| Plotitem represents an item that can be plotted by gnuplot.    For the finest control over the output, you can create PlotItemsyourself with additional keyword options, or derive new classes
    fromPlotItem.     The handling of options is complicated by the attempt to allow
    options and their setting mechanism to be inherited conveniently.
    Note first that there are some options that can only be set in the
    constructor then never modified, and others that can be set in the
    constructor and/or modified using the set_option()member
    function.  The former are always processed within__init__.  The
    latter are always processed withinset_option, which is called
    by the constructor.     set_optionis driven by a class-wide dictionary called_option_list, which is a mapping{ <option> : <setter> }from
    option name to the function object used to set or change the
    option.  <setter> is a function object that takes two parameters:self(thePlotIteminstance) and the new value requested for
    the option.  If <setter> isNone, then the option is not allowed
    to be changed after construction and an exception is raised.     Any PlotItemthat needs to add options can add to this
    dictionary within its class definition.  Follow one of the
    examples in this file.  Alternatively it could override theset_optionmember function if it needs to do wilder things.     Members:
      _basecommanda string holding the elementary argument that
          must be passed to gnuplot's `plot' command for this item;
          e.g., sin(x)or"filename.dat".      _optionsa dictionary of (<option>,<string>) tuples
          corresponding to the plot options that have been set for
          this instance of the PlotItem.  <option> is the option as
          specified by the user; <string> is the string that needs to
          be set in the command line to set that option (or None if no
          string is needed).  Example:
              {'title' : ('Data', 'title "Data"'),
               'with' : ('linespoints', 'with linespoints')}
 
        
            | Methods |  |  
        | __init__ clear_option
 command
 get_base_command_string
 get_command_option_string
 get_option
 pipein
 set_option
 set_string_option
 
 |  
            |  | __init__ |  
        | 
__init__ ( self,  **keyw )
 Construct a PlotItem.        Keyword options:
          with=<string>choose how item will be plotted, e.g.,
              with=points 3 3.          title=<string>set the title to be associated with the item
              in the plot legend.          title=Nonechoose notitleoption (omit item from legend).         Note that omitting the title option is different than setting
        'title=None'; the former chooses gnuplot's default whereas the
        latter chooses notitle. |  
            |  | clear_option |  
        | 
clear_option ( self,  name )
 Clear (unset) a plot option.  No error if option was not set. |  
            |  | command |  
        | 
command ( self )
 Build the plot command to be sent to gnuplot.        Build and return the plot command, with options, necessary to
        display this item.  If anything else needs to be done once per
        plot, it can be done here too. |  
            |  | get_base_command_string |  
        | 
get_base_command_string ( self )
 |  
            |  | get_command_option_string |  
        | 
get_command_option_string ( self )
 |  
            |  | get_option |  
        | 
get_option ( self,  name )
 Return the setting of an option.  May be overridden. 
        
            | Exceptions |  |  
        | KeyError( 'option %s is not set!' % name ) 
 |  |  
            |  | pipein |  
        | 
pipein ( self,  f )
 Pipe necessary inline data to gnuplot.        If the plot command requires data to be put on stdin (i.e.,
        plot "-"), this method should put that data there.  Can be
        overridden in derived classes. |  
            |  | set_option |  
        | 
set_option ( self,  **keyw )
 Set or change a plot option for this PlotItem.        See documentation for __init__for information about allowed
        options.  This function can be overridden by derived classes
        to allow additional options, in which case those options will
        also be allowed by__init__for the derived class.  However,
        it is easier to define a new_option_listvariable for the
        derived class. 
        
            | Exceptions |  |  
        | Errors.OptionError( 'Cannot modify %s option after construction!', option ) Errors.OptionError('%s=%s' %( option, value ) )
 
 |  |  
            |  | set_string_option |  
        | 
set_string_option (
        self,
        option,
        value,
        default,
        fmt,
        )
Set an option that takes a string value. |  |