feat(letsplot): implement piano-roll-midi

plots/piano-roll-midi/implementations/python/letsplot.py

@@ -1,53 +1,63 @@
-""" pyplots.ai
+""" anyplot.ai
 piano-roll-midi: MIDI Piano Roll Visualization
-Library: letsplot 4.8.2 | Python 3.14.3
-Quality: 90/100 | Created: 2026-03-07
+Library: letsplot 4.10.1 | Python 3.13.13
+Quality: 90/100 | Updated: 2026-06-03
 """
 
 import os
+import shutil
 
 import numpy as np
 import pandas as pd
 from lets_plot import *
+from lets_plot.export import ggsave as export_ggsave
 
 
 LetsPlot.setup_html()
 
-# Data - A chord progression with melody (Cmaj - Am - F - G pattern, 8 measures)
+# Theme tokens (Imprint palette — theme-adaptive chrome)
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+
+# Black key row background — slightly offset from PAGE_BG for subtle contrast
+BLACK_KEY_BG = "#E4E3DC" if THEME == "light" else "#252522"
+BEAT_LINE = "rgba(26,26,23,0.18)" if THEME == "light" else "rgba(240,239,232,0.18)"
+MEASURE_LINE = "rgba(26,26,23,0.50)" if THEME == "light" else "rgba(240,239,232,0.50)"
+
+# Data — Cmaj–Am–F–G chord progression with melody, 8 measures
 np.random.seed(42)
 
-# Black key semitone positions within an octave (1=C#, 3=D#, 6=F#, 8=G#, 10=A#)
 black_semitones = {1, 3, 6, 8, 10}
 black_key_pitches = {p for p in range(0, 128) if (p % 12) in black_semitones}
 
-# Chord progression: C major - A minor - F major - G major (repeated twice)
-# Mix of whole-note and half-note accompaniment for rhythmic variety
 chords = [
-    # Measure 1: C major - building (half notes for movement)
+    # Measure 1: C major — building (half notes)
     (0, 2, [48, 52, 55], [55, 50, 45]),
     (2, 2, [48, 52, 55], [60, 55, 50]),
-    # Measure 2: A minor - softer
+    # Measure 2: A minor — softer
     (4, 4, [45, 52, 57, 60], [42, 40, 38, 48]),
-    # Measure 3: F major - growing (half notes)
+    # Measure 3: F major — growing (half notes)
     (8, 2, [53, 57, 60], [65, 60, 55]),
     (10, 2, [53, 57, 60], [72, 68, 62]),
-    # Measure 4: G major - strong
+    # Measure 4: G major — strong
     (12, 4, [47, 50, 55, 59], [82, 78, 72, 88]),
-    # Measure 5: C major - restart softer (half notes)
+    # Measure 5: C major — restart softer (half notes)
     (16, 2, [48, 52, 55], [48, 42, 38]),
     (18, 2, [48, 52, 55], [52, 48, 42]),
-    # Measure 6: A minor - quiet
+    # Measure 6: A minor — quiet
     (20, 4, [45, 52, 57, 60], [40, 38, 35, 45]),
-    # Measure 7: F major - building to climax (half notes)
+    # Measure 7: F major — building to climax (half notes)
     (24, 2, [53, 57, 60], [75, 70, 65]),
     (26, 2, [53, 57, 60], [85, 80, 75]),
-    # Measure 8: G major -> resolve fortissimo
+    # Measure 8: G major — fortissimo resolve
     (28, 4, [47, 50, 55, 59], [98, 92, 88, 105]),
 ]
 
-# Melody with passing tones through D4-F4 range to fill the gap
 melody_notes = [
-    # Measure 1-2: ascending phrase through mid-range (mf)
     (0, 1, 72, 85),
     (1, 0.5, 74, 75),
     (1.5, 0.5, 76, 70),
@@ -56,35 +66,32 @@
     (3.5, 0.5, 72, 70),
     (4, 1, 69, 90),
     (5, 0.5, 67, 70),
-    (5.5, 0.5, 65, 65),  # F4 - fills gap
-    (6, 1, 64, 75),  # E4 - fills gap
-    (7, 0.5, 62, 55),  # D4 - fills gap
-    (7.5, 0.5, 64, 60),  # E4 - fills gap
-    # Measure 3-4: responding phrase, ascending through gap (f)
-    (8, 0.5, 62, 70),  # D4
-    (8.5, 0.5, 64, 75),  # E4
-    (9, 0.5, 65, 80),  # F4
-    (9.5, 0.5, 67, 85),  # G4
+    (5.5, 0.5, 65, 65),
+    (6, 1, 64, 75),
+    (7, 0.5, 62, 55),
+    (7.5, 0.5, 64, 60),
+    (8, 0.5, 62, 70),
+    (8.5, 0.5, 64, 75),
+    (9, 0.5, 65, 80),
+    (9.5, 0.5, 67, 85),
     (10, 1, 72, 95),
     (11, 1, 77, 105),
     (12, 1, 76, 90),
     (13, 0.5, 74, 75),
     (13.5, 0.5, 72, 68),
     (14, 2, 76, 100),
-    # Measure 5-6: lyrical descent through mid-range (pp -> mp)
     (16, 0.5, 79, 95),
     (16.5, 0.5, 76, 70),
     (17, 1, 72, 80),
     (18, 0.5, 69, 60),
     (18.5, 0.5, 67, 55),
-    (19, 0.5, 65, 50),  # F4
-    (19.5, 0.5, 64, 48),  # E4
-    (20, 1, 62, 55),  # D4
-    (21, 0.5, 64, 50),  # E4
-    (21.5, 0.5, 65, 55),  # F4
+    (19, 0.5, 65, 50),
+    (19.5, 0.5, 64, 48),
+    (20, 1, 62, 55),
+    (21, 0.5, 64, 50),
+    (21.5, 0.5, 65, 55),
     (22, 1, 67, 60),
     (23, 1, 69, 58),
-    # Measure 7-8: climax and resolution (ff -> fff)
     (24, 0.5, 72, 100),
     (24.5, 0.5, 74, 95),
     (25, 0.5, 76, 110),
@@ -95,7 +102,6 @@
     (30, 2, 72, 110),
 ]
 
-# Build note list with role labels for visual hierarchy
 starts, durations, pitches, velocities, roles = [], [], [], [], []
 
 for beat, dur, chord_pitches, chord_vels in chords:
@@ -116,19 +122,17 @@
 df = pd.DataFrame({"start": starts, "duration": durations, "pitch": pitches, "velocity": velocities, "role": roles})
 df["end"] = df["start"] + df["duration"]
 
-# Melody notes are taller to stand out visually
+# Melody notes slightly taller for visual hierarchy
 df["pitch_top"] = np.where(df["role"] == "Melody", df["pitch"] + 0.45, df["pitch"] + 0.35)
 df["pitch_bottom"] = np.where(df["role"] == "Melody", df["pitch"] - 0.45, df["pitch"] - 0.35)
 
-# Note labels for tooltips
 note_names_all = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"]
 df["note_name"] = [f"{note_names_all[p % 12]}{p // 12 - 1}" for p in df["pitch"]]
 
-# Determine pitch range
 pitch_min = df["pitch"].min() - 1
 pitch_max = df["pitch"].max() + 1
 
-# Background rows for black keys - much more visible contrast
+# Black key row shading across full width
 all_pitches = list(range(pitch_min, pitch_max + 1))
 black_pitches_in_range = [p for p in all_pitches if p in black_key_pitches]
 bg_rows = pd.DataFrame(
@@ -140,20 +144,17 @@
     }
 )
 
-# Y-axis labels: only show note names for white keys
+# Y-axis labels — white keys only
 y_breaks = [p for p in all_pitches if p not in black_key_pitches]
 white_note_letters = {0: "C", 2: "D", 4: "E", 5: "F", 7: "G", 9: "A", 11: "B"}
 y_labels = [f"{white_note_letters[p % 12]}{p // 12 - 1}" for p in y_breaks]
 
-# Beat and measure grid lines
 beat_lines = pd.DataFrame({"x": [float(b) for b in range(0, 33)]})
 measure_lines = pd.DataFrame({"x": [float(m) for m in range(0, 33, 4)]})
 
-# Separate melody and accompaniment for layered rendering
 df_accomp = df[df["role"] == "Accompaniment"].copy()
 df_melody = df[df["role"] == "Melody"].copy()
 
-# Section labels for dynamic arc storytelling
 sections = pd.DataFrame(
     {
         "x": [2.0, 10.0, 18.0, 26.0],
@@ -162,83 +163,83 @@
     }
 )
 
-# Role annotations
 role_labels = pd.DataFrame({"x": [31.5, 31.5], "y": [76.0, 52.0], "label": ["Melody", "Accomp."]})
 
+title = "piano-roll-midi · python · letsplot · anyplot.ai"
+
 # Plot
 plot = (
     ggplot()
-    # Black key background shading - subtle distinction
+    # Black key row shading — stronger contrast than previous
     + geom_rect(
         data=bg_rows,
         mapping=aes(xmin="xmin", xmax="xmax", ymin="pitch_bottom", ymax="pitch_top"),
-        fill="#E8E8EC",
+        fill=BLACK_KEY_BG,
         color="rgba(0,0,0,0)",
-        alpha=0.6,
+        alpha=0.8,
     )
-    # Beat grid lines (light)
-    + geom_vline(data=beat_lines, mapping=aes(xintercept="x"), color="#E0E0E0", size=0.3)
-    # Measure grid lines (stronger)
-    + geom_vline(data=measure_lines, mapping=aes(xintercept="x"), color="#9E9E9E", size=1.0)
-    # Accompaniment notes (more transparent, thinner)
+    # Beat grid lines (subtle)
+    + geom_vline(data=beat_lines, mapping=aes(xintercept="x"), color=BEAT_LINE, size=0.3)
+    # Measure grid lines (stronger — mark bars)
+    + geom_vline(data=measure_lines, mapping=aes(xintercept="x"), color=MEASURE_LINE, size=0.8)
+    # Accompaniment notes — semi-transparent
     + geom_rect(
         data=df_accomp,
         mapping=aes(xmin="start", xmax="end", ymin="pitch_bottom", ymax="pitch_top", fill="velocity"),
-        color="#FFFFFF",
+        color=PAGE_BG,
         size=0.3,
-        alpha=0.75,
+        alpha=0.80,
         tooltips=layer_tooltips().line("@note_name").line("vel: @velocity").line("beat: @start — @end"),
     )
-    # Melody notes (opaque, taller, with border)
+    # Melody notes — fully opaque, taller, dark border for hierarchy
     + geom_rect(
         data=df_melody,
         mapping=aes(xmin="start", xmax="end", ymin="pitch_bottom", ymax="pitch_top", fill="velocity"),
-        color="#1A1A2E",
-        size=0.6,
+        color=INK,
+        size=0.5,
         alpha=1.0,
         tooltips=layer_tooltips().line("@note_name").line("vel: @velocity").line("beat: @start — @end"),
     )
-    # Section labels showing dynamic arc
-    + geom_text(data=sections, mapping=aes(x="x", y="y", label="label"), size=11, color="#666666", fontface="italic")
-    # Role annotations on right side
-    + geom_text(data=role_labels, mapping=aes(x="x", y="y", label="label"), size=10, color="#444444", fontface="bold")
-    # Perceptually uniform color scale for velocity with refined legend
-    + scale_fill_viridis(
+    # Section labels showing dynamic arc (pp → fff)
+    + geom_text(data=sections, mapping=aes(x="x", y="y", label="label"), size=4, color=INK_MUTED, fontface="italic")
+    # Role labels on right edge
+    + geom_text(data=role_labels, mapping=aes(x="x", y="y", label="label"), size=3.5, color=INK_SOFT, fontface="bold")
+    # Imprint sequential colormap — quiet (green) → loud (blue), single-polarity
+    + scale_fill_gradient(
+        low="#009E73",
+        high="#4467A3",
         name="Velocity",
         limits=[30, 127],
-        option="plasma",
-        direction=1,
-        guide=guide_colorbar(barwidth=12, barheight=280),
+        guide=guide_colorbar(barwidth=8, barheight=140),
     )
     + scale_x_continuous(name="Time (beats)", breaks=[0, 4, 8, 12, 16, 20, 24, 28, 32])
     + scale_y_continuous(name="Pitch", breaks=y_breaks, labels=y_labels)
     + coord_cartesian(xlim=[-0.5, 33], ylim=[pitch_min - 0.5, pitch_max + 2.5])
-    + labs(title="piano-roll-midi · letsplot · pyplots.ai")
+    + labs(title=title)
     + theme_minimal()
     + theme(
-        plot_title=element_text(size=26, face="bold", color="#1A1A2E"),
-        axis_title_x=element_text(size=20, color="#333333"),
-        axis_title_y=element_text(size=20, color="#333333"),
-        axis_text_x=element_text(size=16, color="#555555"),
-        axis_text_y=element_text(size=14, color="#555555"),
-        axis_line=element_line(color="#CCCCCC", size=0.5),
-        axis_ticks=element_line(color="#CCCCCC", size=0.3),
-        legend_title=element_text(size=18),
-        legend_text=element_text(size=14),
+        plot_title=element_text(size=16, face="bold", color=INK),
+        axis_title_x=element_text(size=12, color=INK),
+        axis_title_y=element_text(size=12, color=INK),
+        axis_text_x=element_text(size=10, color=INK_SOFT),
+        axis_text_y=element_text(size=11, color=INK_SOFT),
+        axis_line=element_line(color=INK_SOFT, size=0.5),
+        axis_ticks=element_line(color=INK_SOFT, size=0.3),
+        legend_title=element_text(size=10, color=INK),
+        legend_text=element_text(size=10, color=INK_SOFT),
+        legend_background=element_rect(fill=ELEVATED_BG, color=INK_SOFT),
         legend_position="right",
         panel_grid_major=element_blank(),
         panel_grid_minor=element_blank(),
-        panel_background=element_rect(fill="#FAFAFA", color="#BBBBBB", size=0.3),
-        plot_background=element_rect(fill="#FFFFFF"),
+        panel_background=element_rect(fill=PAGE_BG, color=INK_SOFT, size=0.3),
+        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
     )
-    + ggsize(1600, 900)
+    + ggsize(800, 450)
 )
 
 # Save
-ggsave(plot, "plot.png", scale=3, path=".")
-ggsave(plot, "plot.html", path=".")
+export_ggsave(plot, filename=f"plot-{THEME}.png", path=".", scale=4)
+export_ggsave(plot, filename=f"plot-{THEME}.html", path=".")
 
 if os.path.exists("lets-plot-images"):
-    import shutil
-
     shutil.rmtree("lets-plot-images")