+"""
+ Progress bar (TTY version)
+
+ Written by Broytman, Jan 1997 - Sep 2003. Copyright (C) 1997-2003 PhiloSoft Design
+"""
+
+
+import sys, os
+
+
+class ttyProgressBar:
+ """
+ Simple progress indicator - displays bar "graph" using standard tty
+ commands - space, backspace, etc. This method is compatible with
+ (almost) all UNIX consoles and DOS boxes.
+
+ Example:
+
+ ====------ 42%
+
+ This is a "bar" (width 10 chars) for 42%
+
+ Certainly, to use it nicely, do not write anything on screen
+ (to stdout or stderr), while using it (or use erase()/redraw() methods).
+ Erase or delete it after using.
+ """
+
+ left_c = '#' # Chars for "graphics"
+ right_c = '_'
+ space_c = ' ' # a space
+ back_c = chr(8) # a backspace
+
+ if os.name == 'dos' or os.name == 'nt' : # Use nice chars on DOS screen
+ left_c = chr(178)
+ right_c = chr(176)
+
+
+ def __init__(self, min, max, out = sys.stderr, width1 = 10,
+ width2 = 1+3+1): # 1 space + 3 chars for "100" + 1 for "%"
+ self.min = min
+ self.current = min
+ self.max = max - min
+
+ self.width1 = width1
+ self.width2 = width2
+ self.out = out
+
+ self.redraw()
+
+
+ def __del__(self):
+ self.erase()
+
+
+ def display(self, current):
+ """
+ Draw current value on indicator.
+ Optimized to draw as little as possible.
+ """
+
+ self.current = current
+ current -= self.min
+ lng = (current * self.width1) / self.max
+
+ if current >= self.max:
+ percent = 100
+ else:
+ percent = (current * 100) / self.max
+
+ flush = False
+
+ if self.lng <> lng:
+ self.lng = lng
+ self.out.write(ttyProgressBar.back_c*(self.width1+self.width2))
+ self.out.write(ttyProgressBar.left_c*lng)
+ self.out.write(ttyProgressBar.right_c*(self.width1-lng) + ttyProgressBar.space_c)
+ self.percent = -1 # force to redraw percentage; the bug was fixed by William McVey
+ flush = True
+
+ elif self.percent <> percent:
+ self.out.write(ttyProgressBar.back_c * (self.width2-1))
+ flush = True
+
+
+ if self.percent <> percent:
+ self.percent = percent
+ self.out.write(str(percent).rjust(3) + '%')
+ flush = True
+
+
+ if flush:
+ self.out.flush()
+
+ self.visible = True
+
+
+ def erase(self):
+ if self.visible: # Prevent erase() to be called twice - explicitly and from __del__()
+ self.out.write(ttyProgressBar.back_c*(self.width1+self.width2))
+ self.out.write(ttyProgressBar.space_c*(self.width1+self.width2))
+ self.out.write(ttyProgressBar.back_c*(self.width1+self.width2))
+ self.out.flush()
+ self.visible = False
+
+
+ def redraw(self):
+ self.lng = -1 # force to draw bar on the first call
+ self.percent = -1
+
+ # Clear space - just in case there was some cruft left
+ self.out.write(ttyProgressBar.space_c*(self.width1+self.width2))
+ # redraw everything
+ self.display(self.current)