最近在開(kāi)發(fā)中遇到一個(gè)自定義色值的需求眷蜈，界面如下：

效果圖

概述部分

1. HSV（六角錐形體模型）：

H - 色調(diào)
S - 飽和度
V - 明度
電視驶忌、顯示器顯示的顏色模式。

2. 確定HSV后惕耕，效果圖功能：

· 色相（下半部分）- hue

色相

· 色板（上半部分）- sat备闲、val

看成坐標(biāo)系的話晌端，
S = 1, V = 1原色，純色
S = 0, V = x顏色最淺恬砂，被描述為灰色（即為黑白兩色）咧纠，H無(wú)意義。
V = 0, S = x顏色都是黑色泻骤，無(wú)亮度漆羔，H、S均無(wú)意義狱掂。

色板

代碼部分

1. 下邊這段代碼是：已知RGB換算出HSV演痒，進(jìn)而在效果圖中確定選中點(diǎn)。
此處說(shuō)明下符欠，剛開(kāi)始使用了系統(tǒng)API嫡霞，得到的hsv值有問(wèn)題，所以使用了自定義獲取方法希柿，使用后OK诊沪。

//系統(tǒng)
- (BOOL)getHue:(nullable CGFloat *)hue saturation:(nullable CGFloat *)saturation brightness:(nullable CGFloat *)brightness alpha:(nullable CGFloat *)alpha API_AVAILABLE(ios(5.0));

// 自定義： rgb -> hsv
- (MyHSV)getHSVWithRGB:(MyColor)color{
    MyHSV hsv;
    CGFloat var_R = (color.r/255.0);                     //RGB from 0 to 255
    CGFloat var_G = (color.g/255.0);
    CGFloat var_B = (color.b/255.0);

    CGFloat var_Min = MIN(var_R, MIN(var_G, var_B));    //Min. value of RGB
    CGFloat var_Max = MAX(var_R, MAX(var_G, var_B));  //Max. value of RGB
    CGFloat del_Max = var_Max - var_Min;             //Delta RGB value

    hsv.v = var_Max;

    if ( del_Max == 0 ){                     //This is a gray, no chroma...{
        hsv.h = 0;                                //HSV results from 0 to 1
        hsv.s = 0;
    }else{                                    //Chromatic data...
    
        hsv.s = del_Max / var_Max;

        CGFloat del_R = ( ( ( var_Max - var_R ) / 6.0 ) + ( del_Max / 2.0 ) ) / del_Max;
        CGFloat del_G = ( ( ( var_Max - var_G ) / 6.0 ) + ( del_Max / 2.0 ) ) / del_Max;
        CGFloat del_B = ( ( ( var_Max - var_B ) / 6.0 ) + ( del_Max / 2.0 ) ) / del_Max;

        if( var_R == var_Max ){
            hsv.h = del_B - del_G;
        }else if ( var_G == var_Max ){
            hsv.h = ( 1 / 3.0 ) + del_R - del_B;
        }else if (var_B == var_Max) {
            hsv.h = ( 2 / 3.0 ) + del_G - del_R;
        }

        if ( hsv.h < 0 )  {
            hsv.h += 1;
        }else if (hsv.h > 1){
            hsv.h -= 1;
        }
    }
    return hsv;
}

2. 下邊兩段代碼是根據(jù)色相、色板（hsv）確定RGB
色相（顏色條）手勢(shì)

- (void)touchBarWithPoint:(CGPoint)point flag:(short)flag{
    //改變指示器位置
    CGRect frame = self.barPoint.frame;
    frame.origin.x = point.x - 7;
    self.barPoint.frame = frame;
    
    //顏色計(jì)算器部分
    int r,g,b;
    int n = 1530 * [self check: point.x / self.colorBar.frame.size.width];
    //初始化顏色顯示（1曾撤，0端姚， 0）- > (1, 0, 1) - > (0, 0, 1) - > (0, 1, 1) - > (0, 1, 0) - > (1, 1, 0) - > (1, 0, 0)
    switch (n/255) {
        case 0: r = 255; g = 0; b = n; break;
        case 1: r = 255 - (n % 255); g = 0; b = 255; break;
        case 2: r = 0; g = n % 255; b = 255; break;
        case 3: r = 0; g = 255; b = 255 - (n % 255); break;
        case 4: r = n % 255; g = 255; b = 0; break;
        case 5: r = 255; g = 255 - (n % 255); b = 0; break;
        default: r = 255; g = 0; b = 0; break;
    }
         
    self.colora = [self setMyColorWithR:r G:g B:b A:1];
    self.brightImageView.backgroundColor = [self transformMyColorToUIColor:self.colora];
    [self touchBrightWithPoint:CGPointMake(0, 0) flag:-1];
}

色板手勢(shì)

- (void)touchBrightWithPoint:(CGPoint)point flag:(short)flag{
   if(flag == -1)
   {
       point = self.brightPoint.frame.origin;
       point.x += 7;
       point.y += 7;
   }
   //改變指示器位置
   CGRect frame = self.brightPoint.frame;
   frame.origin.x = point.x - 7;
   frame.origin.y = point.y - 7;
   self.brightPoint.frame = frame;
   
   int r,g,b;
   double xrate = [self check: point.x / self.brightImageView.frame.size.width];
   double yrate = 1 - [self check: point.y / self.brightImageView.frame.size.height];
   
   // sv圖 - 左側(cè)焦點(diǎn)
   MyColor tempa = [self setMyColorWithR:255 * yrate G:255 * yrate B:255 * yrate A:1];
   
   r = self.colora.r * yrate;
   g = self.colora.g * yrate;
   b = self.colora.b * yrate;
   // sv圖 - 右側(cè)焦點(diǎn)
   MyColor tempb = [self setMyColorWithR:r G:g B:b A:1];
   r = tempb.r + (1 - xrate) * (tempa.r - tempb.r);
   g = tempb.g + (1 - xrate) * (tempa.g - tempb.g);
   b = tempb.b + (1 - xrate) * (tempa.b - tempb.b);
   MyColor tempColor = [self setMyColorWithR:r G:g B:b A:1];
   NSString *xColor = [NSString stringWithFormat:@"#%02x%02x%02x", tempColor.r, tempColor.g, tempColor.b];
   if ([xColor isKindOfClass:[NSString class]]) {
       [self.valueLabel showColor:xColor.uppercaseString];
       if (_tempBlock) {
           if (_selAlpha < 1) {
               _tempBlock([CommUtls getRGBAcolorWithHexString:xColor colorAlpha:_selAlpha]);
           }else{
               _tempBlock(xColor);
           }
       }
   }
}