TTPhotoViewController - pre-load imagines in background?

[Bill]

Is there any way to make the TTPhotoViewController load pictures in
the background? I've gotten a couple complaints that when viewing
picture galleries that it takes too long for the high resolution
pictures to load.

When you launch the gallery you're presented with the thumbnail then
after a couple of seconds the image changes to the higher resolution
image. Is there a way to continue loading pictures in the background
so when someone flips to the next picture it's clear right away?

Many Thanx!

[AhmadTK]

hello Bill have you found any solution for this?

[Yoshi Sugawara]

This is actually quite simple - in the photo view controller, maybe in viewWillAppear, make a TTURLRequest to the upcoming photos in the photo source. 

You might need to adjust the image cache size in TTURLCache to cache larger size images. 

I don't have a code example since I'm on my iPhone but the gist of it is you exploit the image caching to preload the images. I have this working on my app. 

Yoshi

Sent from my iPhone

On Jan 16, 2012, at 9:58 PM, AhmadTK <kayyal...@gmail.com> wrote:

hello Bill have you found any solution for this?

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[Yoshi Sugawara]

Here's a code sample:

I subclassed TTPhotoViewController, and overrode the updateChrome method:

-(void) preFetchNextImages:(NSInteger)count {
for (int i = 1; i<=count; i++) {
NSInteger nextIndex = self.centerPhotoIndex + i;
if ( nextIndex >= [[self photoSource] numberOfPhotos] ) {
// we're at the end, stop
return;
}
[self preFetchImageAtIndex:nextIndex];
}
}

-(void) preFetchImageAtIndex:(NSInteger)index {
id<TTPhoto> nextPhoto = [[self photoSource] photoAtIndex:index];
TTDINFO(@"prefetching photo at index: %d file:
%@",index,[nextPhoto URLForVersion:TTPhotoVersionLarge]);
TTURLRequest *request = [TTURLRequest requestWithURL:[nextPhoto
URLForVersion:TTPhotoVersionLarge] delegate:self];
request.response = [[[TTURLImageResponse alloc] init] autorelease];
[request send];
}

- (void)updateChrome {
[super updateChrome];
TTDINFO(@"update chrome called: prefetching next image");
NSInteger numberOfImagesToPrefetch = 5;
[self preFetchNextImages:numberOfImagesToPrefetch];
// just for my debug purposes
[[TTURLCache sharedCache] logMemoryUsage];
}

I locally modified TTURLCache to adjust the kLargeImageSize constant
to cache larger images:
static const CGFloat kLargeImageSize = 2048 * 2048;

There are better ways to do the above override but alas, I am lazy :)

Hope that helps,
Yoshi

[Ahmad Kayyali]

Thank you Yoshi I am going to try that right now.