[Semi-PATCH] Dolphin - Previews in Tooltips

[Peter Penz]

Hi Simon,

Am Sunday, 17. August 2008 16:29:21 schrieb Simon St James:
> May as well forward this to the list to get some more brains on it while
> Fredrik recovers from flu :)
>
> I've tried to duplicate the KDE3 behaviour of using a very large image for
> the actual preview, and a small one for when no preview is available: a
> small preview is, in my experience, not very useful, and nor is a large
> not-preview ;)
>
> This of course causes an issue with the tooltip possibly changing size
> during its lifespan, which can cause it to go out of screen bounds (or
> worse - appear under the cursor - try it and see what happens! ;)) as it is
> currently simply re-drawn at the point at which it was originally
> requested.

In KDE 3 the tooltip changed its size as soon as the preview had been 
received, which is quite confusing in my opinion. I don't see it as an issue 
if we have a fixed size for previews in KDE 4. Sure: if no preview is 
available (e. g. for a directory) the increased size does not add any value, 
but it also does not harm.

If we go for the approach that the tooltip size depends on the current size of 
the preview (= KDE 3 approach), then a resizing of the tooltip after it is 
already open cannot be prevented. This is because we cannot assure that 
generating of a preview can be done within the ~300 ms where the tooltip has 
been requested but not opened yet.

This especially gets a problem with >= 8 megapixel JPEGs: at least on my 
computer (2 GHz Intel Core Duo) the preview of the JPEG cannot be done within 
the 300 ms (cold disk cache and preview has not been generated once -> loading 
the image from the harddisk is the bottleneck). Here we have the rare 
situation that the performance improvement of computers during the last years 
was slower than the increased size of a "typical photo" because of the 
megapixel-hype.

I personally would prefer having a fixed size for previews to prevent a 
resizing of the tooltip.

[...]

Best regards,
Peter