Strange rectangle corner display

[anweid]

The display of corners in the German Affinity Designer 1.9.2.1035 for Windows depends on the current zoom level. In the attached video, the red outlined rectangle uses sharp corners with a miter limit of 1.414, which seems to be some default (I would never enter this number myself). The following happens:

• Depending on the zoom level, the corners are all OK (0:00), or cannot really decide whether to be mitered or sharp (0:04), or are all mitered (0:13).
• This could be the result of problematic floating point rounding for the miter limit: 1.414 is very near sqrt(2), and sqrt(2) happens at exactly 90 degree corners. It appears that, depending on the zoom level, each corner's miter value is sometimes rounded to more than 1.414, resulting in mitered corners, and sometimes rounded to less than 1.414, resulting in sharp corners.

Should this be the case, I suggest the following things:

• Set the default miter limit to a value that can be exactly (without round-off error) represented as binary floating point and is a bit larger than sqrt(2), e.g. 1.5. This would ensure that (1) sharp corners with 90 degree still behave as expected and (2) rounding does not depend on the least significant floating point bits.
• Do the rounding independent of the current zoom level – the corner display should be the same no matter how far you zoom in or out.

Andreas Weidner

[anweid]

Apparently, 1.414 is not Designer's miter limit default – all rectangles I created in new documents always used 1.5, which is exactly what I suggested, anyway. Wonderful. I don't have the slightest idea where the miter limit of 1.414 came from in that document...

This still leaves the matter of making the rounding zoom-independent.

Andreas Weidner

[Sean P]

Hi anweid,

I think 1.414 was used a long time ago, but has been changed to 1.5 since. I can only assume that value may have come from an older document or object.

With regards to the mitre changing at different zooms, this is something we do have logged. I will get your comments passed on.