Recipe for changing curve appearance properties in a TaurusTrend

trendcurveprops.py

import sys
from taurus.qt.qtgui.application import TaurusApplication
from taurus.qt.qtgui.plot import TaurusTrend

app = TaurusApplication()

w = TaurusTrend()

model = 'sys/tg_test/1/ampli'
w.setModel(model)

#TaurusTrend uses Trendsets instead of Curves. Trendsets are collections of
# curves, but they delay the curve creation until at least one event arrives
# (in order to know how many curves are needed, depending on the data size)
# Therefore, calling w.getCurveAppearancePropertiesDict() immediately after the
# setModel returns an empty dict.
# As a workaround, one can force the app to process events before trying to get
# the curve

app.processEvents()

# after calling processEvents, we can access the curve and its properties

# Demo1 accessing via propdict (safer):
propdict = w.getCurveAppearancePropertiesDict()
propdict['sys/tg_test/1/ampli[0]'].lWidth = 9  # Note the "[0]"!!!!
w.setCurveAppearanceProperties(propdict)

# Demo2, accessing via trendset and the curve (more control, be careful with
# threads)
ts = w.getTrendSet(model)
curve = ts[0]
prop = curve.getAppearanceProperties()
prop.lColor = 'red'
curve.setAppearanceProperties(prop)

w.show()

sys.exit(app.exec_())