Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #include "mozilla/StyleComplexColor.h"
       8             : 
       9             : #include "mozilla/ComputedStyle.h"
      10             : #include "mozilla/ComputedStyleInlines.h"
      11             : #include "nsIFrame.h"
      12             : #include "nsStyleStruct.h"
      13             : 
      14             : using namespace mozilla;
      15             : 
      16             : // Blend one RGBA color with another based on a given ratios.
      17             : // It is a linear combination of each channel with alpha premultipled.
      18             : static nscolor
      19           0 : LinearBlendColors(nscolor aBg, float aBgRatio, nscolor aFg, float aFgRatio)
      20             : {
      21           0 :   constexpr float kFactor = 1.0f / 255.0f;
      22             : 
      23           0 :   float p1 = aBgRatio;
      24           0 :   float a1 = kFactor * NS_GET_A(aBg);
      25           0 :   float r1 = a1 * NS_GET_R(aBg);
      26           0 :   float g1 = a1 * NS_GET_G(aBg);
      27           0 :   float b1 = a1 * NS_GET_B(aBg);
      28             : 
      29           0 :   float p2 = aFgRatio;
      30           0 :   float a2 = kFactor * NS_GET_A(aFg);
      31           0 :   float r2 = a2 * NS_GET_R(aFg);
      32           0 :   float g2 = a2 * NS_GET_G(aFg);
      33           0 :   float b2 = a2 * NS_GET_B(aFg);
      34             : 
      35           0 :   float a = p1 * a1 + p2 * a2;
      36           0 :   if (a <= 0.f) {
      37             :     return NS_RGBA(0, 0, 0, 0);
      38             :   }
      39             : 
      40           0 :   if (a > 1.f) {
      41           0 :     a = 1.f;
      42             :   }
      43             : 
      44           0 :   auto r = ClampColor((p1 * r1 + p2 * r2) / a);
      45           0 :   auto g = ClampColor((p1 * g1 + p2 * g2) / a);
      46           0 :   auto b = ClampColor((p1 * b1 + p2 * b2) / a);
      47           0 :   return NS_RGBA(r, g, b, NSToIntRound(a * 255));
      48             : }
      49             : 
      50             : bool
      51           0 : StyleComplexColor::MaybeTransparent() const {
      52             :   // We know that the color is opaque when it's a numeric color with
      53             :   // alpha == 255.
      54             :   // TODO(djg): Should we extend this to check Complex with bgRatio =
      55             :   // 0, and fgRatio * alpha >= 255?
      56           0 :   return mTag != eNumeric || NS_GET_A(mColor) != 255;
      57             : }
      58             : 
      59             : nscolor
      60         799 : StyleComplexColor::CalcColor(mozilla::ComputedStyle* aStyle) const {
      61             :   // Common case that is numeric color, which is pure background, we
      62             :   // can skip resolving StyleColor().
      63           0 :   if (mTag == eNumeric) {
      64           0 :     return mColor;
      65             :   }
      66             : 
      67          31 :   MOZ_ASSERT(aStyle);
      68           0 :   auto fgColor = aStyle->StyleColor()->mColor;
      69             : 
      70           0 :   if (mTag == eComplex) {
      71           0 :     return LinearBlendColors(mColor, mBgRatio, fgColor, mFgRatio);
      72             :   }
      73             : 
      74             :   // eForeground and eAuto return the currentcolor.
      75             :   return fgColor;
      76             : }
      77             : 
      78             : nscolor
      79             : StyleComplexColor::CalcColor(const nsIFrame* aFrame) const {
      80             :   return CalcColor(aFrame->Style());
      81             : }