Thanks for reply,
It doesn't work quite well. It draw four lines instead one line. For me is more suitable to have variables in usercommands like I wrote before.
Code:
GLCDDHL  var1,0,var2,0
GLCDDVL  var1,0,var2,0
GLCD_CLR var1,0,var2,0
because in this case I can point exactly what and where I want to clear the line, or draw a for example 10pixel wide line and move it horizontally wherever I want with changing variables.
Code:
do
for n=0 to 120 step 1
GLCDDHL 0,0,n,1
next n


for n=120 to 0 step -1
GLCD_CLR 0,0,120,1 ;is a lot more efficient
GLCDDHL 0,0,n,1
next n
loop
This solution I tried before as well, it still flicker if line goes from 120 to 0.