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List:       kde-core-devel
Subject:    Alpha Pixie thumbnail manager in kdenonbeta
From:       mosfet <mosfet () mandrakesoft ! com>
Date:       2001-02-09 2:13:02
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I've rewritten the iconview for Pixie's thumbnail manager, and since I've 
gotten a lot of comments and suggestions about it I figured I would post the 
changes:

First of all, it's hellua fast :) Previously, when entering a directory *all* 
the thumbnails were loaded. This was okay if there were only a few images, 
but killed performance when there were a few thousand ;-) Also, Pixie used to 
try to give a lot of interactive feedback when loading a directory of images. 
This included interactively showing the thumbnails as they were loaded 
(scrolling as needed). The end result was it took about 40secs to preview a 
directory with 1,578 images. Not nice. XV, ee and virtually all other 
thumbnail viewers worked this way, but it was too slow for me. Suprisingly, 
zgv (an old console image viewer), seems to do things the way I do it now and 
was what got me thinking about what I was doing wrong ;-)

As a result, the thumbnail manager now only loads thumbnails as they are 
needed - on demand. This makes entering the same directory of 1,578 images 
take <6 secs vs. 40 on my box. Of course, the overhead of loading the 
thumbnails has to happen somewhere, and now that is when you scroll. 
Nonetheless, this doesn't seem to be much a problem. Basically, I went into 
directories with large amounts of images and scrolled back and forth really 
fast - and Pixie was able to keep up without delay. This signaled to me that 
it was the right solution ;)

There are other speed improvements, such as delaying all QIconView layout 
until everything is loaded, a lot less updates, and other nifty stuff.

Now for the bugs - it's alpha quality ya' know ;-)
1) This isn't really a bug, but Pixie no longer shows the thumbnails as they 
are loaded. They are only displayed once processing the directory is done. No 
big deal if it takes < 6 secs to load 1,578 items :)

2) Thumbnail sizes are restricted to large right now. 

3) There is a crash when using the scrollbar arrow up button past the first 
thumbnail. Using the scrollbar slider is fine.

4) There is slight flickering when scrolling. I need to add an update delay.

5) Generating thumbnails no longer updates the scrollbar.

6) The code needs a cleanup. This is essentially me experimenting and some of 
it's kindof messy.

This will be the new default thumbnail manager after 2.1. To download it 
checkout kdenonbeta and install the kdenonbeta/pixie-thumbmanager 
subdirectory. Since it's a plugin it will automatically replace the old (and 
stabler ;-) one, so use it at your own risk... as a side note people don't 
seem to realize that most Pixie features are plugins that are loaded as 
needed ;P

Anyways - have fun! If you want to hack it use the one in kdenonbeta. I've 
gotten some patches for the old one but can't use them now, but please feel 
free to hack this new one. People have had a lot of nice ideas!

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