This variable has meaning only on graphical systems such as Windows. Set this
variable to "1" (on, true, yes) to cause the runtime to display lines and
boxes with 3-D shading. This makes the lines appear to be inscribed into the
surface of the screen. The variable is especially helpful in giving a 3-D look to a
program originally designed on a character system. Only black lines on a
non-black background are shown with shading. Other lines are displayed normally.
The set of colors available to ACUCOBOL-GT significantly impacts how effective
the shading is. Normally, the shading is most effective when the background
is low-intensity white. The other low-intensity colors are next best.
The shading is only marginally effective with a high-intensity background.
For this reason, the 3D_LINES setting is not used when a high-intensity
background is drawn. Note that, by default, ACUCOBOL-GT shows background colors in
high-intensity, so you need to use at least one other variable to arrange for a
low-intensity background color. For example, the BACKGROUND_INTENSITY variable could be set to "1" to force a low-intensity background.
You may freely change the way lines are displayed in COBOL by using the SET
ENVIRONMENT verb to set 3D_LINES prior to displaying a line or a box.
The runtime remembers which lines are drawn with 3-D, so you don't need to keep track of this yourself. Note, however, that if you attach a 3-D line to a non-3-D line, the intersection uses the 3D_LINES setting currently in effect. The default value is "0".