Graphics Characters - Enhanced
Many terminals have the ability to display simple graphics characters. These characters are usually referred to as "box drawing characters." This is a set of characters that is used to form the sides and each of the four corners of a box. The following fields are used to describe such a capability:
|
Field |
Description |
|
GS= |
If present, this field will be sent prior to any box character. Some terminals require that the terminal be placed into a "graphics mode" before recognizing a box character. The necessary sequence should be given here. |
|
GE= |
If GS= is present, then GE= should provide the sequence to exit graphics mode. This string is sent after each box character. |
|
G1= |
Sequence to draw upper-right corner of box (┐). |
|
G2= |
Sequence to draw upper-left corner of box (┌). |
|
G3= |
Sequence to draw lower-left corner of box (└). |
|
G4= |
Sequence to draw lower-right corner of box (┘). |
|
GH= |
Sequence to draw a horizontal line (─). |
|
GV= |
Sequence to draw a vertical line (│). |
For example, the Wyse 60 manual describes the sequence to display a graphics character as "ESC H key". A legend shows the various values for key and the character displayed by each value. Since there is no need for GS= and GE= they are not included in the termcap entry. The remaining values are:
:G1=\EH3:G2=\EH2:G3=\EH1:G4=\EH5:GH=\EH\072:GV=\EH6:
In addition to drawing rectangular boxes, there are box characters available to draw intersections between lines. Additional termcap fields are used to describe these graphic characters:
|
Field |
Description |
|
GR= |
Intersect from the right (├). |
|
GL= |
Intersect from the left (┤). |
|
GU= |
Intersect from above (┴). |
|
GD= |
Intersect from below (┬). |
|
GC= |
Cross intersection (┼). |