[pyqtgraph] How to add LegendItem to GLViewWidget displaying 3d stacked bars

[Jiří Chroustovský]

Hi I am trying to figure out a way how to add legend to GLViewWidget that
displays 3d stacked bars (these are created using GLBarGraphItem). The
problem here is that I have no plotItem so I cannot set any parent to the
LegendItem using .setParentItem() method. Is there any other way then
drawing rectangle and then adding items one by one by myself?

Here below is an example of my code:

from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph.opengl as gl
import numpy as np
import pyqtgraph as pg

class NestedDict(dict):
def __getitem__(self, item):
if item not in self:
self[item] = NestedDict()
return super().__getitem__(item)

mainList = [['BM', 'Butterfly', 'E-shop', '1400'],
['BM', 'Butterfly', 'Fler', '2450'],
['BM', 'Butterfly', 'Holesovice', '2450'],
['Climbing presents', 'Ear-rings', 'Holesovice', '136'],
['Climbing presents', 'Other jewellery', 'E-shop', '160'],
['Climbing presents', 'Other jewellery', 'Other', '112'],
['PP', 'Skirts', 'Fler', '1380'],
['PP', 'Skirts', 'Holesovice', '1320'],
['PP', 'Skirts', 'Sashe', '450'],
['PP', 'Bags', 'E-shop', '2500'],
['PP', 'Skirts', 'E-shop', '5600'],
['PP', 'Dresses', 'Other', '6551'],
['Mar', 'Dresses', 'Holesovice', '1000'],
['Mar', 'Skirts', 'Holesovice', '3000'],
['Mar', 'Ear-rings', 'Holesovice', '2000']]

app = QtGui.QApplication([])
w = gl.GLViewWidget()
w.opts['distance'] = 50
w.showMaximized()
w.setWindowTitle('pyqtgraph example: GLViewWidget')

ax = gl.GLAxisItem()
ax.setSize(10,10,10)
w.addItem(ax)

labels = dict(zip(list(set([x[0] for x in mainList])), [2*i for i,j in
enumerate(list(set([x[0] for x in mainList])))]))
shops = dict(zip(list(set([x[2] for x in mainList])), [2*i for i,j in
enumerate(list(set([x[2] for x in mainList])))]))
items = dict(zip(list(set([x[1] for x in mainList])), [2*i for i,j in
enumerate(list(set([x[1] for x in mainList])))]))

d = NestedDict()

for tag, item, source, qty in mainList:
d[tag][source][item] = qty

legend = pg.LegendItem()

colors = {}
for i in items.keys():
colors[i] = (round(5*np.random.rand()*np.random.rand(),2),
round(5*np.random.rand()*np.random.rand(),2),
round(5*np.random.rand()*np.random.rand(),2),
round(5*np.random.rand()*np.random.rand(),2))

for key, value in d.items():
for nkey, nvalue in value.items():
val = []
for index, nvalue_ in enumerate(nvalue.values()):
if index == 0:
val.append(0)
else:
val.append(float(list(nvalue.values())[index-1])/1000)
size = np.empty((1,1,3))
size[...,0:2] = 1
size[...,2] = float(list(nvalue.values())[index])/1000
bg = gl.GLBarGraphItem(np.array([[[labels[key], shops[nkey],
sum(val)]]]), size)
bg.setColor(colors[list(nvalue.keys())[index]])
w.addItem(bg)
## legend.addItem(colors[list(nvalue.keys())[index]],
list(nvalue.keys())[index])
## w.addItem(legend)

if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()

I will be grateful for any tip, thanks.