Adding BlendCurve to the docs

docs/assets/example_blend_curve.svg

@@ -0,0 +1,12 @@
+<?xml version='1.0' encoding='utf-8'?>
+<svg width="53.437087mm" height="100.089999mm" viewBox="-3.542734 -5.0072 8.549934 16.0144" version="1.1" xmlns="http://www.w3.org/2000/svg">
+  <g transform="scale(1,-1)" stroke-linecap="round">
+    <g fill="none" stroke="rgb(0,0,0)" stroke-width="0.01440000009">
+      <path d="M 5.0,0.0 C 5.00028,-0.417137 4.985935,-0.83158 4.937625,-1.209787 C 4.890768,-1.590627 4.807318,-1.930241 4.687277,-2.228627 C 4.447554,-2.825457 4.043062,-3.22477 3.531938,-3.510073 C 3.022136,-3.79718 2.414809,-3.986061 1.805109,-4.210727 C 1.192462,-4.429798 0.586549,-4.700437 0.0,-5.0" />
+    </g>
+    <g fill="none" stroke="rgb(0,0,0)" stroke-width="0.01440000009" id="dashed" stroke-dasharray="0.1728 0.2592">
+      <path d="M -3.535534,3.535534 A 5.0,5.0 0.0 0,0 5.0,0.0" />
+      <path d="M 0.0,-5.0 Q -6.0,-8.0 0.0,-11.0" />
+    </g>
+  </g>
+</svg>

docs/objects.rst

@@ -83,6 +83,13 @@ The following objects all can be used in BuildLine contexts. Note that
         +++
         Curve defined by control points and weights
 
+    .. grid-item-card:: :class:`~objects_curve.BlendCurve`
+
+        .. image:: assets/example_blend_curve.svg
+
+        +++
+        Curve blending curvature of two curves
+
     .. grid-item-card:: :class:`~objects_curve.CenterArc`
 
         .. image:: assets/center_arc_example.svg
@@ -222,6 +229,7 @@ Reference
 
 .. autoclass:: BaseLineObject
 .. autoclass:: Bezier
+.. autoclass:: BlendCurve
 .. autoclass:: CenterArc
 .. autoclass:: DoubleTangentArc
 .. autoclass:: EllipticalCenterArc

docs/objects_1d_blend_curve.py

@@ -0,0 +1,18 @@
+from build123d import *
+
+# from ocp_vscode import show_all, set_defaults, Camera
+
+# set_defaults(reset_camera=Camera.KEEP)
+
+with BuildLine() as blend_curve:
+    l1 = CenterArc((0, 0), 5, 135, -135)
+    l2 = Spline((0, -5), (-3, -8), (0, -11))
+    l3 = BlendCurve(l1, l2, tangent_scalars=(2, 5))
+s = 100 / max(*blend_curve.line.bounding_box().size)
+svg = ExportSVG(scale=s)
+svg.add_layer("dashed", line_type=LineType.ISO_DASH_SPACE)
+svg.add_shape(l1, "dashed")
+svg.add_shape(l2, "dashed")
+svg.add_shape(l3)
+svg.write("assets/example_blend_curve.svg")
+# show_all()