几种颜色模型的转换公式
XYZ —> RGB
var_X = X / 100 //X from 0 to 95.047
var_Y = Y / 100 //Y from 0 to 100.000
var_Z = Z / 100 //Z from 0 to 108.883
var_R = var_X * 3.2406 + var_Y * -1.5372 + var_Z * -0.4986
var_G = var_X * -0.9689 + var_Y * 1.8758 + var_Z * 0.0415
var_B = var_X * 0.0557 + var_Y * -0.2040 + var_Z * 1.0570
if ( var_R > 0.0031308 ) var_R = 1.055 * ( var_R ^ ( 1 / 2.4 ) ) - 0.055
else var_R = 12.92 * var_R
if ( var_G > 0.0031308 ) var_G = 1.055 * ( var_G ^ ( 1 / 2.4 ) ) - 0.055
else var_G = 12.92 * var_G
if ( var_B > 0.0031308 ) var_B = 1.055 * ( var_B ^ ( 1 / 2.4 ) ) - 0.055
else var_B = 12.92 * var_B
R = var_R * 255
G = var_G * 255
B = var_B * 255
RGB —> XYZ
var_R = ( R / 255 ) //R from 0 to 255
var_G = ( G / 255 ) //G from 0 to 255
var_B = ( B / 255 ) //B from 0 to 255
if ( var_R > 0.04045 ) var_R = ( ( var_R + 0.055 ) / 1.055 ) ^ 2.4
else var_R = var_R / 12.92
if ( var_G > 0.04045 ) var_G = ( ( var_G + 0.055 ) / 1.055 ) ^ 2.4
else var_G = var_G / 12.92
if ( var_B > 0.04045 ) var_B = ( ( var_B + 0.055 ) / 1.055 ) ^ 2.4
else var_B = var_B / 12.92
var_R = var_R * 100
var_G = var_G * 100
var_B = var_B * 100
X = var_R * 0.4124 + var_G * 0.3576 + var_B * 0.1805
Y = var_R * 0.2126 + var_G * 0.7152 + var_B * 0.0722
Z = var_R * 0.0193 + var_G * 0.1192 + var_B * 0.9505
XYZ —> Yxy
//X from 0 to 95.047
//Y from 0 to 100.000
//Z from 0 to 108.883
Y = Y
x = X / ( X + Y + Z )
y = Y / ( X + Y + Z )
Yxy —> XYZ
//Y from 0 to 100
//x from 0 to 1
//y from 0 to 1
X = x * ( Y / y )
Y = Y
Z = ( 1 - x - y ) * ( Y / y )
XYZ —> Hunter-Lab
(H)L = 10 * sqrt( Y )
(H)a = 17.5 * ( ( ( 1.02 * X ) - Y ) / sqrt( Y ) )
(H)b = 7 * ( ( Y - ( 0.847 * Z ) ) / sqrt( Y ) )
Hunter-Lab —> XYZ
var_Y = (H)L / 10
var_X = (H)a / 17.5 * (H)L / 10
var_Z = (H)b / 7 * (H)L / 10
Y = var_Y ^ 2
X = ( var_X + Y ) / 1.02
Z = -( var_Z - Y ) / 0.847
XYZ —> CIE-L*ab
var_X = X / ref_X //ref_X = 95.047
var_Y = Y / ref_Y //ref_Y = 100.000
var_Z = Z / ref_Z //ref_Z = 108.883
if ( var_X > 0.008856 ) var_X = var_X ^ ( 1/3 )
else var_X = ( 7.787 * var_X ) + ( 16 / 116 )
if ( var_Y > 0.008856 ) var_Y = var_Y ^ ( 1/3 )
else var_Y = ( 7.787 * var_Y ) + ( 16 / 116 )
if ( var_Z > 0.008856 ) var_Z = var_Z ^ ( 1/3 )
else var_Z = ( 7.787 * var_Z ) + ( 16 / 116 )
CIE-L* = ( 116 * var_Y ) - 16
CIE-a* = 500 * ( var_X - var_Y )
CIE-b* = 200 * ( var_Y - var_Z )
CIE-L*ab —> XYZ
var_Y = ( CIE-L* + 16 ) / 116
var_X = CIE-a* / 500 + var_Y
var_Z = var_Y - CIE-b* / 200
if ( var_Y^3 > 0.008856 ) var_Y = var_Y^3
else var_Y = ( var_Y - 16 / 116 ) / 7.787
if ( var_X^3 > 0.008856 ) var_X = var_X^3
else var_X = ( var_X - 16 / 116 ) / 7.787
if ( var_Z^3 > 0.008856 ) var_Z = var_Z^3
else var_Z = ( var_Z - 16 / 116 ) / 7.787
X = ref_X * var_X //ref_X = 95.047
Y = ref_Y * var_Y //ref_Y = 100.000
Z = ref_Z * var_Z //ref_Z = 108.883
CIE-L*ab —> CIE-L*CH°
var_H = arc_tangent( CIE-b*, CIE-a* ) //Quadrant by signs
if ( var_H > 0 ) var_H = ( var_H / PI ) * 180
else var_H = 360 - ( abs( var_H ) / PI ) * 180
CIE-L* = CIE-L*
CIE-C* = sqrt( CIE-a* ^ 2 + CIE-b* ^ 2 )
CIE-H° = var_H
CIE-L*CH° —>CIE-L*ab
//CIE-H° from 0 to 360°
CIE-L* = CIE-L*
CIE-a* = cos( degree_2_radian( CIE-H° ) ) * CIE-C*
CIE-b* = sin( degree_2_radian( CIE-H° ) ) * CIE-C*
XYZ —> CIE-L*uv
var_U = ( 4 * X ) / ( X + ( 15 * Y ) + ( 3 * Z ) )
var_V = ( 9 * Y ) / ( X + ( 15 * Y ) + ( 3 * Z ) )
var_Y = Y / 100
if ( var_Y > 0.008856 ) var_Y = var_Y ^ ( 1/3 )
else var_Y = ( 7.787 * var_Y ) + ( 16 / 116 )
ref_X = 95.047
ref_Y = 100.000
ref_Z = 108.883
ref_U = ( 4 * ref_X ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) )
ref_V = ( 9 * ref_Y ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) )
CIE-L* = ( 116 * var_Y ) - 16
CIE-u* = 13 * CIE-L* * ( var_U - ref_U )
CIE-v* = 13 * CIE-L* * ( var_V - ref_V )
CIE-L*uv —> XYZ
var_Y = ( CIE-L* + 16 ) / 116
if ( var_Y^3 > 0.008856 ) var_Y = var_Y^3
else var_Y = ( var_Y - 16 / 116 ) / 7.787
ref_X = 95.047
ref_Y = 100.000
ref_Z = 108.883
ref_U = ( 4 * ref_X ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) )
ref_V = ( 9 * ref_Y ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) )
var_U = CIE-u* / ( 13 * CIE-L* ) + ref_U
var_V = CIE-v* / ( 13 * CIE-L* ) + ref_V
Y = var_Y * 100
X = - ( 9 * Y * var_U ) / ( ( var_U - 4 ) * var_V - var_U * var_V )
Z = ( 9 * Y - ( 15 * var_V * Y ) - ( var_V * X ) ) / ( 3 * var_V )
RGB —> HSL
var_R = ( R / 255 ) //RGB from 0 to 255
var_G = ( G / 255 )
var_B = ( B / 255 )
var_Min = min( var_R, var_G, var_B ) //Min. value of RGB
var_Max = max( var_R, var_G, var_B ) //Max. value of RGB
del_Max = var_Max - var_Min //Delta RGB value
L = ( var_Max + var_Min ) / 2
if ( del_Max == 0 ) //This is a gray, no chroma...
{
H = 0 //HSL results from 0 to 1
S = 0
}
else //Chromatic data...
{
if ( L < 0.5 ) S = del_Max / ( var_Max + var_Min )
else S = del_Max / ( 2 - var_Max - var_Min )
del_R = ( ( ( var_Max - var_R ) / 6 ) + ( del_Max / 2 ) ) / del_Max
del_G = ( ( ( var_Max - var_G ) / 6 ) + ( del_Max / 2 ) ) / del_Max
del_B = ( ( ( var_Max - var_B ) / 6 ) + ( del_Max / 2 ) ) / del_Max
if ( var_R == var_Max ) H = del_B - del_G
else if ( var_G == var_Max ) H = ( 1 / 3 ) + del_R - del_B
else if ( var_B == var_Max ) H = ( 2 / 3 ) + del_G - del_R
if ( H < 0 ) ; H += 1
if ( H > 1 ) ; H -= 1
}
HSL —> RGB
if ( S == 0 ) //HSL from 0 to 1
{
R = L * 255 //RGB results from 0 to 255
G = L * 255
B = L * 255
}
else
{
if ( L < 0.5 ) var_2 = L * ( 1 + S )
else var_2 = ( L + S ) - ( S * L )
var_1 = 2 * L - var_2
R = 255 * Hue_2_RGB( var_1, var_2, H + ( 1 / 3 ) )
G = 255 * Hue_2_RGB( var_1, var_2, H )
B = 255 * Hue_2_RGB( var_1, var_2, H - ( 1 / 3 ) )
}
Hue_2_RGB( v1, v2, vH ) //Function Hue_2_RGB
{
if ( vH < 0 ) vH += 1
if ( vH > 1 ) vH -= 1
if ( ( 6 * vH ) < 1 ) return ( v1 + ( v2 - v1 ) * 6 * vH )
if ( ( 2 * vH ) < 1 ) return ( v2 )
if ( ( 3 * vH ) < 2 ) return ( v1 + ( v2 - v1 ) * ( ( 2 / 3 ) - vH ) * 6 )
return ( v1 )
}
RGB —> HSV
var_R = ( R / 255 ) //RGB from 0 to 255
var_G = ( G / 255 )
var_B = ( B / 255 )
var_Min = min( var_R, var_G, var_B ) //Min. value of RGB
var_Max = max( var_R, var_G, var_B ) //Max. value of RGB
del_Max = var_Max - var_Min //Delta RGB value
V = var_Max
if ( del_Max == 0 ) //This is a gray, no chroma...
{
H = 0 //HSV results from 0 to 1
S = 0
}
else //Chromatic data...
{
S = del_Max / var_Max
del_R = ( ( ( var_Max - var_R ) / 6 ) + ( del_Max / 2 ) ) / del_Max
del_G = ( ( ( var_Max - var_G ) / 6 ) + ( del_Max / 2 ) ) / del_Max
del_B = ( ( ( var_Max - var_B ) / 6 ) + ( del_Max / 2 ) ) / del_Max
if ( var_R == var_Max ) H = del_B - del_G
else if ( var_G == var_Max ) H = ( 1 / 3 ) + del_R - del_B
else if ( var_B == var_Max ) H = ( 2 / 3 ) + del_G - del_R
if ( H < 0 ) ; H += 1
if ( H > 1 ) ; H -= 1
}
HSV —> RGB
if ( S == 0 ) //HSV from 0 to 1
{
R = V * 255
G = V * 255
B = V * 255
}
else
{
var_h = H * 6
if ( var_h == 6 ) var_h = 0 //H must be < 1
var_i = int( var_h ) //Or ... var_i = floor( var_h )
var_1 = V * ( 1 - S )
var_2 = V * ( 1 - S * ( var_h - var_i ) )
var_3 = V * ( 1 - S * ( 1 - ( var_h - var_i ) ) )
if ( var_i == 0 ) { var_r = V ; var_g = var_3 ; var_b = var_1 }
else if ( var_i == 1 ) { var_r = var_2 ; var_g = V ; var_b = var_1 }
else if ( var_i == 2 ) { var_r = var_1 ; var_g = V ; var_b = var_3 }
else if ( var_i == 3 ) { var_r = var_1 ; var_g = var_2 ; var_b = V }
else if ( var_i == 4 ) { var_r = var_3 ; var_g = var_1 ; var_b = V }
else { var_r = V ; var_g = var_1 ; var_b = var_2 }
R = var_r * 255 //RGB results from 0 to 255
G = var_g * 255
B = var_b * 255
}
RGB —> CMY
//RGB values from 0 to 255
//CMY results from 0 to 1
C = 1 - ( R / 255 )
M = 1 - ( G / 255 )
Y = 1 - ( B / 255 )
CMY —> RGB
//CMY values from 0 to 1
//RGB results from 0 to 255
R = ( 1 - C ) * 255
G = ( 1 - M ) * 255
B = ( 1 - Y ) * 255
CMY —> CMYK
//CMYK and CMY values from 0 to 1
var_K = 1
if ( C < var_K ) var_K = C
if ( M < var_K ) var_K = M
if ( Y < var_K ) var_K = Y
if ( var_K == 1 ) { //Black
C = 0
M = 0
Y = 0
}
else {
C = ( C - var_K ) / ( 1 - var_K )
M = ( M - var_K ) / ( 1 - var_K )
Y = ( Y - var_K ) / ( 1 - var_K )
}
K = var_K
CMYK —> CMY
//CMYK and CMY values from 0 to 1
C = ( C * ( 1 - K ) + K )
M = ( M * ( 1 - K ) + K )
Y = ( Y * ( 1 - K ) + K )
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