Use the Panel.getBoundingBox method to get the panel dimensions:
Code:
import viz
import vizshape
import vizdlg
viz.go()
myPanel = vizdlg.Panel(align=viz.ALIGN_LEFT_BOTTOM)
row = vizdlg.Panel(layout=vizdlg.LAYOUT_HORZ_BOTTOM,border=False,background=False,margin=0)
row.addItem(viz.addText('Textbox'))
textbox = row.addItem(viz.addTextbox())
myPanel.addItem(row)
circle = vizshape.addCircle(parent=viz.ORTHO,scale=[20,20,1],color=viz.RED)
def showPanelDimensions():
box = myPanel.getBoundingBox()
width = box.width
height = box.height
print width,height
circle.setPosition([width,height,0])
myPanel.setPanelScale(2)
showPanelDimensions()