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/*
* Copyright (C) 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "TextPaintStyle.h"
#include "ColorLuminance.h"
#include "FocusController.h"
#include "Frame.h"
#include "GraphicsContext.h"
#include "Page.h"
#include "PaintInfo.h"
#include "RenderStyle.h"
#include "RenderText.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "Settings.h"
namespace WebCore {
TextPaintStyle::TextPaintStyle(const Color& color)
: fillColor(color)
, strokeColor(color)
{
}
bool TextPaintStyle::operator==(const TextPaintStyle& other) const
{
return fillColor == other.fillColor && strokeColor == other.strokeColor && emphasisMarkColor == other.emphasisMarkColor
&& strokeWidth == other.strokeWidth && paintOrder == other.paintOrder && lineJoin == other.lineJoin
#if HAVE(OS_DARK_MODE_SUPPORT)
&& useDarkAppearance == other.useDarkAppearance
#endif
&& lineCap == other.lineCap && miterLimit == other.miterLimit;
}
bool textColorIsLegibleAgainstBackgroundColor(const Color& textColor, const Color& backgroundColor)
{
// Uses the WCAG 2.0 definition of legibility: a contrast ratio of 4.5:1 or greater.
// https://www.w3.org/TR/WCAG20/#visual-audio-contrast-contrast
return contrastRatio(textColor, backgroundColor) >= 4.5;
}
static Color adjustColorForVisibilityOnBackground(const Color& textColor, const Color& backgroundColor)
{
if (textColorIsLegibleAgainstBackgroundColor(textColor, backgroundColor))
return textColor;
if (textColor.luminance() > 0.5)
return textColor.darkened();
return textColor.lightened();
}
TextPaintStyle computeTextPaintStyle(const Frame& frame, const RenderStyle& lineStyle, const PaintInfo& paintInfo)
{
TextPaintStyle paintStyle;
#if HAVE(OS_DARK_MODE_SUPPORT)
paintStyle.useDarkAppearance = frame.document() ? frame.document()->useDarkAppearance(&lineStyle) : false;
#endif
auto viewportSize = frame.view() ? frame.view()->size() : IntSize();
paintStyle.strokeWidth = lineStyle.computedStrokeWidth(viewportSize);
paintStyle.paintOrder = lineStyle.paintOrder();
paintStyle.lineJoin = lineStyle.joinStyle();
paintStyle.lineCap = lineStyle.capStyle();
paintStyle.miterLimit = lineStyle.strokeMiterLimit();
if (paintInfo.forceTextColor()) {
paintStyle.fillColor = paintInfo.forcedTextColor();
paintStyle.strokeColor = paintInfo.forcedTextColor();
paintStyle.emphasisMarkColor = paintInfo.forcedTextColor();
return paintStyle;
}
if (lineStyle.insideDefaultButton()) {
Page* page = frame.page();
if (page && page->focusController().isActive()) {
OptionSet<StyleColorOptions> options;
if (page->useSystemAppearance())
options.add(StyleColorOptions::UseSystemAppearance);
paintStyle.fillColor = RenderTheme::singleton().defaultButtonTextColor(options);
return paintStyle;
}
}
paintStyle.fillColor = lineStyle.visitedDependentColorWithColorFilter(CSSPropertyWebkitTextFillColor);
bool forceBackgroundToWhite = false;
if (frame.document() && frame.document()->printing()) {
if (lineStyle.printColorAdjust() == PrintColorAdjust::Economy)
forceBackgroundToWhite = true;
if (frame.settings().shouldPrintBackgrounds())
forceBackgroundToWhite = false;
}
// Make the text fill color legible against a white background
if (forceBackgroundToWhite)
paintStyle.fillColor = adjustColorForVisibilityOnBackground(paintStyle.fillColor, Color::white);
paintStyle.strokeColor = lineStyle.colorByApplyingColorFilter(lineStyle.computedStrokeColor());
// Make the text stroke color legible against a white background
if (forceBackgroundToWhite)
paintStyle.strokeColor = adjustColorForVisibilityOnBackground(paintStyle.strokeColor, Color::white);
paintStyle.emphasisMarkColor = lineStyle.visitedDependentColorWithColorFilter(CSSPropertyWebkitTextEmphasisColor);
// Make the text stroke color legible against a white background
if (forceBackgroundToWhite)
paintStyle.emphasisMarkColor = adjustColorForVisibilityOnBackground(paintStyle.emphasisMarkColor, Color::white);
return paintStyle;
}
TextPaintStyle computeTextSelectionPaintStyle(const TextPaintStyle& textPaintStyle, const RenderText& renderer, const RenderStyle& lineStyle, const PaintInfo& paintInfo, std::optional<ShadowData>& selectionShadow)
{
TextPaintStyle selectionPaintStyle = textPaintStyle;
#if ENABLE(TEXT_SELECTION)
Color foreground = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : renderer.selectionForegroundColor();
if (foreground.isValid() && foreground != selectionPaintStyle.fillColor)
selectionPaintStyle.fillColor = foreground;
Color emphasisMarkForeground = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : renderer.selectionEmphasisMarkColor();
if (emphasisMarkForeground.isValid() && emphasisMarkForeground != selectionPaintStyle.emphasisMarkColor)
selectionPaintStyle.emphasisMarkColor = emphasisMarkForeground;
if (auto pseudoStyle = renderer.selectionPseudoStyle()) {
selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : pseudoStyle->textShadow());
auto viewportSize = renderer.frame().view() ? renderer.frame().view()->size() : IntSize();
float strokeWidth = pseudoStyle->computedStrokeWidth(viewportSize);
if (strokeWidth != selectionPaintStyle.strokeWidth)
selectionPaintStyle.strokeWidth = strokeWidth;
Color stroke = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : pseudoStyle->computedStrokeColor();
if (stroke != selectionPaintStyle.strokeColor)
selectionPaintStyle.strokeColor = stroke;
} else
selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : lineStyle.textShadow());
#else
UNUSED_PARAM(renderer);
UNUSED_PARAM(lineStyle);
UNUSED_PARAM(paintInfo);
selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : lineStyle.textShadow());
#endif
return selectionPaintStyle;
}
void updateGraphicsContext(GraphicsContext& context, const TextPaintStyle& paintStyle, FillColorType fillColorType)
{
TextDrawingModeFlags mode = context.textDrawingMode();
TextDrawingModeFlags newMode = mode;
if (paintStyle.strokeWidth > 0 && paintStyle.strokeColor.isVisible())
newMode.add(TextDrawingMode::Stroke);
if (mode != newMode) {
context.setTextDrawingMode(newMode);
mode = newMode;
}
#if HAVE(OS_DARK_MODE_SUPPORT)
context.setUseDarkAppearance(paintStyle.useDarkAppearance);
#endif
Color fillColor = fillColorType == UseEmphasisMarkColor ? paintStyle.emphasisMarkColor : paintStyle.fillColor;
if (mode.contains(TextDrawingMode::Fill) && (fillColor != context.fillColor()))
context.setFillColor(fillColor);
if (mode & TextDrawingMode::Stroke) {
if (paintStyle.strokeColor != context.strokeColor())
context.setStrokeColor(paintStyle.strokeColor);
if (paintStyle.strokeWidth != context.strokeThickness())
context.setStrokeThickness(paintStyle.strokeWidth);
context.setLineJoin(paintStyle.lineJoin);
context.setLineCap(paintStyle.lineCap);
if (paintStyle.lineJoin == LineJoin::Miter)
context.setMiterLimit(paintStyle.miterLimit);
}
}
}