[Merkaartor] Inaccuracy in Projection

Timo Schlüßler timo at schluessler.org
Mon Apr 13 23:03:38 BST 2009


I noticed a small (or little?) inaccuracy when e.g. creating a node. The 
node doesn't appear there where I clicked but some pixels away from that 
point. When zooming in to a high zoom value (1meter scale) this effect 
is intensified.

The appended patch changes some (int) - casts to qRound() s but the 
problem still lasts but much lesser.
Could it be that the lasting inaccuracy results through converting every 
coordinate to an integer? The inserted debug outputs show that the 
projection (the boost projection library) itself doesn't contain 
rounding mistakes.

Any ideas how to solve this completely? Or has nobody else noticed this 

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