/*

 File:      ImageBrowserBackgroundLayer.m

 Abstract:  IKImageBrowserView is a view that can display and browse a 

 large amount of images and movies. This sample code demonstrates 

 how to use the view in a Cocoa Application.

 Version:   1.1

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

 Inc. ("Apple") in consideration of your agreement to the

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 license, under Apple's copyrights in this original Apple software (the

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 text and disclaimers in all such redistributions of the Apple Software. 

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 may be used to endorse or promote products derived from the Apple

 Software without specific prior written permission from Apple.  Except

 as expressly stated in this notice, no other rights or licenses, express

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 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

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 */

#import "ImageBrowserBackgroundLayer.h"

#import "Utilities.h"

static CGImageRef backgroundImage()

{

    static CGImageRef image = NULL;

    if(image == NULL)

        image = createImageWithName(@"metal_background.tif");

    return image;

}

@implementation ImageBrowserBackgroundLayer

@synthesize owner;

// -------------------------------------------------------------------------

//  init

// -------------------------------------------------------------------------

- (id) init

{

    if((self = [super init])){

        //needs to redraw when bounds change

        [self setNeedsDisplayOnBoundsChange:YES];

    }

    return self;

}

// -------------------------------------------------------------------------

//  actionForKey:

//

// always return nil, to never animate

// -------------------------------------------------------------------------

- (id<CAAction>)actionForKey:(NSString *)event

{

    return nil;

}

// -------------------------------------------------------------------------

//  drawInContext:

//

// draw a metal background that scrolls when the image browser scroll

// -------------------------------------------------------------------------

- (void)drawInContext:(CGContextRef)context

{

    //retreive bounds and visible rect

    NSRect visibleRect = [owner visibleRect];

    NSRect bounds = [owner bounds];

    //retreive background image

    CGImageRef image = backgroundImage();

    float width = (float) CGImageGetWidth(image);

    float height = (float) CGImageGetHeight(image);

    //compute coordinates to fill the view

    float left, top, right, bottom;

    top = bounds.size.height - NSMaxY(visibleRect);

    top = fmod(top, height);

    top = height - top;

    right = NSMaxX(visibleRect);

    bottom = -height;

    // tile the image and take in account the offset to 'emulate' a scrolling background

    for (top = visibleRect.size.height-top; top>bottom; top -= height){

        for(left=0; left<right; left+=width){

            CGContextDrawImage(context, CGRectMake(left, top, width, height), image);

        }

    }

}

@end