59 lines
2.0 KiB
Python
59 lines
2.0 KiB
Python
"""
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Demonstrate creation of a custom graphic (a candlestick plot)
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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 import QtCore, QtGui
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## Create a subclass of GraphicsObject.
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## The only required methods are paint() and boundingRect()
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## (see QGraphicsItem documentation)
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class CandlestickItem(pg.GraphicsObject):
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def __init__(self, data):
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pg.GraphicsObject.__init__(self)
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self.data = data ## data must have fields: time, open, close, min, max
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self.generatePicture()
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def generatePicture(self):
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## pre-computing a QPicture object allows paint() to run much more quickly,
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## rather than re-drawing the shapes every time.
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self.picture = QtGui.QPicture()
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p = QtGui.QPainter(self.picture)
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p.setPen(pg.mkPen('w'))
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w = (self.data[1][0] - self.data[0][0]) / 3.
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for (t, open, close, min, max) in self.data:
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p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t, max))
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if open > close:
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p.setBrush(pg.mkBrush('r'))
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else:
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p.setBrush(pg.mkBrush('g'))
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p.drawRect(QtCore.QRectF(t-w, open, w*2, close-open))
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p.end()
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def paint(self, p, *args):
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p.drawPicture(0, 0, self.picture)
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def boundingRect(self):
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## boundingRect _must_ indicate the entire area that will be drawn on
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## or else we will get artifacts and possibly crashing.
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## (in this case, QPicture does all the work of computing the bouning rect for us)
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return QtCore.QRectF(self.picture.boundingRect())
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data = [ ## fields are (time, open, close, min, max).
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(1., 10, 13, 5, 15),
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(2., 13, 17, 9, 20),
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(3., 17, 14, 11, 23),
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(4., 14, 15, 5, 19),
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(5., 15, 9, 8, 22),
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(6., 9, 15, 8, 16),
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]
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item = CandlestickItem(data)
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plt = pg.plot()
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plt.addItem(item)
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plt.setWindowTitle('pyqtgraph example: customGraphicsItem')
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if __name__ == '__main__':
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pg.exec()
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