Add axis control, point limits, and dimension params to plot_waveform

Expose x_min/x_max/y_min/y_max, max_points, width/height, and title
override through the MCP tool. Data is clipped to X range before
stride-based downsampling for better zoomed resolution. All params
default to None/current behavior for backward compatibility.

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mcltspice"
-version = "2026.02.10"
+version = "2026.02.14"
 description = "MCP server for LTspice circuit simulation automation"
 readme = "README.md"
 requires-python = ">=3.11"

src/mcltspice/server.py

@@ -1321,6 +1321,14 @@ async def plot_waveform(
     signal: str = "V(out)",
     plot_type: str = "auto",
     output_path: str | None = None,
+    max_points: int = 10000,
+    x_min: float | None = None,
+    x_max: float | None = None,
+    y_min: float | None = None,
+    y_max: float | None = None,
+    width: int = 800,
+    height: int | None = None,
+    title: str | None = None,
 ) -> dict:
     """Generate an SVG plot from simulation results.
 
@@ -1332,6 +1340,14 @@ async def plot_waveform(
         signal: Signal name to plot (e.g. "V(out)", "I(R1)")
         plot_type: "auto" (detect from data), "time", "bode", or "spectrum"
         output_path: Where to save SVG file (None = auto in /tmp)
+        max_points: Maximum data points to plot (stride-sampled if exceeded)
+        x_min: Left X-axis bound (seconds for time, Hz for frequency). None = auto
+        x_max: Right X-axis bound. None = auto
+        y_min: Lower Y-axis bound (volts for time, dB for bode/spectrum). None = auto
+        y_max: Upper Y-axis bound. None = auto
+        width: SVG width in pixels
+        height: SVG height in pixels (None = 500 for bode, 400 otherwise)
+        title: Plot title (None = auto-generated from signal name and plot type)
     """
     raw_path = Path(raw_file)
     if not raw_path.exists():
@@ -1379,29 +1395,70 @@ async def plot_waveform(
         else:
             plot_type = "time"
 
+    # Clip to X range (before downsampling for efficiency)
+    real_x = np.real(x_data)
+    if x_min is not None or x_max is not None:
+        mask = np.ones(len(real_x), dtype=bool)
+        if x_min is not None:
+            mask &= real_x >= x_min
+        if x_max is not None:
+            mask &= real_x <= x_max
+        x_data = x_data[mask]
+        values = values[mask]
+        real_x = real_x[mask]
+        if mag_db is not None:
+            mag_db = mag_db[mask]
+        if phase_deg is not None:
+            phase_deg = phase_deg[mask]
+
+    # Downsample (stride-based, same pattern as get_waveform)
+    if max_points and len(x_data) > max_points:
+        step = max(1, len(x_data) // max_points)
+        x_data = x_data[::step]
+        values = values[::step]
+        real_x = real_x[::step]
+        if mag_db is not None:
+            mag_db = mag_db[::step]
+        if phase_deg is not None:
+            phase_deg = phase_deg[::step]
+
+    # Height default
+    if height is None:
+        height = 500 if plot_type == "bode" else 400
+
+    # Title default
+    if title is None:
+        if plot_type == "bode":
+            title = f"Bode Plot \u2014 {actual_name}"
+        elif plot_type == "spectrum":
+            title = f"Spectrum \u2014 {actual_name}"
+        else:
+            title = f"Time Domain \u2014 {actual_name}"
+
     # Generate SVG
     if plot_type == "bode":
         if mag_db is None:
             mag_db = np.real(values)
             phase_deg = None
-        freq = np.real(x_data)
         svg = plot_bode(
-            freq=freq, mag_db=mag_db, phase_deg=phase_deg,
+            freq=real_x, mag_db=mag_db, phase_deg=phase_deg,
-            title=f"Bode Plot — {actual_name}",
+            title=title, width=width, height=height,
+            x_min=x_min, x_max=x_max, y_min=y_min, y_max=y_max,
         )
     elif plot_type == "spectrum":
-        freq = np.real(x_data)
         if mag_db is None:
             mag_db = 20.0 * np.log10(np.maximum(np.abs(np.real(values)), 1e-30))
         svg = plot_spectrum(
-            freq=freq, mag_db=mag_db,
+            freq=real_x, mag_db=mag_db,
-            title=f"Spectrum — {actual_name}",
+            title=title, width=width, height=height,
+            x_min=x_min, x_max=x_max, y_min=y_min, y_max=y_max,
         )
     else:  # time
         svg = plot_timeseries(
-            time=np.real(x_data), values=np.real(values),
+            time=real_x, values=np.real(values),
-            title=f"Time Domain — {actual_name}",
+            title=title, ylabel=actual_name,
-            ylabel=actual_name,
+            width=width, height=height,
+            x_min=x_min, x_max=x_max, y_min=y_min, y_max=y_max,
         )
 
     # Save SVG
@@ -1416,6 +1473,7 @@ async def plot_waveform(
         "plot_type": plot_type,
         "signal": actual_name,
         "points": len(x_data),
+        "dimensions": f"{width}x{height}",
     }
 
 

src/mcltspice/svg_plot.py

@@ -334,6 +334,10 @@ def plot_timeseries(
     ylabel: str = "Voltage (V)",
     width: int = 800,
     height: int = 400,
+    x_min: float | None = None,
+    x_max: float | None = None,
+    y_min: float | None = None,
+    y_max: float | None = None,
 ) -> str:
     """Plot a time-domain signal. Linear X axis (time), linear Y axis.
 
@@ -350,8 +354,12 @@ def plot_timeseries(
     plot_w = float(width - margin_l - margin_r)
     plot_h = float(height - margin_t - margin_b)
 
-    x_min, x_max = _data_extent(t)
+    auto_xmin, auto_xmax = _data_extent(t)
-    y_min, y_max = _data_extent(v)
+    auto_ymin, auto_ymax = _data_extent(v)
+    x_min = x_min if x_min is not None else auto_xmin
+    x_max = x_max if x_max is not None else auto_xmax
+    y_min = y_min if y_min is not None else auto_ymin
+    y_max = y_max if y_max is not None else auto_ymax
 
     inner = _render_subplot(
         xs=t,
@@ -380,12 +388,18 @@ def plot_bode(
     title: str = "Bode Plot",
     width: int = 800,
     height: int = 500,
+    x_min: float | None = None,
+    x_max: float | None = None,
+    y_min: float | None = None,
+    y_max: float | None = None,
 ) -> str:
     """Plot frequency response (Bode plot). Log10 X, linear Y (dB).
 
     If *phase_deg* is provided, the SVG contains two stacked subplots:
     magnitude on top, phase on the bottom.
 
+    *y_min*/*y_max* apply to the magnitude subplot only; phase auto-ranges.
+
     Returns a complete ``<svg>`` XML string.
     """
     f = np.asarray(freq, dtype=float).ravel()
@@ -404,7 +418,11 @@ def plot_bode(
     plot_w = float(width - margin_l - margin_r)
 
     # Frequency range (shared)
-    f_min, f_max = _data_extent(f[f > 0] if np.any(f > 0) else f, pad_frac=0.0)
+    auto_fmin, auto_fmax = _data_extent(f[f > 0] if np.any(f > 0) else f, pad_frac=0.0)
+    if auto_fmin <= 0:
+        auto_fmin = 1.0
+    f_min = x_min if x_min is not None else auto_fmin
+    f_max = x_max if x_max is not None else auto_fmax
     if f_min <= 0:
         f_min = 1.0
     freq_ticks = _log_ticks(f_min, f_max)
@@ -418,7 +436,9 @@ def plot_bode(
         mag_y = float(margin_t)
         phase_y = float(margin_t + mag_h + gap)
 
-        m_min, m_max = _data_extent(m)
+        auto_mmin, auto_mmax = _data_extent(m)
+        m_min = y_min if y_min is not None else auto_mmin
+        m_max = y_max if y_max is not None else auto_mmax
         p_min, p_max = _data_extent(p)
 
         mag_svg = _render_subplot(
@@ -463,7 +483,9 @@ def plot_bode(
     else:
         plot_y = float(margin_t)
         plot_h = float(height - margin_t - margin_b)
-        m_min, m_max = _data_extent(m)
+        auto_mmin, auto_mmax = _data_extent(m)
+        m_min = y_min if y_min is not None else auto_mmin
+        m_max = y_max if y_max is not None else auto_mmax
 
         inner = _render_subplot(
             xs=f,
@@ -492,6 +514,10 @@ def plot_spectrum(
     title: str = "FFT Spectrum",
     width: int = 800,
     height: int = 400,
+    x_min: float | None = None,
+    x_max: float | None = None,
+    y_min: float | None = None,
+    y_max: float | None = None,
 ) -> str:
     """Plot an FFT spectrum. Log10 X axis, linear Y axis (dB).
 
@@ -508,10 +534,16 @@ def plot_spectrum(
     plot_w = float(width - margin_l - margin_r)
     plot_h = float(height - margin_t - margin_b)
 
-    f_min, f_max = _data_extent(f[f > 0] if np.any(f > 0) else f, pad_frac=0.0)
+    auto_fmin, auto_fmax = _data_extent(f[f > 0] if np.any(f > 0) else f, pad_frac=0.0)
+    if auto_fmin <= 0:
+        auto_fmin = 1.0
+    auto_mmin, auto_mmax = _data_extent(m)
+    f_min = x_min if x_min is not None else auto_fmin
+    f_max = x_max if x_max is not None else auto_fmax
     if f_min <= 0:
         f_min = 1.0
-    m_min, m_max = _data_extent(m)
+    m_min = y_min if y_min is not None else auto_mmin
+    m_max = y_max if y_max is not None else auto_mmax
 
     inner = _render_subplot(
         xs=f,

tests/test_svg_plot.py

@@ -197,3 +197,82 @@ class TestSvgDimensions:
         svg = plot_spectrum(freq, mag, width=1000, height=500)
         assert 'width="1000"' in svg
         assert 'height="500"' in svg
+
+
+# ---------------------------------------------------------------------------
+# Axis range overrides
+# ---------------------------------------------------------------------------
+
+
+class TestAxisRangeOverrides:
+    def test_timeseries_custom_axis_range(self, sine_wave):
+        """Explicit x/y ranges produce valid SVG without crashing."""
+        t, v = sine_wave
+        svg = plot_timeseries(
+            t, v, x_min=0.002, x_max=0.005, y_min=-0.5, y_max=0.5,
+        )
+        assert svg.startswith("<svg")
+        assert "<path" in svg
+        assert "</svg>" in svg
+
+    def test_bode_custom_freq_range(self, bode_data):
+        """Bode plot with explicit frequency range includes ticks in range."""
+        freq, mag_db, phase_deg = bode_data
+        svg = plot_bode(
+            freq, mag_db, phase_deg,
+            x_min=100.0, x_max=100_000.0,
+            y_min=-40.0, y_max=0.0,
+        )
+        assert svg.startswith("<svg")
+        assert "<path" in svg
+        # Tick labels should include values within 100 Hz – 100 kHz
+        found = sum(1 for lbl in ("1k", "10k") if lbl in svg)
+        assert found >= 1, f"Expected freq tick labels in range; found {found}"
+
+    def test_spectrum_custom_range(self, spectrum_data):
+        """Spectrum with explicit ranges produces valid SVG."""
+        freq, mag_db = spectrum_data
+        svg = plot_spectrum(
+            freq, mag_db,
+            x_min=100.0, x_max=50_000.0,
+            y_min=-80.0, y_max=10.0,
+        )
+        assert svg.startswith("<svg")
+        assert "<path" in svg
+
+    def test_partial_range_override(self, sine_wave):
+        """Setting only y_min while leaving others auto should work."""
+        t, v = sine_wave
+        svg = plot_timeseries(t, v, y_min=-2.0)
+        assert svg.startswith("<svg")
+        assert "<path" in svg
+
+    def test_none_defaults_match_current(self, sine_wave):
+        """Passing None for all range params produces identical output."""
+        t, v = sine_wave
+        svg_default = plot_timeseries(t, v)
+        svg_explicit_none = plot_timeseries(
+            t, v,
+            x_min=None, x_max=None, y_min=None, y_max=None,
+        )
+        assert svg_default == svg_explicit_none
+
+    def test_bode_none_defaults_match_current(self, bode_data):
+        """Bode with explicit None params matches default output."""
+        freq, mag_db, phase_deg = bode_data
+        svg_default = plot_bode(freq, mag_db, phase_deg)
+        svg_explicit_none = plot_bode(
+            freq, mag_db, phase_deg,
+            x_min=None, x_max=None, y_min=None, y_max=None,
+        )
+        assert svg_default == svg_explicit_none
+
+    def test_spectrum_none_defaults_match_current(self, spectrum_data):
+        """Spectrum with explicit None params matches default output."""
+        freq, mag_db = spectrum_data
+        svg_default = plot_spectrum(freq, mag_db)
+        svg_explicit_none = plot_spectrum(
+            freq, mag_db,
+            x_min=None, x_max=None, y_min=None, y_max=None,
+        )
+        assert svg_default == svg_explicit_none