pyqtgraph/examples/CustomGraphItem.py

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# -*- coding: utf-8 -*-
"""
Simple example of subclassing GraphItem.
"""
import initExample ## Add path to library (just for examples; you do not need this)
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
# Enable antialiasing for prettier plots
pg.setConfigOptions(antialias=True)
w = pg.GraphicsLayoutWidget(show=True)
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w.setWindowTitle('pyqtgraph example: CustomGraphItem')
v = w.addViewBox()
v.setAspectLocked()
class Graph(pg.GraphItem):
def __init__(self):
self.dragPoint = None
self.dragOffset = None
self.textItems = []
pg.GraphItem.__init__(self)
self.scatter.sigClicked.connect(self.clicked)
def setData(self, **kwds):
self.text = kwds.pop('text', [])
self.data = kwds
if 'pos' in self.data:
npts = self.data['pos'].shape[0]
self.data['data'] = np.empty(npts, dtype=[('index', int)])
self.data['data']['index'] = np.arange(npts)
self.setTexts(self.text)
self.updateGraph()
def setTexts(self, text):
for i in self.textItems:
i.scene().removeItem(i)
self.textItems = []
for t in text:
item = pg.TextItem(t)
self.textItems.append(item)
item.setParentItem(self)
def updateGraph(self):
pg.GraphItem.setData(self, **self.data)
for i,item in enumerate(self.textItems):
item.setPos(*self.data['pos'][i])
def mouseDragEvent(self, ev):
if ev.button() != QtCore.Qt.MouseButton.LeftButton:
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ev.ignore()
return
if ev.isStart():
# We are already one step into the drag.
# Find the point(s) at the mouse cursor when the button was first
# pressed:
pos = ev.buttonDownPos()
pts = self.scatter.pointsAt(pos)
if len(pts) == 0:
ev.ignore()
return
self.dragPoint = pts[0]
ind = pts[0].data()[0]
self.dragOffset = self.data['pos'][ind] - pos
elif ev.isFinish():
self.dragPoint = None
return
else:
if self.dragPoint is None:
ev.ignore()
return
ind = self.dragPoint.data()[0]
self.data['pos'][ind] = ev.pos() + self.dragOffset
self.updateGraph()
ev.accept()
def clicked(self, pts):
print("clicked: %s" % pts)
g = Graph()
v.addItem(g)
## Define positions of nodes
pos = np.array([
[0,0],
[10,0],
[0,10],
[10,10],
[5,5],
[15,5]
], dtype=float)
## Define the set of connections in the graph
adj = np.array([
[0,1],
[1,3],
[3,2],
[2,0],
[1,5],
[3,5],
])
## Define the symbol to use for each node (this is optional)
symbols = ['o','o','o','o','t','+']
## Define the line style for each connection (this is optional)
lines = np.array([
(255,0,0,255,1),
(255,0,255,255,2),
(255,0,255,255,3),
(255,255,0,255,2),
(255,0,0,255,1),
(255,255,255,255,4),
], dtype=[('red',np.ubyte),('green',np.ubyte),('blue',np.ubyte),('alpha',np.ubyte),('width',float)])
## Define text to show next to each symbol
texts = ["Point %d" % i for i in range(6)]
## Update the graph
g.setData(pos=pos, adj=adj, pen=lines, size=1, symbol=symbols, pxMode=False, text=texts)
if __name__ == '__main__':
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pg.exec()