Fixes linear joint, moves revolute joint to new package "joints".

CHANGELOG.md

@@ -20,6 +20,9 @@ optimization, related to ([#5](https://github.com/HugoFara/pylinkage/issues/5)).
 - Some run configuration files added *for users of PyCharm*:
   - Run all tests with "All Tests".
   - Regenerate documentation with "Sphinx Documentation".
+- The ``Linear`` joint is here! His geometric model was of course implemented.
+- ``line_from_points`` and ``circle_line_intersection``.
+- New exception ``NotCompletelyDefinedError``, when a joint is reloading but its anchor coordinates are set to None.
 
 ### Changed
 
@@ -52,12 +55,16 @@ iteration.
   - From the user perspective, no change (execution *may* be a bit faster)
   - ``source/`` renamed to ``sphinx/`` because it was confusing and only for Sphinx configuration.
 - Transition from Numpydoc to reST for docstrings ([#12](https://github.com/HugoFara/pylinkage/issues/12)).
+- ``__secant_circles_intersections__`` renamed to
+``secant_circles_intersections`` in ``geometry.py``.
 
 ### Fixed
 
 - ``swarm_tiled_repr`` in ``visualizer.py`` was wrongly assigning dimensions.
 - Setting ``locus_highlight`` in ``plot_static_linkage`` would result in an error.
-- ``Pivot.reload`` was returning arbitrary point when we had an infinity of solutions. 
+- ``Pivot.reload`` was returning arbitrary point when we had an infinity of solutions.
+- The highlighted locus was sometimes buggy in ``plot_static_linkage`` in 
+``visualizer.py``.
 
 ### Deprecated
 
@@ -66,6 +73,9 @@ iteration.
 - The ``Pivot`` class is deprecated in favor of the ``Revolute`` class. 
 The name "Pivot joint" is not standard. 
 Related to [#13](https://github.com/HugoFara/pylinkage/issues/13).
+- The ``hyperstaticity`` method is renamed ``indeterminacy`` in ``Linkage`` 
+(linkage.py)
+
 
 ## [0.5.3] - 2023-06-23
 
@@ -103,8 +113,8 @@ It will no longer be tested, use it at your own risks!
 
 ### Added in 0.5.2
 
-- You can see the best score and the best dimensions updating in 
-  ``trials_and_errors_optimization``.
+ - You can see the best score and best dimensions updating in 
+   ``trials_and_errors_optimization``.
 
 ### Changed in 0.5.2
 

README.md

@@ -36,7 +36,7 @@ import pylinkage as pl
 # Main motor
 crank = pl.Crank(0, 1, joint0=(0, 0), angle=.31, distance=1)
 # Close the loop
-pin = pl.Pivot(
+pin = pl.Revolute(
     3, 2, joint0=crank, joint1=(3, 0), 
     distance0=3, distance1=1
 )
@@ -108,7 +108,7 @@ The pin will be created on the position of the parent, which is the head of the
 Now we add a pin joint to close the kinematic loop.
 
 ```python
-pin = pl.Pivot(3, 2, joint0=crank, joint1=(3, 0), distance0=3, distance1=1)
+pin = pl.Revolute(3, 2, joint0=crank, joint1=(3, 0), distance0=3, distance1=1)
 ```
 
 In human language, here is what is happening:
@@ -127,7 +127,7 @@ then we keep the intersection closer to the previous position as the solution.
 Wait! A linkage with a single motor and only one pin joint? That doesn't make sense!
 : Behind the curtain, many joints are created on the fly. 
 When you define a ``Crank`` joint, it creates a motor **and** a pin joint on the crank's link head. 
-For a ``Pivot`` joint, it creates **3 pin joints**: one on each of its parents' positions, and one its position, 
+For a ``Revolute`` joint, it creates **3 pin joints**: one on each of its parents' positions, and one its position, 
 which forms a deformable triangle. 
 This is why pylinkage is so short to write.
 
@@ -159,7 +159,7 @@ import pylinkage as pl
 # Main motor
 crank = pl.Crank(0, 1, joint0=(0, 0), angle=.31, distance=1)
 # Close the loop
-pin = pl.Pivot(
+pin = pl.Revolute(
     3, 2, joint0=crank, joint1=(3, 0), 
     distance0=3, distance1=1
 )
@@ -195,7 +195,7 @@ Last recap, rearranging names:
 # Main motor
 crank = pl.Crank(0, 1, joint0=(0, 0), angle=.31, distance=1, name="B")
 # Close the loop
-pin = pl.Pivot(
+pin = pl.Revolute(
     3, 2, joint0=crank, joint1=(3, 0), 
     distance0=3, distance1=1, name="C"
 )

examples/fourbar_linkage.py

@@ -1,10 +1,10 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
-The fourbar_linkage module demonstrates the functionalities of pylinkage.
+The fourbar_linkage module demonstrates the features of pylinkage.
 
-It is not intended to be imported in another project, but fell welcome to
-copy-paste chunks of code.
+It is not intended to be imported in another project,
+but feel welcome to copy-paste chunks of code.
 
 Created on Sat Jun 19, 12:32:37 2021.
 

examples/inverted_stroke_engine.py

@@ -0,0 +1,18 @@
+"""
+An inverted four-stroke engine, that converts a rotary motion into a linear one.
+
+See: https://en.wikipedia.org/wiki/Four-stroke_engine for details
+"""
+import pylinkage as pl
+
+crank = pl.Crank(x=0, y=0, joint0=(0, 0), distance=1, angle=0.1, name="Crank")
+
+slider = pl.Linear(x=2, y=0, joint0=crank, joint1=(0, 0), joint2=(1, 0), revolute_radius=1.5, name="Slider")
+
+my_linkage = pl.Linkage(
+    joints=(crank, slider),
+    order=(crank, slider),
+    name="Simple four-stroke engine"
+)
+
+pl.show_linkage(my_linkage, duration=5)