Unified waveform plotter

src/lung_utils/hamilton_ventilator/waveform_plotter.py

@@ -4,6 +4,7 @@
 import pandas as pd
 import plotly.graph_objs as go
 from dash import Input, Output, dcc, html
+from plotly.subplots import make_subplots
 
 
 # ==== Load waveform file ====
@@ -21,7 +22,16 @@ def load_waveform_txt(filepath):
     df = df.dropna(how="all")
     df["Date_Time"] = pd.to_numeric(df["Date_Time"], errors="coerce")
     df = df.dropna(subset=["Date_Time"])
-    df["Time (s)"] = df["Date_Time"] - df["Date_Time"].iloc[0]
+
+    # Calculate relative time in seconds from start
+    start_time_val = df["Date_Time"].iloc[0]
+    df["Time (s)"] = (df["Date_Time"] - start_time_val) * 24 * 3600
+
+    # Convert OLE Automation Date (Excel date) to absolute datetime
+    df["Absolute_Time"] = pd.to_datetime(
+        df["Date_Time"], unit="D", origin="1899-12-30"
+    )
+
     return df
 
 
@@ -31,24 +41,43 @@ def create_dash_app(df, file_path):
     app.title = "Hamilton Waveform Viewer"
 
     # Select waveform columns
-    exclude_cols = ["Date_Time", "Time (s)", "Breath Number", "Status"]
+    exclude_cols = [
+        "Date_Time",
+        "Time (s)",
+        "Absolute_Time",
+        "Breath Number",
+        "Status",
+    ]
     waveform_columns = [col for col in df.columns if col not in exclude_cols]
 
+    # Get absolute start time
+    start_time_str = ""
+    if not df.empty and "Absolute_Time" in df.columns:
+        start_time_str = (
+            df["Absolute_Time"].iloc[0].strftime("%Y-%m-%d %H:%M:%S")
+        )
+
     app.layout = html.Div(
         [
             html.H2("Hamilton Ventilator Waveform Viewer"),
             html.Div(
                 f"Loaded file: {file_path}",
                 id="file-info",
-                style={"marginBottom": "10px"},
+                style={"marginBottom": "5px"},
             ),
-            html.Label("Select waveform:"),
+            html.Div(
+                f"Recording Start Time: {start_time_str}",
+                id="start-time-info",
+                style={"marginBottom": "10px", "fontWeight": "bold"},
+            ),
+            html.Label("Select up to 3 waveforms:"),
             dcc.Dropdown(
                 id="waveform-dropdown",
                 options=[
                     {"label": col, "value": col} for col in waveform_columns
                 ],
-                value=waveform_columns[0] if waveform_columns else None,
+                value=[waveform_columns[0]] if waveform_columns else [],
+                multi=True,
             ),
             dcc.Graph(id="waveform-plot"),
         ]
@@ -57,21 +86,63 @@ def create_dash_app(df, file_path):
     @app.callback(
         Output("waveform-plot", "figure"), Input("waveform-dropdown", "value")
     )
-    def update_graph(selected_waveform):
-        if selected_waveform is None or df.empty:
+    def update_graph(selected_waveforms):
+        if not selected_waveforms or df.empty:
             return go.Figure()
 
-        y_data = pd.to_numeric(df[selected_waveform], errors="coerce")
-        trace = go.Scatter(
-            x=df["Time (s)"], y=y_data, mode="lines", name=selected_waveform
+        # Enforce maximum of 3 plots
+        if isinstance(selected_waveforms, str):
+            selected_waveforms = [selected_waveforms]
+
+        selected_waveforms = selected_waveforms[:3]
+        num_plots = len(selected_waveforms)
+
+        fig = make_subplots(
+            rows=num_plots,
+            cols=1,
+            shared_xaxes=True,
+            vertical_spacing=0.05,
+            subplot_titles=selected_waveforms,
         )
-        layout = go.Layout(
+
+        for i, waveform in enumerate(selected_waveforms, start=1):
+            y_data = pd.to_numeric(df[waveform], errors="coerce")
+
+            # Format absolute time for hover (hours:minutes:seconds.ms)
+            abs_time_str = (
+                df["Absolute_Time"].dt.strftime("%H:%M:%S.%f").str[:-3]
+            )
+
+            trace = go.Scatter(
+                x=df["Time (s)"],
+                y=y_data,
+                mode="lines",
+                name=waveform,
+                customdata=abs_time_str,
+                hovertemplate=(
+                    "<b>%{y}</b><br>"
+                    "Time: %{x:.2f} s<br>"
+                    "Abs Time: %{customdata}"
+                    "<extra></extra>"
+                ),
+            )
+            fig.add_trace(trace, row=i, col=1)
+            fig.update_yaxes(title_text=waveform, row=i, col=1)
+
+        # Calculate dynamic height (approx 300px per plot)
+        plot_height = max(400, 300 * num_plots)
+
+        fig.update_layout(
+            height=plot_height,
             xaxis={"title": "Time (s)"},
-            yaxis={"title": selected_waveform},
             margin={"l": 50, "r": 10, "t": 40, "b": 50},
-            hovermode="closest",
+            hovermode="x unified",
         )
-        return {"data": [trace], "layout": layout}
+
+        # Ensure the bottom-most x-axis has a title
+        fig.update_xaxes(title_text="Time (s)", row=num_plots, col=1)
+
+        return fig
 
     return app
 

tests/lung_utils/hamilton_ventilator/test_waveform_plotter.py

@@ -10,10 +10,15 @@
 def sample_dataframe():
     """Fixture for a sample dataframe."""
     data = {
-        "Date_Time": [0, 1, 2, 3],
+        "Date_Time": [44917.617693, 44917.617705, 44917.617716, 44917.617728],
         "Time (s)": [0, 1, 2, 3],
         "Waveform1": [10, 20, 30, 40],
         "Waveform2": [5, 15, 25, 35],
+        "Absolute_Time": pd.to_datetime(
+            [44917.617693, 44917.617705, 44917.617716, 44917.617728],
+            unit="D",
+            origin="1899-12-30",
+        ),
     }
     return pd.DataFrame(data)
 
@@ -37,8 +42,9 @@ def test_create_dash_app(sample_dataframe):
         in app.layout.children[0].children
     )
     assert f"Loaded file: {file_path}" in app.layout.children[1].children
-    assert app.layout.children[3].id == "waveform-dropdown"
-    assert app.layout.children[4].id == "waveform-plot"
+    assert app.layout.children[2].id == "start-time-info"
+    assert app.layout.children[4].id == "waveform-dropdown"
+    assert app.layout.children[5].id == "waveform-plot"
 
 
 @patch("src.lung_utils.hamilton_ventilator.waveform_plotter.dcc.Dropdown")
@@ -60,13 +66,16 @@ def test_create_dash_app_layout(mock_graph, mock_dropdown, sample_dataframe):
         == "Hamilton Ventilator Waveform Viewer"
     )
     assert app.layout.children[1].children == f"Loaded file: {file_path}"
-    assert app.layout.children[2].children == "Select waveform:"
+    assert app.layout.children[2].id == "start-time-info"
+    assert "Recording Start Time:" in app.layout.children[2].children
+    assert app.layout.children[3].children == "Select up to 3 waveforms:"
     mock_dropdown.assert_called_once_with(
         id="waveform-dropdown",
         options=[
             {"label": "Waveform1", "value": "Waveform1"},
             {"label": "Waveform2", "value": "Waveform2"},
         ],
-        value="Waveform1",
+        value=["Waveform1"],
+        multi=True,
     )
     mock_graph.assert_called_once_with(id="waveform-plot")