The Line( command is used to draw lines at any angle, as opposed to only drawing vertical or horizontal lines. Line(X1,Y1,X2,Y2) will draw a line from (X1,Y1) to (X2,Y2). Line( is affected by the window settings, although you can use a friendly window so there is no impact on the command.
Line has an optional fifth argument. It can be any real number, but the default is one. If the fifth argument, erase, is something other than 0, then it will simply draw the line. If erase is 0, then it will erase the line.
Leave off the ending argument if you are just drawing the line.
:Line(5,5,20,3,1) can be :Line(5,5,20,3)
The ending argument can be a formula, which is useful for movement applications and other things such as health bars where the lines drawn are constantly different. The following draws or erases a line depending on whether a key is pressed.
If working on a TI 84+CSE or TI 84+CE, then the fifth argument of the Line( command can be a color name or ID number:
The last argument, line style, is an optional argument that chooses what style of line to draw on the color calculators.
1 pixel wide line :Line(5,5,20,3,RED,1 2 pixel wide line :Line(5,5,20,3,RED,2 shaded above :Line(5,5,20,3,RED,3 shaded below :Line(5,5,20,3,RED,4