@@ -662,6 +662,22 @@ class Ticker(object):
662662formatter = None
663663
664664
665+ class _LazyTickList (object ):
666+ def __init__ (self ,major ):
667+ self ._major = major
668+
669+ def __get__ (self ,instance ,cls ):
670+ if instance is None :
671+ return self
672+ else :
673+ if self ._major :
674+ instance .majorTicks = [instance ._get_tick (major = True )]
675+ return instance .majorTicks
676+ else :
677+ instance .minorTicks = [instance ._get_tick (major = False )]
678+ return instance .minorTicks
679+
680+
665681class Axis (artist .Artist ):
666682"""
667683 Public attributes
@@ -696,8 +712,6 @@ def __init__(self, axes, pickradius=15):
696712self .label = self ._get_label ()
697713self .labelpad = rcParams ['axes.labelpad' ]
698714self .offsetText = self ._get_offset_text ()
699- self .majorTicks = []
700- self .minorTicks = []
701715self .unit_data = None
702716self .pickradius = pickradius
703717
@@ -708,6 +722,12 @@ def __init__(self, axes, pickradius=15):
708722self .cla ()
709723self ._set_scale ('linear' )
710724
725+ # During initialization, Axis objects often create ticks that are later
726+ # unused; this turns out to be a very slow step. Instead, use a custom
727+ # descriptor to make the tick lists lazy and instantiate them as needed.
728+ majorTicks = _LazyTickList (major = True )
729+ minorTicks = _LazyTickList (major = False )
730+
711731def set_label_coords (self ,x ,y ,transform = None ):
712732"""
713733 Set the coordinates of the label. By default, the x
@@ -798,11 +818,15 @@ def reset_ticks(self):
798818
799819 Each list starts with a single fresh Tick.
800820 """
801- del self .majorTicks [:]
802- del self .minorTicks [:]
803-
804- self .majorTicks .extend ([self ._get_tick (major = True )])
805- self .minorTicks .extend ([self ._get_tick (major = False )])
821+ # Restore the lazy tick lists.
822+ try :
823+ del self .majorTicks
824+ except AttributeError :
825+ pass
826+ try :
827+ del self .minorTicks
828+ except AttributeError :
829+ pass
806830self ._lastNumMajorTicks = 1
807831self ._lastNumMinorTicks = 1
808832