Apologies, the minimum working example had a mistake in it. Here is the
corrected code:
from <filename> import EllipseItem
pw = pg.PlotWidget()
item = EllipseItem([0,1],[1,0.5])
pw.addItem(item)
item.setRadius([0.5,1])
On Wednesday, 5 August 2020 23:54:29 UTC+2, Magne Lauritzen wrote:
>
> Good day.
>
> I am attempting to rapidly animate an ellipse in the form of a
> GraphicsObject in a PlotWidget. When the parameters of the ellipse changes,
> I call the requisite :
> self.update()
> self.informViewBoundsChanged()
> However, this appears to only schedule an update of the scene for later.
> This is not sufficient for me, as I will be rapidly updating the parameters
> of the GraphicsObject and require update speeds on the same order as
> PlotDataItem, i.e. near-instantaneous.
>
> Could this perhaps be solved by subclassing an implementation of Viewbox
> that catches an emitted signal from the GraphicsObject and forces an
> update? I believe this is how instantaneous updates of PlotDataItem is
> achieved, through the sigPlotChanged signal.
>
> Anyways, the following is the class definition for the custom ellipse
> GraphicsObject.
> class EllipseItem(pg.GraphicsObject):
> def __init__(self, center:Union[float,List[float]],
> radius:Union[float,List[float]]):
> pg.GraphicsObject.__init__(self)
> self.center = None
> self.radius = None
> self.setCenter(center)
> self.setRadius(radius)
>
> def setCenter(self,center:Union[float,List[float]]):
> self.center = center
> self.generatePicture()
>
> def setRadius(self,radius:Union[float,List[float]]):
> self.radius = radius
> self.generatePicture()
>
> def generatePicture(self):
> if self.center is not None and self.radius is not None:
> self.picture = QtGui.QPicture()
> p = QtGui.QPainter(self.picture)
> p.setPen(pg.mkPen('w'))
> try:
> r1 = self.radius[0]
> r2 = self.radius[1]
> except (TypeError, IndexError):
> r1 = r2 = self.radius
> try:
> c1 = self.center[0] - r1
> c2 = self.center[1] - r2
> except (TypeError, IndexError):
> c1 = self.center - r1
> c2 = self.center - r2
> p.drawEllipse(QtCore.QRectF(c1,c2,r1*2,r2*2))
> p.end()
> self.update()
> self.informViewBoundsChanged()
>
> def paint(self, p, *args):
> p.drawPicture(0, 0, self.picture)
>
> def boundingRect(self):
> return QtCore.QRectF(self.picture.boundingRect())
>
> The following is a minimal working example showing that update is not
> immediate. Note the delay between updating the radius of the Ellipse and
> the change becoming apparent in the PlotWindow.
>
> from <filename> import EllipseItem
> pw = pg.PlotWidget()
> item = EllipseItem([0,1],[1,0.5])
> plotui.addItem(item)
> item.setRadius([0.5,1])
>
>
> Regards,
> Magne Lauritzen
>
>
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