Initial commit

ticks.py

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+# ticks.py
+# ------------
+# By MWC Contributors
+# The functions in this module calculate suitable placements 
+# for ticks on a plot axis which will display values. 
+# These functions are all complete; you don't need to edit this file.
+
+from math import floor, ceil, log
+from transform import bounds
+
+def get_tick_values(low, high):
+    """Returns a list of values to use for ticks (labeled points along an axis). 
+    Includes the lowest value, a bunch of "nice" intermediate values, and the highest value.
+    """
+    tick_interval = get_tick_interval(high - low)
+    first_tick = ceil(low / tick_interval) * tick_interval
+    return [low] + list(range(first_tick, high, tick_interval)) + [high]
+
+def get_tick_interval(span):
+    """Returns a 'nice' interval for ticks across span.
+    The interval is a power of ten (e.g. 1000, 100, 0.1)
+    scaled so that there will be between 0 and 10 internal ticks.
+    """
+    log_span = log(span, 10)
+    return 10 ** floor(log_span)
+