CHANGELOG.md

@@ -8,7 +8,12 @@ All notable changes to seismo-relay are documented here.
 
 ### Added
 
-- **Event Report PDF generation** — `GET /db/events/{id}/report.pdf` returns a single-page letter-portrait PDF for any event with waveform data on disk.  Covers every field a Blastware Event Report includes: header metadata (date/time, trigger source, range, sample rate, project/client/operator/location, serial+firmware, battery, calibration, file name), microphone block (PSPL in dB(L) + psi, ZC freq, channel test), per-channel stats table (PPV / ZC Freq / Time of Peak / Peak Accel / Peak Disp / Sensor Check), Peak Vector Sum, and the 4-channel waveform plot stacked Instantel-style (MicL top → Tran bottom, shared time axis, trigger marker, symmetric Y on geo channels, zero-anchored on mic).  Histogram events render as per-interval bar charts instead of waveform plots.  USBM RI8507 / OSMRE compliance chart still stubbed — separate work item.  Backed by matplotlib (vector PDF output, no headless-browser dep); new `sfm/report_pdf.py` does data assembly + rendering.  **Visual layout is approximate** until reference PDFs land at `docs/reference/instantel/` to iterate against.
+- **Event Report PDF generation** — `GET /db/events/{id}/report.pdf` returns a single-page letter-portrait PDF for any event with waveform data on disk.  Covers every field a Blastware Event Report includes: header metadata (date/time, trigger source, range, sample rate, project/client/operator/location, serial+firmware, battery, calibration, file name), microphone block (PSPL in dB(L) + psi, ZC freq, channel test), per-channel stats table (rows differ for waveform vs histogram), Peak Vector Sum, and the 4-channel plot.  Iterated against real Blastware reference PDFs (uploaded to `example-events/pdfsnstuff/`):
+   - **Waveform layout**: header shows Date/Time, Trigger Source, Range, Sample Rate; stats table has PPV / ZC Freq / Time (Rel. to Trig) / Peak Accel / Peak Disp / Sensor Check; bottom plot is 4-channel line waveform (MicL top → Tran bottom), shared time axis in seconds, dashed trigger line + triangle marker at t=0, symmetric Y on geo channels, zero-anchored on mic, "0.0" baseline label on right per BW convention; footer shows `Time X sec/div   Amplitude Geo: Y in/s/div   Mic: 0.001 psi(L)/div` and the trigger window `▶━━◀` marker.  USBM RI8507/OSMRE compliance chart placeholder upper-right.
+   - **Histogram layout**: header shows Start / Finish / Intervals At Size / Range / Sample Rate (no Trigger Source — histograms aren't triggered); NO USBM chart; stats table has PPV / ZC Freq / Date / Time / Sensor Check; bottom plot is per-interval bar chart, Y-axis 0-to-peak (never negative), 0.0 baseline at the bottom; footer shows `Time INTERVAL_SIZE /div   Amplitude Geo: Y in/s/div   Mic: 0.001 psi(L)/div`.
+   - Backed by matplotlib (vector PDF, no headless-browser dep).  Adds matplotlib>=3.8 to deps.
+   - **Known gap**: histogram codec returns per-block granularity (~200 bars for a 4-interval event) instead of BW's per-interval aggregation.  Visual difference vs BW's 4-bar display.  XML-driven data source (parsing the structured `_XML.XML` files BW also exports) is the planned fix; that route also resolves the bw_ascii_report PPV-miss bug.
+   - **Stubbed**: USBM RI8507 / OSMRE compliance chart curves (separate work item; requires coding the regulatory piecewise functions).
 - **"Download PDF" button** in the event modal's footer — triggers the new endpoint; opens in a new tab so the browser handles save-or-display + surfaces any 404 / server errors visibly.
 
 - **SFM webapp now opens to Database view by default** and the History table is fully interactive.  Click any column header to sort ascending / descending (timestamp, serial, per-channel PPV, PVS, mic dB(L), project, client, record type, key — all sortable).  Click any event row to open the event modal, which now renders a **4-channel waveform plot inline** (MicL / Long / Vert / Tran stacked, Instantel-printout order) alongside the existing sidecar review fields.  Headers are sticky so the columns stay visible while scrolling long event lists.  No more "where is the viewer" — pick a unit from the filter dropdown, scan the table, click the event, see the waveform.

sfm/report_pdf.py

@@ -123,6 +123,16 @@ class ReportData:
     record_type:            Optional[str] = None
     is_histogram:           bool = False
 
+    # Histogram-only fields — only populated for record_type starts with 'Hist'
+    histogram_start_str:    Optional[str] = None       # "22:30:38 May 16, 2026"
+    histogram_stop_str:     Optional[str] = None
+    histogram_n_intervals:  Optional[float] = None     # 4.00
+    histogram_interval_size: Optional[str] = None      # "1 minute"
+    histogram_interval_times: list[str] = field(default_factory=list)  # per-interval timestamps for x-axis
+
+    # Peak Vector Sum metadata (histograms show absolute date+time)
+    peak_vector_sum_when_str: Optional[str] = None
+
     # Bookkeeping
     event_id:               Optional[str] = None
     server_received_at:     Optional[str] = None
@@ -231,6 +241,19 @@ def gather_report_data(
         rd.peak_vector_sum_ips    = vs.get("ips")
         rd.peak_vector_sum_time_s = vs.get("time_s")
 
+        # Histogram-specific header fields.  These come from the BW XML
+        # at ingest time (when present); the parsed bw_report dict
+        # carries them under the 'histogram' sub-block (added by the
+        # BW XML parser once that lands).  For now, derive from the
+        # event timestamp + recording config as a best-effort.
+        if rd.is_histogram:
+            hist = bw.get("histogram") or {}
+            rd.histogram_start_str = hist.get("start_str") or rd.event_datetime_str
+            rd.histogram_stop_str  = hist.get("stop_str")
+            rd.histogram_n_intervals = hist.get("n_intervals")
+            rd.histogram_interval_size = hist.get("interval_size")
+            rd.histogram_interval_times = hist.get("interval_times") or []
+
     # ── Waveform samples — from the .h5 via the existing helper ──
     from sfm import event_hdf5
     h5_path = store.hdf5_path_for(serial, filename)
@@ -258,53 +281,31 @@ def gather_report_data(
 def render_event_report_pdf(rd: ReportData) -> bytes:
     """Render an event report dict to a single-page letter PDF.
 
-    Returns the raw PDF bytes — caller streams them back via FastAPI.
+    Branches on ``rd.is_histogram`` — waveform and histogram layouts
-
+    differ in their header fields, stats-table rows, and bottom plot.
-    NOTE: this is a v0.20.0 stub layout.  The visual hierarchy will be
+    Layout modeled on Blastware's Event Report PDFs (samples in
-    refined once reference PDFs land at docs/reference/instantel/.  All
+    docs/reference/instantel/).
-    fields the printout includes are surfaced; spacing and typography
-    are approximate.
     """
     # Letter portrait — 8.5"×11"
     fig = plt.figure(figsize=(8.5, 11), dpi=100)
     fig.patch.set_facecolor("white")
 
-    # Grid: header rows on top, stats in the middle, waveform plot at bottom
-    # height_ratios sum doesn't matter, only the relative proportions
-    gs = fig.add_gridspec(
-        nrows=4, ncols=1,
-        left=0.07, right=0.96, top=0.96, bottom=0.04,
-        height_ratios=[2.2, 1.0, 1.4, 5.0],
-        hspace=0.35,
-    )
-
-    # ── Header area (top) ──
-    ax_header = fig.add_subplot(gs[0])
-    ax_header.axis("off")
-    _draw_header(ax_header, rd)
-
-    # ── Mic block (left) + USBM chart placeholder (right) ──
-    ax_mic = fig.add_subplot(gs[1])
-    ax_mic.axis("off")
-    _draw_mic_block(ax_mic, rd)
-
-    # ── Per-channel stats table + Peak Vector Sum ──
-    ax_stats = fig.add_subplot(gs[2])
-    ax_stats.axis("off")
-    _draw_channel_stats(ax_stats, rd)
-
-    # ── Waveform / histogram plot ──
     if rd.is_histogram:
-        _draw_histogram_subplot(fig, gs[3], rd)
+        _render_histogram_layout(fig, rd)
     else:
-        _draw_waveform_subplot(fig, gs[3], rd)
+        _render_waveform_layout(fig, rd)
 
-    # Footer
+    # Footer (common to both layouts) — Created date + Xmark-like attribution.
     fig.text(
         0.07, 0.015,
-        f"Generated by seismo-relay  •  event_id={rd.event_id or '—'}",
+        f"Created: {rd.server_received_at or '—'}  •  seismo-relay",
         fontsize=7, color="#888", ha="left",
     )
+    fig.text(
+        0.93, 0.015,
+        f"Event {rd.event_id[:8] if rd.event_id else '—'}",
+        fontsize=7, color="#888", ha="right",
+    )
 
     buf = io.BytesIO()
     fig.savefig(buf, format="pdf")
@@ -312,6 +313,69 @@ def render_event_report_pdf(rd: ReportData) -> bytes:
     return buf.getvalue()
 
 
+def _render_waveform_layout(fig, rd: ReportData) -> None:
+    """Waveform layout: header / mic+USBM / per-channel stats / waveform plot.
+
+    Stats table includes Time (Rel. to Trig), Peak Accel, Peak Disp.
+    Left margin sized to fit the channel labels (MicL/Long/Vert/Tran).
+    """
+    gs = fig.add_gridspec(
+        nrows=4, ncols=1,
+        left=0.11, right=0.94, top=0.97, bottom=0.06,
+        height_ratios=[1.7, 2.0, 1.8, 5.5],
+        hspace=0.35,
+    )
+    ax_header = fig.add_subplot(gs[0]); ax_header.axis("off")
+    _draw_header_waveform(ax_header, rd)
+
+    ax_mid = fig.add_subplot(gs[1]); ax_mid.axis("off")
+    _draw_mic_and_usbm(ax_mid, rd)
+
+    ax_stats = fig.add_subplot(gs[2]); ax_stats.axis("off")
+    _draw_channel_stats_waveform(ax_stats, rd)
+
+    _draw_waveform_subplot(fig, gs[3], rd)
+
+
+def _render_histogram_layout(fig, rd: ReportData) -> None:
+    """Histogram layout: header / mic-only / per-channel stats / bar plot.
+
+    No USBM compliance chart (it's a waveform-only concept).  Stats table
+    uses Date + Time-of-peak instead of relative-time + accel + disp.
+    Left margin sized to fit the channel labels.
+    """
+    gs = fig.add_gridspec(
+        nrows=4, ncols=1,
+        left=0.11, right=0.94, top=0.97, bottom=0.06,
+        height_ratios=[1.8, 0.9, 1.7, 5.6],
+        hspace=0.35,
+    )
+    ax_header = fig.add_subplot(gs[0]); ax_header.axis("off")
+    _draw_header_histogram(ax_header, rd)
+
+    ax_mic = fig.add_subplot(gs[1]); ax_mic.axis("off")
+    _draw_mic_only(ax_mic, rd)
+
+    ax_stats = fig.add_subplot(gs[2]); ax_stats.axis("off")
+    _draw_channel_stats_histogram(ax_stats, rd)
+
+    _draw_histogram_subplot(fig, gs[3], rd)
+
+
+def _fmt_iso_to_bw(iso: Optional[str]) -> Optional[str]:
+    """Convert a ISO-8601 timestamp like '2026-05-16T22:30:37' to BW's
+    display format '22:30:37 May 16, 2026'.  Returns input unchanged if
+    it doesn't look like ISO."""
+    if not iso or "T" not in iso:
+        return iso
+    try:
+        import datetime as _dt
+        dt = _dt.datetime.fromisoformat(iso.replace("Z", "+00:00"))
+        return dt.strftime("%H:%M:%S %B %d, %Y").replace(" 0", " ")
+    except Exception:
+        return iso
+
+
 def _kv(ax, x, y, label, value, *, label_w=0.18):
     """Render a 'Label  Value' row at axes-coordinates (x, y)."""
     ax.text(x, y, label, fontsize=8, color="#555", ha="left", va="top",
@@ -329,11 +393,10 @@ def _fmt(v):
     return str(v)
 
 
-def _draw_header(ax, rd: ReportData) -> None:
+def _draw_header_waveform(ax, rd: ReportData) -> None:
-    """Two-column metadata header — matches BW printout layout."""
+    """Two-column metadata header — waveform variant."""
-    # Left column
     rows_left = [
-        ("Date/Time",      rd.event_datetime_str),
+        ("Date/Time",      _fmt_iso_to_bw(rd.event_datetime_str)),
         ("Trigger Source", rd.trigger_source),
         ("Range",          rd.geo_range_str),
         ("Sample Rate",    rd.sample_rate_str),
@@ -343,18 +406,45 @@ def _draw_header(ax, rd: ReportData) -> None:
         ("User Name:",     rd.operator),
         ("Seis. Loc:",     rd.sensor_location),
     ]
+    _draw_header_columns(ax, rows_left, rd)
+
+
+def _draw_header_histogram(ax, rd: ReportData) -> None:
+    """Two-column metadata header — histogram variant.
+
+    Histograms have Start / Finish / Intervals fields instead of
+    Trigger Source (there's no trigger event for a histogram capture).
+    """
+    intervals_str = None
+    if rd.histogram_n_intervals is not None and rd.histogram_interval_size:
+        intervals_str = f"{rd.histogram_n_intervals} At {rd.histogram_interval_size}"
+    rows_left = [
+        ("Start",      _fmt_iso_to_bw(rd.histogram_start_str or rd.event_datetime_str)),
+        ("Finish",     _fmt_iso_to_bw(rd.histogram_stop_str)),
+        ("Intervals",  intervals_str),
+        ("Range",      rd.geo_range_str),
+        ("Sample Rate", (f"{rd.sample_rate_sps} Sps" if rd.sample_rate_sps else None)),
+        ("Notes",      rd.notes),
+        ("Project:",   rd.project),
+        ("Client:",    rd.client),
+        ("User Name:", rd.operator),
+        ("Seis. Loc:", rd.sensor_location),
+    ]
+    _draw_header_columns(ax, rows_left, rd)
+
+
+def _draw_header_columns(ax, rows_left, rd: ReportData) -> None:
+    """Shared 2-column header rendering used by both layouts."""
     rows_right = [
-        ("Serial Number",   f"{rd.serial or '—'}"
+        ("Serial Number", f"{rd.serial or '—'}" + (f"  {rd.firmware}" if rd.firmware else "")),
-                            + (f"  {rd.firmware}" if rd.firmware else "")),
         ("Battery Level", f"{rd.battery_volts:.1f} Volts" if rd.battery_volts is not None else None),
-        ("Unit Calibration", (f"{rd.calibration_date}"
+        ("Unit Calibration", (f"{rd.calibration_date}" + (f" by {rd.calibration_by}" if rd.calibration_by else ""))
-                              + (f" by {rd.calibration_by}" if rd.calibration_by else ""))
                               if rd.calibration_date else None),
         ("File Name", rd.file_name),
         ("Post Event Notes", rd.post_event_notes),
     ]
     y = 0.95
-    dy = 0.10
+    dy = 0.095
     for label, value in rows_left:
         _kv(ax, 0.0, y, label, value, label_w=0.18)
         y -= dy
@@ -364,12 +454,43 @@ def _draw_header(ax, rd: ReportData) -> None:
         y -= dy
 
 
-def _draw_mic_block(ax, rd: ReportData) -> None:
+def _draw_mic_only(ax, rd: ReportData) -> None:
-    """Microphone block — PSPL, ZC Freq, Channel Test.  USBM chart
+    """Mic block (histogram variant — no USBM chart)."""
-    placeholder on the right (filled in a separate work item)."""
     ax.text(0.0, 0.95, "Microphone   Linear Weighting", fontsize=8, color="#555",
             transform=ax.transAxes, va="top")
-    rows = []
+    rows = _mic_rows(rd)
+    y = 0.70
+    for label, value in rows:
+        _kv(ax, 0.0, y, label, value, label_w=0.18)
+        y -= 0.22
+
+
+def _draw_mic_and_usbm(ax, rd: ReportData) -> None:
+    """Mic block on the left + USBM compliance chart placeholder on right.
+    (Waveform variant — USBM is a velocity-vs-frequency compliance plot
+    that doesn't apply to histograms.)"""
+    ax.text(0.0, 0.95, "Microphone   Linear Weighting", fontsize=8, color="#555",
+            transform=ax.transAxes, va="top")
+    rows = _mic_rows(rd)
+    y = 0.80
+    for label, value in rows:
+        _kv(ax, 0.0, y, label, value, label_w=0.18)
+        y -= 0.15
+
+    # USBM chart placeholder — upper-right.  Real piecewise compliance
+    # curves are a separate work item; for now this just shows the title
+    # + a "see report" message so the layout is correct.
+    ax.text(0.72, 0.97, "USBM RI8507 And OSMRE",
+            fontsize=9, weight="bold", color="#333", ha="center", va="top",
+            transform=ax.transAxes)
+    ax.text(0.72, 0.50, "[compliance chart\ncoming soon]",
+            fontsize=8, color="#bbb", ha="center", va="center",
+            transform=ax.transAxes, style="italic")
+
+
+def _mic_rows(rd: ReportData) -> list[tuple[str, Optional[str]]]:
+    """Build the mic-section value rows (shared by both layouts)."""
+    rows: list[tuple[str, Optional[str]]] = []
     if rd.mic_pspl_dbl is not None:
         line = f"{rd.mic_pspl_dbl:.1f} dB(L)"
         if rd.mic_pspl_time_s is not None:
@@ -383,47 +504,78 @@ def _draw_mic_block(ax, rd: ReportData) -> None:
             line += (f" (Freq = {rd.mic_channel_test_freq_hz:.1f} Hz, "
                      f"Amp = {rd.mic_channel_test_amp_mv:.0f} mv)")
         rows.append(("Channel Test", line))
-
+    return rows
-    y = 0.70
-    for label, value in rows:
-        _kv(ax, 0.0, y, label, value, label_w=0.18)
-        y -= 0.22
-
-    # USBM chart placeholder — upper-right of this row
-    ax.text(0.75, 0.95, "USBM RI8507 / OSMRE",
-            fontsize=8, color="#555", ha="center", va="top",
-            transform=ax.transAxes)
-    ax.text(0.75, 0.45, "[compliance chart\nrenders here]",
-            fontsize=8, color="#bbb", ha="center", va="center",
-            transform=ax.transAxes, style="italic")
 
 
-def _draw_channel_stats(ax, rd: ReportData) -> None:
+def _draw_channel_stats_waveform(ax, rd: ReportData) -> None:
-    """Per-channel stats table + Peak Vector Sum row."""
+    """Waveform stats table — has Time (Rel. to Trig), Peak Accel, Peak Disp.
-    # Build a 2-D array of strings: header row + 3 channel rows
+    Followed by Peak Vector Sum line."""
-    headers = ["", "Tran", "Vert", "Long", ""]
+    rows_spec = [
-    rows = [
+        ("PPV",                  "ppv_ips",        "in/s"),
-        ["PPV",                "ppv_ips",        "in/s"],
+        ("ZC Freq",              "zc_freq_hz",     "Hz"),
-        ["ZC Freq",            "zc_freq_hz",     "Hz"],
+        ("Time (Rel. to Trig)",  "time_of_peak_s", "sec"),
-        ["Time (Rel. to Trig)", "time_of_peak_s", "sec"],
+        ("Peak Acceleration",    "peak_accel_g",   "g"),
-        ["Peak Acceleration",   "peak_accel_g",   "g"],
+        ("Peak Displacement",    "peak_disp_in",   "in"),
-        ["Peak Displacement",   "peak_disp_in",   "in"],
+        ("Sensor Check",         "sensor_check",   ""),
-        ["Sensor Check",        "sensor_check",   ""],
     ]
+    _draw_stats_table(ax, rd, rows_spec)
+    if rd.peak_vector_sum_ips is not None:
+        line = f"Peak Vector Sum   {rd.peak_vector_sum_ips:.3f} in/s"
+        if rd.peak_vector_sum_time_s is not None:
+            line += f" At {rd.peak_vector_sum_time_s:.3f} sec."
+        ax.text(0.0, -0.08, line, fontsize=9, weight="bold",
+                ha="left", va="top", transform=ax.transAxes)
+        ax.text(0.0, -0.18, "NA: Not Applicable", fontsize=7, color="#888",
+                ha="left", va="top", transform=ax.transAxes)
+
+
+def _draw_channel_stats_histogram(ax, rd: ReportData) -> None:
+    """Histogram stats table — PPV, ZC Freq, Date, Time of peak, Sensor Check.
+    Followed by Peak Vector Sum line."""
+    # Date / Time of peak are per-channel timestamps for the interval at peak.
+    # bw_report stores time_of_peak_s as relative seconds, but for histograms
+    # BW shows them as absolute date+time.  We populate from rd.channel_stats
+    # if those absolute fields are present; otherwise fall back to relative.
+    rows_spec = [
+        ("PPV",          "ppv_ips",         "in/s"),
+        ("ZC Freq",      "zc_freq_hz",      "Hz"),
+        ("Date",         "peak_date",       ""),
+        ("Time",         "peak_time",       ""),
+        ("Sensor Check", "sensor_check",    ""),
+    ]
+    _draw_stats_table(ax, rd, rows_spec)
+    if rd.peak_vector_sum_ips is not None:
+        when = rd.peak_vector_sum_when_str or ""
+        line = f"Peak Vector Sum   {rd.peak_vector_sum_ips:.3f} in/s"
+        if when:
+            line += f" on {when}"
+        ax.text(0.0, -0.08, line, fontsize=9, weight="bold",
+                ha="left", va="top", transform=ax.transAxes)
+        ax.text(0.0, -0.18, "NA: Not Applicable", fontsize=7, color="#888",
+                ha="left", va="top", transform=ax.transAxes)
+
+
+def _draw_stats_table(ax, rd: ReportData, rows_spec: list[tuple[str, str, str]]) -> None:
+    """Render a per-channel stats table (Tran/Vert/Long).
+
+    rows_spec: list of (label, field_name_in_channel_stats, unit_string)
+    """
+    headers = ["", "Tran", "Vert", "Long", ""]
     ch_lookup = {c["name"]: c for c in rd.channel_stats}
 
     def _cell(field, ch_name):
         val = ch_lookup.get(ch_name, {}).get(field)
         if val is None:
             return "—"
-        if field == "sensor_check":
-            return str(val)
         if isinstance(val, float):
+            # ZC Freq is integer-formatted in BW; everything else with 3 decimals
+            if field == "zc_freq_hz":
+                return f"{val:.0f}"
             return f"{val:.3f}"
         return str(val)
 
     table_data = [headers]
-    for label, field_name, unit in rows:
+    for label, field_name, unit in rows_spec:
         table_data.append([
             label,
             _cell(field_name, "Tran"),
@@ -431,27 +583,16 @@ def _draw_channel_stats(ax, rd: ReportData) -> None:
             _cell(field_name, "Long"),
             unit,
         ])
-
     tbl = ax.table(
         cellText=table_data, loc="upper left",
-        colWidths=[0.30, 0.13, 0.13, 0.13, 0.10],
+        colWidths=[0.28, 0.14, 0.14, 0.14, 0.10],
         cellLoc="left", edges="open",
     )
     tbl.auto_set_font_size(False)
     tbl.set_fontsize(8)
     tbl.scale(1, 1.4)
-    # Header row styling
     for j in range(5):
-        cell = tbl[(0, j)]
+        tbl[(0, j)].set_text_props(weight="bold", color="#555")
-        cell.set_text_props(weight="bold", color="#555")
-
-    # Peak Vector Sum
-    if rd.peak_vector_sum_ips is not None:
-        line = f"Peak Vector Sum   {rd.peak_vector_sum_ips:.3f} in/s"
-        if rd.peak_vector_sum_time_s is not None:
-            line += f" At {rd.peak_vector_sum_time_s:.3f} sec."
-        ax.text(0.0, -0.05, line, fontsize=9, weight="bold",
-                ha="left", va="top", transform=ax.transAxes)
 
 
 def _channel_axis_color(ch: str) -> str:
@@ -460,59 +601,142 @@ def _channel_axis_color(ch: str) -> str:
 
 def _draw_waveform_subplot(fig, gridspec_cell, rd: ReportData) -> None:
     """4-channel stacked waveform plot — Instantel printout order
-    (MicL on top, Tran on bottom), shared x-axis."""
+    (MicL on top, Tran on bottom), shared x-axis in SECONDS, trigger
+    triangle markers at t=0, '0.0' baseline label on right of each."""
     inner = gridspec_cell.subgridspec(4, 1, hspace=0.0)
     order = ["MicL", "Long", "Vert", "Tran"]
     sr = rd.sample_rate_sps or 1024
-    dt_ms = rd.dt_ms or (1000.0 / sr)
+    # Convert ms-based time axis to seconds for the x-axis
-    t0_ms = rd.t0_ms if rd.t0_ms is not None else 0.0
+    dt_s = (rd.dt_ms or (1000.0 / sr)) / 1000.0
+    t0_s = (rd.t0_ms if rd.t0_ms is not None else 0.0) / 1000.0
 
     last_idx = len(order) - 1
     for i, ch in enumerate(order):
         ax = fig.add_subplot(inner[i])
         values = rd.channels.get(ch) or []
-        times = [t0_ms + j * dt_ms for j in range(len(values))]
+        times = [t0_s + j * dt_s for j in range(len(values))]
 
         if values:
             color = _channel_axis_color(ch)
-            ax.plot(times, values, color=color, linewidth=0.6)
+            ax.plot(times, values, color=color, linewidth=0.5)
-            # Symmetric y-axis for geo; zero-anchored for mic
+            # Symmetric y-axis for geo; zero-anchored for mic.
             if ch != "MicL":
                 amax = max((abs(v) for v in values), default=0.001)
-                ax.set_ylim(-amax * 1.1, amax * 1.1)
+                ax.set_ylim(-amax * 1.10, amax * 1.10)
-        # Channel label on left
+            else:
+                amax = max((abs(v) for v in values), default=0.001)
+                ax.set_ylim(-amax * 1.10, amax * 1.10)
+
+        # Channel label on the LEFT (matches BW)
         ax.set_ylabel(ch, fontsize=8, rotation=0, ha="right", va="center",
                       color=_channel_axis_color(ch), weight="bold", labelpad=14)
-        ax.grid(True, linestyle=":", linewidth=0.4, alpha=0.5)
+        # "0.0" on the RIGHT (BW convention)
-        # Dashed trigger line at t=0
+        ax.text(1.005, 0.5, "0.0", transform=ax.transAxes,
-        ax.axvline(0.0, color="#cc0000", linestyle="--", linewidth=0.8, alpha=0.7)
+                fontsize=7, color="#555", va="center", ha="left")
-        # Zero baseline
+
-        ax.axhline(0.0, color="#888", linestyle="-", linewidth=0.4, alpha=0.5)
+        ax.grid(True, linestyle="--", linewidth=0.3, color="#bbb", alpha=0.6)
+        # Vertical dashed trigger line at t=0
+        ax.axvline(0.0, color="#cc0000", linestyle="--", linewidth=0.6, alpha=0.7)
+        # Zero baseline horizontal
+        ax.axhline(0.0, color=_channel_axis_color(ch), linestyle="-",
+                   linewidth=0.4, alpha=0.5)
 
         if i != last_idx:
             ax.set_xticklabels([])
+            ax.tick_params(axis="x", length=0)
         else:
-            ax.set_xlabel("Time (ms)", fontsize=8)
+            ax.tick_params(axis="x", labelsize=7)
-        ax.tick_params(axis="both", labelsize=7)
+        ax.tick_params(axis="y", labelsize=6)
+
+    # Trigger triangle marker ▼ above the top channel at t=0
+    top_ax = fig.axes[-4]  # MicL is the first added in this gridspec
+    top_ax.plot([0], [top_ax.get_ylim()[1]], marker="v", color="black",
+                markersize=8, clip_on=False, zorder=10)
+
+    # Compute scale-per-division for the footer (10 divs across the chart)
+    # and find peak geo amplitude for the geo amp/div setting.
+    total_s = times[-1] - times[0] if values else 0
+    div_s = total_s / 10 if total_s > 0 else 0
+    geo_amp_div = "—"
+    for ch in ("Tran", "Vert", "Long"):
+        v = rd.channels.get(ch) or []
+        if v:
+            amax = max(abs(x) for x in v)
+            geo_amp_div = f"{(amax * 1.1 * 2) / 10:.3f}"
+            break
+    fig.text(
+        0.07, 0.045,
+        f"Time(Seconds) {div_s:.2f} sec/div   Amplitude Geo: {geo_amp_div} in/s/div   Mic: 0.001 psi(L)/div",
+        fontsize=7, color="#444", ha="left",
+    )
+    fig.text(
+        0.07, 0.030,
+        "Trigger = ▶━━━━━ ━━━━━━◀",
+        fontsize=7, color="#444", ha="left",
+    )
 
 
 def _draw_histogram_subplot(fig, gridspec_cell, rd: ReportData) -> None:
-    """4-channel stacked histogram bar chart — per-interval peaks."""
+    """4-channel stacked histogram bar chart — per-interval peaks.
+
+    X-axis labeled with the actual times from rd.histogram_interval_times
+    when available; otherwise interval index.
+    """
     inner = gridspec_cell.subgridspec(4, 1, hspace=0.0)
     order = ["MicL", "Long", "Vert", "Tran"]
     last_idx = len(order) - 1
+
+    # X-axis: use absolute time labels if we have them, else interval index
+    have_times = bool(rd.histogram_interval_times)
+
     for i, ch in enumerate(order):
         ax = fig.add_subplot(inner[i])
         values = rd.channels.get(ch) or []
         if values:
-            xs = np.arange(1, len(values) + 1)
+            # Histograms record per-interval PEAK magnitudes — always
+            # non-negative.  Codec output occasionally includes signed
+            # values when the underlying .h5 was scaled like a waveform;
+            # take the absolute value so the bars rise from zero.
+            abs_vals = [abs(v) if v is not None else 0 for v in values]
+            xs = np.arange(len(abs_vals))
             color = _channel_axis_color(ch)
-            ax.bar(xs, values, color=color, width=1.0, linewidth=0)
+            ax.bar(xs, abs_vals, color=color, width=0.85, linewidth=0)
+            amax = max(abs_vals, default=0)
+            if amax > 0:
+                ax.set_ylim(0, amax * 1.10)
         ax.set_ylabel(ch, fontsize=8, rotation=0, ha="right", va="center",
                       color=_channel_axis_color(ch), weight="bold", labelpad=14)
-        ax.grid(True, axis="y", linestyle=":", linewidth=0.4, alpha=0.5)
+        ax.text(1.005, 0.02, "0.0", transform=ax.transAxes,
+                fontsize=7, color="#555", va="bottom", ha="left")
+        ax.grid(True, axis="y", linestyle="--", linewidth=0.3, color="#bbb", alpha=0.6)
         if i != last_idx:
             ax.set_xticklabels([])
+            ax.tick_params(axis="x", length=0)
+        else:
+            if have_times and len(rd.histogram_interval_times) == len(values):
+                # Show 2-4 labels evenly spaced
+                n = len(values)
+                step = max(1, n // 4)
+                tick_positions = list(range(0, n, step))
+                ax.set_xticks(tick_positions)
+                ax.set_xticklabels([rd.histogram_interval_times[t] for t in tick_positions],
+                                   rotation=0, fontsize=6)
             else:
                 ax.set_xlabel("Interval", fontsize=8)
-        ax.tick_params(axis="both", labelsize=7)
+            ax.tick_params(axis="x", labelsize=7)
+        ax.tick_params(axis="y", labelsize=6)
+
+    # Footer scale info — histograms use minute/div
+    interval_str = rd.histogram_interval_size or "—"
+    geo_amp_div = "—"
+    for ch in ("Tran", "Vert", "Long"):
+        v = rd.channels.get(ch) or []
+        if v:
+            amax = max(abs(x) for x in v)
+            geo_amp_div = f"{amax / 5:.3f}"
+            break
+    fig.text(
+        0.07, 0.045,
+        f"Time {interval_str} /div   Amplitude Geo: {geo_amp_div} in/s/div   Mic: 0.001 psi(L)/div",
+        fontsize=7, color="#444", ha="left",
+    )