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Defines the GridMapper class, which maps from a 2-D region in data space
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into a structured (gridded) 1-D output space.
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# Major library imports
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from numpy import transpose
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# Enthought library imports
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from enthought.traits.api import Bool, DelegatesTo, Instance, Float, Property
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# Local relative imports
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from abstract_mapper import AbstractMapper
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from base_1d_mapper import Base1DMapper
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from data_range_2d import DataRange2D
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from linear_mapper import LinearMapper
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from log_mapper import LogMapper
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class GridMapper(AbstractMapper):
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Maps a 2-D data space to and from screen space by specifying a 2-tuple in
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data space or by specifying a pair of screen coordinates.
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The mapper concerns itself only with metric and not with orientation. So, to
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"flip" a screen space orientation, swap the appropriate screen space
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values for **x_low_pos**, **x_high_pos**, **y_low_pos**, and **y_high_pos**.
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# The data-space bounds of the mapper.
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range = Instance(DataRange2D)
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# The screen space position of the lower bound of the horizontal axis.
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x_low_pos = Float(0.0)
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# The screen space position of the upper bound of the horizontal axis.
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x_high_pos = Float(1.0)
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# The screen space position of the lower bound of the vertical axis.
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y_low_pos = Float(0.0)
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# The screen space position of the upper bound of the vertical axis.
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y_high_pos = Float(1.0)
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# Convenience property for low and high positions in one structure.
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# Must be a tuple (x_low_pos, x_high_pos, y_low_pos, y_high_pos).
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screen_bounds = Property
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# Should the mapper stretch the dataspace when its screen space bounds are
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# modified (default), or should it preserve the screen-to-data ratio and
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# resize the data bounds? If the latter, it will only try to preserve
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# the ratio if both screen and data space extents are non-zero.
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stretch_data_x = DelegatesTo("_xmapper", prefix="stretch_data")
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stretch_data_y = DelegatesTo("_ymapper", prefix="stretch_data")
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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_updating_submappers = Bool(False)
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_xmapper = Instance(Base1DMapper)
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_ymapper = Instance(Base1DMapper)
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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def __init__(self, x_type="linear", y_type="linear", range=None, **kwargs):
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# TODO: This is currently an implicit assumption, i.e. that the range
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# will be passed in to the constructor. It would be impossible to
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# create the xmapper and ymapper otherwise. However, this should be
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# changed so that the mappers get created or modified in response to
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# the .range attribute changing, instead of requiring the range to
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# be passed in at construction time.
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if "_xmapper" not in kwargs:
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if x_type == "linear":
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self._xmapper = LinearMapper(range=self.range.x_range)
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self._xmapper = LogMapper(range=self.range.x_range)
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raise ValueError("Invalid x axis type: %s" % x_type)
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self._xmapper = kwargs.pop("_xmapper")
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if "_ymapper" not in kwargs:
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if y_type == "linear":
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self._ymapper = LinearMapper(range=self.range.y_range)
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self._ymapper = LogMapper(range=self.range.y_range)
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raise ValueError("Invalid y axis type: %s" % y_type)
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self._ymapper = kwargs.pop("_ymapper")
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# Now that the mappers are created, we can go to the normal HasTraits
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# constructor, which might set values that depend on us having a valid
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super(GridMapper, self).__init__(**kwargs)
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def map_screen(self, data_pts):
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""" map_screen(data_pts) -> screen_array
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Maps values from data space into screen space.
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xs, ys = transpose(data_pts)
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screen_xs = self._xmapper.map_screen(xs)
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screen_ys = self._ymapper.map_screen(ys)
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return zip(screen_xs,screen_ys)
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def map_data(self, screen_pts):
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""" map_data(screen_pts) -> data_vals
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Maps values from screen space into data space.
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screen_xs, screen_ys = transpose(screen_pts)
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xs = self._xmapper.map_data(screen_xs)
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ys = self._ymapper.map_data(screen_ys)
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def map_data_array(self, screen_pts):
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return self.map_data(screen_pts)
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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def _update_bounds(self):
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self._updating_submappers = True
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self._xmapper.screen_bounds = (self.x_low_pos, self.x_high_pos)
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self._ymapper.screen_bounds = (self.y_low_pos, self.y_high_pos)
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self._updating_submappers = False
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def _update_range(self):
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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def _range_changed(self, old, new):
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old.on_trait_change(self._update_range, "updated", remove=True)
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new.on_trait_change(self._update_range, "updated")
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if self._xmapper is not None:
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self._xmapper.range = new.x_range
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if self._ymapper is not None:
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self._ymapper.range = new.y_range
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def _x_low_pos_changed(self):
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self._xmapper.low_pos = self.x_low_pos
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def _x_high_pos_changed(self):
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self._xmapper.high_pos = self.x_high_pos
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def _y_low_pos_changed(self):
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self._ymapper.low_pos = self.y_low_pos
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def _y_high_pos_changed(self):
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self._ymapper.high_pos = self.y_high_pos
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def _set_screen_bounds(self, new_bounds):
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# TODO: figure out a way to not need to do this check:
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if self.screen_bounds == new_bounds:
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self.set(x_low_pos = new_bounds[0], trait_change_notify=False)
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self.set(x_high_pos = new_bounds[1], trait_change_notify=False)
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self.set(y_low_pos = new_bounds[2], trait_change_notify=False)
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self.set(y_high_pos = new_bounds[3], trait_change_notify=False)
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self._update_bounds( )
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def _get_screen_bounds(self):
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return (self.x_low_pos, self.x_high_pos,
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self.y_low_pos, self.y_high_pos)
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def _updated_fired_for__xmapper(self):
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if not self._updating_submappers:
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def _updated_fired_for__ymapper(self):
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if not self._updating_submappers:
added
removed
enthought/chaco/grid_mapper.py
