This somewhat related to another post - but that one got kinda messed up - so I start from scratch:
I have a CATiledLayer with a HUGE image in it (5780x6700px).
The tiled layer is in a scrollview. When I start to scroll around, everything's fine up to a point where obviously too many tiles have been rendered. Then I get a memory warning and the app crashes.
I tried to remove the tiledlayer from the view when I get the memory warning, clear it's contents (rootLayer.contents = nil AND tiledLayer.contents = nil) and then re-attach it empty to the view. didn't work...
Would be thankful for any input...
Edit:
Thanks for the hints so far. Some of my assumptions seem to be wrong. I loaded the image in a function and then retained it - which is a contradiction to the CATiledLayer behaviour, I guess. Plus the UIImage imageNamed:
seemed to cause some errors as well.
Now I load the image in drawLayer:(CALayer *) inContentext(CGContextRef) ctx
and use UIImage imageWithContentsOfFile:
to load it.
This seems to work without causing the memory to go low.
However - the tiles are drawn painfully slow :(
Here's my setup for the tiledLayer:
-(CATiledLayer *)initTiledLayers: (int)level{
//[tiledLayer release];
CGRect pageRect;
CATiledLayer *myLayer = [CATiledLayer layer];
myLayer.delegate = self;
if(level == 1){
pageRect = CGRectMake(0, 0, 690, 800);
myLayer.tileSize = CGSizeMake(800, 800);
myLayer.levelsOfDetail = 10;
myLayer.levelsOfDetailBias = 2;
}else if(level == 2){
pageRect = CGRectMake(0, 0, 1445, 1675);
myLayer.tileSize = CGSizeMake(600, 600);
myLayer.levelsOfDetail = 8;
myLayer.levelsOfDetailBias = 2;
}else if(level == 3){
pageRect = CGRectMake(0, 0, 2890, 3350);
myLayer.tileSize = CGSizeMake(400, 400);
myLayer.levelsOfDetail = 4;
myLayer.levelsOfDetailBias = 1;
}else if(level == 4){
pageRect = CGRectMake(0, 0, 5780, 6700);
myLayer.tileSize = CGSizeMake(150, 150);
myLayer.levelsOfDetail = 4;
myLayer.levelsOfDetailBias = 0;
}
myLayer.frame = pageRect;
return myLayer;
[myLayer release];
}
(int)level indicates which image to be used (I'm switching images on certain zoom-levels). Level4 is the biggest image...
And here's the drawLayer-function:
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx
{
CGContextSetRGBFillColor(ctx, 1.0, 1.0, 1.0, 1.0);
CGContextFillRect(ctx, CGContextGetClipBoundingBox(ctx));
CGContextTranslateCTM(ctx, 0.0, layer.bounds.size.height);
CGContextClearRect(ctx, CGRectMake(0,0,layer.bounds.size.width, layer.bounds.size.height));
CGContextScaleCTM(ctx, 1.0, -1.0);
UIImage *map = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"Karte0%d", actLevel] ofType:@"jpg"]];
UIImage *wanderwege = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"Karte0%d_wanderwege", actLevel] ofType:@"png"]];
UIImage *rhb = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"Karte0%d_rhb", actLevel] ofType:@"png"]];
UIImage *abstecher = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"Karte0%d_abstecher", actLevel] ofType:@"png"]];
CGRect imageRect = CGRectMake (0.0, 0.0, map.size.width, map.size.height);
CGContextDrawImage (ctx, imageRect, [map CGImage]);
imageRect = CGRectMake (0.0, 0.0, wanderwege.size.width, wanderwege.size.height);
CGContextDrawImage (ctx, imageRect, [wanderwege CGImage]);
imageRect = CGRectMake (0.0, 0.0, rhb.size.width, rhb.size.height);
CGContextDrawImage (ctx, imageRect, [rhb CGImage]);
imageRect = CGRectMake (0.0, 0.0, abstecher.size.width, abstecher.size.height);
CGContextDrawImage (ctx, imageRect, [abstecher CGImage]);
}
Yeah - I know - I actually draw 4 images into the context. The PNGs are overlays which I need to dynamically add to the main-image...
I tried to merge the images into one - but this seems to be even more mem/cpu-consuming ;)
Any further help is greatly appreciated!