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stl-repo/app/stl_parser.py
Consultoria AS 14b307110d feat: implementar 12 mejoras, tests, docs y optimizaciones
- Fase A: license templates, search history, cost estimator
- Fase B: import URL, bulk ZIP, batch download
- Fase C: comparison mode, mesh validation, measurement tool
- Fase D: cross-section clipping, overhang heatmap, layer animation
- Refactor Pydantic/SQLAlchemy warnings
- 24 tests pytest
- README actualizado
- WebP thumbnails, lazy loading, cache headers
2026-04-27 09:14:58 +00:00

128 lines
3.9 KiB
Python

import struct
import numpy as np
from PIL import Image, ImageDraw
import os
def parse_stl(file_path: str):
"""Parse an STL file (binary or ASCII) and return mesh data + metadata."""
with open(file_path, 'rb') as f:
header = f.read(80)
is_binary = False
if not header.startswith(b'solid'):
is_binary = True
else:
# Some binary files also start with 'solid', check further
with open(file_path, 'rb') as f:
f.read(80)
tri_count_bytes = f.read(4)
if len(tri_count_bytes) == 4:
tri_count = struct.unpack('<I', tri_count_bytes)[0]
file_size = os.path.getsize(file_path)
expected = 80 + 4 + tri_count * 50
if file_size == expected:
is_binary = True
if is_binary:
return _parse_binary(file_path)
else:
return _parse_ascii(file_path)
def _parse_binary(file_path: str):
with open(file_path, 'rb') as f:
f.read(80) # skip header
tri_count = struct.unpack('<I', f.read(4))[0]
vertices = []
for _ in range(tri_count):
f.read(12) # normal
v1 = struct.unpack('<3f', f.read(12))
v2 = struct.unpack('<3f', f.read(12))
v3 = struct.unpack('<3f', f.read(12))
f.read(2) # attribute byte count
vertices.extend([v1, v2, v3])
vertices = np.array(vertices, dtype=np.float32)
return _compute_metadata(vertices, tri_count)
def _parse_ascii(file_path: str):
vertices = []
with open(file_path, 'r', encoding='utf-8', errors='ignore') as f:
for line in f:
line = line.strip().lower()
if line.startswith('vertex'):
parts = line.split()
if len(parts) >= 4:
v = [float(parts[1]), float(parts[2]), float(parts[3])]
vertices.append(v)
vertices = np.array(vertices, dtype=np.float32)
tri_count = len(vertices) // 3
return _compute_metadata(vertices, tri_count)
def _compute_metadata(vertices: np.ndarray, tri_count: int):
if len(vertices) == 0:
return {
'vertices': vertices,
'faces': 0,
'width': 0.0,
'height': 0.0,
'depth': 0.0,
}
min_v = vertices.min(axis=0)
max_v = vertices.max(axis=0)
dims = max_v - min_v
return {
'vertices': vertices,
'faces': tri_count,
'width': float(dims[0]),
'height': float(dims[1]),
'depth': float(dims[2]),
}
def generate_thumbnail(vertices: np.ndarray, output_path: str, size: int = 256):
"""Generate a simple orthographic thumbnail from vertices."""
if len(vertices) == 0:
img = Image.new('RGB', (size, size), color=(30, 30, 30))
img.save(output_path)
return
# Project to XY plane, normalize to image coords
min_v = vertices.min(axis=0)
max_v = vertices.max(axis=0)
dims = max_v - min_v
scale = max(dims[0], dims[1])
if scale == 0:
scale = 1.0
margin = 20
img_size = size - 2 * margin
img = Image.new('RGB', (size, size), color=(30, 30, 30))
draw = ImageDraw.Draw(img)
# Draw triangles
for i in range(0, len(vertices), 3):
tri = vertices[i:i+3]
pts = []
for v in tri:
x = margin + int(((v[0] - min_v[0]) / scale) * img_size)
y = margin + int(((1.0 - (v[1] - min_v[1]) / scale)) * img_size)
pts.append((x, y))
if len(pts) == 3:
# Simple shading based on Z
z_avg = sum(v[2] for v in tri) / 3.0
z_norm = (z_avg - min_v[2]) / (dims[2] if dims[2] > 0 else 1)
brightness = int(80 + z_norm * 120)
color = (brightness, brightness, int(brightness * 1.1))
draw.polygon(pts, fill=color, outline=(50, 50, 60))
img.save(output_path, 'PNG')