finalized porting examples

examples/projection_algebra.py

@@ -0,0 +1,77 @@
+from build123d import *
+
+# A sphere used as a projection target
+sphere = Sphere(50)
+
+"""Example 1 - Mapping A Face on Sphere"""
+projection_direction = Vector(0, 1, 0)
+
+square = Plane.ZX.offset(-80) * Rectangle(20, 20)
+square_projected = square.faces()[0].project_to_shape(sphere, projection_direction)
+square_solids = Part() + [f.thicken(2) for f in square_projected]
+face = square.faces()[0]
+projection_beams = loft(face, Pos(0, 160, 0) * face)
+
+
+"""Example 2 - Flat Projection of Text on Sphere"""
+projection_direction = Vector(0, -1, 0)
+
+flat_planar_text = Rot(90, 0, 0) * Text("Flat", font_size=30)
+flat_projected_text_faces = Sketch() + [
+    f.project_to_shape(sphere, projection_direction)[0]
+    for f in flat_planar_text.faces()
+]
+flat_projection_beams = Part() + [
+    extrude(f, dir=projection_direction, amount=80) for f in flat_planar_text.faces()
+]
+
+
+"""Example 3 - Project a text string along a path onto a shape"""
+cyl = Plane.YZ * Cylinder(80, 100, align=(Align.CENTER, Align.CENTER, Align.MIN))
+obj = sphere - Pos(-50, 0, -70) * cyl
+
+arch_path: Edge = obj.edges().sort_by().first
+
+arch_path_start = Vertex(arch_path.position_at(0))
+text = Text(
+    "'the quick brown fox jumped over the lazy dog'",
+    font_size=15,
+    align=(Align.MIN, Align.CENTER),
+)
+projected_text = sphere.project_faces(text.faces(), path=arch_path)
+
+if "show_object" in locals():
+    # Example 1
+    show_object(sphere, name="sphere_solid", options={"alpha": 0.8})
+    show_object(square, name="square")
+    show_object(square_solids, name="square_solids")
+    show_object(
+        Compound.make_compound(projection_beams),
+        name="projection_beams",
+        options={"alpha": 0.9, "color": (170 / 255, 170 / 255, 255 / 255)},
+    )
+
+    # Example 2
+    show_object(
+        Pos(-100, -100) * sphere,
+        name="sphere_solid for text",
+        options={"alpha": 0.8},
+    )
+    show_object(
+        Pos(-100, -100) * flat_projected_text_faces, name="flat_projected_text_faces"
+    )
+    show_object(
+        Pos(-100, -100) * flat_projection_beams,
+        name="flat_projection_beams",
+        options={"alpha": 0.95, "color": (170 / 255, 170 / 255, 255 / 255)},
+    )
+
+    # Example 3
+    show_object(
+        sphere.moved(Location((100, 100))),
+        name="sphere_solid for text on path",
+        options={"alpha": 0.8},
+    )
+    show_object(
+        projected_text.moved(Location((100, 100))), name="projected_text on path"
+    )