PWIDGET - Basic Plotting Widget

PWIDGET is a basic widget to produce simple plots.  It allows easy
customization and annotation via a point-and-click interface.


PWIDGET is called with the vectors to plot as parameters.  N
observations of M variables are displayed with the call:

	PWIDGET, x, y
Where: 
	x = an optional N element parameter, containing the X value of each
		point. 
	y = an (N, M) vector containing the ordinate values for each
		point, for each variable.


The parameter settings may be saved and restored in a structure via
the SAVE and RESTORE keywords. 


************************* Operation ***************************

---------------Top row buttons:

Done - exits PWIDGET.

Reset/All - Resets the scaling, line settings and colors to their
	original default values.
Reset/Annotation -  Clears the annotation list which contains 
	arrows, boxes, text, and legends.
Reset/Redraw - Redraws the plot.
Reset/Scaling - Restores the scaling to its original value.
Help - Prints this text.
Print - Makes a hard-copy of the plot on the selected output device.
	The name of the output file for PostScript is idl.ps, for HPGL
	it is idl.hp, for LJ-250 it is idl.lj, for PCL its idl.pcl,
	and for CGM it is idl.cgm.  The file is not closed, so that
	multiple plots are placed in one file.
Hide Controls - Removes the controls from the screen and displays only
	the plot.


---------------Mode buttons:
General - Displays the general main control panel.
Title - 
Sub-title - Enter the text for the main plot title and sub-title here.
Nsum - The number of points to average for each plotted point.
Tick Style - Selects the tick style of the plot.
Bkgd - Selects the background color of the plot.  Click on the desired
	color or shade.
Char Size - Selects the size of the characters.  

---------------Line Box:
This control box selects the name, color, linestyle, thickness, marker
symbol and marker size for each variable.  Press the variable's button
to select the variable.  To change the name of the current variable,
enter the new name, followed by a Carriage-Return  in the Name widget.
Variable names are used when making legends.


---------------Mouse Movement:
Moving the mouse over the plot displays the coordinates in the lower
left control.

To zoom a region of the plot to fit the entire window, select a
rectangular region by clicking the middle mouse button on one corner
and dragging the mouse to the diagonally opposite corner.

To pan the plot, drag the mouse with the left button down in the
direction of the movement.


---------------Axis Boxes:
X Axis button - Displays the X axis control panel.
Y Axis button - Displays the Y axis control panel.

The type, style, title, range, and margins for each axis are
manipulated by this control box.  In general, controls are self
explanatory.  If the default values are not appropriate, enter the
desired value into the respective text widget followed by a
Carriage-Return. 



---------------Annotation Box:
This control box allows the addition of arrows, boxes, text, and
legends to the plot.  Select the appropriate type of object by
clicking its button.

To draw:
Arrow: select the arrow mode.  Then click where the tail of the arrow
	should go, and drag the mouse with the button down to the end
	of the head.
Box:   select the box mode, and drag the mouse with the button down
	from one diagonal corner of the box to the other.
Text:  enter the text in the Text window.  Click on spot where the
	text should go.
Legend: draws a box containing the variable names, and their line
	patterns.  Select one corner, and drag the mouse to the
	diagonal opposite corner of the legend's box.


Controls:
Undo Button:  removes the last object.
Coordinates/Data:  objects are located by data values.  Changing the
	scaling will move the object with the data.
Coordinates/Relative: objects are located at a specific point on the
	screen.  Changes in scaling do not move the objects.
Box Background: Selects between erasing the area underneath boxes, and 
	leaving it unchanged.
Text: Enter the text for the annotation here.

The remaining controls affect the color, thickness, character size,
and text alignment.