Build your first Taurus GUI in Python

This tutorial introduces the basic Taurus GUI building blocks by progressively creating a small interface for a Tango device. You will start by displaying a single attribute and then move to editable values and panel.TaurusForm.

Set up the example device

The device server used for the examples can be obtained here.

For the examples to work as provided, create and run a TaurusTest device with the following configuration:

Server (ServerName/Instance):

TaurusTest/taurustest

Class:

TaurusTest

Devices:

sys/taurustest/1

You can configure it from Jive by going to Edit -> Create server and entering the parameters above.

Create the application window

Start with a minimal Qt application and a horizontal layout:

import sys
from taurus.external.qt import Qt
from taurus.qt.qtgui.application import TaurusApplication

app = TaurusApplication(sys.argv, cmd_line_parser=None)
panel = Qt.QWidget()
layout = Qt.QHBoxLayout()
panel.setLayout(layout)

The following examples only show the code that changes. Unless otherwise stated, add the snippets between the code above and this common footer:

panel.show()
sys.exit(app.exec_())

Display an attribute value

A display.TaurusLabel can display a Tango attribute value. Add the following code before the common footer:

from taurus.qt.qtgui.display import TaurusLabel

w = TaurusLabel()
layout.addWidget(w)
w.model = "sys/taurustest/1/position#rvalue.magnitude"

If the #rvalue.magnitude fragment is omitted from the model, the units are also displayed when they are defined by the attribute.

Add the attribute label

Use the #label fragment to display the Tango label next to the value:

from taurus.qt.qtgui.display import TaurusLabel

w1, w2 = TaurusLabel(), TaurusLabel()
layout.addWidget(w1)
layout.addWidget(w2)
w1.model, w1.bgRole = "sys/taurustest/1/position#label", ""
w2.model = "sys/taurustest/1/position#rvalue.magnitude"

Add separate units

Taurus model fragments let different widgets display different parts of the same attribute model. Extend the previous example with a third label:

from taurus.qt.qtgui.display import TaurusLabel

w1, w2, w3 = TaurusLabel(), TaurusLabel(), TaurusLabel()
layout.addWidget(w1)
layout.addWidget(w2)
layout.addWidget(w3)

w1.model, w1.bgRole = "sys/taurustest/1/position#label", ""
w2.model = "sys/taurustest/1/position#rvalue.magnitude"
w3.model, w3.bgRole = "sys/taurustest/1/position#rvalue.units", ""

The interface now displays the attribute label, its current value, and its units independently.

Make the value editable

To let the user change the attribute, add a Taurus input widget for the write value. For example:

from taurus.qt.qtgui.display import TaurusLabel
from taurus.qt.qtgui.input import TaurusValueLineEdit

w1 = TaurusLabel()
w2 = TaurusLabel()
w3 = TaurusValueLineEdit()
w4 = TaurusLabel()

layout.addWidget(w1)
layout.addWidget(w2)
layout.addWidget(w3)
layout.addWidget(w4)

w1.model, w1.bgRole = "sys/taurustest/1/position#label", ""
w2.model = "sys/taurustest/1/position#rvalue.magnitude"
w3.model = "sys/taurustest/1/position#wvalue.magnitude"
w4.model, w4.bgRole = "sys/taurustest/1/position#rvalue.units", ""

Editing the write value with TaurusValueLineEdit.

Other Taurus input widgets, such as input.TaurusValueSpinBox and input.TaurusWheelEdit, can be used in the same way.

Use a TaurusForm for several attributes

Creating individual widgets becomes tedious when you need to display many attributes. panel.TaurusForm provides a higher-level interface that selects suitable widgets for the models it receives.

For this step, replace the generic panel created earlier with a TaurusForm:

from taurus.qt.qtgui.panel import TaurusForm

panel = TaurusForm()
props = ["state", "status", "position", "velocity", "acceleration"]
model = ["sys/taurustest/1/%s" % p for p in props]
panel.setModel(model)

The form aligns the rows, manages write operations, and chooses appropriate widgets according to each model.

Customize the form

You can override the automatically selected widgets for individual rows:

from taurus.qt.qtgui.display import TaurusLabel

panel[0].readWidgetClass = TaurusLabel
panel[2].writeWidgetClass = "TaurusWheelEdit"

You can also customize the appearance with Qt stylesheets:

panel.setStyleSheet("font-size: 40px;")

The recommended way to change the style is to use setStyleSheet on the TaurusForm (or another top-level widget). If you need to style a specific widget inside a TaurusValue, use Qt methods directly:

from taurus.external.qt import Qt

for row in panel:
    row.readWidget().setFont(Qt.QFont("Sans Serif", 40))

For more detailed form customization options, see Use Taurus forms.

Next steps

You now have a small Taurus application that can display and edit live Tango attributes and can scale from individual widgets to a complete form.

Continue with Plot data with Taurus to add live plots and trends, or see Build a GUI with the TaurusGUI framework to build a larger application using the TaurusGUI framework.