pjs/gfx/public/nsColor.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#ifndef nsColor_h___
#define nsColor_h___
#include "nscore.h"
class nsString;
// A color is a 32 bit unsigned integer with four components: R, G, B
// and A.
typedef PRUint32 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) ((PRUint8) ((_rgba) & 0xff))
#define NS_GET_G(_rgba) ((PRUint8) (((_rgba) >> 8) & 0xff))
#define NS_GET_B(_rgba) ((PRUint8) (((_rgba) >> 16) & 0xff))
#define NS_GET_A(_rgba) ((PRUint8) (((_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
// Blending macro
//
// equivalent to target=(bg*(255-alpha)+fg*alpha)/255
#define MOZ_BLEND(target, bg, fg, alpha) \
FAST_DIVIDE_BY_255(target, (bg)*(255-(alpha)) + (fg)*(alpha))
// Translate a hex string to a color. Return true if it parses ok,
// otherwise return false.
// This accepts only 3, 6 or 9 digits
extern "C" NS_GFX_(PRBool) NS_HexToRGB(const nsString& aBuf, nscolor* aResult);
// 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)
extern "C" NS_GFX_(PRBool) NS_LooseHexToRGB(const nsString& aBuf, nscolor* aResult);
// Translate a color name to a color. Return true if it parses ok,
// otherwise return false.
extern "C" NS_GFX_(PRBool) NS_ColorNameToRGB(const nsString& aBuf, nscolor* aResult);
// Weird color computing code stolen from winfe which was stolen
// from the xfe which was written originally by Eric Bina. So there.
extern "C" NS_GFX_(void) NS_Get3DColors(nscolor aResult[2], nscolor aColor);
// To determin colors based on the background brightness
extern "C" NS_GFX_(void) NS_GetSpecial3DColors(nscolor aResult[2],
nscolor aBackgroundColor,
nscolor aBorderColor);
// Special method to brighten a Color and have it shift to white when
// fully saturated.
extern "C" NS_GFX_(nscolor) NS_BrightenColor(nscolor inColor);
// Special method to darken a Color and have it shift to black when
// darkest component underflows
extern "C" NS_GFX_(nscolor) NS_DarkenColor(nscolor inColor);
// Determins brightness for a specific color
extern "C" NS_GFX_(int) NS_GetBrightness(PRUint8 aRed, PRUint8 aGreen, PRUint8 aBlue);
#endif /* nsColor_h___ */