[Digikam-devel] Speed of new filters

[Gilles Caulier]

Another comment : The histogram on the top right side is computed with
image area data visibile on preview. In case of you zoom to fit, whole
image data are used. See this entry for details :

https://bugs.kde.org/show_bug.cgi?id=163286

Gilles Caulier

2010/2/13 Gilles Caulier <caulier.gilles at gmail.com>:
> 2010/2/13 Julien Narboux <jnarboux at narboux.fr>:
>> Gilles,
>>
>> Did you notice the speed of the new threaded filters (hsl for instance)
>> ? it seems to me that they are far slower than they used to be.
>> Did the old implementation computed the preview on the downscaled
>> version of the picture  ?
>
> yes, it is. This is relevant of imageguidewidget to imageregionwidget
> port. If you fit to window preview with imageregionwidget as
> imageguidewidget do, you compute on whole image.
>
> Imageguidewidget use a downscaled version of preview, in fact the
> screen size of widget. This is why it's very fast. But of course
> zoom/pan is not possible here.
>
> Note : with imageregionwidget, the computation is done on visible
> preview area, not always on whole image. If you zoom down on, the
> computation will be done on visible part of image. In this case it's
> fast.
>
> Gilles
>