feat(bokeh): implement donut-basic (#1394)

## Implementation: `donut-basic` - bokeh

Implements the **bokeh** version of `donut-basic`.

**File:** `plots/donut-basic/implementations/bokeh.py`

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20447973231)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/donut-basic/implementations/bokeh.py

@@ -1,7 +1,7 @@
 """ pyplots.ai
 donut-basic: Basic Donut Chart
 Library: bokeh 3.8.1 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-14
+Quality: 91/100 | Created: 2025-12-23
 """
 
 from math import pi
@@ -13,19 +13,20 @@
 from bokeh.transform import cumsum
 
 
-# Data
+# Data - Portfolio allocation by asset class
 categories = ["Technology", "Healthcare", "Finance", "Energy", "Retail"]
 values = [35, 25, 20, 12, 8]
+total = sum(values)
 
 # Calculate angles for donut segments
 data = {
     "category": categories,
     "value": values,
-    "angle": [v / sum(values) * 2 * pi for v in values],
-    "percentage": [f"{v / sum(values) * 100:.1f}%" for v in values],
+    "angle": [v / total * 2 * pi for v in values],
+    "percentage": [f"{v / total * 100:.1f}%" for v in values],
 }
 
-# Cumulative angles for start/end positions
+# Cumulative angles for label positioning
 cumulative = np.cumsum([0] + data["angle"][:-1]).tolist()
 data["start_angle"] = cumulative
 data["end_angle"] = np.cumsum(data["angle"]).tolist()
@@ -36,63 +37,66 @@
 
 source = ColumnDataSource(data=data)
 
-# Create figure
+# Create figure (square format for circular chart)
 p = figure(
-    width=4800,
-    height=2700,
+    width=3600,
+    height=3600,
     title="donut-basic · bokeh · pyplots.ai",
     toolbar_location=None,
     tools="",
-    x_range=(-1.2, 1.8),
-    y_range=(-1.2, 1.2),
+    x_range=(-1.4, 1.8),
+    y_range=(-1.3, 1.3),
 )
 
 # Draw donut using annular wedge
 p.annular_wedge(
     x=0,
     y=0,
-    inner_radius=0.4,
-    outer_radius=0.9,
+    inner_radius=0.45,
+    outer_radius=0.95,
     start_angle=cumsum("angle", include_zero=True),
     end_angle=cumsum("angle"),
     line_color="white",
-    line_width=3,
+    line_width=4,
     fill_color="color",
     source=source,
 )
 
 # Add percentage labels on segments
-for pct, start, end in zip(data["percentage"], data["start_angle"], data["end_angle"], strict=True):
+for pct, start, end, color in zip(data["percentage"], data["start_angle"], data["end_angle"], colors, strict=True):
     mid_angle = (start + end) / 2
     # Position labels at middle of the ring
-    label_radius = 0.65
+    label_radius = 0.70
+    # Adjust angle to start from top and go clockwise
     x = label_radius * np.cos(mid_angle - pi / 2 + pi)
     y = label_radius * np.sin(mid_angle - pi / 2 + pi)
 
+    # Use white text for dark backgrounds, dark for light backgrounds
+    text_color = "white" if color in ["#306998", "#FF6B6B", "#4ECDC4"] else "#333333"
+
     label = Label(
         x=x,
         y=y,
         text=pct,
-        text_font_size="24pt",
-        text_color="white",
+        text_font_size="26pt",
+        text_color=text_color,
         text_font_style="bold",
         text_align="center",
         text_baseline="middle",
     )
     p.add_layout(label)
 
 # Add center text showing total
-total = sum(values)
 center_label = Label(
-    x=0, y=0.05, text="Total", text_font_size="28pt", text_color="#333333", text_align="center", text_baseline="middle"
+    x=0, y=0.08, text="Total", text_font_size="32pt", text_color="#555555", text_align="center", text_baseline="middle"
 )
 p.add_layout(center_label)
 
 center_value = Label(
     x=0,
-    y=-0.1,
+    y=-0.12,
     text=str(total),
-    text_font_size="40pt",
+    text_font_size="48pt",
     text_color="#306998",
     text_font_style="bold",
     text_align="center",
@@ -101,28 +105,28 @@
 p.add_layout(center_value)
 
 # Add legend entries on the right
-legend_x = 1.15
-legend_y_start = 0.5
-legend_spacing = 0.2
+legend_x = 1.20
+legend_y_start = 0.6
+legend_spacing = 0.24
 
 for i, (cat, val, color) in enumerate(zip(categories, values, colors, strict=True)):
     y_pos = legend_y_start - i * legend_spacing
     # Color box
-    p.rect(x=legend_x, y=y_pos, width=0.08, height=0.08, fill_color=color, line_color=None)
+    p.rect(x=legend_x, y=y_pos, width=0.10, height=0.10, fill_color=color, line_color=None)
     # Label text
     legend_label = Label(
-        x=legend_x + 0.08,
+        x=legend_x + 0.10,
         y=y_pos,
-        text=f"{cat} ({val})",
-        text_font_size="20pt",
+        text=f"{cat} ({val}%)",
+        text_font_size="22pt",
         text_color="#333333",
         text_align="left",
         text_baseline="middle",
     )
     p.add_layout(legend_label)
 
 # Style
-p.title.text_font_size = "32pt"
+p.title.text_font_size = "36pt"
 p.title.text_color = "#333333"
 p.axis.visible = False
 p.grid.visible = False

plots/donut-basic/metadata/bokeh.yaml

@@ -1,17 +1,27 @@
 library: bokeh
 specification_id: donut-basic
-created: 2025-12-14 10:15:17+00:00
-updated: 2025-12-14 10:15:17+00:00
+created: '2025-12-23T00:48:41Z'
+updated: '2025-12-23T01:22:13Z'
 generated_by: claude-opus-4-5-20251101
-workflow_run: 20206400232
-issue: 733
+workflow_run: 20447973231
+issue: 0
 python_version: 3.13.11
 library_version: 3.8.1
 preview_url: https://storage.googleapis.com/pyplots-images/plots/donut-basic/bokeh/plot.png
 preview_thumb: https://storage.googleapis.com/pyplots-images/plots/donut-basic/bokeh/plot_thumb.png
 preview_html: https://storage.googleapis.com/pyplots-images/plots/donut-basic/bokeh/plot.html
 quality_score: 91
 review:
-  strengths: []
-  weaknesses: []
-  improvements: []
+  strengths:
+  - Excellent use of Bokeh annular_wedge for creating donut shape with proper inner/outer
+    radius
+  - 'Clean center annotation showing summary statistic (Total: 100) as spec recommends'
+  - Good use of ColumnDataSource and cumsum transform for angle calculations
+  - Proper white segment separators (line_width=4) enhance readability
+  - Smart text color contrast logic (white on dark backgrounds, dark on light)
+  - Outputs both PNG and interactive HTML versions
+  weaknesses:
+  - Legend shows percentage values redundantly - should show actual values instead
+    of duplicating percentages visible on segments
+  - 'Two similar teal colors (#4ECDC4 and #95E1D3) could be harder to distinguish
+    for some users'