Hi Gerd I could have changed it to this, but it is looking for lowest val <= 0 and highest val >= 0 so 0 seemed the better choice.
The slight improvement is because it gives up after 2 tries that don't show improvement, and before, for unsigned, one of these tries was wasted. Ticker On Thu, 2021-04-08 at 15:11 +0000, Gerd Petermann wrote: > Hi Ticker, > > Funny, I would have used Integer.MinValue for maxDx/maxDy to make it > less confusing. > Do you have an explanation for the change in size? My understanding > is that your patch just skips a test which will never find a better > encoding? > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk> im Auftrag > von Ticker Berkin <rwb-mkg...@jagit.co.uk> > Gesendet: Donnerstag, 8. April 2021 13:58 > An: mkgmap development > Betreff: [mkgmap-dev] Polyline base optimisation > > Hi Gerd > > If starting with unsigned deltas in polyline encoding, and attempting > to reduce the length by testing reduced x/yBase values, there isn't > any > point in testing Base-1, as the normal number of bits will be the > same > (added sign bit) and there will be some overflows. > > Patch attached to change this - it gives me a very slight reduction > in > RGN size and might give a performance improvement (I didn't detect > any). > > I've also fixed a couple of log. logic errors and changed minDx/y > initial to 0, which is much less confusing because they are symmetric > with maxDx/y which do use 0. > > Ticker > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
