/*

     File: TiledImageView.m 

 Abstract: View backed by CATiledLayer which is good for particularly large views. 

  Version: 1.1 

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*/

#import "TiledImageView.h"

#import <QuartzCore/QuartzCore.h>

@implementation TiledImageView

@synthesize image;

// Set the layer's class to be CATiledLayer.

+ (Class)layerClass {

    return [CATiledLayer class];

}

- (void)dealloc {

    [image release];

    //--

    [super dealloc];

}

// Create a new TiledImageView with the desired frame and scale.

-(id)initWithFrame:(CGRect)_frame image:(UIImage*)img scale:(CGFloat)scale {

    if ((self = [super initWithFrame:_frame])) {

        self.image = img;

        imageRect = CGRectMake(0.0f, 0.0f, CGImageGetWidth(image.CGImage), CGImageGetHeight(image.CGImage));

        imageScale = scale;

        CATiledLayer *tiledLayer = (CATiledLayer *)[self layer];

        // levelsOfDetail and levelsOfDetailBias determine how

        // the layer is rendered at different zoom levels.  This

        // only matters while the view is zooming, since once the 

        // the view is done zooming a new TiledImageView is created

        // at the correct size and scale.

        tiledLayer.levelsOfDetail = 4;

        tiledLayer.levelsOfDetailBias = 4;

        tiledLayer.tileSize = CGSizeMake(512.0, 512.0); 

    }

    return self;

}

-(void)drawRect:(CGRect)rect {

    CGContextRef context = UIGraphicsGetCurrentContext();    

    CGContextSaveGState(context);

    // Scale the context so that the image is rendered 

    // at the correct size for the zoom level.

    CGContextScaleCTM(context, imageScale,imageScale);  

    CGContextDrawImage(context, imageRect, image.CGImage);

    CGContextRestoreGState(context);    

}

@end