Don't know how to solve your smooth zooming problem, but have a look at Dr Geo: 
zooming is very smooth there!

- Francisco


On 1 May 2012, at 12:24, Martin Drautzburg <[email protected]> wrote:

> Hello all,
> 
> in my (first) pharo programm, I have a pane with apx 100 Morphs. The pane can 
> be zoomed and scrolled  both vertically and horizontally. The horizontal 
> scrolling means scrolling time and is self-written. I implemented some sort 
> of 
> kinetic scrolling using the mouse wheel, where a scroll destination is set 
> and 
> in a step method I halve the distance to the destination with each step. 
> 
> This looks kind of nice, but not nice enough. Scrolling is not as smooth as I 
> had hoped. Sometimes there is a delay between the wheel move and the display 
> actually showing some motion. Also I have the impression, that not all parts 
> of the pane are redrawn at the same time. Morphs which are exactly below each 
> other, appear minimally skewed during the scroll.
> 
> Strange enough the zooming, which has to do about the same underlying 
> geometry 
> calculations is a lot more snappy (but not kinetic). Likewise the vertical 
> scrolling which used a StandardScrollPane appears  more snappy.
> 
> I looks like using a stepper is the root of the problem. I just could not 
> figure out where the time goes. I put a MessageTally into the step method, 
> only to find out, that doing 1000 steps takes less than a second. So the 
> problem must be elsewehere. 
> 
> Any ideas would be much appreciated.
> 
> 
> -- 
> Martin
> 

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