shapely, simplify, accumulate error

axi/__init__.py

@@ -1,6 +1,6 @@
 from .device import Device
 from .drawing import Drawing
-from .paths import sort_paths, join_paths
+from .paths import simplify_paths, sort_paths, join_paths
 from .planner import Planner
 from .turtle import Turtle
 from .util import draw, reset

axi/device.py

@@ -19,7 +19,7 @@ PEN_DOWN_SPEED = 150
 PEN_DOWN_DELAY = 100
 
 ACCELERATION = 8
-MAX_VELOCITY = 4
+MAX_VELOCITY = 8
 CORNER_FACTOR = 0.01
 
 VID_PID = '04D8:FD92'
@@ -46,6 +46,8 @@ class Device(object):
         for k, v in kwargs.items():
             setattr(self, k, v)
 
+        self.error = (0, 0) # accumulated step error
+
         port = find_port()
         if port is None:
             raise Exception('cannot find axidraw device')
@@ -102,17 +104,17 @@ class Device(object):
             time.sleep(0.1)
 
     def run_plan(self, plan):
-        step_ms = 30
+        step_ms = 10
         step_s = step_ms / 1000
         t = 0
-        ex = 0
-        ey = 0
         while t < plan.t:
             i1 = plan.instant(t)
             i2 = plan.instant(t + step_s)
             d = i2.p.sub(i1.p)
+            ex, ey = self.error
             ex, sx = modf(d.x * self.steps_per_unit + ex)
             ey, sy = modf(d.y * self.steps_per_unit + ey)
+            self.error = ex, ey
             self.move(step_ms, int(sx), int(sy))
             t += step_s
         self.wait()

axi/drawing.py

@@ -2,7 +2,7 @@ from __future__ import division
 
 from math import sin, cos, radians
 
-from .paths import sort_paths, join_paths
+from .paths import simplify_paths, sort_paths, join_paths
 
 class Drawing(object):
     def __init__(self, paths=None):
@@ -33,6 +33,9 @@ class Drawing(object):
         x1, y1, x2, y2 = self.bounds
         return y2 - y1
 
+    def simplify_paths(self, tolerance):
+        return Drawing(simplify_paths(self.paths, tolerance))
+
     def sort_paths(self, reversable=True):
         return Drawing(sort_paths(self.paths, reversable))
 
@@ -42,9 +45,6 @@ class Drawing(object):
     # def remove_duplicates(self):
     #     return Drawing(util.remove_duplicates(self.paths))
 
-    # def simplify_paths(self, tolerance=0.05):
-    #     return Drawing(util.simplify_paths(self.paths, tolerance))
-
     def transform(self, func):
         return Drawing([[func(x, y) for x, y in path] for path in self.paths])
 

axi/paths.py

@@ -1,7 +1,18 @@
 from math import hypot
+from shapely.geometry import LineString
 
 from .spatial import Index
 
+def simplify_path(points, tolerance):
+    if len(points) < 2:
+        return points
+    line = LineString(points)
+    line = line.simplify(tolerance)
+    return list(line.coords)
+
+def simplify_paths(paths, tolerance):
+    return [simplify_path(x, tolerance) for x in paths]
+
 def sort_paths(paths, reversable=True):
     first = paths[0]
     paths.remove(first)

examples/motor_test.py

@@ -0,0 +1,22 @@
+import axi
+import random
+import time
+
+def main():
+    d = axi.Device()
+    d.pen_up()
+    d.enable_motors()
+    time.sleep(0.2)
+    points = []
+    points.append((0, 0))
+    for i in range(10):
+        x = random.random() * 11
+        y = random.random() * 8.5
+        points.append((x, y))
+    points.append((0, 0))
+    d.run_path(points)
+    d.wait()
+    d.disable_motors()
+
+if __name__ == '__main__':
+    main()

setup.py

@@ -7,7 +7,7 @@ setup(
     author='Michael Fogleman',
     author_email='michael.fogleman@gmail.com',
     packages=['axi'],
-    install_requires=['pyserial'],
+    install_requires=['pyserial', 'shapely'],
     license='MIT',
     classifiers=(
         'Development Status :: 3 - Alpha',