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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* 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/. */

 #ifndef nsColor_h___

 #define nsColor_h___

 #include <stddef.h>                     // for size_t

 #include <stdint.h>                     // for uint8_t, uint32_t

 #include "gfxCore.h"                    // for NS_GFX_

 #include "nscore.h"                     // for nsAString

 class nsAString;

 class nsString;

 class nsCString;

 // A color is a 32 bit unsigned integer with four components: R, G, B

 // and A.

 typedef uint32_t nscolor;

 // Make a color out of r,g,b values. This assumes that the r,g,b values are

 // properly constrained to 0-255. This also assumes that a is 255.

 #define NS_RGB(_r,_g,_b) \

   ((nscolor) ((255 << 24) | ((_b)<<16) | ((_g)<<8) | (_r)))

 // Make a color out of r,g,b,a values. This assumes that the r,g,b,a

 // values are properly constrained to 0-255.

 #define NS_RGBA(_r,_g,_b,_a) \

   ((nscolor) (((_a) << 24) | ((_b)<<16) | ((_g)<<8) | (_r)))

 // Extract color components from nscolor

 #define NS_GET_R(_rgba) ((uint8_t) ((_rgba) & 0xff))

 #define NS_GET_G(_rgba) ((uint8_t) (((_rgba) >> 8) & 0xff))

 #define NS_GET_B(_rgba) ((uint8_t) (((_rgba) >> 16) & 0xff))

 #define NS_GET_A(_rgba) ((uint8_t) (((_rgba) >> 24) & 0xff))

 // Fast approximate division by 255. It has the property that

 // for all 0 <= n <= 255*255, FAST_DIVIDE_BY_255(n) == n/255.

 // But it only uses two adds and two shifts instead of an 

 // integer division (which is expensive on many processors).

 //

 // equivalent to target=v/255

 #define FAST_DIVIDE_BY_255(target,v)               \

   PR_BEGIN_MACRO                                   \

     unsigned tmp_ = v;                             \

     target = ((tmp_ << 8) + tmp_ + 255) >> 16;     \

   PR_END_MACRO

 // Translate a hex string to a color. Return true if it parses ok,

 // otherwise return false.

 // This accepts only 3 or 6 digits

 NS_GFX_(bool) NS_HexToRGB(const nsAString& aBuf, nscolor* aResult);

 // Compose one NS_RGB color onto another. The result is what

 // you get if you draw aFG on top of aBG with operator OVER.

 NS_GFX_(nscolor) NS_ComposeColors(nscolor aBG, nscolor aFG);

 // Translate a hex string to a color. Return true if it parses ok,

 // otherwise return false.

 // This version accepts 1 to 9 digits (missing digits are 0)

 NS_GFX_(bool) NS_LooseHexToRGB(const nsString& aBuf, nscolor* aResult);

 // There is no function to translate a color to a hex string, because

 // the hex-string syntax does not support transparency.

 // Translate a color name to a color. Return true if it parses ok,

 // otherwise return false.

 NS_GFX_(bool) NS_ColorNameToRGB(const nsAString& aBuf, nscolor* aResult);

 // Returns an array of all possible color names, and sets

 // *aSizeArray to the size of that array. Do NOT call |free()| on this array.

 NS_GFX_(const char * const *) NS_AllColorNames(size_t *aSizeArray);

 // function to convert from HSL color space to RGB color space

 // the float parameters are all expected to be in the range 0-1

 NS_GFX_(nscolor) NS_HSL2RGB(float h, float s, float l);

 // Return a color name for the given nscolor.  If there is no color

 // name for it, returns null.  If there are multiple possible color

 // names for the given color, the first one in nsColorNameList.h

 // (which is generally the first one in alphabetical order) will be

 // returned.

 NS_GFX_(const char*) NS_RGBToColorName(nscolor aColor);

 #endif /* nsColor_h___ */