ROI wont update its handle coordinates when dragging

[Friedrich]

heyho

i am fooling around with a PolyLineROI. when i add it to my viewbox and start moving it (to the desired position) it won't update the positions of its handles. even if it is at its new position and i am starting to drag the handles, the position-change is relative to its handles' original position.

import pyqtgraph as pg

def roiMove():

   """Print the coordinates of the ROI."""

   print(roi.getState()['points'])

win = pg.GraphicsWindow()

vb = win.addViewBox()

# roi in triangle shape

roi = pg.PolyLineROI([[1, 2], [1.5, 2], [1, 0]],

           closed=True,

           pen=pg.mkPen(color=(0, 201, 255, 255), width=3)

               )

# connect to printing function when moving something

# NOTE: when dragging the whole ROI the positions won't be updated

roi.sigRegionChanged.connect(roiMove)

vb.addItem(roi)

vb.setXRange(-5, 5)

vb.setYRange(-5, 5)

pg.QtGui.QApplication.exec_()

i feel like i am close to the solution or just missed some important point...

[Friedrich]

as it turns out, i really was close. instead of taking the points from the state, the handle postions needed to be mapped to parent. i adjusted the MWE for those who are interested:

import pyqtgraph as pg

def roiMove():

   """Print the coordinates of the ROI."""

   pts = roi.getSceneHandlePositions()

   print([roi.mapSceneToParent(pt[1]) for pt in pts])

win = pg.GraphicsWindow()

vb = win.addViewBox()

# roi in triangle shape

roi = pg.PolyLineROI([[1, 2], [1.5, 2], [1, 0]],

           closed=True,

           pen=pg.mkPen(color=(0, 201, 255, 255), width=3)

               )

# connect to printing function when moving something

roi.sigRegionChanged.connect(roiMove)

vb.addItem(roi)

vb.setXRange(-5, 5)

vb.setYRange(-5, 5)

pg.QtGui.QApplication.exec_()

Code hier eingeben...

[Tim Williams]

Thanks for this. I was just getting ready to do something very similar. 

[jean Bilheux]

Thanks a lot Friedrich. Me too, that will be very useful for my project.