layout/base/nsCSSColorUtils.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* functions that manipulate colors */
   8
   9 #ifndef __nsCSSColorUtils_h
  10 #define __nsCSSColorUtils_h
  11
  12 #include "nsColor.h"
  13
  14 // "Sufficient contrast" is determined by
  15 // "Techniques For Accessibility Evalution And Repair Tools".
  16 // See http://www.w3.org/TR/AERT#color-contrast
  17 #define NS_SUFFICIENT_LUMINOSITY_DIFFERENCE 125000
  18 // NS_SUFFICIENT_LUMINOSITY_DIFFERENCE is the a11y standard for text
  19 // on a background. Use 20% of that standard since we have a background
  20 // on top of another background
  21 #define NS_SUFFICIENT_LUMINOSITY_DIFFERENCE_BG \
  22   (NS_SUFFICIENT_LUMINOSITY_DIFFERENCE / 5)
  23
  24 #define NS_LUMINOSITY_DIFFERENCE(a, b)                    \
  25   int32_t(mozilla::Abs(NS_GetLuminosity(a | 0xff000000) - \
  26                        NS_GetLuminosity(b | 0xff000000)))
  27
  28 // Maximum value that NS_GetLuminosity can return.
  29 #define NS_MAX_LUMINOSITY 255000
  30
  31 // To determine 3D colors for groove / ridge borders based on the border color
  32 void NS_GetSpecial3DColors(nscolor aResult[2], nscolor aBorderColor);
  33
  34 // Determins brightness for a specific color
  35 int NS_GetBrightness(uint8_t aRed, uint8_t aGreen, uint8_t aBlue);
  36
  37 // Get Luminosity of a specific color. That is same as Y of YIQ color space.
  38 // The range of return value is 0 to NS_MAX_LUMINOSITY.
  39 int32_t NS_GetLuminosity(nscolor aColor);
  40
  41 // function to convert from RGBA color space to HSVA color space
  42 void NS_RGB2HSV(nscolor aColor, uint16_t& aHue, uint16_t& aSat,
  43                 uint16_t& aValue, uint8_t& aAlpha);
  44
  45 // function to convert from HSVA color space to RGBA color space
  46 void NS_HSV2RGB(nscolor& aColor, uint16_t aHue, uint16_t aSat, uint16_t aValue,
  47                 uint8_t aAlpha);
  48
  49 #endif