fgrayplot
=========

2D plot of a surface defined by a function using colors



Calling Sequence
~~~~~~~~~~~~~~~~


::

    fgrayplot(x,y,f,[strf,rect,nax])
    fgrayplot(x,y,f,<opt_args>)




Arguments
~~~~~~~~~

:x,y real row vectors.
: :f external of type `y=f(x,y)`.
: :<opt_args> This represents a sequence of statements `key1=value1,
  key2=value2`,... where `key1`, `key2,...` can be one of the following:
  rect, nax, strf or axesflag and frameflag (see `plot2d`).
: :strf,rect,nax see `plot2d`.
:



Description
~~~~~~~~~~~

`fgrayplot` makes a 2D plot of the surface given by `z=f(x,y)` on a
grid defined by `x` and `y`. Each rectangle on the grid is filled with
a gray or color level depending on the average value of `z` on the
corners of the rectangle.

Enter the command `fgrayplot()` to see a demo.



Sample
~~~~~~



Examples
~~~~~~~~


::

    t=-1:0.1:1;
    `deff`_("[z]=my_surface(x,y)","z=x**2+y**2")
    fgrayplot(t,t,my_surface,rect=[-2,-2,2,2])




See Also
~~~~~~~~


+ `grayplot`_ 2D plot of a surface using colors
+ `plot2d`_ 2D plot
+ `Sgrayplot`_ smooth 2D plot of a surface using colors
+ `Sfgrayplot`_ smooth 2D plot of a surface defined by a function
  using colors


.. _grayplot: grayplot.html
.. _plot2d: plot2d.html
.. _Sfgrayplot: Sfgrayplot.html
.. _Sgrayplot: Sgrayplot.html