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Lasso selection of data points
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Draws a simple scatterplot of random data. Drag the mouse to use the lasso
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selector, which allows you to circle all the points in a region.
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Upon completion of the lasso operation, the indices of the selected points are
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printed to the console.
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Uncomment 'lasso_selection.incremental_select' line (line 74) to see the
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indices of the selected points computed in real time.
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# Major library imports
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from numpy import sort, compress, arange
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from numpy.random import random
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# Enthought library imports
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from enable.api import Component, ComponentEditor
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from traits.api import HasTraits, Instance
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from traitsui.api import Item, Group, View
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from chaco.api import ArrayPlotData, Plot, LassoOverlay
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from chaco.tools.api import LassoSelection, ScatterInspector
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#===============================================================================
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# # Create the Chaco plot.
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#===============================================================================
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def _create_plot_component():
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x = sort(random(npts))
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# Create a plot data obect and give it this data
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pd.set_data("index", x)
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pd.set_data("value", y)
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plot.plot(("index", "value"),
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index_sort="ascending",
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# Tweak some of the plot properties
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plot.title = "Scatter Plot With Lasso Selection"
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# Right now, some of the tools are a little invasive, and we need the
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# actual ScatterPlot object to give to them
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my_plot = plot.plots["my_plot"][0]
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# Attach some tools to the plot
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lasso_selection = LassoSelection(component=my_plot,
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selection_datasource=my_plot.index)
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my_plot.active_tool = lasso_selection
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my_plot.tools.append(ScatterInspector(my_plot))
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lasso_overlay = LassoOverlay(lasso_selection=lasso_selection,
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my_plot.overlays.append(lasso_overlay)
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# Uncomment this if you would like to see incremental updates:
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#lasso_selection.incremental_select = True
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#===============================================================================
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# Attributes to use for the plot view.
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title="Scatter plot with selection"
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#===============================================================================
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# # Demo class that is used by the demo.py application.
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#===============================================================================
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class Demo(HasTraits):
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plot = Instance(Component)
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Item('plot', editor=ComponentEditor(size=size),
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orientation = "vertical"),
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resizable=True, title=title
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def _selection_changed(self):
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mask = self.index_datasource.metadata['selection']
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print "New selection: "
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print compress(mask, arange(len(mask)))
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# Ensure that the points are printed immediately:
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def _plot_default(self):
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plot = _create_plot_component()
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# Retrieve the plot hooked to the LassoSelection tool.
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my_plot = plot.plots["my_plot"][0]
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lasso_selection = my_plot.active_tool
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# Set up the trait handler for the selection
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self.index_datasource = my_plot.index
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lasso_selection.on_trait_change(self._selection_changed,
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if __name__ == "__main__":
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demo.configure_traits()
added
removed
examples/demo/basic/scatter_select.py
