feat(pygal): implement timeline-basic

plots/timeline-basic/implementations/pygal.py

@@ -0,0 +1,148 @@
+""" pyplots.ai
+timeline-basic: Event Timeline
+Library: pygal 3.1.0 | Python 3.13.11
+Quality: 91/100 | Created: 2025-12-29
+"""
+
+from datetime import date
+
+import cairosvg
+import pygal
+from pygal.style import Style
+
+
+# Data - Software project milestones
+events = [
+    (date(2024, 1, 15), "Project Kickoff", "Planning"),
+    (date(2024, 2, 10), "Requirements Complete", "Planning"),
+    (date(2024, 3, 20), "Architecture Design", "Design"),
+    (date(2024, 4, 25), "Development Start", "Development"),
+    (date(2024, 6, 15), "Alpha Release", "Development"),
+    (date(2024, 8, 1), "Beta Release", "Testing"),
+    (date(2024, 9, 10), "User Acceptance", "Testing"),
+    (date(2024, 10, 20), "Production Launch", "Deployment"),
+]
+
+# Sort events by date
+events = sorted(events, key=lambda x: x[0])
+
+# Category colors mapped to pygal color indices
+categories = ["Planning", "Design", "Development", "Testing", "Deployment"]
+category_colors = {
+    "Planning": "#306998",
+    "Design": "#FFD43B",
+    "Development": "#4ECDC4",
+    "Testing": "#FF6B6B",
+    "Deployment": "#45B7D1",
+}
+
+# Custom style for large canvas (4800x2700)
+custom_style = Style(
+    background="white",
+    plot_background="white",
+    foreground="#333333",
+    foreground_strong="#333333",
+    foreground_subtle="#666666",
+    colors=tuple(category_colors[c] for c in categories),
+    title_font_size=60,
+    label_font_size=32,
+    major_label_font_size=32,
+    legend_font_size=36,
+    value_font_size=28,
+    tooltip_font_size=28,
+)
+
+# Reference date for x-axis positioning
+reference_date = date(2024, 1, 1)
+
+# Create XY chart - using native pygal scatter capabilities
+chart = pygal.XY(
+    width=4800,
+    height=2700,
+    style=custom_style,
+    title="Software Project Milestones · timeline-basic · pygal · pyplots.ai",
+    show_legend=True,
+    legend_at_bottom=False,
+    legend_box_size=32,
+    x_title="Month (2024)",
+    y_title="Project Phase",
+    show_dots=True,
+    dots_size=18,
+    stroke=False,
+    show_x_guides=True,
+    show_y_guides=True,
+    margin=120,
+    x_labels_major_every=1,
+    truncate_legend=-1,
+)
+
+# Custom x-axis labels for months
+chart.x_labels = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov"]
+chart.x_labels_major = chart.x_labels
+
+# Y positions for alternating above/below layout - spread vertically to use more canvas
+y_positions = {
+    0: 4,  # Above
+    1: 1,  # Below
+    2: 4,  # Above
+    3: 1,  # Below
+    4: 4,  # Above
+    5: 1,  # Below
+    6: 4,  # Above
+    7: 1,  # Below
+}
+
+# Group events by category for legend
+category_data = {cat: [] for cat in categories}
+
+for i, (event_date, event_name, category) in enumerate(events):
+    # X position: days since Jan 1, scaled to month
+    days = (event_date - reference_date).days
+    x_val = days / 30.44  # Average days per month
+
+    # Y position for alternating layout
+    y_val = y_positions[i]
+
+    # Add data point with label
+    category_data[category].append({"value": (x_val, y_val), "label": f"{event_name}\n{event_date.strftime('%b %d')}"})
+
+# Add each category as a series
+for category in categories:
+    if category_data[category]:
+        chart.add(category, category_data[category])
+
+# Set y range to maximize vertical usage (values 0-5 with padding)
+chart.range = (0, 5)
+
+# Render base SVG
+svg_string = chart.render().decode("utf-8")
+
+# Add a horizontal timeline axis in the middle (y=2.5) as visual anchor
+# Calculate plot area based on pygal defaults with our margins
+PLOT_LEFT = 400
+PLOT_RIGHT = 4550
+PLOT_TOP = 300
+PLOT_BOTTOM = 2200
+PLOT_HEIGHT = PLOT_BOTTOM - PLOT_TOP
+
+# Timeline at y=2.5 (middle of 0-5 range)
+timeline_y = PLOT_TOP + PLOT_HEIGHT * (1 - 2.5 / 5)  # Invert because SVG y goes down
+
+# Create timeline axis elements
+timeline_svg = f"""
+<g class="timeline-axis">
+  <line x1="{PLOT_LEFT}" y1="{timeline_y:.0f}" x2="{PLOT_RIGHT}" y2="{timeline_y:.0f}"
+        stroke="#999999" stroke-width="4" stroke-dasharray="15,8"/>
+  <text x="{PLOT_LEFT - 80}" y="{timeline_y + 10:.0f}" font-family="Consolas, sans-serif"
+        font-size="28" fill="#666666" text-anchor="end">Timeline</text>
+</g>
+"""
+
+# Inject timeline before </svg>
+svg_output = svg_string.replace("</svg>", f"{timeline_svg}\n</svg>")
+
+# Save outputs
+with open("plot.html", "w") as f:
+    f.write(svg_output)
+
+cairosvg.svg2png(bytestring=svg_output.encode(), write_to="plot.png")

plots/timeline-basic/metadata/pygal.yaml

@@ -0,0 +1,25 @@
+library: pygal
+specification_id: timeline-basic
+created: '2025-12-29T22:48:52Z'
+updated: '2025-12-29T23:04:30Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20584332106
+issue: 0
+python_version: 3.13.11
+library_version: 3.1.0
+preview_url: https://storage.googleapis.com/pyplots-images/plots/timeline-basic/pygal/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/timeline-basic/pygal/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/timeline-basic/pygal/plot.html
+quality_score: 91
+review:
+  strengths:
+  - Excellent alternating above/below layout prevents text overlap and creates clear
+    visual hierarchy
+  - Good use of pygal XY chart with custom styling for timeline visualization
+  - Creative SVG injection to add dashed timeline axis as visual anchor
+  - Realistic software project milestone data with meaningful categories
+  - Color-coded categories with distinct, accessible colors
+  weaknesses:
+  - Vertical canvas utilization could be improved - timeline occupies narrow horizontal
+    band with large empty areas above and below
+  - Legend placement at bottom left is distant from the actual data points