Software: pattern player, web page with a design library, GRBL tools

- python3 -m sandtable web: local web page to play designs from a library of
  27 built-in patterns, upload .thr or .svg, pause/skip/stop, jog and calibrate.
  Reconnects by itself when the USB cable comes back.
- Plays .thr files and built-in generators with an erase spiral between them,
  constant ball speed, host-side homing on stock GRBL 1.1 (Uno + CNC shield),
  FluidNC for the ESP32 board.
- Home switch guard: patterns never press the switch, so a press means lost
  steps and stops the machine at once with an alert.
- lineart.py turns SVG line drawings into one continuous path.
- Tests against a GRBL simulator.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

software/tests/test_lineart.py

@@ -0,0 +1,103 @@
+"""Line drawings (SVG and the fan-art designs) joined into one sand-table path.
+Run from the software folder:  python3 -m unittest discover -s tests -v"""
+import math
+import os
+import sys
+import tempfile
+import unittest
+
+os.environ['SANDTABLE_QUIET'] = '1'
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'tools'))
+
+from sandtable import config, thr
+from sandtable.lineart import drawing_to_polar, join_strokes, path_polylines, svg_strokes
+
+SVG = """<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
+  <defs><circle cx="0" cy="0" r="99"/></defs>
+  <rect x="10" y="10" width="20" height="20"/>
+  <g transform="translate(50 50) scale(2)"><circle cx="0" cy="0" r="10"/></g>
+  <path d="M10 80 C20 70 30 90 40 80 Q50 70 60 80 A10 10 0 0 1 80 80 L90 90 h-5 v5 z"/>
+  <text x="0" y="0">ignored</text>
+</svg>"""
+
+
+def unit_xy(pts):
+    return [(r * math.cos(t), r * math.sin(t)) for t, r in pts]
+
+
+class TestSvg(unittest.TestCase):
+    def test_shapes_and_transforms(self):
+        s = svg_strokes(SVG)
+        self.assertEqual(len(s), 3)                          # defs and text are skipped
+        circle = s[1]
+        self.assertAlmostEqual(max(p[0] for p in circle), 70, delta=0.1)   # r 10 scaled 2x, moved to 50
+        self.assertAlmostEqual(min(p[0] for p in circle), 30, delta=0.1)
+        path = s[2]
+        self.assertAlmostEqual(math.dist(path[0], path[-1]), 0, places=6)  # z closes it
+        self.assertAlmostEqual(min(p[1] for p in path), 70, delta=0.6)     # the arc's top (centre 70,80, r 10)
+
+    def test_arc_and_relative(self):
+        (semi,) = path_polylines('M0 0 a10 10 0 0 1 20 0', tol=0.1)
+        self.assertAlmostEqual(min(p[1] for p in semi), -10, delta=0.05)   # sweep 1 bulges up the page (y down)
+        lines = path_polylines('m0 0 l10 0 10 0 M0 5 H20 V9')
+        self.assertEqual(lines[0][-1], (20.0, 0.0))                         # implicit repeated l
+        self.assertEqual(lines[1][-1], (20.0, 9.0))
+
+
+class TestJoin(unittest.TestCase):
+    def check_path(self, xy, strokes):
+        for a, b in zip(xy, xy[1:]):
+            self.assertLess(math.dist(a, b), 0.008)                      # one continuous line
+        for end in (xy[0], xy[-1]):
+            r = math.hypot(*end)
+            self.assertTrue(r < 1e-9 or abs(r - 1) < 1e-9, end)          # starts and ends at the centre or the edge
+        for st in strokes:                                               # every stroke is drawn
+            for p in st[::7]:
+                self.assertLess(min(math.dist(p, q) for q in xy), 0.01)
+
+    def test_triangle_from_three_lines_needs_no_jumps(self):
+        a, b, c = (0.0, 0.85), (-0.74, -0.42), (0.74, -0.42)
+        strokes = [[a, b], [c, b], [c, a]]
+        stats = {}
+        xy = join_strokes(strokes, stats=stats)
+        self.check_path(xy, strokes)
+        self.assertLess(stats['jump'], 0.35)          # only the short lines in from and out to the edge
+
+    def test_separate_shapes(self):
+        sq = lambda x, y, d: [(x, y), (x + d, y), (x + d, y + d), (x, y + d), (x, y)]
+        strokes = [sq(-0.6, -0.6, 0.3), sq(0.3, 0.3, 0.3), sq(0.3, -0.6, 0.3), [(-0.5, 0.5), (-0.2, 0.2)]]
+        xy = join_strokes(strokes)
+        self.check_path(xy, strokes)
+
+    def test_fan_art_designs(self):
+        try:
+            import make_fan_art                       # not in the public repository (trademarks)
+        except ImportError:
+            self.skipTest('tools/make_fan_art.py is not here')
+        for name, (fn, opts) in make_fan_art.DESIGNS.items():
+            pts = drawing_to_polar(fn(), **opts)
+            self.assertGreater(len(pts), 100, name)
+            for end in (pts[0][1], pts[-1][1]):
+                self.assertTrue(end < 0.02 or end > 0.98, f'{name} ends at rho {end}')
+            xy = unit_xy(pts)
+            for a, b in zip(xy, xy[1:]):
+                self.assertLess(math.dist(a, b), 0.06, name)
+
+
+class TestUpload(unittest.TestCase):
+    def test_svg_upload_becomes_a_design(self):
+        from sandtable.web import Library
+        with tempfile.TemporaryDirectory() as d:
+            lib = Library(config.load('/nonexistent.toml'), root=os.path.join(d, 'p'), cache=os.path.join(d, 'c'),
+                          removed=os.path.join(d, 'r'))
+            ident = lib.add('My Logo.svg', SVG)
+            self.assertEqual(ident, 'uploads/My-Logo.thr')
+            pts = thr.load(lib.path(ident))
+            self.assertGreater(len(pts), 100)
+            with self.assertRaises(ValueError):
+                lib.add('empty.svg', '<svg xmlns="http://www.w3.org/2000/svg"><text>hi</text></svg>')
+
+
+if __name__ == '__main__':
+    unittest.main()