
plimagefr: Plot a 2D matrix using color map1 

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 (PLFLT**, 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) :    Plot coordinates to strecth
    the image data to.  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 transformation between indices
    in array idata and the world coordinates (C only).  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 that is
    externally supplied. 
