michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsColor_h___
michael@0: #define nsColor_h___
michael@0: 
michael@0: #include <stddef.h>                     // for size_t
michael@0: #include <stdint.h>                     // for uint8_t, uint32_t
michael@0: #include "gfxCore.h"                    // for NS_GFX_
michael@0: #include "nscore.h"                     // for nsAString
michael@0: 
michael@0: class nsAString;
michael@0: class nsString;
michael@0: class nsCString;
michael@0: 
michael@0: // A color is a 32 bit unsigned integer with four components: R, G, B
michael@0: // and A.
michael@0: typedef uint32_t nscolor;
michael@0: 
michael@0: // Make a color out of r,g,b values. This assumes that the r,g,b values are
michael@0: // properly constrained to 0-255. This also assumes that a is 255.
michael@0: #define NS_RGB(_r,_g,_b) \
michael@0:   ((nscolor) ((255 << 24) | ((_b)<<16) | ((_g)<<8) | (_r)))
michael@0: 
michael@0: // Make a color out of r,g,b,a values. This assumes that the r,g,b,a
michael@0: // values are properly constrained to 0-255.
michael@0: #define NS_RGBA(_r,_g,_b,_a) \
michael@0:   ((nscolor) (((_a) << 24) | ((_b)<<16) | ((_g)<<8) | (_r)))
michael@0: 
michael@0: // Extract color components from nscolor
michael@0: #define NS_GET_R(_rgba) ((uint8_t) ((_rgba) & 0xff))
michael@0: #define NS_GET_G(_rgba) ((uint8_t) (((_rgba) >> 8) & 0xff))
michael@0: #define NS_GET_B(_rgba) ((uint8_t) (((_rgba) >> 16) & 0xff))
michael@0: #define NS_GET_A(_rgba) ((uint8_t) (((_rgba) >> 24) & 0xff))
michael@0: 
michael@0: // Fast approximate division by 255. It has the property that
michael@0: // for all 0 <= n <= 255*255, FAST_DIVIDE_BY_255(n) == n/255.
michael@0: // But it only uses two adds and two shifts instead of an 
michael@0: // integer division (which is expensive on many processors).
michael@0: //
michael@0: // equivalent to target=v/255
michael@0: #define FAST_DIVIDE_BY_255(target,v)               \
michael@0:   PR_BEGIN_MACRO                                   \
michael@0:     unsigned tmp_ = v;                             \
michael@0:     target = ((tmp_ << 8) + tmp_ + 255) >> 16;     \
michael@0:   PR_END_MACRO
michael@0: 
michael@0: // Translate a hex string to a color. Return true if it parses ok,
michael@0: // otherwise return false.
michael@0: // This accepts only 3 or 6 digits
michael@0: NS_GFX_(bool) NS_HexToRGB(const nsAString& aBuf, nscolor* aResult);
michael@0: 
michael@0: // Compose one NS_RGB color onto another. The result is what
michael@0: // you get if you draw aFG on top of aBG with operator OVER.
michael@0: NS_GFX_(nscolor) NS_ComposeColors(nscolor aBG, nscolor aFG);
michael@0: 
michael@0: // Translate a hex string to a color. Return true if it parses ok,
michael@0: // otherwise return false.
michael@0: // This version accepts 1 to 9 digits (missing digits are 0)
michael@0: NS_GFX_(bool) NS_LooseHexToRGB(const nsString& aBuf, nscolor* aResult);
michael@0: 
michael@0: // There is no function to translate a color to a hex string, because
michael@0: // the hex-string syntax does not support transparency.
michael@0: 
michael@0: // Translate a color name to a color. Return true if it parses ok,
michael@0: // otherwise return false.
michael@0: NS_GFX_(bool) NS_ColorNameToRGB(const nsAString& aBuf, nscolor* aResult);
michael@0: 
michael@0: // Returns an array of all possible color names, and sets
michael@0: // *aSizeArray to the size of that array. Do NOT call |free()| on this array.
michael@0: NS_GFX_(const char * const *) NS_AllColorNames(size_t *aSizeArray);
michael@0: 
michael@0: // function to convert from HSL color space to RGB color space
michael@0: // the float parameters are all expected to be in the range 0-1
michael@0: NS_GFX_(nscolor) NS_HSL2RGB(float h, float s, float l);
michael@0: 
michael@0: // Return a color name for the given nscolor.  If there is no color
michael@0: // name for it, returns null.  If there are multiple possible color
michael@0: // names for the given color, the first one in nsColorNameList.h
michael@0: // (which is generally the first one in alphabetical order) will be
michael@0: // returned.
michael@0: NS_GFX_(const char*) NS_RGBToColorName(nscolor aColor);
michael@0: 
michael@0: #endif /* nsColor_h___ */