I AM try to mark some location in pyqtgraph,
Here is the code.
def set_history_arrow(self): print(f"===> up: {len(self.up)} down: {len(self.down)}") for up in self.up: print("up", self.up.index(up)) up_arrow = pg.TextItem('↑', fill=(255, 0, 0)) self.plot_widget.addItem(up_arrow) up_arrow.setPos(up, self.data[up]) for down in self.down: print("down", self.down.index(down)) down_arrow = pg.TextItem("↓", fill=(0, 238, 118)) self.plot_widget.addItem(down_arrow) down_arrow.setPos(down, self.data[down])
the sum of data is: 41363
the count of them,
===> up: 4259 down: 2559
it is slow to execute it.
How can I improve the speed?
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Answer
just use ScatterPlotItem
will work