valuemax (PLFLT, input) :    The minimum and maximum data
    values to use for value to color mappings.  A datum equal to or
    less than valuemin will be plotted with color 0.0, while a datum
    equal to or greater than valuemax will be plotted with color 1.0. 
    Data between valuemin and valuemax map linearly to colors between
    0.0 and 1.0. 

    pltr (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer) , input) : 
      Pointer to function that defines a transformation between the
    data in the array idata and world coordinates.    An input
    coordinate of (0, 0) corresponds to the "top-left" corner of idata
    while (nx, ny) corresponds to the "bottom-right" corner of idata. 
    Some transformation functions are provided in the PLplot library:
    pltr0 for identity mapping, and pltr1 and pltr2 for arbitrary
    mappings respectively defined by one- and two-dimensional arrays. 
    In addition, user-supplied routines for the transformation can be
    used as well.  Examples of all of these approaches are given in
    the PLplot documentation.  The transformation function should have
    the form given by any of pltr0, pltr1, or pltr2. 

    pltr_data (PLPointer, input) :    Extra parameter to help pass
    information to pltr0, pltr1, pltr2, or whatever routine is
    externally supplied. 
