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/*
* Copyright (C) 2015-2017 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 "TextSizeAdjustment.h"
#if ENABLE(TEXT_AUTOSIZING)
#include "RenderStyle.h"
#include "RenderStyleInlines.h"
namespace WebCore {
bool AutosizeStatus::probablyContainsASmallFixedNumberOfLines(const RenderStyle& style)
{
auto& lineHeightAsLength = style.specifiedLineHeight();
if (!lineHeightAsLength.isFixed() && !lineHeightAsLength.isPercent())
return false;
auto& maxHeight = style.maxHeight();
std::optional<Length> heightOrMaxHeightAsLength;
if (maxHeight.isFixed())
heightOrMaxHeightAsLength = style.maxHeight();
else if (style.height().isFixed() && (!maxHeight.isSpecified() || maxHeight.isUndefined()))
heightOrMaxHeightAsLength = style.height();
if (!heightOrMaxHeightAsLength)
return false;
float heightOrMaxHeight = heightOrMaxHeightAsLength->value();
if (heightOrMaxHeight <= 0)
return false;
float approximateLineHeight = lineHeightAsLength.isPercent() ? lineHeightAsLength.percent() * style.specifiedFontSize() / 100 : lineHeightAsLength.value();
if (approximateLineHeight <= 0)
return false;
float approximateNumberOfLines = heightOrMaxHeight / approximateLineHeight;
auto& lineClamp = style.lineClamp();
if (!lineClamp.isNone() && !lineClamp.isPercentage()) {
int lineClampValue = lineClamp.value();
return lineClampValue && std::floor(approximateNumberOfLines) == lineClampValue;
}
const int maximumNumberOfLines = 5;
const float thresholdForConsideringAnApproximateNumberOfLinesToBeCloseToAnInteger = 0.01;
return approximateNumberOfLines <= maximumNumberOfLines + thresholdForConsideringAnApproximateNumberOfLinesToBeCloseToAnInteger
&& approximateNumberOfLines - std::floor(approximateNumberOfLines) <= thresholdForConsideringAnApproximateNumberOfLinesToBeCloseToAnInteger;
}
auto AutosizeStatus::computeStatus(const RenderStyle& style) -> AutosizeStatus
{
auto result = style.autosizeStatus().fields();
auto shouldAvoidAutosizingEntireSubtree = [&] {
if (style.display() == DisplayType::None)
return true;
const float maximumDifferenceBetweenFixedLineHeightAndFontSize = 5;
auto& lineHeight = style.specifiedLineHeight();
if (lineHeight.isFixed() && lineHeight.value() - style.specifiedFontSize() > maximumDifferenceBetweenFixedLineHeightAndFontSize)
return false;
if (style.whiteSpaceCollapse() == WhiteSpaceCollapse::Collapse && style.textWrapMode() == TextWrapMode::NoWrap)
return false;
return probablyContainsASmallFixedNumberOfLines(style);
};
if (shouldAvoidAutosizingEntireSubtree())
result.add(Fields::AvoidSubtree);
if (style.height().isFixed())
result.add(Fields::FixedHeight);
if (style.width().isFixed())
result.add(Fields::FixedWidth);
if (style.overflowX() == Overflow::Hidden)
result.add(Fields::OverflowXHidden);
if (style.isFloating())
result.add(Fields::Floating);
return AutosizeStatus(result);
}
void AutosizeStatus::updateStatus(RenderStyle& style)
{
style.setAutosizeStatus(AutosizeStatus(computeStatus(style)));
}
float AutosizeStatus::idempotentTextSize(float specifiedSize, float pageScale)
{
if (pageScale >= 1)
return specifiedSize;
// This describes a piecewise curve when the page scale is 2/3.
static constexpr std::array points = {
FloatPoint { 0.0f, 0.0f },
FloatPoint { 6.0f, 9.0f },
FloatPoint { 14.0f, 17.0f }
};
// When the page scale is 1, the curve should be the identity.
// Linearly interpolate between the curve above and identity based on the page scale.
// Beware that depending on the specific values picked in the curve, this interpolation might change the shape of the curve for very small pageScales.
pageScale = std::min(std::max(pageScale, 0.5f), 1.0f);
auto scalePoint = [&](FloatPoint point) {
float fraction = 3.0f - 3.0f * pageScale;
point.setY(point.x() + (point.y() - point.x()) * fraction);
return point;
};
if (specifiedSize <= 0)
return 0;
float result = scalePoint(points.back()).y();
for (size_t i = 1; i < points.size(); ++i) {
if (points[i].x() < specifiedSize)
continue;
auto leftPoint = scalePoint(points[i - 1]);
auto rightPoint = scalePoint(points[i]);
float fraction = (specifiedSize - leftPoint.x()) / (rightPoint.x() - leftPoint.x());
result = leftPoint.y() + fraction * (rightPoint.y() - leftPoint.y());
break;
}
return std::max(std::round(result), specifiedSize);
}
}
#endif
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