iOS去除图片背景颜色的方法

- (UIImage *)removeColorWithMinHueAngle:(float)minHueAngle maxHueAngle:(float)maxHueAngle image:(UIImage *)originalImage{
 CIImage *image = [CIImage imageWithCGImage:originalImage.CGImage];
 CIContext *cOntext= [CIContext contextWithOptions:nil];// kCIContextUseSoftwareRenderer : CPURender
 /** 注意
 * UIImage 通过CIimage初始化，得到的并不是一个通过类似CGImage的标准UIImage
 * 所以如果不用context进行渲染处理，是没办法正常显示的
 */
 CIImage *renderBgImage = [self outputImageWithOriginalCIImage:image minHueAngle:minHueAngle maxHueAngle:maxHueAngle];
 CGImageRef renderImg = [context createCGImage:renderBgImage fromRect:image.extent];
 UIImage *renderImage = [UIImage imageWithCGImage:renderImg];
 return renderImage;
}
struct CubeMap {
 int length;
 float dimension;
 float *data;
};
- (CIImage *)outputImageWithOriginalCIImage:(CIImage *)originalImage minHueAngle:(float)minHueAngle maxHueAngle:(float)maxHueAngle{
 
 struct CubeMap map = createCubeMap(minHueAngle, maxHueAngle);
 const unsigned int size = 64;
 // Create memory with the cube data
 NSData *data = [NSData dataWithBytesNoCopy:map.data
   length:map.length
   freeWhenDone:YES];
 CIFilter *colorCube = [CIFilter filterWithName:@"CIColorCube"];
 [colorCube setValue:@(size) forKey:@"inputCubeDimension"];
 // Set data for cube
 [colorCube setValue:data forKey:@"inputCubeData"];
 
 [colorCube setValue:originalImage forKey:kCIInputImageKey];
 CIImage *result = [colorCube valueForKey:kCIOutputImageKey];
 
 return result;
}
struct CubeMap createCubeMap(float minHueAngle, float maxHueAngle) {
 const unsigned int size = 64;
 struct CubeMap map;
 map.length = size * size * size * sizeof (float) * 4;
 map.dimension = size;
 float *cubeData = (float *)malloc (map.length);
 float rgb[3], hsv[3], *c = cubeData;
 
 for (int z = 0; z  minHueAngle && hsv[0] 

void rgbToHSV(float *rgb, float *hsv) {
 float min, max, delta;
 float r = rgb[0], g = rgb[1], b = rgb[2];
 float *h = hsv, *s = hsv + 1, *v = hsv + 2;
 min = fmin(fmin(r, g), b );
 max = fmax(fmax(r, g), b );
 *v = max;
 delta = max - min;
 if( max != 0 )
 *s = delta / max;
 else {
 *s = 0;
 *h = -1;
 return;
 }
 if( r == max )
 *h = ( g - b ) / delta;
 else if( g == max )
 *h = 2 + ( b - r ) / delta;
 else
 *h = 4 + ( r - g ) / delta;
 *h *= 60;
 if( *h <0 )
 *h += 360;
}

[[SPImageChromaFilterManager sharedManager] removeColorWithMinHueAngle:50 maxHueAngle:170 image:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"nb" ofType:@"jpeg"]]]