diff options
Diffstat (limited to 'gerber')
| -rw-r--r-- | gerber/rs274x.py | 33 | ||||
| -rw-r--r-- | gerber/utils.py | 6 |
2 files changed, 38 insertions, 1 deletions
diff --git a/gerber/rs274x.py b/gerber/rs274x.py index 7b3a3b9..86785bc 100644 --- a/gerber/rs274x.py +++ b/gerber/rs274x.py @@ -21,6 +21,7 @@ import copy import json import re +import sys try: from cStringIO import StringIO @@ -30,6 +31,7 @@ except(ImportError): from .gerber_statements import * from .primitives import * from .cam import CamFile, FileSettings +from .utils import sq_distance def read(filename): @@ -548,7 +550,7 @@ class GerberParser(object): else: i = 0 if stmt.i is None else stmt.i j = 0 if stmt.j is None else stmt.j - center = (start[0] + i, start[1] + j) + center = self._find_center(start, end, (i, j)) if self.region_mode == 'off': self.primitives.append(Arc(start, end, center, self.direction, self.apertures[self.aperture], quadrant_mode=self.quadrant_mode, level_polarity=self.level_polarity, units=self.settings.units)) else: @@ -579,6 +581,35 @@ class GerberParser(object): self.primitives.append(primitive) self.x, self.y = x, y + + def _find_center(self, start, end, offsets): + """ + In single quadrant mode, the offsets are always positive, which means there are 4 possible centers. + The correct center is the only one that results in an arc with sweep angle of less than or equal to 90 degrees + """ + + if self.quadrant_mode == 'single-quadrant': + + # The Gerber spec says single quadrant only has one possible center, and you can detect + # based on the angle. But for real files, this seems to work better - there is usually + # only one option that makes sense for the center (since the distance should be the same + # from start and end). Find the center that makes the most sense + sqdist_diff_min = sys.maxint + center = None + for factors in [(1, 1), (1, -1), (-1, 1), (-1, -1)]: + + test_center = (start[0] + offsets[0] * factors[0], start[1] + offsets[1] * factors[1]) + + sqdist_start = sq_distance(start, test_center) + sqdist_end = sq_distance(end, test_center) + + if abs(sqdist_start - sqdist_end) < sqdist_diff_min: + center = test_center + sqdist_diff_min = abs(sqdist_start - sqdist_end) + + return center + else: + return (start[0] + offsets[0], start[1] + offsets[1]) def _evaluate_aperture(self, stmt): self.aperture = stmt.d diff --git a/gerber/utils.py b/gerber/utils.py index 72bf2d1..41d264a 100644 --- a/gerber/utils.py +++ b/gerber/utils.py @@ -297,3 +297,9 @@ def nearly_equal(point1, point2, ndigits = 6): '''Are the points nearly equal''' return round(point1[0] - point2[0], ndigits) == 0 and round(point1[1] - point2[1], ndigits) == 0 + +def sq_distance(point1, point2): + + diff1 = point1[0] - point2[0] + diff2 = point1[1] - point2[1] + return diff1 * diff1 + diff2 * diff2 |