space-ios/Libraries external/NYXImagesKit/Categories/UIImage+Blurring.m

//
//  UIImage+Blurring.m
//  NYXImagesKit
//
//  Created by @Nyx0uf on 03/06/11.
//  Copyright 2012 Nyx0uf. All rights reserved.
//  www.cocoaintheshell.com
//


#import "UIImage+Blurring.h"
#import <Accelerate/Accelerate.h>


static int16_t __s_gaussianblur_kernel_5x5[25] = {
	1, 4, 6, 4, 1, 
	4, 16, 24, 16, 4,
	6, 24, 36, 24, 6,
	4, 16, 24, 16, 4,
	1, 4, 6, 4, 1
};


@implementation UIImage (NYX_Blurring)

-(UIImage*)gaussianBlurWithBias:(NSInteger)bias
{
	/// Create an ARGB bitmap context
	const size_t width = (size_t)self.size.width;
	const size_t height = (size_t)self.size.height;
	const size_t bytesPerRow = width * kNyxNumberOfComponentsPerARBGPixel;
	CGContextRef bmContext = NYXCreateARGBBitmapContext(width, height, bytesPerRow);
	if (!bmContext) 
		return nil;

	/// Draw the image in the bitmap context
	CGContextDrawImage(bmContext, (CGRect){.origin.x = 0.0f, .origin.y = 0.0f, .size.width = width, .size.height = height}, self.CGImage); 

	/// Grab the image raw data
	UInt8* data = (UInt8*)CGBitmapContextGetData(bmContext);
	if (!data)
	{
		CGContextRelease(bmContext);
		return nil;
	}

	const size_t n = sizeof(UInt8) * width * height * 4;
	void* outt = malloc(n);
	vImage_Buffer src = {data, height, width, bytesPerRow};
	vImage_Buffer dest = {outt, height, width, bytesPerRow};
	vImageConvolveWithBias_ARGB8888(&src, &dest, NULL, 0, 0, __s_gaussianblur_kernel_5x5, 5, 5, 256/*divisor*/, (int)bias, NULL, kvImageCopyInPlace);
	memcpy(data, outt, n);
	free(outt);

	CGImageRef blurredImageRef = CGBitmapContextCreateImage(bmContext);
	UIImage* blurred = [UIImage imageWithCGImage:blurredImageRef];

	/// Cleanup
	CGImageRelease(blurredImageRef);
	CGContextRelease(bmContext);

	return blurred;
}

@end