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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/. */
#include "mozilla/StyleColorInlines.h"
#include "mozilla/ComputedStyle.h"
#include "mozilla/ComputedStyleInlines.h"
#include "nsIFrame.h"
#include "nsStyleStruct.h"
namespace mozilla {
// Blend one RGBA color with another based on a given ratios.
// It is a linear combination of each channel with alpha premultipled.
static nscolor LinearBlendColors(const StyleRGBA& aBg, float aBgRatio,
const StyleRGBA& aFg, float aFgRatio) {
constexpr float kFactor = 1.0f / 255.0f;
float p1 = aBgRatio;
float a1 = kFactor * aBg.alpha;
float r1 = a1 * aBg.red;
float g1 = a1 * aBg.green;
float b1 = a1 * aBg.blue;
float p2 = aFgRatio;
float a2 = kFactor * aFg.alpha;
float r2 = a2 * aFg.red;
float g2 = a2 * aFg.green;
float b2 = a2 * aFg.blue;
float a = p1 * a1 + p2 * a2;
if (a <= 0.f) {
return NS_RGBA(0, 0, 0, 0);
}
if (a > 1.f) {
a = 1.f;
}
auto r = ClampColor((p1 * r1 + p2 * r2) / a);
auto g = ClampColor((p1 * g1 + p2 * g2) / a);
auto b = ClampColor((p1 * b1 + p2 * b2) / a);
return NS_RGBA(r, g, b, NSToIntRound(a * 255));
}
template <>
bool StyleColor::MaybeTransparent() const {
// We know that the color is opaque when it's a numeric color with
// alpha == 255.
// TODO(djg): Should we extend this to check Complex with bgRatio =
// 0, and fgRatio * alpha >= 255?
return !IsNumeric() || AsNumeric().alpha != 255;
}
template <>
nscolor StyleColor::CalcColor(nscolor aColor) const {
return CalcColor(StyleRGBA::FromColor(aColor));
}
template <>
nscolor StyleColor::CalcColor(const StyleRGBA& aForegroundColor) const {
if (IsNumeric()) {
return AsNumeric().ToColor();
}
if (IsCurrentColor()) {
return aForegroundColor.ToColor();
}
MOZ_ASSERT(IsComplex());
const auto& complex = AsComplex();
return LinearBlendColors(complex.color, complex.ratios.bg, aForegroundColor,
complex.ratios.fg);
}
template <>
nscolor StyleColor::CalcColor(const ComputedStyle& aStyle) const {
// Common case that is numeric color, which is pure background, we
// can skip resolving StyleText().
// TODO(djg): Is this optimization worth it?
if (IsNumeric()) {
return AsNumeric().ToColor();
}
return CalcColor(aStyle.StyleText()->mColor);
}
template <>
nscolor StyleColor::CalcColor(const nsIFrame* aFrame) const {
return CalcColor(*aFrame->Style());
}
} // namespace mozilla
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