improve render

Author: scivision

app/main.f90

@@ -5,6 +5,8 @@ program donut
 implicit none (type, external)
 
 character, parameter :: ESC = achar(27)
+character(3), parameter :: LF = ESC // "[d" !< line feed
+character(3), parameter :: TL = ESC // "[2J" !< erase screen and move to top left
 character, parameter :: TAB(0:11) = [".", ",", "-", "~", ":", ";", "=", "!", "*", "#", "$", "@"]
 real(wp), parameter :: PI = 4*atan(1.)
 
@@ -22,6 +24,8 @@ program donut
 character(:), allocatable :: dumpfn
 logical :: dump
 
+print *, ESC // "[?25l" !< hide cursor
+
 Nloop = 300
 dump = .false.
 do ii = 1, command_argument_count()
@@ -49,7 +53,8 @@ program donut
 
 if(dump) open(newunit=u, file=dumpfn, status='replace', action='write')
 
-write(stdout,"(a)", advance="no") ESC // "[2J"  !< move cursor to top left
+write(stdout,"(a)", advance="no") TL
+!! move cursor to top left
 
 do ii = 1,Nloop
   z=0
@@ -82,7 +87,7 @@ program donut
     j = j + 0.07
   enddo
 
-  write(stdout, "(a)", advance="no") ESC // "[d" !< line feed
+  write(stdout, "(a)", advance="no") LF
 
   do k=0, rows-2
     print '(81a)', screen(k*cols:k*cols+cols)
@@ -95,4 +100,6 @@ program donut
 
 if(dump) close(u)
 
+print *, ESC // "[?25h" !< show cursor
+
 end program

fpm.toml

@@ -0,0 +1,3 @@
+name = "donut"
+description = "Spinning donut TTY"
+version = "1.0.0"