update(candlestick-basic): altair — comprehensive quality review

Comprehensive quality review of altair implementation for candlestick-basic.

Author: MarkusNeusinger

plots/candlestick-basic/implementations/altair.py

@@ -1,7 +1,7 @@
 """ pyplots.ai
 candlestick-basic: Basic Candlestick Chart
-Library: altair 6.0.0 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-23
+Library: altair 6.0.0 | Python 3.14.3
+Quality: /100 | Updated: 2026-02-24
 """
 
 import altair as alt
@@ -12,8 +12,7 @@
 # Data - Simulated 30 days of stock price data
 np.random.seed(42)
 n_days = 30
-start_date = pd.Timestamp("2024-01-01")
-dates = pd.date_range(start=start_date, periods=n_days, freq="B")  # Business days
+dates = pd.date_range(start="2024-01-01", periods=n_days, freq="B")
 
 # Generate realistic OHLC data with random walk
 prices = [100.0]
@@ -42,22 +41,18 @@
     )
 
 df = pd.DataFrame(data)
+df["direction"] = np.where(df["close"] >= df["open"], "Bullish", "Bearish")
 
-# Add direction column for color encoding
-df["direction"] = df.apply(lambda row: "Bullish" if row["close"] >= row["open"] else "Bearish", axis=1)
-
-# Color scale: green for bullish, red for bearish (most common convention)
-color_scale = alt.Scale(domain=["Bullish", "Bearish"], range=["#26A69A", "#EF5350"])
+# Colors - colorblind-safe: teal for bullish, warm orange for bearish
+color_scale = alt.Scale(domain=["Bullish", "Bearish"], range=["#26A69A", "#FF8F00"])
 
 # Candlestick wicks (high-low lines)
 wicks = (
     alt.Chart(df)
-    .mark_rule(strokeWidth=3)
+    .mark_rule(strokeWidth=1.5)
     .encode(
-        x=alt.X("date:T", title="Date", axis=alt.Axis(labelFontSize=18, titleFontSize=22, format="%b %d")),
-        y=alt.Y(
-            "low:Q", title="Price ($)", scale=alt.Scale(zero=False), axis=alt.Axis(labelFontSize=18, titleFontSize=22)
-        ),
+        x=alt.X("date:T", title="Date", axis=alt.Axis(format="%b %d")),
+        y=alt.Y("low:Q", title="Price ($)", scale=alt.Scale(zero=False)),
         y2="high:Q",
         color=alt.Color("direction:N", scale=color_scale, legend=None),
     )
@@ -66,7 +61,7 @@
 # Candlestick bodies (open-close bars)
 bodies = (
     alt.Chart(df)
-    .mark_bar(size=24)
+    .mark_bar(size=20)
     .encode(
         x="date:T",
         y="open:Q",
@@ -84,16 +79,21 @@
     )
 )
 
-# Layer wicks and bodies
+# Layer wicks and bodies with interactive zoom/pan
 chart = (
     alt.layer(wicks, bodies)
+    .resolve_scale(color="independent")
     .properties(
-        width=1600, height=900, title=alt.Title("candlestick-basic · altair · pyplots.ai", fontSize=28, anchor="middle")
+        width=1600,
+        height=900,
+        title=alt.Title("candlestick-basic \u00b7 altair \u00b7 pyplots.ai", fontSize=28, anchor="middle"),
     )
-    .configure_axis(labelFontSize=18, titleFontSize=22, gridOpacity=0.3)
+    .configure_axis(labelFontSize=18, titleFontSize=22, gridOpacity=0.15)
+    .configure_legend(labelFontSize=16, titleFontSize=18)
     .configure_view(strokeWidth=0)
+    .interactive()
 )
 
-# Save as PNG and HTML
+# Save
 chart.save("plot.png", scale_factor=3.0)
 chart.save("plot.html")

plots/candlestick-basic/metadata/altair.yaml

@@ -1,16 +1,16 @@
 library: altair
 specification_id: candlestick-basic
 created: '2025-12-23T10:01:24Z'
-updated: '2025-12-23T10:07:56Z'
-generated_by: claude-opus-4-5-20251101
+updated: '2026-02-24T20:50:21+00:00'
+generated_by: claude-opus-4-6
 workflow_run: 20457531337
 issue: 0
-python_version: 3.13.11
-library_version: 6.0.0
+python_version: "3.14.3"
+library_version: "6.0.0"
 preview_url: https://storage.googleapis.com/pyplots-images/plots/candlestick-basic/altair/plot.png
 preview_thumb: https://storage.googleapis.com/pyplots-images/plots/candlestick-basic/altair/plot_thumb.png
 preview_html: https://storage.googleapis.com/pyplots-images/plots/candlestick-basic/altair/plot.html
-quality_score: 91
+quality_score: null
 impl_tags:
   dependencies: []
   techniques: