Add terminalHeight, terminalHeightIoctl & terminalSize

lib/pure/terminal.nim

@@ -83,6 +83,13 @@ when defined(windows):
         return int(csbi.srWindow.Right - csbi.srWindow.Left + 1)
     return 0
 
+  proc terminalHeightIoctl*(handles: openArray[Handle]): int =
+    var csbi: CONSOLE_SCREEN_BUFFER_INFO
+    for h in handles:
+      if getConsoleScreenBufferInfo(h, addr csbi) != 0:
+        return int(csbi.srWindow.Bottom - csbi.srWindow.Top + 1)
+    return 0
+
   proc terminalWidth*(): int =
     var w: int = 0
     w = terminalWidthIoctl([ getStdHandle(STD_INPUT_HANDLE),
@@ -91,6 +98,14 @@ when defined(windows):
     if w > 0: return w
     return 80
 
+  proc terminalHeight*(): int =
+    var h: int = 0
+    h = terminalHeightIoctl([ getStdHandle(STD_INPUT_HANDLE),
+                              getStdHandle(STD_OUTPUT_HANDLE),
+                              getStdHandle(STD_ERROR_HANDLE) ] )
+    if h > 0: return h
+    return 0
+
   proc setConsoleCursorPosition(hConsoleOutput: HANDLE,
                                 dwCursorPosition: COORD): WINBOOL{.
       stdcall, dynlib: "kernel32", importc: "SetConsoleCursorPosition".}
@@ -177,7 +192,17 @@ else:
         return int(win.ws_col)
     return 0
 
+  proc terminalHeightIoctl*(fds: openArray[int]): int =
+    ## Returns terminal height from first fd that supports the ioctl.
+
+    var win: IOctl_WinSize
+    for fd in fds:
+      if ioctl(cint(fd), TIOCGWINSZ, addr win) != -1:
+        return int(win.ws_row)
+    return 0
+
   var L_ctermid{.importc, header: "<stdio.h>".}: cint
+
   proc terminalWidth*(): int =
     ## Returns some reasonable terminal width from either standard file
     ## descriptors, controlling terminal, environment variables or tradition.
@@ -195,6 +220,29 @@ else:
       return w
     return 80                               #Finally default to venerable value
 
+  proc terminalHeight*(): int =
+    ## Returns some reasonable terminal height from either standard file
+    ## descriptors, controlling terminal, environment variables or tradition.
+    ## Zero is returned if the height could not be determined.
+
+    var h = terminalHeightIoctl([0, 1, 2])  # Try standard file descriptors
+    if h > 0: return h
+    var cterm = newString(L_ctermid)        # Try controlling tty
+    var fd = open(ctermid(cstring(cterm)), O_RDONLY)
+    if fd != -1:
+      h = terminalHeightIoctl([ int(fd) ])
+    discard close(fd)
+    if h > 0: return h
+    var s = getEnv("LINES")                 # Try standard env var
+    if len(s) > 0 and parseInt(string(s), h) > 0 and h > 0:
+      return h
+    return 0                                # Could not determine height
+
+proc terminalSize*(): tuple[w, h: int] =
+  ## Returns the terminal width and height as a tuple. Internally calls
+  ## `terminalWidth` and `terminalHeight`, so the same assumptions apply.
+  result = (terminalWidth(), terminalHeight())
+
 when defined(windows):
   proc setCursorVisibility(f: File, visible: bool) =
     var ccsi: CONSOLE_CURSOR_INFO

web/news/e029_version_0_16_0.rst

@@ -39,7 +39,8 @@ Library Additions
   ``deques`` provides a superset of ``queues`` API with clear naming.
   ``queues`` module is now deprecated and will be removed in the future.
 
-- Added ``hideCursor`` and ``showCursor`` to the ``terminal``
+- Added ``hideCursor``, ``showCursor``, ``terminalWidth``,
+  ``terminalWidthIoctl`` and ``terminalSize`` to the ``terminal``
   `(doc) <http://nim-lang.org/docs/terminal.html>`_ module.