Introducing the pirouette FPV frame for GFPV

Signed-off-by: Arnaud Morin <arnaud.gfpv@mailops.fr>

render.py

@@ -0,0 +1,138 @@
+# SPDX-License-Identifier: Apache-2.0
+# @author Arnaud Morin <arnaud.gfpv@mailops.fr>
+
+"""Headless 3D render helper -- shared by every part module and the assembly.
+
+    from render import render
+    render(shape_or_assembly, "build/foo.png", view="iso")
+
+Views: iso, top, front, right, or an (elev, azim) tuple.
+"""
+
+import matplotlib
+matplotlib.use("Agg")
+
+import matplotlib.pyplot as plt
+import numpy as np
+from mpl_toolkits.mplot3d.art3d import Poly3DCollection
+
+import cadquery as cq
+
+VIEWS = {
+    "iso": (26, -55),
+    "iso2": (20, 35),
+    "top": (89, -90),
+    "front": (0, -90),
+    "right": (0, 0),
+}
+
+DEFAULT_COLOR = (0.20, 0.20, 0.22)
+
+
+def _iter_parts(assy, parent_loc=None):
+    """Yield (located_shape, rgba|None) for every solid in an Assembly."""
+    loc = assy.loc if parent_loc is None else parent_loc * assy.loc
+    if assy.obj is not None:
+        shape = assy.obj.val() if isinstance(assy.obj, cq.Workplane) else assy.obj
+        col = assy.color.toTuple() if assy.color is not None else None
+        yield shape.moved(loc), col
+    for child in assy.children:
+        yield from _iter_parts(child, loc)
+
+
+def _shapes(obj):
+    if isinstance(obj, cq.Assembly):
+        return list(_iter_parts(obj))
+    if isinstance(obj, cq.Workplane):
+        return [(obj.val(), None)]
+    return [(obj, None)]
+
+
+def render(obj, path, view="iso", tol=0.08, figsize=(9, 9), dpi=110,
+           edges=True, title=None):
+    parts = _shapes(obj)
+
+    fig = plt.figure(figsize=figsize)
+    ax = fig.add_subplot(111, projection="3d")
+
+    lo = np.array([+1e9, +1e9, +1e9])
+    hi = np.array([-1e9, -1e9, -1e9])
+
+    for shape, col in parts:
+        verts, tris = shape.tessellate(tol)
+        if not tris:
+            continue
+        v = np.array([[p.x, p.y, p.z] for p in verts])
+        lo = np.minimum(lo, v.min(axis=0))
+        hi = np.maximum(hi, v.max(axis=0))
+        face = col[:3] if col else DEFAULT_COLOR
+        pc = Poly3DCollection(
+            v[np.array(tris)],
+            facecolor=face,
+            edgecolor=(0, 0, 0, 0.25) if edges else "none",
+            linewidth=0.15 if edges else 0,
+        )
+        pc.set_alpha(col[3] if col else 1.0)
+        ax.add_collection3d(pc)
+
+    ctr = (lo + hi) / 2.0
+    span = float((hi - lo).max()) * 0.55 or 1.0
+    ax.set_xlim(ctr[0] - span, ctr[0] + span)
+    ax.set_ylim(ctr[1] - span, ctr[1] + span)
+    ax.set_zlim(ctr[2] - span, ctr[2] + span)
+    try:
+        ax.set_box_aspect((1, 1, 1))
+    except Exception:
+        pass
+
+    elev, azim = VIEWS.get(view, view) if isinstance(view, str) else view
+    ax.view_init(elev=elev, azim=azim)
+    ax.set_axis_off()
+    if title:
+        ax.set_title(title)
+    fig.savefig(path, dpi=dpi, bbox_inches="tight", facecolor="white")
+    plt.close(fig)
+    print(f"wrote {path}")
+    return path
+
+
+def render_grid(obj, path, views=("iso", "top", "front", "right"), tol=0.08, dpi=100):
+    """2x2 contact sheet -- the quickest way to eyeball a part or assembly."""
+    parts = _shapes(obj)
+    fig = plt.figure(figsize=(12, 12))
+    for i, view in enumerate(views, start=1):
+        ax = fig.add_subplot(2, 2, i, projection="3d")
+        lo = np.array([+1e9] * 3)
+        hi = np.array([-1e9] * 3)
+        for shape, col in parts:
+            verts, tris = shape.tessellate(tol)
+            if not tris:
+                continue
+            v = np.array([[p.x, p.y, p.z] for p in verts])
+            lo = np.minimum(lo, v.min(axis=0))
+            hi = np.maximum(hi, v.max(axis=0))
+            pc = Poly3DCollection(
+                v[np.array(tris)],
+                facecolor=col[:3] if col else DEFAULT_COLOR,
+                edgecolor=(0, 0, 0, 0.25),
+                linewidth=0.15,
+            )
+            pc.set_alpha(col[3] if col else 1.0)
+            ax.add_collection3d(pc)
+        ctr = (lo + hi) / 2.0
+        span = float((hi - lo).max()) * 0.55 or 1.0
+        ax.set_xlim(ctr[0] - span, ctr[0] + span)
+        ax.set_ylim(ctr[1] - span, ctr[1] + span)
+        ax.set_zlim(ctr[2] - span, ctr[2] + span)
+        try:
+            ax.set_box_aspect((1, 1, 1))
+        except Exception:
+            pass
+        elev, azim = VIEWS.get(view, view) if isinstance(view, str) else view
+        ax.view_init(elev=elev, azim=azim)
+        ax.set_axis_off()
+        ax.set_title(str(view))
+    fig.savefig(path, dpi=dpi, bbox_inches="tight", facecolor="white")
+    plt.close(fig)
+    print(f"wrote {path}")
+    return path