/*

     File: TargetView.m 

 Abstract: A simple NSImageView subclass that draws little green circles where the user clicks on top of the image.

  Version: 1.1 

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 */

#import "TargetView.h"

@implementation TargetView

- (id)initWithFrame:(NSRect)frame {

    self = [super initWithFrame:frame];

    if (self) {

        self.image = [NSImage imageNamed:@"bullseye"];

        [self setAutoresizingMask: (NSViewMinYMargin | NSViewMinXMargin)];

    }

    return self;

}

- (void)dealloc {

    [_path release];

    [super dealloc];

}

#pragma mark NSResponder

- (void)mouseDown:(NSEvent *)event {

    // We use an NSBezierPath to store and draw the clicked points. We create it lazily on the first click in the view.

    if (!_path){

        _path = [[NSBezierPath bezierPath] retain];

    }

    // Convert the clicked point into the views coordinate space and add the green circle to the bezierPath. Any point within the bounds of the view is considered a hit.

    NSPoint cursorLocation = [event locationInWindow];

    cursorLocation = [self convertPoint:cursorLocation fromView:nil];

    // Test if the hit occured in the opaque part of the image.  We create a 1x1 rectange at the click point and test for intersection with a non-transparent section of the image.

    NSRect cursorLocationRect = { cursorLocation, {1, 1} };

    if ( [self.image hitTestRect:cursorLocationRect withImageDestinationRect:self.bounds 

                       context:nil hints:nil flipped:NO] == NO ) {

        // If the click missed then we ignore it here.

        [super mouseDown:event];

        return;

    }

    static const CGFloat kHoleRadius = 6.0f;

    CGFloat kHoleDiameter = kHoleRadius * 2.0f;

    NSRect holeFrame = NSMakeRect(cursorLocation.x - kHoleRadius, cursorLocation.y - kHoleRadius, kHoleDiameter, kHoleDiameter);

    [_path appendBezierPath:[NSBezierPath bezierPathWithOvalInRect:holeFrame]];

    [self setNeedsDisplayInRect:holeFrame];

}

#pragma mark NSView

- (void)drawRect:(NSRect)dirtyRect {

    // Let super handle drawing of the image.

    [super drawRect:dirtyRect];

    // All we need to draw are the green circles where the user clicked.

    [[NSColor greenColor] set];

    [_path fill];

}

@end