Color conversion utility based on Processing

colors.red

Red []
; Color conversion utility based on Processing
; Collaborator: Gemini AI

hsb-to-rgb: func [
    "Converts p5.js HSB values (H: 0-360, S: 0-100, B: 0-100) to a Red tuple!"
    h [number!] ; hue 0-360
    s [number!] ; saturation 0-255
    b [number!] ; brightness 0-255
    /local c x m r g b-val
][
    ; 1. Normalize Saturation and Brightness to 0.0 - 1.0 fractions
    s: s / 255.0
    b: b / 255.0
    
    ; Ensure Hue wraps perfectly around the 360-degree circle
    h: mod h 360.0
    if h < 0 [h: h + 360.0]

    ; 2. Calculate Chroma (Intensity) and intermediate step
    c: b * s
    x: c * (1.0 - absolute ((mod (h / 60.0) 2.0) - 1.0))
    m: b - c
    
    ; 3. Match raw components based on which 60-degree sector the hue lands in
    set [r g b-val] case [
        h < 60.0  [reduce [c x 0.0]]
        h < 120.0 [reduce [x c 0.0]]
        h < 180.0 [reduce [0.0 c x]]
        h < 240.0 [reduce [0.0 x c]]
        h < 300.0 [reduce [x 0.0 c]]
        true      [reduce [c 0.0 x]]
    ]
    
    ; 4. Add the baseline brightness match, scale to 0-255, and return a native tuple!
    as-color 
        to integer! (r + m * 255)
        to integer! (g + m * 255)
        to integer! (b-val + m * 255)
]

hsl-to-rgb: func [
    "Converts p5.js HSL values (H: 0-360, S: 0-255, L: 0-255) to a Red tuple!"
    h [number!] ; hue 0-360
    s [number!] ; saturation 0-255
    l [number!] ; brightness 0-255
    /local c x m r g b-val
][
    ; 1. Normalize Saturation and Lightness to 0.0 - 1.0 fractions
    s: s / 255.0
    l: l / 255.0
    
    h: mod h 360.0
    if h < 0 [h: h + 360.0]

    ; 2. HSL Specific Chroma Calculation:
    ; Chroma = (1 - |2L - 1|) * S
    c: (1.0 - absolute ((2.0 * l) - 1.0)) * s
    
    x: c * (1.0 - absolute ((mod (h / 60.0) 2.0) - 1.0))
    m: l - (c / 2.0)
    
    ; 3. Map to sectors (Same component logic as HSB)
    set [r g b-val] case [
        h < 60.0  [reduce [c x 0.0]]
        h < 120.0 [reduce [x c 0.0]]
        h < 180.0 [reduce [0.0 c x]]
        h < 240.0 [reduce [0.0 x c]]
        h < 300.0 [reduce [x 0.0 c]]
        true      [reduce [c 0.0 x]]
    ]
    
    ; 4. Scale to 8-bit using strict Red evaluation order rules
    as-color 
        to integer! ((r + m) * 255)
        to integer! ((g + m) * 255)
        to integer! ((b-val + m) * 255)
]

cycle-hue: func [
    h [number!] ; hue 0-360
    /local x
][
    h: mod h 360.0
    if h < 0 [h: h + 360.0]
    
    ; Calculate intermediate color projection value
    x: to integer! (255.0 * (1.0 - absolute ((mod (h / 60.0) 2.0) - 1.0)))
    
    ; Directly route to RGB tuple based on the 60-degree wheel sector
    case [
        h < 60.0  [as-color 255 x 0]
        h < 120.0 [as-color x 255 0]
        h < 180.0 [as-color 0 255 x]
        h < 240.0 [as-color 0 x 255]
        h < 300.0 [as-color x 0 255]
        true      [as-color 255 0 x]
    ]
]