Quelle nsColor.h Sprache: C

/* -*- 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.

#endif /* nsColor_h___ */

quality100%

¤ Dauer der Verarbeitung: 0.28 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.