12.1.10.5.16. Draw pickers 1D plot

This demo shows how to programmatically set pickers to the line of a 1D plot.

The most important slots for these features are implemented in the designer widget itom1dqwtplot:

myPlotHandle.call("setPicker", axis-values [, curveIndex = 0, physicalCoordinates=True])
myPlotHandle.call("appendPicker", axis-values [, curveIndex = 0, physicalCoordinates=True])
myPlotHandle.call("deletePicker", [index])

setPicker and appendPicker are used to set a new set of pickers or append further pickers to the existing set of pickers. deletePicker is used to clear existing pickers.

For settings pickers, a list or tuple of axis-values has to be given. The corresponding value is calculated based on the current curve, that is displayed. In order to stick the new picker to another than the first curve, use another curveIndex parameter. Usually, the axis-values are considered to be given in physical coordinates (which are displayed in the coordinate system).

If you want to give the coordinate of a picker in real pixel-coordinates of the dataObject, set physicalCoordinates to False.

import numpy as np
from itom import plot
from itom import dataObject


def pickerChangedSlot(pickerIdx, posX, posY, curveIdx):
    print(
        "picker %i changed. New pos: (%.2f, %.2f), curve: %i"
        % (pickerIdx, posX, posY, curveIdx)
    )


# create demo data
# 1d sine
sine = np.sin(np.arange(0, 10 * np.pi, (1 / 20) * np.pi))
sine2 = np.sin(np.arange(0, 5 * np.pi, (1 / 40) * np.pi))
twosines = dataObject([2, len(sine)], "float64")
twosines[0, :] = sine
twosines[1, :] = sine2

twosines.axisScales = (1, np.pi / 20)

[i, h] = plot(twosines, "itom1dqwtplot")

h.connect("pickerChanged(int,double,double,int)", pickerChangedSlot)

# increase the maximum number of pickers to 7
h["pickerLimit"] = 7

# set two pickers to the first curve
h.call("setPicker", (1.5 * np.pi, 2.5 * np.pi), 0)

# set two pickers to the second curve
h.call("appendPicker", (40, 80, 120, 160, 200), 1, False)