UIColor-HSVAdditions.h

//
//  UIColor-HSVAdditions.h
//
//  Created by Matt Reagan (bravobug.com) on 12/31/09.
//  
//

//  Copyright 2010 Fabián Cañas. All rights reserved.
//
//    Redistribution and use in source and binary forms, with or without
//    modification, are permitted provided that the following conditions are met:
//    * Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//    * Neither the name of the <organization> nor the
//    names of its contributors may be used to endorse or promote products
//    derived from this software without specific prior written permission.
//
//    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
//    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
//    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//    DISCLAIMED. IN NO EVENT SHALL FABIAN CANAS BE LIABLE FOR ANY
//    DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
//    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
//     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
//    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
//    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
//    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


#import <UIKit/UIKit.h>

#import "UIColor-Expanded.h"
//  get it here:
//  http://github.com/ars/uicolor-utilities

#define MIN3(x,y,z)  ((y) <= (z) ? \
((x) <= (y) ? (x) : (y)) \
: \
((x) <= (z) ? (x) : (z)))

#define MAX3(x,y,z)  ((y) >= (z) ? \
((x) >= (y) ? (x) : (y)) \
: \
((x) >= (z) ? (x) : (z)))


struct rgb_color {
    CGFloat r, g, b;
};

struct hsv_color {
    CGFloat hue;        
    CGFloat sat;        
    CGFloat val;        
};

@interface UIColor (UIColor_HSVAdditions)

@property (nonatomic, readonly) CGFloat hue; // Only valid if canProvideRGBComponents is YES
@property (nonatomic, readonly) CGFloat saturation; // Only valid if canProvideRGBComponents is YES
@property (nonatomic, readonly) CGFloat brightness; // Only valid if canProvideRGBComponents is YES
@property (nonatomic, readonly) CGFloat value; // (same as brightness, added for naming consistency)


//workhorse method, does conversion:
+(struct hsv_color)HSVfromRGB:(struct rgb_color)rgb;
//individual value accessors:
-(CGFloat)hue;
-(CGFloat)saturation;
-(CGFloat)brightness;
-(CGFloat)value;
@end

UIColor-HSVAdditions.m

//
//  UIColor-HSVAdditions.m
//
//  Created by Matt Reagan (bravobug.com) on 12/31/09.
//
// Released into the public domain
// Original code: http://en.literateprograms.org/RGB_to_HSV_color_space_conversion_%28C%29

//  Copyright 2010 Fabián Cañas. All rights reserved.
//
//    Redistribution and use in source and binary forms, with or without
//    modification, are permitted provided that the following conditions are met:
//    * Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//    * Neither the name of the <organization> nor the
//    names of its contributors may be used to endorse or promote products
//    derived from this software without specific prior written permission.
//
//    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
//    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
//    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//    DISCLAIMED. IN NO EVENT SHALL FABIAN CANAS BE LIABLE FOR ANY
//    DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
//    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
//     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
//    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
//    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
//    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


#import "UIColor-HSVAdditions.h"

@implementation UIColor (UIColor_HSVAdditions)
+(struct hsv_color)HSVfromRGB:(struct rgb_color)rgb
{
	struct hsv_color hsv;

	CGFloat rgb_min, rgb_max;
	rgb_min = MIN3(rgb.r, rgb.g, rgb.b);
	rgb_max = MAX3(rgb.r, rgb.g, rgb.b);

	hsv.val = rgb_max;
	if (hsv.val == 0) {
		hsv.hue = hsv.sat = 0;
		return hsv;
	}

	rgb.r /= hsv.val;
	rgb.g /= hsv.val;
	rgb.b /= hsv.val;
	rgb_min = MIN3(rgb.r, rgb.g, rgb.b);
	rgb_max = MAX3(rgb.r, rgb.g, rgb.b);

	hsv.sat = rgb_max - rgb_min;
	if (hsv.sat == 0) {
		hsv.hue = 0;
		return hsv;
	}

	if (rgb_max == rgb.r) {
		hsv.hue = 0.0 + 60.0*(rgb.g - rgb.b);
		if (hsv.hue < 0.0) {
			hsv.hue += 360.0;
		}
	} else if (rgb_max == rgb.g) {
		hsv.hue = 120.0 + 60.0*(rgb.b - rgb.r);
	} else /* rgb_max == rgb.b */ {
		hsv.hue = 240.0 + 60.0*(rgb.r - rgb.g);
	}

	return hsv;
}
-(CGFloat)hue
{
	struct hsv_color hsv;
	struct rgb_color rgb;
	rgb.r = [self red];
	rgb.g = [self green];
	rgb.b = [self blue];
	hsv = [UIColor HSVfromRGB: rgb];
	return (hsv.hue / 360.0);
}
-(CGFloat)saturation
{
	struct hsv_color hsv;
	struct rgb_color rgb;
	rgb.r = [self red];
	rgb.g = [self green];
	rgb.b = [self blue];
	hsv = [UIColor HSVfromRGB: rgb];
	return hsv.sat;
}
-(CGFloat)brightness
{
	struct hsv_color hsv;
	struct rgb_color rgb;
	rgb.r = [self red];
	rgb.g = [self green];
	rgb.b = [self blue];
	hsv = [UIColor HSVfromRGB: rgb];
	return hsv.val;
}
-(CGFloat)value
{
	return [self brightness];
}
@end