45 lines
1.6 KiB
Python
45 lines
1.6 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Demonstrate programmatic setting of log transformation modes.
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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 numpy as np
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import pyqtgraph as pg
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app = pg.mkQApp("Log Axis Example")
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w = pg.GraphicsLayoutWidget(show=True)
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w.resize(800,800)
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w.setWindowTitle('pyqtgraph example: Log Axis, or How to Recognise Different Types of Curves from Quite a Long Way Away')
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p0 = w.addPlot(0,0, title="Linear")
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p1 = w.addPlot(0,1, title="X Semilog")
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p2 = w.addPlot(1,0, title="Y Semilog")
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p3 = w.addPlot(1,1, title="XY Log")
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# configure logarithmic axis scaling:
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p1.setLogMode(True, False)
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p2.setLogMode(False, True)
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p3.setLogMode(True, True)
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# 1000 points from 0.1 to 10, chosen to give a compatible range of values across curves:
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x = np.logspace(-1, 1, 1000)
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plotdata = ( # legend entry, color, and plotted equation:
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('1 / 3x' , '#ff9d47', 1./(3*x) ),
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('sqrt x' , '#b3cf00', 1/np.sqrt(x) ),
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('exp. decay', '#00a0b5', 5 * np.exp(-x/1) ),
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('-log x' , '#a54dff', - np.log10(x) )
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)
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p0.addLegend(offset=(-20,20)) # include legend only in top left plot
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for p in (p0, p1, p2, p3): # draw identical numerical data in all four plots
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p.showGrid(True, True) # turn on grid for all four plots
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p.showAxes(True, size=(40,None)) # show a full frame, and reserve identical room for y labels
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for name, color, y in plotdata: # draw all four curves as defined in plotdata
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pen = pg.mkPen(color, width=2)
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p.plot( x,y, pen=pen, name=name )
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w.show()
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if __name__ == '__main__':
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pg.exec()
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