feat(waveform): add no-line curve style

bec_widgets/cli/client.py

@@ -974,7 +974,8 @@ class Curve(RPCBase):
             - symbol_color: str
             - symbol_size: int
             - pen_width: int
-            - pen_style: Literal["solid", "dash", "dot", "dashdot"]
+            - pen_style: Literal["solid", "dash", "dot", "dashdot", "none"]
+              Use "none" to display markers without connecting lines.
         """
 
     @rpc_call
@@ -1046,12 +1047,15 @@ class Curve(RPCBase):
         """
 
     @rpc_call
-    def set_pen_style(self, pen_style: "Literal['solid', 'dash', 'dot', 'dashdot']"):
+    def set_pen_style(
+        self, pen_style: "Literal['solid', 'dash', 'dot', 'dashdot', 'none']"
+    ) -> "None":
         """
         Change the pen style of the curve.
 
         Args:
-            pen_style(Literal["solid", "dash", "dot", "dashdot"]): Style of the pen.
+            pen_style(Literal["solid", "dash", "dot", "dashdot", "none"]): Style of the pen.
+                Use "none" to display markers without connecting lines.
         """
 
     @rpc_call

bec_widgets/widgets/plots/waveform/curve.py

@@ -41,8 +41,8 @@ class CurveConfig(ConnectionConfig):
     )
     symbol_size: int | None = Field(7, description="The size of the symbol of the curve.")
     pen_width: int | None = Field(4, description="The width of the pen of the curve.")
-    pen_style: Literal["solid", "dash", "dot", "dashdot"] | None = Field(
-        "solid", description="The style of the pen of the curve."
+    pen_style: Literal["solid", "dash", "dot", "dashdot", "none"] | None = Field(
+        "solid", description="The style of the curve's connecting line; 'none' disables the line."
     )
     source: Literal["device", "dap", "custom", "history"] = Field(
         "custom", description="The source of the curve."
@@ -134,6 +134,7 @@ class Curve(BECConnector, pg.PlotDataItem):
             "dash": QtCore.Qt.DashLine,
             "dot": QtCore.Qt.DotLine,
             "dashdot": QtCore.Qt.DashDotLine,
+            "none": QtCore.Qt.NoPen,
         }
         pen_style = pen_style_map.get(self.config.pen_style, QtCore.Qt.SolidLine)
 
@@ -238,7 +239,8 @@ class Curve(BECConnector, pg.PlotDataItem):
             - symbol_color: str
             - symbol_size: int
             - pen_width: int
-            - pen_style: Literal["solid", "dash", "dot", "dashdot"]
+            - pen_style: Literal["solid", "dash", "dot", "dashdot", "none"]
+              Use "none" to display markers without connecting lines.
         """
 
         # Mapping of keywords to setter methods
@@ -310,12 +312,13 @@ class Curve(BECConnector, pg.PlotDataItem):
         self.config.pen_width = pen_width
         self.apply_config()
 
-    def set_pen_style(self, pen_style: Literal["solid", "dash", "dot", "dashdot"]):
+    def set_pen_style(self, pen_style: Literal["solid", "dash", "dot", "dashdot", "none"]) -> None:
         """
         Change the pen style of the curve.
 
         Args:
-            pen_style(Literal["solid", "dash", "dot", "dashdot"]): Style of the pen.
+            pen_style(Literal["solid", "dash", "dot", "dashdot", "none"]): Style of the pen.
+                Use "none" to display markers without connecting lines.
         """
         self.config.pen_style = pen_style
         self.apply_config()

bec_widgets/widgets/plots/waveform/settings/curve_settings/curve_tree.py

@@ -282,8 +282,10 @@ class CurveRow(QTreeWidgetItem):
 
         # Style in col 5
         self.style_combo = QComboBox()
-        self.style_combo.addItems(["solid", "dash", "dot", "dashdot"])
-        idx = self.style_combo.findText(self.config.pen_style)
+        for style in ("solid", "dash", "dot", "dashdot"):
+            self.style_combo.addItem(style, style)
+        self.style_combo.addItem("No line", "none")
+        idx = self.style_combo.findData(self.config.pen_style)
         if idx >= 0:
             self.style_combo.setCurrentIndex(idx)
         self.tree.setItemWidget(self, 5, self.style_combo)
@@ -495,7 +497,7 @@ class CurveRow(QTreeWidgetItem):
         # Common style fields
         self.config.color = self.color_button.color
         self.config.symbol_color = self.color_button.color
-        self.config.pen_style = self.style_combo.currentText()
+        self.config.pen_style = self.style_combo.currentData()
         self.config.pen_width = self.width_spin.value()
         self.config.symbol_size = self.symbol_spin.value()
 

bec_widgets/widgets/plots/waveform/waveform.py

@@ -1938,7 +1938,7 @@ class Waveform(PlotBase):
         Curve items, by deactivating the symbol and activating downsampling auto, method='mean',
         if the data length exceeds N points. If the data length is less than N points, the
         symbol will be activated and downsampling will be deactivated. Maximum points will be
-        5x the limit.
+        5x the limit. Curves without a connecting line retain their markers at any length.
 
         Args:
             curve(Curve): The curve to adjust.
@@ -1949,15 +1949,19 @@ class Waveform(PlotBase):
         if limit <= 1:
             logger.warning("Limit must be greater than 1.")
             return
+        if curve.config.pen_style == "none" and curve.config.symbol is None:
+            curve.set_symbol("o")
+            curve.apply_config()
         if data_length > limit:
-            if curve.config.symbol is not None:
+            if curve.config.pen_style != "none" and curve.config.symbol is not None:
                 curve.set_symbol(None)
             if curve.config.pen_width > 3:
                 curve.set_pen_width(3)
             curve.setDownsampling(ds=None, auto=True, method=method)
             curve.setClipToView(True)
         elif data_length <= limit:
-            curve.set_symbol("o")
+            if curve.config.pen_style != "none":
+                curve.set_symbol("o")
             curve.set_pen_width(4)
             curve.setDownsampling(ds=1, auto=None, method=method)
             curve.setClipToView(True)

tests/unit_tests/test_curve_settings.py

@@ -3,6 +3,7 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 from bec_lib.scan_history import ScanHistory
+from qtpy.QtCore import Qt
 from qtpy.QtWidgets import QComboBox, QVBoxLayout
 
 from bec_widgets.widgets.plots.waveform.settings.curve_settings.curve_setting import CurveSetting
@@ -84,6 +85,40 @@ def test_curve_setting_accept_changes(curve_setting_fixture, qtbot):
     send_spy.assert_called_once()
 
 
+@pytest.mark.parametrize(
+    "style, label, expected_pen",
+    [
+        ("none", "No line", Qt.NoPen),
+        ("solid", "solid", Qt.SolidLine),
+        ("dash", "dash", Qt.DashLine),
+        ("dot", "dot", Qt.DotLine),
+        ("dashdot", "dashdot", Qt.DashDotLine),
+    ],
+)
+def test_curve_setting_style_round_trip(curve_setting_fixture, style, label, expected_pen):
+    """Applying and restoring curve styles preserves the selection and rendered pen."""
+    settings, wf = curve_setting_fixture
+    wf.plot("bpm4i")
+    settings.refresh()
+    row = settings.curve_manager.all_items[0]
+    row.style_combo.setCurrentText(label)
+    settings.accept_changes()
+
+    serialized = wf.curve_json
+    assert json.loads(serialized)[0]["pen_style"] == style
+    wf.curve_json = serialized
+    curve = wf.curves[0]
+    curve.setData([1, 2, 3], [4, 5, 6])
+    assert curve.curve.opts["pen"].style() == expected_pen
+    assert curve.scatter.isVisible()
+    assert curve.scatter.opts["symbol"] == "o"
+
+    settings.refresh()
+    restored_row = settings.curve_manager.all_items[0]
+    assert restored_row.style_combo.currentText() == label
+    assert restored_row.style_combo.currentData() == style
+
+
 def test_curve_setting_switch_device_mode(curve_setting_fixture, qtbot):
     """
     If user chooses device mode from the combo, the device_x line edit should be enabled

tests/unit_tests/test_waveform.py

@@ -11,7 +11,7 @@ import pytest
 from bec_lib import messages
 from bec_lib.scan_items import ScanItem
 from pyqtgraph.graphicsItems.DateAxisItem import DateAxisItem
-from qtpy.QtCore import QTimer
+from qtpy.QtCore import Qt, QTimer
 from qtpy.QtWidgets import QApplication, QCheckBox, QDialog, QDialogButtonBox, QDoubleSpinBox
 
 from bec_widgets.widgets.plots.plot_base import UIMode
@@ -1239,6 +1239,79 @@ def test_curve_set_appearance_methods(qtbot, mocked_client):
     assert c.config.pen_style == "dashdot"
 
 
+def test_curve_no_line_style_preserves_markers(qtbot, mocked_client):
+    """Disabling the connecting line preserves markers across appearance and data updates."""
+    wf = create_widget(qtbot, Waveform, client=mocked_client)
+    curve = wf.plot(x=[1, 2, 3], y=[4, 5, 6], symbol="d")
+    curve.set_pen_style("none")
+    assert curve.opts["pen"].style() == Qt.NoPen
+
+    curve.set_color("#123456")
+    curve.set_symbol_color("#654321")
+    curve.set_symbol_size(12)
+    curve.set_pen_width(5)
+    curve.set_data([2, 3, 4], [5, 6, 7])
+
+    assert curve.config.pen_style == "none"
+    assert curve.curve.opts["pen"].style() == Qt.NoPen
+    assert curve.opts["pen"].color().name() == "#123456"
+    assert curve.scatter.isVisible()
+    assert curve.scatter.opts["symbol"] == "d"
+    assert curve.scatter.opts["size"] == 12
+    assert curve.scatter.opts["brush"].color().name() == "#654321"
+    np.testing.assert_array_equal(curve.scatter.getData(), [[2, 3, 4], [5, 6, 7]])
+
+
+@pytest.mark.parametrize("data_length", [500, 1500])
+@pytest.mark.parametrize("symbol", [None, "d"])
+def test_curve_no_line_style_keeps_async_markers(qtbot, mocked_client, data_length, symbol):
+    """Async data retain markers, including when automatic styling previously hid them."""
+    wf = create_widget(qtbot, Waveform, client=mocked_client)
+    curve = wf.plot(
+        x=[1, 2, 3],
+        y=[4, 5, 6],
+        pen_style="none",
+        pen_width=3,
+        symbol=symbol,
+        symbol_color="#654321",
+        symbol_size=12,
+    )
+
+    wf._auto_adjust_async_curve_settings(curve, data_length)
+    curve.setData(np.arange(data_length), np.arange(data_length))
+
+    assert curve.curve.opts["pen"].style() == Qt.NoPen
+    assert curve.scatter.isVisible()
+    assert curve.config.symbol == (symbol or "o")
+    assert curve.scatter.opts["symbol"] == (symbol or "o")
+    assert curve.scatter.opts["size"] == 12
+    assert curve.scatter.opts["brush"].color().name() == "#654321"
+
+
+def test_curve_no_line_style_restores_existing_styles(qtbot, mocked_client):
+    """The no-line style is reversible, and legacy null styles still draw solid lines."""
+    wf = create_widget(qtbot, Waveform, client=mocked_client)
+    curve = wf.plot(x=[1, 2, 3], y=[4, 5, 6], pen_style="none")
+    assert curve.curve.opts["pen"].style() == Qt.NoPen
+
+    for style, expected in (
+        ("solid", Qt.SolidLine),
+        ("dash", Qt.DashLine),
+        ("dot", Qt.DotLine),
+        ("dashdot", Qt.DashDotLine),
+    ):
+        curve.set_pen_style(style)
+        assert curve.curve.opts["pen"].style() == expected
+        assert curve.curve.isVisible()
+        curve.set(pen_style="none")
+        assert curve.curve.opts["pen"].style() == Qt.NoPen
+
+    config = curve.config.model_dump()
+    config["pen_style"] = None
+    curve.apply_config(config)
+    assert curve.curve.opts["pen"].style() == Qt.SolidLine
+
+
 def test_curve_set_custom_data(qtbot, mocked_client):
     """
     Test that custom curves allow setting new data via set_data.