Question

我想知道我是否可以更新pyqtgraph中的自定义图形项（CandlestickItem），就像我更新BarGraphItem一样。如果它是一个BarGraphItem，我可以在收到新值时更新它的值：

barObject = pg.BarGraphItem( x=x_array, height=y_array, width=1, brush=(127, 163, 222, 90))
barObject.setOpts( x=new_x_array, height=new_y_array )

但是当谈到pyqtgraph的CandlestickItem时，我不知道如何做同样的工作。

import pyqtgraph as pg
from pyqtgraph import QtCore, QtGui

## Create a subclass of GraphicsObject.
## The only required methods are paint() and boundingRect() 
## (see QGraphicsItem documentation)
class CandlestickItem(pg.GraphicsObject):
    def __init__(self, data):
        pg.GraphicsObject.__init__(self)
        self.data = data  ## data must have fields: time, open, close, min, max
        self.generatePicture()

    def generatePicture(self):
        ## pre-computing a QPicture object allows paint() to run much more quickly, 
        ## rather than re-drawing the shapes every time.
        self.picture = QtGui.QPicture()
        p = QtGui.QPainter(self.picture)
        p.setPen(pg.mkPen('w'))
        w = (self.data[1][0] - self.data[0][0]) / 3.
        for (t, open, close, min, max) in self.data:
            p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t, max))
            if open > close:
                p.setBrush(pg.mkBrush('r'))
            else:
                p.setBrush(pg.mkBrush('g'))
            p.drawRect(QtCore.QRectF(t-w, open, w*2, close-open))
        p.end()

    def paint(self, p, *args):
        p.drawPicture(0, 0, self.picture)

    def boundingRect(self):
        ## boundingRect _must_ indicate the entire area that will be drawn on
        ## or else we will get artifacts and possibly crashing.
        ## (in this case, QPicture does all the work of computing the bouning rect for us)
        return QtCore.QRectF(self.picture.boundingRect())

data = [  ## fields are (time, open, close, min, max).
    (1., 10, 13, 5, 15),
    (2., 13, 17, 9, 20),
    (3., 17, 14, 11, 23),
    (4., 14, 15, 5, 19),
    (5., 15, 9, 8, 22),
    (6., 9, 15, 8, 16),
]
item = CandlestickItem(data)
plt = pg.plot()
plt.addItem(item)
plt.setWindowTitle('pyqtgraph example: customGraphicsItem')

## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

我提到了这篇文章（The fastest way to add a new data bar with pyqtgraph），但我想要的不是使用调度程序（例如QtCore.QTimer（））更新图形，而是手动更新图形，就像我做的那样致电barObject.setOpts。有没有办法做到这一点？

如何更新pyqtgraph中的自定义图形项？

0 个答案: