50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
# -*- coding: utf-8 -*-
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#
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# Copyright (C) 2000-2005 by Yasushi Saito (yasushi.saito@gmail.com)
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#
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# Jockey is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the
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# Free Software Foundation; either version 2, or (at your option) any
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# later version.
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#
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# Jockey is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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# for more details.
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#
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import coord
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import math
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class T(coord.T):
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def get_canvas_pos(self, size, val, min, max):
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if val <= 0:
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return 0
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xminl = math.log(min)
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xmaxl = math.log(max)
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vl = math.log(val)
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return size * (vl-xminl) / float(xmaxl-xminl)
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def get_tics(self, min, max, interval):
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"Generate the list of places for drawing tick marks."
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v = []
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if min <= 0:
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raise Exception, "Min value (%s) < 0 in a log coordinate." % min
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x = min
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while x <= max:
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v.append(x)
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x = x * interval
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return v
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def get_min_max(self, dmin, dmax, interval):
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interval = interval or 10
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dmin = max(0, dmin) # we can't have a negative value with a log scale.
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v = 1.0
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while v > dmin:
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v = v / interval
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dmin = v
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v = 1.0
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while v < dmax:
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v = v * interval
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dmax = v
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return dmin, dmax, interval
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