[Plot] Polygon interaction first point might not be well displayed

[t20100]

When drawing a polygon, if the plot aspect ratio or zoom changes from another source than mouse wheel (i.e. programmatically or with Ctrl+/-), then the size of the first point area used to close the polygon is not properly displayed.

[woutdenolf]

Cleanup campaign.

The square around to anchor point keeps the same size in axis coordinates instead of screen pixel coordinates. @t20100 Is that the problem?

import sys

from silx.gui import qt
from silx.gui.plot import PlotWidget

app = qt.QApplication(sys.argv)

plot = PlotWidget()

plot.addCurve([0, 100], [0, 100], legend="diag")

plot.setLimits(0, 100, 0, 100)
plot.show()


def zoom_after_start():
    print("Change limits")
    print("3. Continue drawing")
    print("4. Inspect first-point closing marker")
    plot.setLimits(20, 80, 20, 80)

qt.QTimer.singleShot(10000, zoom_after_start)

plot.setInteractiveMode("draw", shape="polygon")

print("1. Click first polygon point")
print("2. Wait for zoom")


sys.exit(app.exec())

[t20100]

The square around to anchor point keeps the same size in axis coordinates instead of screen pixel coordinates.

Yes, only when zooming while drawing the shape.

[woutdenolf]

Yes, only when zooming while drawing the shape.

What do you mean? When we don't zoom, the anchor box size does not change, sure. When we zoom it does and we don't want that. It should stay the same size in terms of pixels on the screen. At least that's what I understood from the request.

Btw, I cannot get the polygon to stay after closing.

[t20100]

When we zoom it does and we don't want that. It should stay the same size in terms of pixels on the screen.

Yes this is the issue

Btw, I cannot get the polygon to stay after closing.

The polygon you see is only created during interaction, to persist it, the application has to create a Shape item at the end of the edition.