feat(matplotlib): implement network-directed (#2893)

## Implementation: `network-directed` - matplotlib

Implements the **matplotlib** version of `network-directed`.

**File:** `plots/network-directed/implementations/matplotlib.py`

**Parent Issue:** #2858

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20608483162)*

---------

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

Author: github-actions[bot]

plots/network-directed/implementations/matplotlib.py

@@ -0,0 +1,128 @@
+""" pyplots.ai
+network-directed: Directed Network Graph
+Library: matplotlib 3.10.8 | Python 3.13.11
+Quality: 92/100 | Created: 2025-12-30
+"""
+
+import matplotlib.patches as mpatches
+import matplotlib.pyplot as plt
+import numpy as np
+from matplotlib.patches import Circle, FancyArrowPatch
+
+
+# Data: Software package dependencies (arrows show import direction)
+np.random.seed(42)
+
+# Define modules with groups (core, utils, api, tests)
+# Positions optimized for 16:9 aspect ratio with better spread
+nodes = {
+    "main": {"group": "core", "pos": (0.45, 0.88)},
+    "config": {"group": "core", "pos": (0.18, 0.68)},
+    "database": {"group": "core", "pos": (0.45, 0.55)},
+    "auth": {"group": "api", "pos": (0.72, 0.73)},
+    "routes": {"group": "api", "pos": (0.88, 0.52)},
+    "handlers": {"group": "api", "pos": (0.68, 0.32)},
+    "validators": {"group": "utils", "pos": (0.32, 0.38)},
+    "helpers": {"group": "utils", "pos": (0.48, 0.15)},
+    "logger": {"group": "utils", "pos": (0.12, 0.38)},
+    "cache": {"group": "utils", "pos": (0.05, 0.58)},
+    "test_auth": {"group": "tests", "pos": (0.92, 0.88)},
+    "test_routes": {"group": "tests", "pos": (0.95, 0.32)},
+    "test_db": {"group": "tests", "pos": (0.25, 0.12)},
+}
+
+# Define dependencies (arrow from source to target means source imports target)
+edges = [
+    ("main", "config"),
+    ("main", "database"),
+    ("main", "routes"),
+    ("main", "logger"),
+    ("config", "validators"),
+    ("database", "logger"),
+    ("database", "config"),
+    ("auth", "database"),
+    ("auth", "validators"),
+    ("auth", "logger"),
+    ("routes", "auth"),
+    ("routes", "handlers"),
+    ("routes", "validators"),
+    ("handlers", "database"),
+    ("handlers", "helpers"),
+    ("handlers", "logger"),
+    ("validators", "helpers"),
+    ("cache", "logger"),
+    ("cache", "config"),
+    ("test_auth", "auth"),
+    ("test_routes", "routes"),
+    ("test_db", "database"),
+]
+
+# Group colors (colorblind-safe palette)
+group_colors = {
+    "core": "#306998",  # Python Blue
+    "api": "#FFD43B",  # Python Yellow
+    "utils": "#4DAF4A",  # Green
+    "tests": "#984EA3",  # Purple
+}
+
+# Create plot (16:9 for directed graph)
+fig, ax = plt.subplots(figsize=(16, 9))
+
+# Node radius for arrow endpoint calculations
+node_radius = 0.055
+
+# Draw edges with arrows
+for source, target in edges:
+    pos1 = nodes[source]["pos"]
+    pos2 = nodes[target]["pos"]
+
+    # Calculate edge start/end points outside node circles
+    dx = pos2[0] - pos1[0]
+    dy = pos2[1] - pos1[1]
+    dist = np.sqrt(dx**2 + dy**2)
+    dx_norm, dy_norm = dx / dist, dy / dist
+    start = (pos1[0] + dx_norm * node_radius, pos1[1] + dy_norm * node_radius)
+    end = (pos2[0] - dx_norm * node_radius * 1.6, pos2[1] - dy_norm * node_radius * 1.6)
+
+    # Create curved arrow
+    arrow = FancyArrowPatch(
+        start,
+        end,
+        arrowstyle="-|>",
+        mutation_scale=25,
+        color="#555555",
+        linewidth=2.5,
+        alpha=0.65,
+        connectionstyle="arc3,rad=0.12",
+    )
+    ax.add_patch(arrow)
+
+# Draw nodes
+for name, props in nodes.items():
+    pos = props["pos"]
+    color = group_colors[props["group"]]
+
+    # Draw node circle
+    circle = Circle(pos, radius=node_radius, facecolor=color, edgecolor="#333333", linewidth=2.5, alpha=0.95, zorder=10)
+    ax.add_patch(circle)
+
+    # Draw label
+    ax.text(pos[0], pos[1], name, ha="center", va="center", fontsize=13, fontweight="bold", color="#222222", zorder=11)
+
+# Create legend
+legend_handles = [
+    mpatches.Patch(color=color, label=group.capitalize(), alpha=0.95) for group, color in group_colors.items()
+]
+ax.legend(
+    handles=legend_handles, loc="upper left", fontsize=16, framealpha=0.95, title="Module Type", title_fontsize=18
+)
+
+# Styling
+ax.set_title("network-directed · matplotlib · pyplots.ai", fontsize=24, fontweight="bold", pad=20)
+ax.set_xlim(-0.02, 1.02)
+ax.set_ylim(0.0, 1.0)
+ax.set_aspect("equal")
+ax.axis("off")
+
+plt.tight_layout()
+plt.savefig("plot.png", dpi=300, bbox_inches="tight", facecolor="white")

plots/network-directed/metadata/matplotlib.yaml

@@ -0,0 +1,26 @@
+library: matplotlib
+specification_id: network-directed
+created: '2025-12-30T23:57:08Z'
+updated: '2025-12-31T00:04:41Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20608483162
+issue: 2858
+python_version: 3.13.11
+library_version: 3.10.8
+preview_url: https://storage.googleapis.com/pyplots-images/plots/network-directed/matplotlib/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/network-directed/matplotlib/plot_thumb.png
+preview_html: null
+quality_score: 92
+review:
+  strengths:
+  - Excellent directed graph visualization with clear arrow directions showing import
+    dependencies
+  - Colorblind-safe palette with good distinction between Core (blue), Api (yellow),
+    Utils (green), and Tests (purple) groups
+  - Well-positioned nodes using manual layout that minimizes edge crossings
+  - Curved arrows effectively handle overlapping paths and clearly show direction
+  - Proper title format following spec-id · library · pyplots.ai convention
+  - Clean KISS code structure with no functions or classes
+  weaknesses:
+  - Some node labels are slightly cramped within circles (e.g., validators, test_routes)
+  - Node radius could be slightly larger to better accommodate longer labels