otko/tests/gui/test_plotly_hover.py
smillmorel 5262d31e33 fix: stop the Plotly hover handler redrawing on every mouse move
plotly_hover/plotly_unhover fire continuously while the mouse moves, and
the unhover handler restyled the snap marker unconditionally - even with
snapping off and nothing visible. That meant a full Plotly.restyle plus
redraw per mouse event, which re-fired hover until the page died with
'RangeError: Maximum call stack size exceeded' and the canvas froze
(reported live after opening a model).

The marker is now updated only when its visible state actually changes: no
marker when snapping is off, and a restyle only when the snapped point
differs from the one already shown. Deliberately synchronous - timers are
throttled to about a second by WebEngine when the page is not compositing,
which stalled the preview. Measured: 200 mouse-move events went from 200
restyles to 0; 200 hovers on one grid dot cost a single restyle.
2026-09-16 20:33:30 -04:00

93 lines
3.3 KiB
Python

"""Regression tests for the Plotly hover/snap-marker contract.
``plotly_hover``/``plotly_unhover`` fire continuously while the mouse moves.
Touching the plot on each one made it redraw per mouse move, re-firing hover
until the stack blew (``RangeError: Maximum call stack size exceeded``) and the
canvas froze. The marker is therefore coalesced and only touched when its
shown/hidden state actually changes.
"""
from __future__ import annotations
from pathlib import Path
import pytest
pytest.importorskip("PySide6")
pytest.importorskip("plotly")
from otko.services import load_project
EXAMPLES = Path(__file__).resolve().parents[2] / "examples"
#: 200 mouse-move events over a *non-snap* point with snapping armed.
_CHURN_PROBE = """(function(){
var gd = document.getElementById('plot');
var n = 0; var original = Plotly.restyle;
Plotly.restyle = function () { n++; return original.apply(Plotly, arguments); };
var point = { data: gd.data[0], customdata: [0, 0, 0] };
try {
for (var i = 0; i < 200; i++) {
gd.emit('plotly_hover', { points: [point] });
gd.emit('plotly_unhover', {});
}
return n;
} finally { Plotly.restyle = original; }
})()"""
_HOVER_MARKER_X = (
"JSON.stringify((document.getElementById('plot').data"
".find(function(d){return d.meta && d.meta.kind === 'hover';}) || {}).x)"
)
_EMIT_SNAP_HOVER = """(function(){
var gd = document.getElementById('plot');
var snap = gd.data.filter(function(d){return d.meta && d.meta.kind === 'snap';})[0];
var point = { data: snap, customdata: [snap.x[0], snap.y[0], snap.z[0]] };
gd.emit('plotly_hover', { points: [point] });
return true;
})()"""
def _open_canvas(qtbot, name: str): # type: ignore[no-untyped-def]
from otko.views.canvas_plotly import PlotlyCanvas
canvas = PlotlyCanvas()
qtbot.addWidget(canvas)
canvas.show_project(load_project(EXAMPLES / name))
qtbot.waitUntil(lambda: canvas._ready, timeout=30000)
qtbot.wait(1500) # let the first Plotly.react settle
return canvas
def _run_js(canvas, qtbot, script: str, timeout: int = 15000): # type: ignore[no-untyped-def]
box: dict[str, object] = {}
canvas._web.page().runJavaScript(script, lambda value: box.update(value=value))
qtbot.waitUntil(lambda: "value" in box, timeout=timeout)
return box["value"]
@pytest.mark.gui
def test_ordinary_mouse_movement_does_not_redraw(qtbot) -> None: # type: ignore[no-untyped-def]
"""The unfixed version restyled once per hover/unhover event."""
canvas = _open_canvas(qtbot, "space_frame_3d.osmodel")
restyles = _run_js(canvas, qtbot, _CHURN_PROBE)
assert restyles == 0, f"mouse movement caused {restyles} plot restyles"
@pytest.mark.gui
def test_snap_marker_shows_and_clears(qtbot) -> None: # type: ignore[no-untyped-def]
canvas = _open_canvas(qtbot, "basic_truss.osmodel")
assert _run_js(canvas, qtbot, _HOVER_MARKER_X) == "[]"
canvas.set_snap_preview_enabled(True)
qtbot.wait(100)
_run_js(canvas, qtbot, _EMIT_SNAP_HOVER)
qtbot.wait(250)
assert _run_js(canvas, qtbot, _HOVER_MARKER_X) != "[]", "snap target not shown"
_run_js(canvas, qtbot, "document.getElementById('plot').emit('plotly_unhover',{})")
qtbot.wait(250)
assert _run_js(canvas, qtbot, _HOVER_MARKER_X) == "[]", "snap target not cleared"