Quelle nsCSSColorUtils.cpp Sprache: C

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* functions that manipulate colors */

#include "nsCSSColorUtils.h"
#include "nsDebug.h"
#include <math.h>

// Weird color computing code stolen from winfe which was stolen
// from the xfe which was written originally by Eric Bina. So there.

#define RED_LUMINOSITY 299
#define GREEN_LUMINOSITY 587
#define BLUE_LUMINOSITY 114
#define INTENSITY_FACTOR 25
#define LUMINOSITY_FACTOR 75

void NS_GetSpecial3DColors(nscolor aResult[2], nscolor aBorderColor) {
  const float kDarkerScale = 2.0f / 3.0f;

  uint8_t r = NS_GET_R(aBorderColor);
  uint8_t g = NS_GET_G(aBorderColor);
  uint8_t b = NS_GET_B(aBorderColor);
  uint8_t a = NS_GET_A(aBorderColor);
  if (r == 0 && g == 0 && b == 0) {
    // 0.3 * black
    aResult[0] = NS_RGBA(76, 76, 76, a);
    // 0.7 * black
    aResult[1] = NS_RGBA(178, 178, 178, a);
    return;
  }

  aResult[0] = NS_RGBA(uint8_t(r * kDarkerScale), uint8_t(g * kDarkerScale),
                       uint8_t(b * kDarkerScale), a);
  aResult[1] = aBorderColor;
}

int NS_GetBrightness(uint8_t aRed, uint8_t aGreen, uint8_t aBlue) {
  uint8_t intensity = (aRed + aGreen + aBlue) / 3;

  uint8_t luminosity = NS_GetLuminosity(NS_RGB(aRed, aGreen, aBlue)) / 1000;

  return ((intensity * INTENSITY_FACTOR) + (luminosity * LUMINOSITY_FACTOR)) /
         100;
}

int32_t NS_GetLuminosity(nscolor aColor) {
  // When aColor is not opaque, the perceived luminosity will depend
  // on what color(s) aColor is ultimately drawn on top of, which we
  // do not know.
  NS_ASSERTION(NS_GET_A(aColor) == 255,
               "impossible to compute luminosity of a non-opaque color");

  return (NS_GET_R(aColor) * RED_LUMINOSITY +
          NS_GET_G(aColor) * GREEN_LUMINOSITY +
          NS_GET_B(aColor) * BLUE_LUMINOSITY);
}

// Function to convert RGB color space into the HSV colorspace
// Hue is the primary color defined from 0 to 359 degrees
// Saturation is defined from 0 to 255.  The higher the number.. the deeper
// the color Value is the brightness of the color. 0 is black, 255 is white.
void NS_RGB2HSV(nscolor aColor, uint16_t& aHue, uint16_t& aSat,
                uint16_t& aValue, uint8_t& aAlpha) {
  uint8_t r, g, b;
  int16_t delta, min, max, r1, b1, g1;
  float hue;

  r = NS_GET_R(aColor);
  g = NS_GET_G(aColor);
  b = NS_GET_B(aColor);

  if (r > g) {
    max = r;
    min = g;
  } else {
    max = g;
    min = r;
  }

  if (b > max) {
    max = b;
  }
  if (b < min) {
    min = b;
  }

  // value or brightness will always be the max of all the colors(RGB)
  aValue = max;
  delta = max - min;
  aSat = (max != 0) ? ((delta * 255) / max) : 0;
  r1 = r;
  b1 = b;
  g1 = g;

  if (aSat == 0) {
    hue = 1000;
  } else {
    if (r == max) {
      hue = (float)(g1 - b1) / (float)delta;
    } else if (g1 == max) {
      hue = 2.0f + (float)(b1 - r1) / (float)delta;
    } else {
      hue = 4.0f + (float)(r1 - g1) / (float)delta;
    }
  }

  if (hue < 999) {
    hue *= 60;
    if (hue < 0) {
      hue += 360;
    }
  } else {
    hue = 0;
  }

  aHue = (uint16_t)hue;

  aAlpha = NS_GET_A(aColor);
}

// Function to convert HSV color space into the RGB colorspace
// Hue is the primary color defined from 0 to 359 degrees
// Saturation is defined from 0 to 255.  The higher the number.. the deeper
// the color Value is the brightness of the color. 0 is black, 255 is white.
void NS_HSV2RGB(nscolor& aColor, uint16_t aHue, uint16_t aSat, uint16_t aValue,
                uint8_t aAlpha) {
  uint16_t r = 0, g = 0, b = 0;
  uint16_t i, p, q, t;
  double h, f, percent;

  if (aSat == 0) {
    // achromatic color, no hue is defined
    r = aValue;
    g = aValue;
    b = aValue;
  } else {
    // hue in in degrees around the color wheel defined from
    // 0 to 360 degrees.
    if (aHue >= 360) {
      aHue = 0;
    }

    // we break the color wheel into 6 areas.. these
    // areas define how the saturation and value define the color.
    // reds behave differently than the blues
    h = (double)aHue / 60.0;
    i = (uint16_t)floor(h);
    f = h - (double)i;
    percent = ((double)aValue /
               255.0);  // this needs to be a value from 0 to 1, so a percentage
                        // can be calculated of the saturation.
    p = (uint16_t)(percent * (255 - aSat));
    q = (uint16_t)(percent * (255 - (aSat * f)));
    t = (uint16_t)(percent * (255 - (aSat * (1.0 - f))));

    // i is guaranteed to never be larger than 5.
    switch (i) {
      case 0:
        r = aValue;
        g = t;
        b = p;
        break;
      case 1:
        r = q;
        g = aValue;
        b = p;
        break;
      case 2:
        r = p;
        g = aValue;
        b = t;
        break;
      case 3:
        r = p;
        g = q;
        b = aValue;
        break;
      case 4:
        r = t;
        g = p;
        b = aValue;
        break;
      case 5:
        r = aValue;
        g = p;
        b = q;
        break;
    }
  }
  aColor = NS_RGBA(r, g, b, aAlpha);
}

#undef RED_LUMINOSITY
#undef GREEN_LUMINOSITY
#undef BLUE_LUMINOSITY
#undef INTENSITY_FACTOR
#undef LUMINOSITY_FACTOR

quality100%

¤ Dauer der Verarbeitung: 0.13 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.