Package stripchart :: Module stripchart :: Class StripChart
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Class StripChart


Basic stripchart widget.

This widget displays data in a stripchart form. The data to be displayed can be set by setting the data member of the class. The data can be any object which can be accessed as a sequence, and for which the length can be queried using len(data). For example, a list or an array is valid for data:
>>> import array, stripchart
>>> s = stripchart.StripChart()
>>> data = array.array("d", range(0,100))
>>> s.data = data
>>> data = [ 1, 2, 3, 4, 5 ]
>>> s.data = data
>>> number = 42.0
>>> s.data = number   # this won't work!
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: data does not support len()

>>>

The data points are displayed as a connected line. If individual data points are spread apart enough for them to be separately distinguished then they are also displayed as small x marks on the line at each point location. The distance between each data point is the sampling period, which is 1/(sampling frequency). The widget can only display data with a constant sampling frequency

The horizontal and vertical scales/extents of the component are controlled by the hadjustment and vadjustment instance variables, To understand the interpretation of these adjustments please see the VGrade widget documentation.

The StripChart may also have a selection enabled. The selection is a single contiguous region of the chart which the user may select by clicking and dragging with the left mouse button. To enable selections, set the selection instance variable to a valid gtk.Adjustment. The selection adjustment has its lower member set to the minimum of the selection range and its upper member set to the maximum of the selection range (note that this is different from the interpretation of gtk.Adjustments used for controlling the range). The gtk.Adjustment used for the selection may be shared among multiple StripCharts to allow the same selection to be displayed on all of them.

For example, the following sets the selection of a StripChart to the range [10.0, 42.0]. Note that the value, step_incr, page_incr and page_size instance variables may be ignored in this step:
>>> import gtk, stripchart
>>> s = stripchart.StripChart()
>>> s.selection = gtk.Adjustment(0, 10.0, 42.0)

Method Summary
  __init__(self, hadjustment, vadjustment, selection)
Initializes the widget.
  __delattr__(self, name)
Delete attributes method.
  __setattr__(self, name, value)
Set attributes method.
  redraw(self)
Queues a redraw event for the widget.

Instance Variable Summary
Any object which can be accessed as a sequence. data: Data displayed by the widget.
gtk.Adjustment hadjustment: Controls the horizontal range displayed.
float period: Sampling period for the data.
gtk.Adjustment selection: The selected region of the StripChart.
gtk.Adjustment vadjustment: Controls the vertical range displayed.
gtk.DrawingArea widget: Read-only pseudo-parent widget.

Method Details

__init__(self, hadjustment=None, vadjustment=None, selection=None)
(Constructor)

Initializes the widget.
Parameters:
hadjustment - See hadjustment. If this is None then a default gtk.Adjustment is created.
vadjustment - See vadjustment. If this is None then a default gtk.Adjustment is created.
selection - See selection. If this is None then no selection is enabled. To set up an empty selection use gtk.Adjustment(-1).

__delattr__(self, name)

Delete attributes method.

__setattr__(self, name, value)

Set attributes method.

redraw(self)

Queues a redraw event for the widget.

This method may be used, for example, when the data instance variable has changed and the widget must be redrawn to reflect the change.

Instance Variable Details

data

Data displayed by the widget.
Type:
Any object which can be accessed as a sequence.

hadjustment

Controls the horizontal range displayed.
Type:
gtk.Adjustment

period

Sampling period for the data. Equal to 1 / (sampling frequency).
Type:
float

selection

The selected region of the StripChart.
Type:
gtk.Adjustment

vadjustment

Controls the vertical range displayed.
Type:
gtk.Adjustment

widget

Read-only pseudo-parent widget.
Type:
gtk.DrawingArea

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