feat(altair): implement ridgeline-basic

plots/ridgeline-basic/implementations/python/altair.py

@@ -1,14 +1,15 @@
 """ anyplot.ai
 ridgeline-basic: Basic Ridgeline Plot
-Library: altair 6.1.0 | Python 3.13.13
-Quality: 87/100 | Updated: 2026-04-30
+Library: altair 6.2.2 | Python 3.13.14
+Quality: 93/100 | Updated: 2026-07-25
 """
 
 import os
 
 import altair as alt
 import numpy as np
 import pandas as pd
+from PIL import Image
 
 
 # Theme tokens
@@ -18,6 +19,14 @@
 INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
 INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
 
+# Imprint sequential colormap (brand green -> blue) for the 12 ordered ridges
+IMPRINT_SEQ = ["#009E73", "#4467A3"]
+_c0 = tuple(int(IMPRINT_SEQ[0][i : i + 2], 16) for i in (1, 3, 5))
+_c1 = tuple(int(IMPRINT_SEQ[1][i : i + 2], 16) for i in (1, 3, 5))
+month_colors = [
+    "#{:02x}{:02x}{:02x}".format(*(round(_c0[j] + (_c1[j] - _c0[j]) * i / 11) for j in range(3))) for i in range(12)
+]
+
 # Data
 np.random.seed(42)
 months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
@@ -43,41 +52,39 @@
         extent=[-15, 40],
         bandwidth=2,
     )
-    .mark_area(fillOpacity=0.8, stroke="#306998", strokeWidth=2, interpolate="monotone")
+    .mark_area(fillOpacity=0.85, stroke=INK_SOFT, strokeWidth=1, interpolate="monotone")
     .encode(
         x=alt.X(
             "temperature:Q",
             title="Temperature (°C)",
-            axis=alt.Axis(labelFontSize=18, titleFontSize=22, grid=False),
+            axis=alt.Axis(labelFontSize=10, titleFontSize=12, grid=False),
             scale=alt.Scale(domain=[-15, 40]),
         ),
         y=alt.Y("density:Q", title=None, axis=None, scale=alt.Scale(domain=[0, 0.15])),
-        fill=alt.Fill(
-            "month_order:O", scale=alt.Scale(scheme="blues", domain=list(range(12)), reverse=True), legend=None
-        ),
+        fill=alt.Fill("month_order:O", scale=alt.Scale(domain=list(range(12)), range=month_colors), legend=None),
         row=alt.Row(
             "month:N",
             sort=months,
             header=alt.Header(
-                labelFontSize=18, labelAngle=0, labelAlign="right", labelPadding=10, title=None, labelColor=INK_SOFT
+                labelFontSize=12, labelAngle=0, labelAlign="right", labelPadding=8, title=None, labelColor=INK_SOFT
             ),
         ),
     )
     .properties(
-        width=1400,
-        height=55,
+        width=650,
+        height=28,
         background=PAGE_BG,
         title=alt.Title(
             text="Monthly Temperature Distribution · ridgeline-basic · altair · anyplot.ai",
-            fontSize=28,
+            fontSize=16,
             anchor="middle",
         ),
     )
-    .configure_facet(spacing=-25)
+    .configure_facet(spacing=-13)
     .configure_view(fill=PAGE_BG, stroke=None)
     .configure_axis(
-        labelFontSize=16,
-        titleFontSize=20,
+        labelFontSize=10,
+        titleFontSize=12,
         labelColor=INK_SOFT,
         titleColor=INK,
         domainColor=INK_SOFT,
@@ -88,5 +95,20 @@
 )
 
 # Save
-chart.save(f"plot-{THEME}.png", scale_factor=3.0)
+chart.save(f"plot-{THEME}.png", scale_factor=4.0)
+
+# PAD-only to exact target canvas — see prompts/library/altair.md "Canvas"
+TW, TH = 3200, 1800
+_img = Image.open(f"plot-{THEME}.png").convert("RGB")
+_w, _h = _img.size
+if _w > TW or _h > TH:
+    raise SystemExit(
+        f"altair vl-convert produced {_w}×{_h}, exceeds target {TW}×{TH}. "
+        f"Shrink chart .properties(width=, height=) values and re-render."
+    )
+if _w < TW or _h < TH:
+    _canvas = Image.new("RGB", (TW, TH), PAGE_BG)
+    _canvas.paste(_img, ((TW - _w) // 2, (TH - _h) // 2))
+    _canvas.save(f"plot-{THEME}.png")
+
 chart.save(f"plot-{THEME}.html")