"""
Draws a scatterplot of a set of random points of variable size.
 - Left-drag pans the plot.
 - Mousewheel up and down zooms the plot in and out.
 - Pressing "z" brings up the Zoom Box, and you can click-drag a rectangular
   region to zoom.  If you use a sequence of zoom boxes, pressing alt-left-arrow
   and alt-right-arrow moves you forwards and backwards through the "zoom
   history".
"""

# Major library imports
import numpy

# Enthought library imports
from enable.api import Component, ComponentEditor
from traits.api import HasTraits, Instance
from traitsui.api import Item, Group, View

# Chaco imports
from chaco.api import ArrayPlotData, Plot
from chaco.tools.api import PanTool, ZoomTool

# ===============================================================================
# # Create the Chaco plot.
# ===============================================================================
def _create_plot_component():

    # Create some data
    numpts = 1000
    x = numpy.arange(0, numpts)
    y = numpy.random.random(numpts)
    marker_size = numpy.random.normal(4.0, 4.0, numpts)

    # Create a plot data object and give it this data
    pd = ArrayPlotData()
    pd.set_data("index", x)
    pd.set_data("value", y)

    # Create the plot
    plot = Plot(pd)
    plot.plot(
        ("index", "value"),
        type="scatter",
        marker="circle",
        index_sort="ascending",
        color=(1.0, 0.0, 0.74, 0.4),
        marker_size=marker_size,
        bgcolor="white",
    )

    # Tweak some of the plot properties
    plot.title = "Scatter Plot"
    plot.line_width = 0.5
    plot.padding = 50

    # Attach some tools to the plot
    plot.tools.append(PanTool(plot, constrain_key="shift"))
    zoom = ZoomTool(component=plot, tool_mode="box", always_on=False)
    plot.overlays.append(zoom)

    return plot


# ===============================================================================
# Attributes to use for the plot view.
size = (650, 650)
title = "Basic scatter plot"
bgcolor = "lightgray"

# ===============================================================================
# # Demo class that is used by the demo.py application.
# ===============================================================================
class Demo(HasTraits):
    plot = Instance(Component)

    traits_view = View(
        Group(
            Item(
                "plot",
                editor=ComponentEditor(size=size, bgcolor=bgcolor),
                show_label=False,
            ),
            orientation="vertical",
        ),
        resizable=True,
        title=title,
    )

    def _plot_default(self):
        return _create_plot_component()


demo = Demo()

if __name__ == "__main__":
    demo.configure_traits()