colinear overlaps not detected

[gferreira]

continuing from hasOverlap() does not detect all overlaps? (RoboFont Forum)

it seems the problem can be generalised to colinear straight segments in different contours. here are some examples with other shapes (red circles show detected overlaps):

some points appear/disappear when the objects are rotated:

here’s a helper to visualize overlaps while editing a glyph:

from vanilla import *
from defconAppKit.windows.baseWindow import BaseWindowController
from mojo.events import addObserver, removeObserver
from mojo.UI import UpdateCurrentGlyphView
from mojo.drawingTools import *

class ShowOverlaps(BaseWindowController):

    def __init__(self):
        self.w = FloatingWindow((130, 40))
        self.w.draw = CheckBox((10, 10, -10, 20), 'show overlaps', value=True, callback=self.updateViewCallback)
        addObserver(self, "drawBackgroundCallback", "drawBackground")
        self.setUpBaseWindowBehavior()
        self.w.open()

    def windowCloseCallback(self, sender):
        removeObserver(self, 'drawBackground')
        super(ShowOverlaps, self).windowCloseCallback(sender)

    def updateViewCallback(self, sender):
        UpdateCurrentGlyphView()

    def drawBackgroundCallback(self, info):
        if not self.w.draw.get():
            return
        g = info["glyph"]
        pts = g.hasOverlap()
        if not len(pts):
            return
        r = 20
        save()
        fill(None)
        stroke(1, 0, 0)
        strokeWidth(10)
        for x, y in pts:
            oval(x-r, y-r, r*2, r*2)
        restore()
        UpdateCurrentGlyphView()

ShowOverlaps()

thanks in advance for looking into it!

[typemytype]

can the glif xml be posted?

thanks!!

[gferreira]

sure, here are some rects :) testOverlaps.ufo.zip thx

[typemytype]

Oh yeah, getIntersections() is just returning all new points... in most of those cases there is no new point as the intersection is on top of an existing point...

see https://github.com/typemytype/booleanOperations/blob/master/Lib/booleanOperations/booleanOperationManager.py#L133