Function:     GgiGauge

Purpose:      Create an analog valuator Ggi element

Category:     USER-INTERFACE

File:         ggi.src

Author:       J.P. Terlouw

Use:          
              #include "ggi.h"
              ident gauge;
              char *keyword, *message;
              int   length;
              float left, right;

              gauge = GgiGauge(keyword, message, length, left, right);

                 gauge    -  'handle' by which element can be referenced.
                 keyword  -  user input keyword.
                 message  -  help text which pops up when the pointer stays
                             in the input area for some time.
                 length   -  gauge's length in pixels.
                 left     -  value corresponding to leftmost position.
                 right    -  value corresponding to rightmost position.

Description:  GgiGauge creates an analog valuator element.
              On the screen is consists of a label field and the actual
              gauge implemented as a scrollbar. By default the supplied keyword
              is taken as the label's value.

              When it is manipulated, it writes its value to the keyword by
              calling wkey_c(). This can be read by any number reading
              routine e.g. userreal_c().

Related documents:
              GgiSetCircular.dc2, GgiSetFormat.dc2, GgiSetRange.dc2
              
Updates:      Jan 13, 1998: JPT, Document created.
              Jan 28, 1999: JPT, GgiSetFormat and GgiSetCircular added.
              Oct  2, 2000: JPT, Fixed bug in keychanged method.