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        example programs using the xvisual lib

	           - - annotations - - - 

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01.marker/

   This program demonstrates the use of the marker visual object;
   it creates several markers using different foreground colors.

   After the manager object parent is put into edit mode (hold down
   shift key and click the left mouse button), the marker can be 
   interactively moved by "grabbing" it with the left mouse button.

   The internal menuform for the marker may be displayed by clicking
   the middle mouse button on the marker; the menuform may then be
   used to set attributes of the marker.

02.marker_color/

   This is an example of a marker object using an event handler.
   It creates a single marker annotation, and adds an event handler, so that
   button press on the marker turns it blue!  Button release turns it red 
   again!

03.indicator/

   This program creates a window with an area object, containing a
   2D axis object and an indicator object.  The indicator object displays
   its world coordinate position within the area object. The internal menuform
   for the indicator is displayed automatically, and may be used to set
   attributes of the indicator.
  
   An event handler is installed which allows you to interactively
   move the indicator by "grabbing" it with the left mouse button and moving
   it around inside the area object; it will update the world coordinate value
   that it displays as it is moved.  The 2D axis object serves to provide a
   reference as to the world coordinate system.

04.menu/
   
   This program tests the use of the annotation menu.
   The annotationmenu object barely qualifies as a prototype.  
   Do not expect this example to be functional yet.

05.line/

   This example creates a window with a single line annotation in it.
   Similar to the 01.marker/ example, the line can be interactively
   moved and its attributes changed via its internal menuform.
  
06.circle/

   This example demonstrates creation of a circle visual object.
   The circle attributes can be changed with the internal menuform which
   is automatically displayed.

07.rectangle/

   This program creates a rectangle visual object.  The rectangle attributes 
   can be changed with the internal menuform which is automatically displayed.

08.string/

   This program creates a string visual object.  The string attributes 
   can be changed with the internal menuform which is automatically displayed.

09.stringvalue/

   This program creates a stringvalue visual object; the stringvalue visual
   object is used to display a floating point number in a particular format.  
   The stringvalue attributes can be changed with the internal menuform which 
   is automatically displayed.

10.textstring/

   This program creates a textstring visual object.  The textstring attributes 
   can be changed with the internal menuform which is automatically displayed.

11.date/

   This program creates a window with a single date annotation in it.
   The date annotation displays the current time and date.  The data attributes
   can be changed with the internal menuform which is automatically displayed.

12.timer/

   This example creates a window with a timer object.  A timer object
   uses the system clock to emulate a stop-watch type capability.

13.polyline/

   This program creates a polyline object.

14.image_annotate/  Under development not functional at this time

   This example displays an image, with 2 inputfile objects underneath,
   one with which you may enter a new image, and one with which 
   you may enter a location file containing coordinates where rectangle
   annotations are to be drawn.  You start it like this:
  
   % example {image file}
  
   By default, it will display the moon image.
  
   When you input a location file, one rectangle is created for each
   location specified.  An event handler is installed on the rectangle so
   that when you click on the rectangle, the location of the rectangle
   is displayed.
   The location file is an ascii file of (x, y) DEVICE coordinates, where the
   device coordinates correspond to the locations of the pixels in the image.
   It is very simpleminded, and has to be like this:
  
   x y
   x y
   x y
  
   When you enter a new file, any rectangles currently displayed will
   be transferred to the new image.  A "Clear" button is provided
   so that you can get rid of the rectangles if desired. An array of the 
   rectangle objects is saved so that they can all be destroyed when
   the you click on the clear button.

