Move plotting to pyqtgraph: interactive, overlay-capable render layer
Replace the fire-and-forget matplotlib pipeline (render() -> throwaway Figure -> canvas teardown) with a three-stage architecture that supports zoom/pan, lin/log toggling, and multi-file overlay: compute(audio_file) -> data # heavy, worker thread, backend-neutral build_spec(data, view) -> PlotSpec # cheap, GUI thread, view-aware show_specs([(label, spec, color)]) # pyqtgraph, persistent PlotItem, overlay - plotspec.py: backend-agnostic descriptors (Curve, Band, HLine, Heatmap, AxisSpec, PlotSpec) + ViewState (recompute-free lin/log) - audio_visualization_widget.py: persistent pyqtgraph plot, never torn down; per-dataset colours for overlay; spectrogram log-freq via row resample (ImageItem is affine-only); ColorBarItem at a fixed cell - Compare/overlay driven by file-list checkboxes; stable per-song colour by row - Custom draggable reference lines (add/clear), persist across redraws - Axis-constrained scroll zoom: Ctrl=time, Shift=value (_AxisZoomViewBox) - RMS render no longer per-segment fill_between (was the slow path) Fixes found in review/testing: - FillBetweenItem needs penned child curves or it fills nothing (RMS/Waveform were blank); band fill verified by pixel count - band overlay alpha was a no-op (QBrush.color() returns a copy) - colorbar could stack across renders; now added/removed at a fixed layout cell Deferred (per scope): stereo retention, deep perf rewrites (eager beat_track, true-peak/crest loops, shared LUFS), per-song colour picker UI. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
+322
-67
@@ -1,74 +1,329 @@
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"""
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Audio visualization widget with embedded matplotlib canvas.
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Pure display responsibility - receives plotting data and shows graphs.
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Interactive visualization widget built on pyqtgraph.
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One persistent PlotItem that is *reused* across renders — never torn down — so
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mouse zoom/pan, the view box, and scale toggles all survive redraws. Consumes a
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list of `(label, PlotSpec)` pairs and draws them onto the same axes, using a
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caller-supplied colour per dataset so a song keeps its colour regardless of which
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others are overlaid.
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Interaction notes:
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- Plain scroll zooms both axes; Ctrl+scroll zooms time only; Shift+scroll zooms
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the value axis only (see `_AxisZoomViewBox`). Scrolling directly over an axis
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also zooms just that axis (pyqtgraph default).
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- User reference lines (`add_user_line`) are draggable, survive redraws within a
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metric, and are cleared by the GUI when the metric changes (units change).
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Why the spectrogram is special: pyqtgraph's ImageItem is affine-only, so it does
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not follow a log-scaled axis. Log frequency is therefore realised by resampling
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the STFT rows onto a log-spaced grid and labelling the axis by row index — see
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`_render_heatmap`.
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"""
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import numpy as np
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import pyqtgraph as pg
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from scipy.interpolate import interp1d
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from PyQt5.QtWidgets import QWidget, QVBoxLayout, QLabel
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from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
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from matplotlib.figure import Figure
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from PyQt5.QtCore import Qt
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from plotspec import PlotSpec, ViewState, DEFAULT_VIEW
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# White canvas / black ink to match the previous matplotlib aesthetic.
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pg.setConfigOption("background", "w")
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pg.setConfigOption("foreground", "k")
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pg.setConfigOptions(antialias=True)
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# Dataset colour cycle for overlay. First colour is the single-dataset default.
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_PALETTE = [
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"#3a7ad6", "#e76f51", "#2a9d8f", "#e09f3e",
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"#7251b5", "#c1121f", "#588157", "#9d4edd",
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]
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# Pen styles for reference lines.
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_PEN_STYLE = {"solid": Qt.SolidLine, "dash": Qt.DashLine, "dot": Qt.DotLine}
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# "Nice" frequencies to label on a log frequency axis, in Hz.
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_LOG_FREQ_TICKS = [20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 20000]
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# Colour for user-added reference lines (neutral so it reads on any metric).
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_USER_LINE_COLOR = "#444444"
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def dataset_color(index: int) -> str:
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"""Stable dataset colour for a given index (e.g. a file's row in the list)."""
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return _PALETTE[index % len(_PALETTE)]
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def _colormap(name: str):
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"""Fetch a colormap, preferring matplotlib's so 'magma' etc. resolve."""
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try:
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return pg.colormap.getFromMatplotlib(name)
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except Exception:
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return pg.colormap.get(name)
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def _fmt_hz(hz: float) -> str:
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return f"{hz / 1000:.0f}k" if hz >= 1000 else f"{hz:.0f}"
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class _AxisZoomViewBox(pg.ViewBox):
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"""ViewBox whose wheel zoom can be constrained to one axis via a modifier.
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Plain scroll keeps pyqtgraph's both-axes zoom; Ctrl constrains to x (time),
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Shift constrains to y (the metric's value axis). This answers the "scroll
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zooms both axes, I want one" problem without taking away the default.
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"""
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def wheelEvent(self, ev, axis=None):
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mods = ev.modifiers()
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if mods & Qt.ControlModifier:
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axis = 0 # x only
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elif mods & Qt.ShiftModifier:
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axis = 1 # y only
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super().wheelEvent(ev, axis=axis)
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class AudioVisualizationWidget(QWidget):
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"""Widget for displaying audio analysis graphs with embedded matplotlib."""
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def __init__(self, parent=None):
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super().__init__(parent)
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self.initUI()
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def initUI(self):
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"""Initialize the UI components."""
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layout = QVBoxLayout()
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# Create matplotlib canvas
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self.figure = Figure(figsize=(10, 4), facecolor='white')
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self.canvas = FigureCanvas(self.figure)
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# Add canvas to layout
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layout.addWidget(self.canvas)
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# Status label for feedback
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self.status_label = QLabel("Ready for audio analysis...")
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layout.addWidget(self.status_label)
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self.setLayout(layout)
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# Initialize with empty plot
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self._create_empty_plot()
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def _create_empty_plot(self):
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"""Creates an empty placeholder plot."""
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self.figure.clear()
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ax = self.figure.add_subplot(111)
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ax.text(0.5, 0.5, 'Drop an audio file to see analysis',
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ha='center', va='center', transform=ax.transAxes,
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fontsize=14, alpha=0.7)
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ax.set_xlim(0, 1)
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ax.set_ylim(0, 1)
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ax.set_xticks([])
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ax.set_yticks([])
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self.canvas.draw()
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def display_figure_direct(self, figure):
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"""
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Display a figure by replacing our canvas figure entirely.
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More reliable than copying elements.
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Args:
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figure: matplotlib.figure.Figure to display
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"""
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# Remove old canvas
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layout = self.layout()
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layout.removeWidget(self.canvas)
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self.canvas.deleteLater()
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# Create new canvas with the provided figure
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self.figure = figure
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self.canvas = FigureCanvas(self.figure)
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layout.insertWidget(0, self.canvas) # Insert at position 0 (before status label)
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self.canvas.draw()
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self.status_label.setText("Analysis complete - displaying power graph")
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def set_status(self, message):
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"""Update the status label."""
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self.status_label.setText(message)
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"""Persistent interactive plot. Call `show_specs` to (re)draw."""
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def __init__(self, parent=None):
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super().__init__(parent)
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layout = QVBoxLayout(self)
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self.glw = pg.GraphicsLayoutWidget()
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self.plot = self.glw.addPlot(row=0, col=0, viewBox=_AxisZoomViewBox())
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self.plot.showGrid(x=True, y=True, alpha=0.3)
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self.plot.setMenuEnabled(True)
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self.legend = self.plot.addLegend(offset=(-10, 10))
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layout.addWidget(self.glw)
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self.status_label = QLabel("Ready for audio analysis...")
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layout.addWidget(self.status_label)
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self._colorbar = None
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# User reference lines persist by value across redraws; the items are rebuilt
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# each render. Cleared by the GUI on metric change (units change).
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self._user_line_values: list[float] = []
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self._user_lines: list[pg.InfiniteLine] = []
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self._show_empty()
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# ---- public API ---------------------------------------------------------
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def show_specs(self, specs, view: ViewState = DEFAULT_VIEW):
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"""Render datasets onto the shared axes.
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`specs` is a list of `(label, PlotSpec)` or `(label, PlotSpec, color)`. When
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no colour is given, the dataset's palette colour by position is used. All
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specs are assumed to be the same metric (compare overlays one metric across
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files), so axis labels/ranges come from the first spec.
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"""
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self._reset_plot()
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if not specs:
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self._show_empty()
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return
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specs = [self._normalise(s, i) for i, s in enumerate(specs)]
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base_axes = specs[0][1].axes
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# Heatmaps do not overlay: render only the first dataset's heatmap.
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if specs[0][1].is_heatmap:
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label, spec, _ = specs[0]
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self._render_heatmap(spec, view)
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if len(specs) > 1:
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self.set_status(f"{spec.title or label}: spectrogram shows one track at a time")
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self._apply_axes(base_axes, log_y_image_handled=True)
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self._draw_user_lines()
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return
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single = len(specs) == 1
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for label, spec, color in specs:
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prefix = "" if single else f"{label}: "
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self._render_curves_and_bands(spec, color, prefix, single=single)
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# Reference lines from the first spec only (identical across same-metric specs).
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for hl in specs[0][1].hlines:
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self._render_hline(hl)
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# Scalar readouts → legend-only proxy entries.
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for label, spec, _ in specs:
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prefix = "" if single else f"{label}: "
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for note in spec.annotations:
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self._legend_note(prefix + note)
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self._apply_axes(base_axes)
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self._draw_user_lines()
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def add_user_line(self, value: float | None = None):
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"""Add a draggable horizontal reference line at `value` (default: view centre)."""
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if value is None:
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(_, _), (y0, y1) = self.plot.viewRange()
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value = (y0 + y1) / 2.0
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self._user_line_values.append(float(value))
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self._draw_user_lines()
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def clear_user_lines(self):
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"""Remove all user reference lines (called when the metric changes)."""
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self._user_line_values.clear()
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self._remove_user_line_items()
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def set_status(self, message: str):
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self.status_label.setText(message)
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# ---- rendering helpers --------------------------------------------------
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def _normalise(self, spec_tuple, index: int):
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"""Coerce a spec tuple to (label, PlotSpec, color), filling colour by index."""
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if len(spec_tuple) == 3:
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return spec_tuple
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label, spec = spec_tuple
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return label, spec, dataset_color(index)
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def _render_curves_and_bands(self, spec: PlotSpec, color: str, prefix: str, single: bool):
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for band in spec.bands:
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lo = np.ascontiguousarray(np.broadcast_to(band.lo, band.x.shape), dtype=float)
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hi = np.ascontiguousarray(np.broadcast_to(band.hi, band.x.shape), dtype=float)
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# FillBetweenItem fills nothing if its child curves have no pen — give them
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# a thin outline in the dataset colour (this is the RMS/Waveform fix).
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edge = pg.mkPen(color, width=1.0)
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c_lo = pg.PlotDataItem(band.x, lo, pen=edge)
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c_hi = pg.PlotDataItem(band.x, hi, pen=edge)
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self.plot.addItem(c_lo)
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self.plot.addItem(c_hi)
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# Build the colour with alpha up front: QBrush.color() returns a copy, so
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# mutating its alpha after mkBrush would be a no-op (opaque overlay bug).
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fill_color = pg.mkColor(color)
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fill_color.setAlpha(200 if single else 90)
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fill = pg.FillBetweenItem(c_lo, c_hi, brush=pg.mkBrush(fill_color))
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self.plot.addItem(fill)
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if band.label:
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self._legend_swatch(prefix + band.label, color)
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for curve in spec.curves:
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pen = pg.mkPen(curve.color or color, width=curve.width)
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item = self.plot.plot(curve.x, curve.y, pen=pen,
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name=(prefix + curve.label) if curve.label else None,
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connect="finite") # gaps at NaN (gated PSR)
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item.setDownsampling(auto=True) # keep big series smooth under zoom
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item.setClipToView(True)
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def _render_hline(self, hl):
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pen = pg.mkPen(hl.color, width=hl.width, style=_PEN_STYLE.get(hl.style, Qt.DotLine))
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line = pg.InfiniteLine(
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pos=hl.y, angle=0, pen=pen, movable=False,
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label=hl.label or None,
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labelOpts={"position": 0.95, "color": hl.color, "fill": (255, 255, 255, 150)},
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)
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self.plot.addItem(line)
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def _render_heatmap(self, spec: PlotSpec, view: ViewState):
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hm = spec.heatmap
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t0, t1 = float(hm.x[0]), float(hm.x[-1])
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f_lo = max(spec.axes.y_range[0] if spec.axes.y_range else hm.y[0], hm.y[0])
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f_hi = spec.axes.y_range[1] if spec.axes.y_range else hm.y[-1]
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y_log = view.resolve_y_log(default=spec.axes.y_log)
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n_rows = len(hm.y)
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if y_log:
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f_grid = np.logspace(np.log10(max(f_lo, 1e-6)), np.log10(f_hi), n_rows)
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else:
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f_grid = np.linspace(f_lo, f_hi, n_rows)
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# Resample every time column from native linear freq bins onto f_grid in one
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# vectorised pass — this runs on each redraw and lin/log toggle, so the loop
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# version would make the toggle feel laggy on long files.
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interp = interp1d(hm.y, hm.z, axis=0, bounds_error=False,
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fill_value=(hm.z[0], hm.z[-1]), assume_sorted=True)
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z_grid = interp(f_grid).astype(np.float32)
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img = pg.ImageItem()
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img.setImage(z_grid.T, autoLevels=False) # ImageItem wants (x, y) -> transpose
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img.setLevels((hm.z_min, hm.z_max))
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img.setColorMap(_colormap(hm.cmap))
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# Map image pixel space (time cols, freq rows) to data coords: x=time, y=row index.
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img.setRect(pg.QtCore.QRectF(t0, 0.0, t1 - t0, float(n_rows)))
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self.plot.addItem(img)
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# Label the row-index y-axis with real frequencies.
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ticks = []
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for hz in _LOG_FREQ_TICKS:
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if f_lo <= hz <= f_hi:
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row = float(np.searchsorted(f_grid, hz))
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ticks.append((row, _fmt_hz(hz)))
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self.plot.getAxis("left").setTicks([ticks])
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self.plot.setYRange(0, n_rows, padding=0)
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self.plot.setXRange(t0, t1, padding=0)
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# Place the colourbar at a fixed layout cell and link it to the image. We
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# add/remove it ourselves (rather than insert_in=) so it can't stack across
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# repeated spectrogram renders.
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self._colorbar = pg.ColorBarItem(values=(hm.z_min, hm.z_max),
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colorMap=_colormap(hm.cmap), label=hm.label)
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self._colorbar.setImageItem(img)
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self.glw.addItem(self._colorbar, row=0, col=1)
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def _apply_axes(self, axes, log_y_image_handled: bool = False):
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self.plot.setLabel("bottom", axes.x_label)
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self.plot.setLabel("left", axes.y_label)
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if axes.x_range:
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self.plot.setXRange(*axes.x_range, padding=0)
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if axes.y_range and not log_y_image_handled:
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self.plot.setYRange(*axes.y_range, padding=0)
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if not log_y_image_handled:
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# Curve metrics: honour log mode if a spec ever opts in (none do today).
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self.plot.setLogMode(x=axes.x_log, y=axes.y_log)
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# ---- user reference lines -----------------------------------------------
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def _draw_user_lines(self):
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"""(Re)create draggable lines from the stored values, preserving positions."""
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self._remove_user_line_items()
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for idx in range(len(self._user_line_values)):
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line = pg.InfiniteLine(
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pos=self._user_line_values[idx], angle=0, movable=True,
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pen=pg.mkPen(_USER_LINE_COLOR, width=1.2, style=Qt.DashLine),
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label="{value:.2f}",
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labelOpts={"position": 0.05, "color": _USER_LINE_COLOR,
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"fill": (255, 255, 255, 180)},
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)
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line.sigPositionChanged.connect(lambda ln, i=idx: self._on_user_line_moved(i, ln))
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self.plot.addItem(line)
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self._user_lines.append(line)
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def _on_user_line_moved(self, index: int, line: pg.InfiniteLine):
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if 0 <= index < len(self._user_line_values):
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self._user_line_values[index] = float(line.value())
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def _remove_user_line_items(self):
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for line in self._user_lines:
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self.plot.removeItem(line)
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self._user_lines.clear()
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# ---- legend / lifecycle -------------------------------------------------
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def _legend_swatch(self, name: str, color: str):
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self.legend.addItem(pg.PlotDataItem(pen=pg.mkPen(color, width=3)), name)
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def _legend_note(self, text: str):
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self.legend.addItem(pg.PlotDataItem(pen=None), text)
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def _reset_plot(self):
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self._remove_user_line_items() # cleared from scene; values persist for redraw
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||||
self.plot.clear()
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if self._colorbar is not None:
|
||||
try:
|
||||
self.glw.removeItem(self._colorbar)
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||||
except Exception:
|
||||
pass
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self._colorbar = None
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self.legend.clear()
|
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self.plot.getAxis("left").setTicks(None) # drop heatmap freq ticks
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self.plot.setLogMode(x=False, y=False)
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def _show_empty(self):
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text = pg.TextItem("Drop an audio file to see analysis", anchor=(0.5, 0.5),
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color=(120, 120, 120))
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self.plot.addItem(text)
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self.plot.setXRange(0, 1)
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self.plot.setYRange(0, 1)
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text.setPos(0.5, 0.5)
|
||||
self.set_status("Ready for audio analysis...")
|
||||
|
||||
Reference in New Issue
Block a user