Subroutines

• gtalph
  Commute to alphanumeric mode. On Windows system, transfer focus to the terminal window.
• gtchar
  Draws a character string.
• gtclal
  Clear alphanumeric screen. On Windows applications, transfer focus to the (current) graphic window, and raise in on top of others to display it.
• gtclear
  Erase the whole plot, all directory structures, destroy all associated windows, etc... An empty top directory is then re-created
• gtclos
  Close the current graphic device
• gtclpl
  Raise alphanumeric window, and returns focus to it.
• gtcurs
  Call the cursor
• gtdls
  Delete the last graphic segment
• gtdraw
  Draw a vector from current pen position to the specified point.
• gtedit
  Edit the current segment properties.
• gterflag, gterrgto, gterrtst
  Control error status of the library
• gtexist
  Controls the existence of a named sub-directory.
• gthard
  Create a hardcopy
• gtinit
  Initialize the GTVIRT drawing space and the GTVL language
• gtopen
  Open a graphic device
• gtpolyl
  Draw a set of lines.
• gtreloc
  Move current pen position to specified coordinates.
• gtsegm
  Open a new segment
• gtview
  Activate the drawing
• gtwhere
  Returns current pen position
• gtg_charlen
  Computes character string length
• gtg_charsiz
  Returns character size
• gtg_curs
  Returns cursor existence
• gtg_screen
  Returns clipping parameters
• gtg_open
  Returns device parameters
• gtstat
  Change GTVIRT mode (Sleep or Wake_up), and returns previous mode.
• gtv_newimage
  Create a new image slot
• gtv_image
  Draw a bitmap to an image slot
• gtv_numimage
  Get a free image slot
• gtv_majimage
  Define parameters of an image slot
• gtv_fillpoly
  Fill a closed polygon.
• init_gtvirt
  Initialize the GTVIRT library
• exit_clear
  Quick exit, to be used at program completion.
• run_gtvl
  Dispatch the GTVL commands to appropriate subroutines
• exec_gtvl
  Execute a GTVL language command or command procedure

Immediate routines are used to produce immediate actions. They use the immediate pen. These subroutines are

• gti_beep: beep
• gti_clear: clear the current window
• gti_draw: draw line to current
• gti_out: flush the normal drawing buffer.
• gti_pen: select the immediate pen
• gti_polyl: draw a polyline
• gti_reloc: relocate the immediate pen
• gti_where: returns immediate pen position