57 lines
1.8 KiB
Python
57 lines
1.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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This example shows how to insert text into a scene using TextItem. This class
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is for displaying text that is anchored to a particular location in the data
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coordinate system, but which is always displayed unscaled.
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For text that scales with the data, use QTextItem.
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For text that can be placed in a layout, use LabelItem.
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"""
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import initExample ## Add path to library (just for examples; you do not need this)
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import pyqtgraph as pg
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from pyqtgraph.Qt import QtCore, QtGui
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import numpy as np
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x = np.linspace(-20, 20, 1000)
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y = np.sin(x) / x
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plot = pg.plot() ## create an empty plot widget
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plot.setYRange(-1, 2)
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plot.setWindowTitle('pyqtgraph example: text')
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curve = plot.plot(x,y) ## add a single curve
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## Create text object, use HTML tags to specify color/size
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text = pg.TextItem(html='<div style="text-align: center"><span style="color: #FFF;">This is the</span><br><span style="color: #FF0; font-size: 16pt;">PEAK</span></div>', anchor=(-0.3,0.5), angle=45, border='w', fill=(0, 0, 255, 100))
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plot.addItem(text)
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text.setPos(0, y.max())
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## Draw an arrowhead next to the text box
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arrow = pg.ArrowItem(pos=(0, y.max()), angle=-45)
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plot.addItem(arrow)
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## Set up an animated arrow and text that track the curve
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curvePoint = pg.CurvePoint(curve)
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plot.addItem(curvePoint)
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text2 = pg.TextItem("test", anchor=(0.5, -1.0))
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text2.setParentItem(curvePoint)
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arrow2 = pg.ArrowItem(angle=90)
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arrow2.setParentItem(curvePoint)
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## update position every 10ms
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index = 0
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def update():
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global curvePoint, index
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index = (index + 1) % len(x)
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curvePoint.setPos(float(index)/(len(x)-1))
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text2.setText('[%0.1f, %0.1f]' % (x[index], y[index]))
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timer = QtCore.QTimer()
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timer.timeout.connect(update)
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timer.start(10)
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if __name__ == '__main__':
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pg.exec()
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