mirror of
https://github.com/maziggy/bambuddy.git
synced 2026-10-05 13:41:36 +02:00
maziggy
db308aa80b
External scan hung on a 1200-subdir NAS because (1) every STL crashed
with TypeError ('str / str') inside generate_stl_thumbnail and (2)
thumbnail generation ran synchronously per file, so the FE timed out
before db.commit() and nothing was persisted.
stl_thumbnail.py now coerces inputs to Path defensively, and
scan_external_folder defers STL thumbnail generation to a background
asyncio task that opens its own session and processes each file
post-commit. Subdirs appear in the sidebar immediately; thumbnails
backfill over the next seconds/minutes.
147 lines
4.7 KiB
Python
147 lines
4.7 KiB
Python
"""STL Thumbnail Generation Service.
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Generates thumbnail images from STL files using trimesh and matplotlib.
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"""
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import logging
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import uuid
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from pathlib import Path
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logger = logging.getLogger(__name__)
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# Bambu green color for rendering
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BAMBU_GREEN = "#00AE42"
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BACKGROUND_COLOR = "#1a1a1a"
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# Maximum vertices before simplification
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MAX_VERTICES = 100000
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def generate_stl_thumbnail(
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stl_path: Path,
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thumbnails_dir: Path,
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size: int = 256,
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) -> str | None:
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"""Generate a thumbnail image from an STL file.
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Args:
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stl_path: Path to the STL file
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thumbnails_dir: Directory to save the thumbnail
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size: Thumbnail size in pixels (default 256x256)
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Returns:
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Path to the generated thumbnail, or None on failure
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"""
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# Callers historically pass either Path or str; coerce so the `thumbnails_dir
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# / thumb_filename` join at the end of this function can't fail with the
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# str-divided-by-str TypeError (see #1299).
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stl_path = Path(stl_path)
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thumbnails_dir = Path(thumbnails_dir)
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try:
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import matplotlib
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import trimesh
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# Use Agg backend for headless rendering
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matplotlib.use("Agg")
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import matplotlib.pyplot as plt
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from mpl_toolkits.mplot3d import Axes3D # noqa: F401
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from mpl_toolkits.mplot3d.art3d import Poly3DCollection
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# Load the STL file
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mesh = trimesh.load(str(stl_path), force="mesh")
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if mesh is None or not hasattr(mesh, "vertices") or len(mesh.vertices) == 0:
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logger.warning("Failed to load STL or empty mesh: %s", stl_path)
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return None
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# Simplify large meshes for performance
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if len(mesh.vertices) > MAX_VERTICES:
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logger.info("Simplifying mesh from %s vertices", len(mesh.vertices))
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try:
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# Calculate reduction ratio (0-1 range)
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# e.g., 124633 vertices -> 100000 means keep ~80%, so reduce by ~20%
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keep_ratio = MAX_VERTICES / len(mesh.vertices)
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target_reduction = 1.0 - keep_ratio
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# Clamp to valid range (0.01 to 0.99)
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target_reduction = max(0.01, min(0.99, target_reduction))
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mesh = mesh.simplify_quadric_decimation(target_reduction)
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logger.info("Simplified mesh to %s vertices", len(mesh.vertices))
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except Exception as e:
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logger.warning("Mesh simplification failed, using original: %s", e)
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# Get mesh bounds and center it
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vertices = mesh.vertices
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bounds_min = vertices.min(axis=0)
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bounds_max = vertices.max(axis=0)
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center = (bounds_min + bounds_max) / 2
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vertices_centered = vertices - center
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# Scale to fit in view
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max_extent = (bounds_max - bounds_min).max()
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if max_extent > 0:
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scale = 1.0 / max_extent
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vertices_scaled = vertices_centered * scale
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else:
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vertices_scaled = vertices_centered
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# Create figure with dark background
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fig = plt.figure(figsize=(size / 100, size / 100), dpi=100)
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fig.patch.set_facecolor(BACKGROUND_COLOR)
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ax = fig.add_subplot(111, projection="3d")
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ax.set_facecolor(BACKGROUND_COLOR)
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# Create polygon collection from mesh faces
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faces = mesh.faces
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poly3d = [[vertices_scaled[vertex] for vertex in face] for face in faces]
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collection = Poly3DCollection(
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poly3d,
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facecolors=BAMBU_GREEN,
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edgecolors=BAMBU_GREEN,
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linewidths=0.1,
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alpha=0.9,
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)
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ax.add_collection3d(collection)
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# Set axis limits
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ax.set_xlim(-0.6, 0.6)
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ax.set_ylim(-0.6, 0.6)
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ax.set_zlim(-0.6, 0.6)
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# Set view angle (isometric-ish)
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ax.view_init(elev=25, azim=45)
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# Remove axes and grid
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ax.set_axis_off()
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ax.grid(False)
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# Remove margins
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plt.subplots_adjust(left=0, right=1, top=1, bottom=0)
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# Save thumbnail
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thumb_filename = f"{uuid.uuid4().hex}.png"
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thumb_path = thumbnails_dir / thumb_filename
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fig.savefig(
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thumb_path,
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format="png",
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facecolor=BACKGROUND_COLOR,
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edgecolor="none",
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bbox_inches="tight",
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pad_inches=0.05,
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dpi=100,
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)
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plt.close(fig)
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logger.info("Generated STL thumbnail: %s", thumb_path)
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return str(thumb_path)
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except ImportError as e:
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logger.warning("STL thumbnail generation unavailable (missing dependencies): %s", e)
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return None
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except Exception as e:
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logger.warning("Failed to generate STL thumbnail for %s: %s", stl_path, e)
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return None
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