return a GaussianBlured NSImage

NSImage+Blur.h

//
//  NSImage+Blur.h
//  BlurView
//
//  Created by 61 on 13-11-19.
//  Copyright (c) 2013年 61. All rights reserved.
//

#import <Cocoa/Cocoa.h>

@interface NSImage (Blur)
- (NSImage *)gaussianBlurOfRadius:(CGFloat)radius;
@end

NSImage+Blur.m

//
//  NSImage+Blur.m
//  BlurView
//
//  Created by 61 on 13-11-19.
//  Copyright (c) 2013年 61. All rights reserved.
//

#import <QuartzCore/QuartzCore.h>
#import "NSImage+Blur.h"


@implementation NSImage (Blur)
- (NSImage *)gaussianBlurOfRadius:(CGFloat)radius
{
    NSScreen *mainScreen = [NSScreen mainScreen];
    NSRect screenFrame = mainScreen.frame;
    NSImage *image = [self scaleToSize:screenFrame.size];
    
    [image lockFocus];
    CIImage *beginImage = [[CIImage alloc] initWithData:[image TIFFRepresentation]];
    CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur" keysAndValues:kCIInputImageKey, beginImage, @"inputRadius", @(radius), nil];
    CIImage *output = [filter valueForKey:@"outputImage"];
    NSRect rect = NSMakeRect(0, 0, NSWidth(screenFrame), NSHeight(screenFrame));
    NSRect sourceRect = NSMakeRect(0, 0, self.size.width, self.size.height);
    [output drawInRect:rect fromRect:sourceRect operation:NSCompositeSourceOver fraction:1.0];
    [image unlockFocus];
    
    return image;
}
@end

No visible @interface for 'NSImage' declares the selector 'scaleToSize:'