Picking for scatter item

[vallsv]

Sounds like the picking for scatters is not implemented for scatter, with raster rendering.

So for now in Flint i use a fallback, which is probably always used.

from silx.gui.plot.items.scatter import Scatter

def isScatter(item):
    return isinstance(item, Scatter)

results = list(plot.pickItems(x, y, isScatter))
for result in results:
    indices = result.getIndices(copy=False)
    return indices

if len(results) == 0:
    selectedScatter = plot.getActiveScatter()
    # Pick on the active curve with a higher tolerance
    if selectedScatter is not None:
        index = __closest(selectedScatter, x, y)
        return index

def __closest(scatter, x, y) -> int | None:
    """Returns the closest index from a scatter item"""
    xx = scatter.getXData()
    yy = scatter.getYData()
    if xx is None or len(xx) == 0:
        return None
    dist = (xx - x) ** 2 + (yy - y) ** 2
    index = numpy.nanargmin(dist)
    return index

[t20100]

From a quick test, I don't seen any issue with any of the scatter visualisation mode:

from silx import sx
w = sx.scatter([0, 0, 0, 1, 1, 1, 2, 2, 2], [0, 1, 2, 0, 1, 2, 0, 1, 2], [0, 1, 2, 3, 4, 5, 6, 7, 8])

When picking at a position where there is a Scatter, you get it:

In [26]: list(w.getPlotWidget().pickItems(279, 232))[0].getIndices()
Out[26]: array([1])

Maybe you are after always getting the closest point as your code suggests? That is not provided by the picking API.

[vallsv]

Yes, sounds good. I probably have a wrong transformation somehow.

The code i have copy-pasted use the picking with data coords, so i have to double check on my side.