impeller::ColorHSB Struct Reference

#include <color.h>

Public Member Functions
constexpr	ColorHSB (Scalar h, Scalar s, Scalar b, Scalar a)
Color	ToRGBA () const

Static Public Member Functions
static ColorHSB	FromRGB (Color rgb)

Public Attributes
Scalar	hue
Scalar	saturation
Scalar	brightness
Scalar	alpha

Detailed Description

Represents a color by its constituent hue, saturation, brightness and alpha

Definition at line 926 of file color.h.

Constructor & Destructor Documentation

ColorHSB()

constexpr impeller::ColorHSB::ColorHSB ( Scalar  h, Scalar  s, Scalar  b, Scalar  a  )

inlineconstexpr

Definition at line 947 of file color.h.

      : hue(h), saturation(s), brightness(b), alpha(a) {}

Referenced by FromRGB().

Member Function Documentation

FromRGB()

ColorHSB impeller::ColorHSB::FromRGB ( Color  rgb )

static

Definition at line 52 of file color.cc.

                                    {
  Scalar R = rgb.red;
  Scalar G = rgb.green;
  Scalar B = rgb.blue;
 
  Scalar v = 0.0;
  Scalar x = 0.0;
  Scalar f = 0.0;
 
  int64_t i = 0;
 
  x = fmin(R, G);
  x = fmin(x, B);
 
  v = fmax(R, G);
  v = fmax(v, B);
 
  if (v == x) {
    return ColorHSB(0.0, 0.0, v, rgb.alpha);
  }
 
  f = (R == x) ? G - B : ((G == x) ? B - R : R - G);
  i = (R == x) ? 3 : ((G == x) ? 5 : 1);
 
  return ColorHSB(((i - f / (v - x)) / 6.0), (v - x) / v, v, rgb.alpha);
}

References impeller::Color::alpha, impeller::Color::blue, ColorHSB(), impeller::Color::green, and impeller::Color::red.

ToRGBA()

Color impeller::ColorHSB::ToRGBA

(

)

const

Definition at line 79 of file color.cc.

                             {
  Scalar h = hue * 6.0;
  Scalar s = saturation;
  Scalar v = brightness;
 
  Scalar m = 0.0;
  Scalar n = 0.0;
  Scalar f = 0.0;
 
  int64_t i = 0;
 
  if (h == 0) {
    h = 0.01;
  }
 
  if (h == 0.0) {
    return Color(v, v, v, alpha);
  }
 
  i = static_cast<int64_t>(floor(h));
 
  f = h - i;
 
  if (!(i & 1)) {
    f = 1 - f;
  }
 
  m = v * (1 - s);
  n = v * (1 - s * f);
 
  switch (i) {
    case 6:
    case 0:
      return Color(v, n, m, alpha);
    case 1:
      return Color(n, v, m, alpha);
    case 2:
      return Color(m, v, n, alpha);
    case 3:
      return Color(m, n, v, alpha);
    case 4:
      return Color(n, m, v, alpha);
    case 5:
      return Color(v, m, n, alpha);
  }
  return Color(0, 0, 0, alpha);
}

References alpha, brightness, hue, and saturation.

Member Data Documentation

alpha

Scalar impeller::ColorHSB::alpha

The alpha of the color (0 to 1)

Definition at line 945 of file color.h.

Referenced by ToRGBA().

brightness

Scalar impeller::ColorHSB::brightness

The brightness of the color (0 to 1)

Definition at line 940 of file color.h.

Referenced by ToRGBA().

hue

Scalar impeller::ColorHSB::hue

The hue of the color (0 to 1)

Definition at line 930 of file color.h.

Referenced by ToRGBA().

saturation

Scalar impeller::ColorHSB::saturation

The saturation of the color (0 to 1)

Definition at line 935 of file color.h.

Referenced by ToRGBA().

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The documentation for this struct was generated from the following files:

• impeller/geometry/color.h
• impeller/geometry/color.cc