Equal sized cells in NSSegmentedControl - objective-c

Question

For my NSSegmentedControl, I use it do display a bar to control a NSTableView. I have code set up to control the size programmatically:
for (NSInteger i = 1; i <= numberOfSegments; i++) {
CGSize textSize = [[NSString stringWithFormat:#"Workspace %ld", (long)i] sizeWithAttributes:#{NSFontAttributeName: [NSFont systemFontOfSize:13.0f]}];
NSInteger segmentWidth = self.workspaceControl.frame.size.width / numberOfSegments;
if (textSize.width > segmentWidth) {
[self.workspaceControl setLabel:[NSString stringWithFormat:#"%ld", (long)i] forSegment:i - 1];
} else {
[self.workspaceControl setLabel:[NSString stringWithFormat:#"Workspace %ld", (long)i] forSegment:i - 1];
}
[self.workspaceControl setWidth:segmentWidth forSegment:i - 1];
}
This works, by a small problem occurs.
At the beginning (with one segment) it looks like this:
As I change the value, the right side gets clipped slightly.
And then back to one segment:
The constraints are as follows:
Im very puzzled by the clipping (probably because a couple pixels t0o large), but I have no idea how to fix it, or is there a better way to get evenly spaced cells?

Answer 1

In my testing the generated width constraints of the NSSegmentedControl segments appear to round to whole numbers despite setWidth(_ width: CGFloat, forSegment segment: Int) taking a CGFloat. Thus the total width of the segments can add up to more than the width of the control itself.
To get even segments pass segmentWidth through the floor. Also, set a manual width for the control and constrain it horizontally by the centerXAnchor instead of by the leading and trailing anchors to preserve its center-alignment.
Drawbacks: the width must be hard-coded and the left and right margins may not match your other views exactly.