Support updating bars graphics from array
This makes a OHLC graphics "sequence" update very similar (actually API compatible) with `pg.PlotCurveItem.setData()`. The difference here is that only latest OHLC datum is used to update the charts last bar.bar_select
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048a13dd0e
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5e8e48c7b7
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@ -185,10 +185,10 @@ class BarItems(pg.GraphicsObject):
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def __init__(self):
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super().__init__()
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self.picture = QtGui.QPicture()
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self.lines = None
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self._last_quote = {}
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# lines container
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self.lines: np.ndarray = None
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# TODO: this is the routine to be retriggered for redraw
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# TODO: can we be faster just dropping this?
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@contextmanager
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def painter(self):
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# pre-computing a QPicture object allows paint() to run much
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@ -221,8 +221,6 @@ class BarItems(pg.GraphicsObject):
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QtCore.QLineF(
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q['index'] + self.w, q['close'], q['index'], q['close'])
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)
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else:
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self._last_quote = q
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# if not _tina_mode: # piker mode
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p.setPen(self.bull_brush)
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p.drawLines(*lines)
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@ -245,17 +243,24 @@ class BarItems(pg.GraphicsObject):
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# p.setPen(self.bear_brush)
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# p.drawLines(*downs)
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def update_last_bar(
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def update_from_array(
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self,
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quote: Dict[str, Any],
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array: np.ndarray,
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) -> None:
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"""Update the last datum's bar graphic from a quote ``dict``.
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"""Update the last datum's bar graphic from input data array.
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This routine should be interface compatible with
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``pg.PlotCurveItem.setData()``. Normally this method in
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``pyqtgraph`` seems to update all the data passed to the
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graphics object, and then update/rerender, but here we're
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assuming the prior graphics havent changed (OHLC history rarely
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does) so this "should" be simpler and faster.
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"""
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last = quote['last']
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body, larm, rarm = self.lines[-3:] # close line is absolute last
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# do we really need to verify the entire past data set?
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last = array['close'][-1]
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body, larm, rarm = self.lines[-3:]
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# XXX: is there a faster way to modify this?
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# update right arm
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rarm.setLine(rarm.x1(), last, rarm.x2(), last)
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@ -270,23 +275,27 @@ class BarItems(pg.GraphicsObject):
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body.setLine(body.x1(), low, body.x2(), high)
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# draw the pic
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with self.painter() as p:
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p.setPen(self.bull_brush)
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p.drawLines(*self.lines)
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# trigger re-draw
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# trigger re-render
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self.update()
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# be compat with ``pg.PlotCurveItem``
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setData = update_from_array
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# XXX: From the customGraphicsItem.py example:
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# The only required methods are paint() and boundingRect()
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def paint(self, p, *args):
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def paint(self, p, opt, widget):
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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
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# drawn on or else we will get artifacts and possibly crashing.
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# (in this case, QPicture does all the work of computing the
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# bouning rect for us)
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# bounding rect for us)
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return QtCore.QRectF(self.picture.boundingRect())
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