Preloading Images

[bialio]

This might seem like a very simple question.

I'm loading up some fanart posters as a list is navigated - how do you preload them so that there isn't a delay - I'm talking about getting them into memory.

If I take my time and navigate all the way through the list, eventually every image in use appear to be loaded and from that point on moving around in the list is lightning fast. So what I want is a way to do all that backend processing without actually having to navigate the list.

btl.

[PLUCKYHD]

Originally Posted by bialio

This might seem like a very simple question.

I'm loading up some fanart posters as a list is navigated - how do you preload them so that there isn't a delay - I'm talking about getting them into memory.

If I take my time and navigate all the way through the list, eventually every image in use appear to be loaded and from that point on moving around in the list is lightning fast. So what I want is a way to do all that backend processing without actually having to navigate the list.

btl.

LoadImage(image) forces them into cache if there is room. On raw images you have to call it twice LoadImage(LoadImage(Image)).

I do it for smm in a forked thread during inactivity definately not something you want to do while the user is active as it can slow stuff down especially on extenders.

[stuckless]

Originally Posted by PLUCKYHD

LoadImage(image) forces them into cache if there is room. On raw images you have to call it twice LoadImage(LoadImage(Image)).

I do it for smm in a forked thread during inactivity definately not something you want to do while the user is active as it can slow stuff down especially on extenders.

Just curious, but what's a "raw" image? And why do you have load it twice? The first LoadImage should return a MetaImage, so I would have thought that calling LoadImage on a MetaImage would do nothing.

[Opus4]

Check the docs for LoadImage() again -- the 2nd call loads the image in to the image cache. The default STV does quite a bit of double calls like that too.

- Andy

[PLUCKYHD]

Yup what Andy said you have to call it twice to load it into cache took me a while to figure that out as well.

[stuckless]

Originally Posted by Opus4

Check the docs for LoadImage() again -- the 2nd call loads the image in to the image cache. The default STV does quite a bit of double calls like that too.

- Andy

Originally Posted by PLUCKYHD

Yup what Andy said you have to call it twice to load it into cache took me a while to figure that out as well.

That's cool. That answers another question that I had outstanding about the LoadImage api. (I guess I should have checked the JavaDoc )

[evilpenguin]

Sorry to bring this back up, but i'm still not getting great performance on my HD300 (Client seems to be working fine).

So i've got a table that displays 5 posters on the screen at a time (w/background loading) in addition to a preloading thread running in the background. As I understand it, it should work this way...

1. On MenuLoad the rendering thread will start he 5 visible posters loading in the background and they'll pop up on the sceen whenever their ready.
2. Left alone, the background thread will run though the posters and run LoadImage(LoadImage()) to pre-caches them.
3. With the images pre-cached they should be already visible when they're scrolled onto the screen.

I've verified in the logs that the background preloading thread is working and running LoadImage(LoadImage()) on all of the posters, but when I scroll around the list the posters still seem like they're only geting cached once they become visible for the first time. Of coarse once i've scrolled through the list and all the posters have been visible once, everything is fast and smooth, but I thought that pre-loading the images would accomplish that on its own

[bialio]

That matches my experience exactly - in the 'Grid' view in phoenix when I do a LoadImage(LoadImage()) call I don't see a speed increase. Only after it's visible does it flow smoothly.

btl.

[evilpenguin]

Think I got it, I turned off background loading in the image widget and now its working like I expect it to. Granted this caused the scrolling to pause whenever it gets to an image that isn't pre-loaded but I think that's fixable too.

I'm thinking about trying two things...

1) In the rendering chain use IsImageLoaded() to conditionally enable background loading in the image widget.
2) Only show images that have been pre-loaded in the rendering chain and call Refresh() from the background thread when images are loaded.

[PLUCKYHD]

Correct background loading must be off or they will still be loaded in the background regardless of wether or not they are cached I have found you can preload about 100 posters on a hd300 without overloading it. and makes a huge speed difference.

Also I wouldn't do it that way EP calling refresh is going to make it even slower experience and isn't needed. Keep in mind with BG loading off if they scroll to a page that isn't cached the scrolling won't happen until the images are loaded.

[jaminben]

Probably a silly question but I'll ask anyway like I always do

Is there a way to tell how much space is left in the cache so you could carry on pre-loading images to the maximum?