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/* -*- 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/. */
#ifndef nsColor_h___
#define nsColor_h___
#include <stdint.h> // for uint8_t, uint32_t
#include "nsCoord.h" // for NSToIntRound
#include "nsStringFwd.h"
// 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))
namespace mozilla {
template <typename T>
inline uint8_t ClampColor(T aColor) {
if (aColor >= 255) {
return 255;
}
if (aColor <= 0) {
return 0;
}
return NSToIntRound(aColor);
}
} // namespace mozilla
enum class nsHexColorType : uint8_t {
NoAlpha, // 3 or 6 digit hex colors only
AllowAlpha, // 3, 4, 6, or 8 digit hex colors
};
// Translate a hex string to a color. Return true if it parses ok,
// otherwise return false.
// This accepts the number of digits specified by aType.
bool NS_HexToRGBA(const nsAString& aBuf, nsHexColorType aType,
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.
nscolor NS_ComposeColors(nscolor aBG, nscolor aFG);
namespace mozilla {
inline uint32_t RoundingDivideBy255(uint32_t n) {
// There is an approximate alternative: ((n << 8) + n + 32896) >> 16
// But that is actually slower than this simple expression on a modern
// machine with a modern compiler.
return (n + 127) / 255;
}
} // namespace mozilla
// 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)
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.
bool NS_ColorNameToRGB(const nsAString& aBuf, nscolor* aResult);
// 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.
const char* NS_RGBToColorName(nscolor aColor);
#endif /* nsColor_h___ */
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