Graphs Scrolling Update, Issue

[Matty Kamp]

Hello everyone,

I'm trying to keep a candlestick chart updated in PyQtGraph, and everything is going well. However, when I update the candlestick, it exhibits a bug where the last candlestick retains parts that should be cleared or doesn't draw the rectangle completely. Interestingly, if I hover my mouse over it, the candlestick redraws correctly, or if I zoom in or out, it also fixes the issue.

I'm wondering if anyone has any suggestions on how to address this? I thought about triggering a range change every time I update the chart, but it doesn't feel like the right approach. Additionally, if I change the focus or switch to another window and come back, the issue is also resolved.

I would appreciate any insights or tips on how to resolve this bug. Thank you in advance!

class CandleStick(pg.GraphicsObject):

def __init__(self, data):

pg.GraphicsObject.__init__(self)

self.data = data

self.generatePicture()

def generatePicture(self):

self.picture = QtGui.QPicture()

p = QtGui.QPainter(self.picture)

w = 0.33

for t, (open, close, min, max) in enumerate(self.data[['open', 'close', 'low', 'high']].to_numpy()):

t = t+1

if open > close:

p.setPen(pg.mkPen('r'))

p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t, max))

p.setBrush(pg.mkBrush('r'))

p.drawRect(QtCore.QRectF(t-w, open, w*2, close-open))

elif open < close:

p.setPen(pg.mkPen('g'))

p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t, max))

p.setBrush(pg.mkBrush('g'))

p.drawRect(QtCore.QRectF(t-w, open, w*2, close-open))

elif open == close:

if max == min:

p.setPen(pg.mkPen('g',width=1))

p.setBrush(pg.mkBrush('g'))

p.drawRect(QtCore.QRectF(t-w, open, w*2, 0))

else:

p.setPen(pg.mkPen('g'))

p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t,max))

p.setBrush(pg.mkBrush('g'))

p.drawRect(QtCore.QRectF(t-w, open, w*2, 0))

p.end()

def update(self, data):

self.data = data

self.generatePicture()

def paint(self, p, *args):

p.drawPicture(0, 0, self.picture)

def boundingRect(self):

return QtCore.QRectF(self.picture.boundingRect())

[Matty Kamp]

I added a workaround of removing and reapplying focus to the widget, and it resolved the issue. However, I'm not happy with this solution as it feels like a hack.