[mkgmap-dev] help needed for graphical problem

Thu Feb 12 09:20:27 GMT 2015

Hi all,

for improvements in the housenumber2 branch I have to split a road segment
into two parts. 
Given: the two (Garmin) points p1 and p2 that build the road
segment and a distance d with d < p1.distance(p2). The normal way to
calculate the wanted point is to use the Coord.makeBetweenPoint() method.

The problem: the simple algo in makeBetweenPoint()
calculates the point without looking at the rounding for the Garmin
raster, so for line segments with a small slope the calculated point
might be too far away from the displayed line. The effect is
that the splitted line has a rather large angle while the originial
line looks - of course - perfectly straight.

I am sure this problem was already solved, but up to now I did 
not find an algo that works without a loop to calculate a set of points
and chose the best one, e.g. using the Bresenham algo.

Any hints?

Gerd

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