If I remember, photoshop is rasterizing all effects and the result in stored in memory( for each object? layer ?) and directly re-applied when panning or changing upper layers without complex calculation.

When the zoom value is changed, the rasterization is remade, etc.
Do you think that something like that could be applied to inkscape ?
One more thing that could be usefull is a "Cancel rendering" key (like escape) because sometimes, on complex graphics, you have to wait 30s-45s that the rendering is completed to change something (color, go to outline mode, etc.) on slower computer.

2009/4/27 Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
Nicu Buculei wrote:
> On 04/27/2009 12:53 PM, Jasper van de Gronde wrote:
>> ...
>> If you feel that blur is too slow for your work, be sure to file a
>> feature request. And preferably include some (simple) example of a
>> situation that is too slow for you.
> In my experience blur is *painfully* slow and always was (now I am
> running a SVN snapshot) tot he degree that for complex files you may
> have to use the Outline mode and to export to PNG with GIMP.
> I spread the various part of an image to various layers and toggle layer
> visibility on and off, to have as little as possible blur visible at a
> time, to carry my work.

I just drew a rectangle and a circle, applied two different blurs and
did some zooming. Only when zooming in considerably did Inkscape become
somewhat slow for my tastes. So obviously at least one of the following
is the case:
 - I use a faster machine (Core 2 Duo at 1.33Ghz)
 - My standards for judging Inkscape's speed are different
 - I use Inkscape for considerably less complex drawings (obviously the
example above was overly simple, but I have also done some more complex
things with blur without having much of a problem with Inkscape's speed)

In the end you'll probably always have situations in which you would
have to switch to outline mode or switch off filters. But in my opinion
there is still a lot of room for improvement in some specific
situations, where it is possible to use a fundamentally faster approach.

So if you can identify specific situations in which blur is clearly too
slow this may help to guide future optimizations.

BTW, if you want to try multi-threading, set the following in the
options group in preferences.xml (if you have more than 2 cores you may
want to experiment with setting numthreads higher):
       id="threading" />

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