I'm able to create a graph of the main roads of my country! I've also created a zoom possibility with the scrollbutton of the mouse (WM_MOUSEWHEEL). The problem however is that when I scroll very gently (only one tick of the scroll button further) the image keeps zooming in/out untill I click somewhere (which is catched by WM_LBUTTONDOWN). Then it stops zooming.
If I scroll faster (multpile clicks at a time) the image zooms in at a bigger step and only once (as it should).
Does anyone have an idea what causes the continuous zoom when scrolling per 1 'click'????