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Add an example of using text strings as a custom smbol in ScatterPlotItem

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This commit is contained in:
Terekhov 2018-01-28 18:14:48 -05:00
parent b6838eb8c4
commit 551ccd105c
1 changed files with 28 additions and 7 deletions
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35
examples/ScatterPlot.py
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@ -11,6 +11,7 @@ import initExample
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg
import numpy as np
from collections import namedtuple
app = QtGui.QApplication([])
mw = QtGui.QMainWindow()
@ -32,8 +33,8 @@ print("Generating data, this takes a few seconds...")
## There are a few different ways we can draw scatter plots; each is optimized for different types of data:
## 1) All spots identical and transform-invariant (top-left plot).
## In this case we can get a huge performance boost by pre-rendering the spot
## 1) All spots identical and transform-invariant (top-left plot).
## In this case we can get a huge performance boost by pre-rendering the spot
## image and just drawing that image repeatedly.
n = 300
@ -57,21 +58,41 @@ s1.sigClicked.connect(clicked)
## 2) Spots are transform-invariant, but not identical (top-right plot).
## In this case, drawing is almsot as fast as 1), but there is more startup
## overhead and memory usage since each spot generates its own pre-rendered
## 2) Spots are transform-invariant, but not identical (top-right plot).
## In this case, drawing is almsot as fast as 1), but there is more startup
## overhead and memory usage since each spot generates its own pre-rendered
## image.
TextSymbol = namedtuple("TextSymbol", "label symbol scale")
def createLabel(label, angle):
symbol = QtGui.QPainterPath()
#symbol.addText(0, 0, QFont("San Serif", 10), label)
f = QtGui.QFont()
f.setPointSize(10)
symbol.addText(0, 0, f, label)
br = symbol.boundingRect()
scale = min(1. / br.width(), 1. / br.height())
tr = QtGui.QTransform()
tr.scale(scale, scale)
tr.rotate(angle)
tr.translate(-br.x() - br.width()/2., -br.y() - br.height()/2.)
return TextSymbol(label, tr.map(symbol), 0.1 / scale)
random_str = lambda : (''.join([chr(np.random.randint(ord('A'),ord('z'))) for i in range(np.random.randint(1,5))]), np.random.randint(0, 360))
s2 = pg.ScatterPlotItem(size=10, pen=pg.mkPen('w'), pxMode=True)
pos = np.random.normal(size=(2,n), scale=1e-5)
spots = [{'pos': pos[:,i], 'data': 1, 'brush':pg.intColor(i, n), 'symbol': i%5, 'size': 5+i/10.} for i in range(n)]
s2.addPoints(spots)
spots = [{'pos': pos[:,i], 'data': 1, 'brush':pg.intColor(i, n), 'symbol': label[1], 'size': label[2]*(5+i/10.)} for (i, label) in [(i, createLabel(*random_str())) for i in range(n)]]
s2.addPoints(spots)
w2.addItem(s2)
s2.sigClicked.connect(clicked)
## 3) Spots are not transform-invariant, not identical (bottom-left).
## This is the slowest case, since all spots must be completely re-drawn
## 3) Spots are not transform-invariant, not identical (bottom-left).
## This is the slowest case, since all spots must be completely re-drawn
## every time because their apparent transformation may have changed.
s3 = pg.ScatterPlotItem(pxMode=False) ## Set pxMode=False to allow spots to transform with the view