kicad-developers team mailing list archive

[Jeff Young <jeff@xxxxxxxxx>]

We need to go to strategy (b) to fix that (use the zone’s fillet radius to round the corners).

I’ll look into it….

> On 16 Jul 2019, at 02:37, Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:
> 
> Hi Jeff-
> 
> I just checked a couple of Eagle boards and the imports are now slightly problematic.  See the attached image.  This corner is square in Eagle.  It can be very difficult to edit zones with a bunch of extra points, so I'd like to avoid this if possible.
> 
> Best-
> Seth
> 
> On 2019-07-15 06:04, Jeff Young wrote:
>> Oh, good.  Not sure how I missed where we set the min-width.
>> So our old algorithm will mimic Eagle irregardless of my change
>> (MiterLimit only comes into play when inflating, not when deflating).
>> However, the new algorithm would need my change to produce the same
>> curves as Eagle — but that puts us nearly back to square one vis a vis
>> the performance issues JP was addressing.
>> So, live with squared-off Eagle corners when the angles are above 90º?
>> (I also though about setting a smooth-sharp-corners option in the
>> Eagle importer, but Eagle imports are more likely to be complicated
>> boards which run into performance issues.)
>> Cheers,
>> Jeff
>>> On 15 Jul 2019, at 01:24, Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:
>>> Hi Jeff-
>>> Right now we do (a) except that we set the min-width to 1/2 the Eagle stroke width [1].  This is because we stroke inside the zone outline.  Eagle rounds using the edge of their line, which is curved to 1/2 the width.
>>> Best-
>>> Seth
>>> [1] https://git.launchpad.net/kicad/commit/?id=490c805319974ec84a8fbe8b10e9b59b9a3922a6
>>> On 2019-07-14 16:13, Jeff Young wrote:
>>>> Hi Seth,
>>>> I’m still not following this.  When Eagle strokes the boundary, it
>>>> does so with a round pen (at least going by the pngs in the bug
>>>> report).  So all corners have a radius of 1/2 the stroke width.
>>>> How do we currently represent that in Kicad?
>>>> a) inflate the boundary by 1/2-eagle-stroke-width and set min-width to
>>>> eagle-stroke-width?
>>>> b) inflate the boundary by 1/2-eagle-stroke-width and set corner
>>>> filleting to 1/2-eagle-stroke-width?
>>>> c) inflate the boundary by 1/2-eagle-stroke-width and let Clipper
>>>> round the corners?
>>>> If it’s (c), I’m saying that doesn’t actually work. (Or at least it
>>>> didn’t.)  You’re probably seeing the effects of (a), only with a
>>>> default min-width so the radiuses won’t necessarily exactly match.
>>>> I’ve changed (c) to also round by 1/2-min-width, so that it can be
>>>> equivalent to (a) when “stroke-zone-boundaries” is off.
>>>> Cheers,
>>>> Jeff.
>>>>> On 14 Jul 2019, at 20:21, Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:
>>>>> Hi Jeff-
>>>>> The bug was that Eagle strokes on the boundary.  We stroke inside.  When we convert, we need to expand strictly as a square to get the equivalent KiCad zone.  Mitering and rounding will give excess polygon points.  The only way I have found to get this in Clipper is to use jtMiter and set the miterlimit to 0.  Oddly, just setting the parameter to jtSquare gave a mitered corner.
>>>>> It sounds from your description that you've changed this behavior in Clipper.  If that is the case, Eagle converted zones will no longer be correct.
>>>>> -Seth
>>>>> On 2019-07-14 14:22, Jeff Young wrote:
>>>>>> Hi Seth,
>>>>>> I looked at that bug report, and all the Eagle zones have rounded
>>>>>> corners, not square.  So I don’t think you were actually getting
>>>>>> anything out of the mitering, but that was being masked by the fact
>>>>>> that we _do_ in fact stroke the outer zone boundary (therefore giving
>>>>>> you rounded corners).
>>>>>> Just to be clear, we stroke with the zone-min-width stroke, rather
>>>>>> than the zone boundary’s linewidth.  We first deflate the zone by
>>>>>> 1/2-min-width (which drops out all the min-width features), and then
>>>>>> stroke it with min-width which expands it back to size and gives us
>>>>>> some corner rounding as a bonus.
>>>>>> JP has recently introduced a new mode where we don’t stroke the
>>>>>> boundary anymore (I think primarily for performance, but I’m not
>>>>>> 100% sure).  Under this algorithm we still deflate the zones by
>>>>>> 1/2-min-width, but we then inflate them again to bring them back to
>>>>>> size.  My changes are largely to add corner rounding to this case.
>>>>>> Cheers,
>>>>>> Jeff.
>>>>>>> On 14 Jul 2019, at 18:53, Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:
>>>>>>> Please be super careful here.  I was using that implicit fallback in
>>>>>>> the Eagle import to get a square inflation that is needed to mimic
>>>>>>> the Eagle zones.  I didn't think we were using that type of
>>>>>>> inflation anywhere else (but that could have changed).  If we are
>>>>>>> using that elsewhere, can you verify that the change to clipper
>>>>>>> doesn't re-introduce https://bugs.launchpad.net/kicad/+bug/1817312 ?
>>>>>>> Thanks-
>>>>>>> Seth
>>>>>>> On 2019-07-14 13:17, Jeff Young wrote:
>>>>>>> Hi Seth,
>>>>>>> We weren’t calling it directly anywhere.  But jtMiter has a
>>>>>>> MiterLimit, after which it falls back to square.  I’ve changed
>>>>>>> that
>>>>>>> fallback to round (and enforced a much lower MiterLimit so that it
>>>>>>> mimics the smoothing we used to get by drawing the border with a
>>>>>>> 1/2-min-width thick stroke).
>>>>>>> Cheers,
>>>>>>> Jeff.
>>>>>>> On 14 Jul 2019, at 17:50, Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:
>>>>>>> On 2019-07-14 05:31, Jeff Young wrote:
>>>>>>> I made another optimisation, this time within the Clipper library.
>>>>>>> When the offset exceeds the MiterLimit it will perform jtRound
>>>>>>> instead
>>>>>>> of jtSquare.  I *think* this makes the zero-width-border algorithm
>>>>>>> materially indistinguishable from the old algorithm (well, except
>>>>>>> that
>>>>>>> several bugs are fixed in the new one and it’s faster).
>>>>>>> Hi Jeff-
>>>>>>> Were we using jtSquare somewhere?  I had added an option to inflate
>>>>>>> using jtMiter but this was for Eagle import only.  I thought all
>>>>>>> other inflations were using jtRound.
>>>>>>> Best-
>>>>>>> Seth
> <RoundedEagleImport.png>