diff options
Diffstat (limited to 'widget/windows/ScrollbarUtil.cpp')
| -rw-r--r-- | widget/windows/ScrollbarUtil.cpp | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/widget/windows/ScrollbarUtil.cpp b/widget/windows/ScrollbarUtil.cpp new file mode 100644 index 0000000000..4c00dd1963 --- /dev/null +++ b/widget/windows/ScrollbarUtil.cpp @@ -0,0 +1,217 @@ +/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* 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 "ScrollbarUtil.h" + +#include "mozilla/RelativeLuminanceUtils.h" +#include "mozilla/StaticPrefs_widget.h" +#include "nsNativeTheme.h" + +/*static*/ +bool ScrollbarUtil::IsScrollbarWidthThin(ComputedStyle* aStyle) { + auto scrollbarWidth = aStyle->StyleUIReset()->mScrollbarWidth; + return scrollbarWidth == StyleScrollbarWidth::Thin; +} + +/*static*/ +bool ScrollbarUtil::IsScrollbarWidthThin(nsIFrame* aFrame) { + ComputedStyle* style = nsLayoutUtils::StyleForScrollbar(aFrame); + return IsScrollbarWidthThin(style); +} + +/*static*/ +ComputedStyle* ScrollbarUtil::GetCustomScrollbarStyle(nsIFrame* aFrame, + bool* aDarkScrollbar) { + ComputedStyle* style = nsLayoutUtils::StyleForScrollbar(aFrame); + if (style->StyleUI()->HasCustomScrollbars()) { + return style; + } + bool useDarkScrollbar = !StaticPrefs::widget_disable_dark_scrollbar() && + nsNativeTheme::IsDarkBackground(aFrame); + if (useDarkScrollbar || IsScrollbarWidthThin(style)) { + if (aDarkScrollbar) { + *aDarkScrollbar = useDarkScrollbar; + } + return style; + } + return nullptr; +} + +/*static*/ +nscolor ScrollbarUtil::GetScrollbarButtonColor(nscolor aTrackColor, + EventStates aStates) { + // See numbers in GetScrollbarArrowColor. + // This function is written based on ratios between values listed there. + + bool isActive = aStates.HasState(NS_EVENT_STATE_ACTIVE); + bool isHover = aStates.HasState(NS_EVENT_STATE_HOVER); + if (!isActive && !isHover) { + return aTrackColor; + } + float luminance = RelativeLuminanceUtils::Compute(aTrackColor); + if (isActive) { + if (luminance >= 0.18f) { + luminance *= 0.134f; + } else { + luminance /= 0.134f; + luminance = std::min(luminance, 1.0f); + } + } else { + if (luminance >= 0.18f) { + luminance *= 0.805f; + } else { + luminance /= 0.805f; + } + } + return RelativeLuminanceUtils::Adjust(aTrackColor, luminance); +} + +/*static*/ +nscolor ScrollbarUtil::GetScrollbarArrowColor(nscolor aButtonColor) { + // In Windows 10 scrollbar, there are several gray colors used: + // + // State | Background (lum) | Arrow | Contrast + // -------+------------------+---------+--------- + // Normal | Gray 240 (87.1%) | Gray 96 | 5.5 + // Hover | Gray 218 (70.1%) | Black | 15.0 + // Active | Gray 96 (11.7%) | White | 6.3 + // + // Contrast value is computed based on the definition in + // https://www.w3.org/TR/WCAG20/#contrast-ratiodef + // + // This function is written based on these values. + + float luminance = RelativeLuminanceUtils::Compute(aButtonColor); + // Color with luminance larger than 0.72 has contrast ratio over 4.6 + // to color with luminance of gray 96, so this value is chosen for + // this range. It is the luminance of gray 221. + if (luminance >= 0.72) { + // ComputeRelativeLuminanceFromComponents(96). That function cannot + // be constexpr because of std::pow. + const float GRAY96_LUMINANCE = 0.117f; + return RelativeLuminanceUtils::Adjust(aButtonColor, GRAY96_LUMINANCE); + } + // The contrast ratio of a color to black equals that to white when its + // luminance is around 0.18, with a contrast ratio ~4.6 to both sides, + // thus the value below. It's the lumanince of gray 118. + if (luminance >= 0.18) { + return NS_RGBA(0, 0, 0, NS_GET_A(aButtonColor)); + } + return NS_RGBA(255, 255, 255, NS_GET_A(aButtonColor)); +} + +/*static*/ +nscolor ScrollbarUtil::AdjustScrollbarFaceColor(nscolor aFaceColor, + EventStates aStates) { + // In Windows 10, scrollbar thumb has the following colors: + // + // State | Color | Luminance + // -------+----------+---------- + // Normal | Gray 205 | 61.0% + // Hover | Gray 166 | 38.1% + // Active | Gray 96 | 11.7% + // + // This function is written based on the ratios between the values. + + bool isActive = aStates.HasState(NS_EVENT_STATE_ACTIVE); + bool isHover = aStates.HasState(NS_EVENT_STATE_HOVER); + if (!isActive && !isHover) { + return aFaceColor; + } + float luminance = RelativeLuminanceUtils::Compute(aFaceColor); + if (isActive) { + if (luminance >= 0.18f) { + luminance *= 0.192f; + } else { + luminance /= 0.192f; + } + } else { + if (luminance >= 0.18f) { + luminance *= 0.625f; + } else { + luminance /= 0.625f; + } + } + return RelativeLuminanceUtils::Adjust(aFaceColor, luminance); +} + +/*static*/ +nscolor ScrollbarUtil::GetScrollbarTrackColor(nsIFrame* aFrame) { + bool darkScrollbar = false; + ComputedStyle* style = GetCustomScrollbarStyle(aFrame, &darkScrollbar); + if (style) { + const nsStyleUI* ui = style->StyleUI(); + auto* customColors = ui->mScrollbarColor.IsAuto() + ? nullptr + : &ui->mScrollbarColor.AsColors(); + if (customColors) { + return customColors->track.CalcColor(*style); + } + } + return darkScrollbar ? NS_RGBA(20, 20, 25, 77) : NS_RGB(240, 240, 240); +} + +/*static*/ +nscolor ScrollbarUtil::GetScrollbarThumbColor(nsIFrame* aFrame, + EventStates aEventStates) { + bool darkScrollbar = false; + ComputedStyle* style = GetCustomScrollbarStyle(aFrame, &darkScrollbar); + if (style) { + const nsStyleUI* ui = style->StyleUI(); + auto* customColors = ui->mScrollbarColor.IsAuto() + ? nullptr + : &ui->mScrollbarColor.AsColors(); + if (customColors) { + nscolor faceColor = customColors->thumb.CalcColor(*style); + return AdjustScrollbarFaceColor(faceColor, aEventStates); + } + } + nscolor faceColor = + darkScrollbar ? NS_RGBA(249, 249, 250, 102) : NS_RGB(205, 205, 205); + return AdjustScrollbarFaceColor(faceColor, aEventStates); +} + +/*static*/ +Maybe<nsITheme::Transparency> ScrollbarUtil::GetScrollbarPartTransparency( + nsIFrame* aFrame, StyleAppearance aAppearance) { + if (nsNativeTheme::IsWidgetScrollbarPart(aAppearance)) { + if (ComputedStyle* style = ScrollbarUtil::GetCustomScrollbarStyle(aFrame)) { + auto* ui = style->StyleUI(); + if (ui->mScrollbarColor.IsAuto() || + ui->mScrollbarColor.AsColors().track.MaybeTransparent()) { + return Some(nsITheme::eTransparent); + } + // These widgets may be thinner than the track, so we need to return + // transparent for them to make the track visible. + switch (aAppearance) { + case StyleAppearance::ScrollbarthumbHorizontal: + case StyleAppearance::ScrollbarthumbVertical: + case StyleAppearance::ScrollbarbuttonUp: + case StyleAppearance::ScrollbarbuttonDown: + case StyleAppearance::ScrollbarbuttonLeft: + case StyleAppearance::ScrollbarbuttonRight: + return Some(nsITheme::eTransparent); + default: + break; + } + } + } + + switch (aAppearance) { + case StyleAppearance::ScrollbarHorizontal: + case StyleAppearance::ScrollbarVertical: + case StyleAppearance::Scrollcorner: + case StyleAppearance::Statusbar: + // Knowing that scrollbars and statusbars are opaque improves + // performance, because we create layers for them. This better be + // true across all Windows themes! If it's not true, we should + // paint an opaque background for them to make it true! + return Some(nsITheme::eOpaque); + default: + break; + } + + return Nothing(); +} |