/*

    Copyright (C) 2015 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This is the "SlideCarrierView" class implementation.

*/

#import "AAPLSlideImageView.h"

@implementation AAPLSlideImageView

// Fill in semitransparent gray bands in any areas that the image doesn't cover, to give a more slide-like appearance.

- (void)drawRect:(NSRect)rect {

    NSImage *image = [self image];

    if (image != nil && [self imageScaling] == NSImageScaleProportionallyUpOrDown) {

        NSSize imageSize = [image size];

        NSSize viewSize = [self bounds].size;

        if (imageSize.height > 0.0 && viewSize.height > 0.0) {

            CGFloat imageAspectRatio = imageSize.width / imageSize.height;

            CGFloat viewAspectRatio = viewSize.width / viewSize.height;

            [[NSColor colorWithCalibratedWhite:0.0 alpha:0.2] set];

            if (imageAspectRatio > viewAspectRatio) {

                // Fill in bands at top and bottom.

                CGFloat thumbnailHeight = viewSize.width / imageAspectRatio;

                CGFloat bandHeight = 0.5 * (viewSize.height - thumbnailHeight);

                NSRectFillUsingOperation(NSMakeRect(0, 0, viewSize.width, bandHeight), NSCompositeSourceOver);

                NSRectFillUsingOperation(NSMakeRect(0, viewSize.height - bandHeight, viewSize.width, bandHeight), NSCompositeSourceOver);

            } else if (imageAspectRatio < viewAspectRatio) {

                // Fill in bands at left and right.

                CGFloat thumbnailWidth = viewSize.height * imageAspectRatio;

                CGFloat bandWidth = 0.5 * (viewSize.width - thumbnailWidth);

                NSRectFillUsingOperation(NSMakeRect(0, 0, bandWidth, viewSize.height), NSCompositeSourceOver);

                NSRectFillUsingOperation(NSMakeRect(viewSize.width - bandWidth, 0, bandWidth, viewSize.height), NSCompositeSourceOver);

            }

        }

    }

    // Now let NSImageView do its drawing.

    [super drawRect:rect];

}

@end