ios ColorLUT滤镜

通过这种方格图片实现滤镜

代码：

"CIFilter+ColorLUT.h"

"CIFilter+ColorLUT.m"

#import "CIFilter+ColorLUT.h"

#import <CoreImage/CoreImage.h>

#import <OpenGLES/EAGL.h>

@implementation CIFilter (ColorLUT)

+ (CIFilter *)colorCubeWithColorLUTImageNamed:(NSString *)imageName dimension:(NSInteger)n

{

UIImage *image = [UIImage imageNamed:imageName];

int width = CGImageGetWidth(image.CGImage);

int height = CGImageGetHeight(image.CGImage);

int rowNum = height / n;

int columnNum = width / n;

if ((width % n != 0) || (height % n != 0) || (rowNum * columnNum != n))

{

NSLog(@"Invalid colorLUT");

return nil;

}

unsigned char *bitmap = [self createRGBABitmapFromImage:image.CGImage];

if (bitmap == NULL)

{

return nil;

}

int size = n * n * n * sizeof(float) * 4;

float *data = malloc(size);

int bitmapOffest = 0;

int z = 0;

for (int row = 0; row <  rowNum; row++)

{

for (int y = 0; y < n; y++)

{

int tmp = z;

for (int col = 0; col < columnNum; col++)

{

for (int x = 0; x < n; x++) {

float r = (unsigned int)bitmap[bitmapOffest];

float g = (unsigned int)bitmap[bitmapOffest + 1];

float b = (unsigned int)bitmap[bitmapOffest + 2];

float a = (unsigned int)bitmap[bitmapOffest + 3];

int dataOffset = (z*n*n + y*n + x) * 4;

data[dataOffset] = r / 255.0;

data[dataOffset + 1] = g / 255.0;

data[dataOffset + 2] = b / 255.0;

data[dataOffset + 3] = a / 255.0;

bitmapOffest += 4;

}

z++;

}

z = tmp;

}

z += columnNum;

}

free(bitmap);

CIFilter *filter = [CIFilter filterWithName:@"CIColorCube"];

[filter setValue:[NSData dataWithBytesNoCopy:data length:size freeWhenDone:YES] forKey:@"inputCubeData"];

[filter setValue:[NSNumber numberWithInteger:n] forKey:@"inputCubeDimension"];

return filter;

}

+ (unsigned char *)createRGBABitmapFromImage:(CGImageRef)image

{

CGContextRef context = NULL;

CGColorSpaceRef colorSpace;

unsigned char *bitmap;

int bitmapSize;

int bytesPerRow;

size_t width = CGImageGetWidth(image);

size_t height = CGImageGetHeight(image);

bytesPerRow   = (width * 4);

bitmapSize     = (bytesPerRow * height);

bitmap = malloc( bitmapSize );

if (bitmap == NULL)

{

return NULL;

}

colorSpace = CGColorSpaceCreateDeviceRGB();

if (colorSpace == NULL)

{

free(bitmap);

return NULL;

}

context = CGBitmapContextCreate (bitmap,

width,

height,

8,

bytesPerRow,

colorSpace,

kCGImageAlphaPremultipliedLast);

CGColorSpaceRelease( colorSpace );

if (context == NULL)

{

free (bitmap);

}

CGContextDrawImage(context, CGRectMake(0, 0, width, height), image);

CGContextRelease(context);

return bitmap;

}

调用时生成使用图片

CIFilter *colorCube = [CIFilter colorCubeWithColorLUTImageNamed:@"方块图片"dimension:64];

CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"选择的照片"]];

[colorCube setValue:inputImage forKey:@"inputImage"];

CIImage *outputImage = [colorCube outputImage];

CIContext *context = [CIContext contextWithOptions:[NSDictionary dictionaryWithObject:(__bridge id)(CGColorSpaceCreateDeviceRGB()) forKey:kCIContextWorkingColorSpace]];

UIImage *newImage = [UIImage imageWithCGImage:[context createCGImage:outputImage fromRect:outputImage.extent]];

生成后的的滤镜图片newImage