/*
 
 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:	1.0
 
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 Inc. ("Apple") in consideration of your agreement to the
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 install, modify or redistribute this Apple software.
 
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 "Apple Software"), to use, reproduce, modify and redistribute the Apple
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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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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