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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
* Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
* Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
* Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
* Copyright (c) 2011, Code Aurora Forum. All rights reserved.
* Copyright (C) Research In Motion Limited 2011. All rights reserved.
* Copyright (C) 2012 Google Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "StyleFontSizeFunctions.h"
#include "CSSValueKeywords.h"
#include "Document.h"
#include "FontMetrics.h"
#include "FrameDestructionObserverInlines.h"
#include "LocalFrame.h"
#include "RenderStyleInlines.h"
#include "Settings.h"
namespace WebCore {
namespace Style {
float computedFontSizeFromSpecifiedSize(float specifiedSize, bool isAbsoluteSize, float zoomFactor, MinimumFontSizeRule minimumSizeRule, const Settings::Values& settings)
{
// Text with a 0px font size should not be visible and therefore needs to be
// exempt from minimum font size rules. Acid3 relies on this for pixel-perfect
// rendering. This is also compatible with other browsers that have minimum
// font size settings (e.g. Firefox).
if (std::abs(specifiedSize) < std::numeric_limits<float>::epsilon())
return 0.0f;
// We support two types of minimum font size. The first is a hard override that applies to
// all fonts. This is "minSize." The second type of minimum font size is a "smart minimum"
// that is applied only when the Web page can't know what size it really asked for, e.g.,
// when it uses logical sizes like "small" or expresses the font-size as a percentage of
// the user's default font setting.
// With the smart minimum, we never want to get smaller than the minimum font size to keep fonts readable.
// However we always allow the page to set an explicit pixel size that is smaller,
// since sites will mis-render otherwise (e.g., http://www.gamespot.com with a 9px minimum).
if (minimumSizeRule == MinimumFontSizeRule::None)
return specifiedSize;
int minSize = settings.minimumFontSize;
int minLogicalSize = settings.minimumLogicalFontSize;
float zoomedSize = specifiedSize * zoomFactor;
// Apply the hard minimum first. We only apply the hard minimum if after zooming we're still too small.
zoomedSize = std::max(zoomedSize, static_cast<float>(minSize));
// Now apply the smart minimum. This minimum is also only applied if we're still too small
// after zooming. The font size must either be relative to the user default or the original size
// must have been acceptable. In other words, we only apply the smart minimum whenever we're positive
// doing so won't disrupt the layout.
if (minimumSizeRule == MinimumFontSizeRule::AbsoluteAndRelative && (specifiedSize >= minLogicalSize || !isAbsoluteSize))
zoomedSize = std::max(zoomedSize, static_cast<float>(minLogicalSize));
// Also clamp to a reasonable maximum to prevent insane font sizes from causing crashes on various
// platforms. (I'm looking at you, Windows.)
return std::min(maximumAllowedFontSize, zoomedSize);
}
float computedFontSizeFromSpecifiedSize(float specifiedSize, bool isAbsoluteSize, bool useSVGZoomRules, const RenderStyle* style, const Document& document)
{
float zoomFactor = 1.0f;
if (!useSVGZoomRules) {
zoomFactor = style->usedZoom();
auto* frame = document.frame();
if (frame && style->textZoom() != TextZoom::Reset)
zoomFactor *= frame->textZoomFactor();
}
return computedFontSizeFromSpecifiedSize(specifiedSize, isAbsoluteSize, zoomFactor, useSVGZoomRules ? MinimumFontSizeRule::None : MinimumFontSizeRule::AbsoluteAndRelative, document.settingsValues());
}
float computedFontSizeFromSpecifiedSizeForSVGInlineText(float specifiedSize, bool isAbsoluteSize, float zoomFactor, const Document& document)
{
return computedFontSizeFromSpecifiedSize(specifiedSize, isAbsoluteSize, zoomFactor, MinimumFontSizeRule::Absolute, document.settingsValues());
}
constexpr int fontSizeTableMax = 16;
constexpr int fontSizeTableMin = 9;
// WinIE/Nav4 table for font sizes. Designed to match the legacy font mapping system of HTML.
static constexpr std::array quirksFontSizeTable {
std::array { 9, 9, 9, 9, 11, 14, 18, 28 },
std::array { 9, 9, 9, 10, 12, 15, 20, 31 },
std::array { 9, 9, 9, 11, 13, 17, 22, 34 },
std::array { 9, 9, 10, 12, 14, 18, 24, 37 },
std::array { 9, 9, 10, 13, 16, 20, 26, 40 }, // fixed font default (13)
std::array { 9, 9, 11, 14, 17, 21, 28, 42 },
std::array { 9, 10, 12, 15, 17, 23, 30, 45 },
std::array { 9, 10, 13, 16, 18, 24, 32, 48 } // proportional font default (16)
};
// HTML 1 2 3 4 5 6 7
// CSS xxs xs s m l xl xxl
// |
// user pref
// Strict mode table matches MacIE and Mozilla's settings exactly.
static constexpr std::array strictFontSizeTable {
std::array { 9, 9, 9, 9, 11, 14, 18, 27 },
std::array { 9, 9, 9, 10, 12, 15, 20, 30 },
std::array { 9, 9, 10, 11, 13, 17, 22, 33 },
std::array { 9, 9, 10, 12, 14, 18, 24, 36 },
std::array { 9, 10, 12, 13, 16, 20, 26, 39 }, // fixed font default (13)
std::array { 9, 10, 12, 14, 17, 21, 28, 42 },
std::array { 9, 10, 13, 15, 18, 23, 30, 45 },
std::array { 9, 10, 13, 16, 18, 24, 32, 48 } // proportional font default (16)
};
// HTML 1 2 3 4 5 6 7
// CSS xxs xs s m l xl xxl
// |
// user pref
// For values outside the range of the table, we use Todd Fahrner's suggested scale
// factors for each keyword value.
static constexpr std::array fontSizeFactors { 0.60f, 0.75f, 0.89f, 1.0f, 1.2f, 1.5f, 2.0f, 3.0f };
float fontSizeForKeyword(unsigned keywordID, bool shouldUseFixedDefaultSize, const Settings::Values& settings, bool inQuirksMode)
{
int mediumSize = shouldUseFixedDefaultSize ? settings.defaultFixedFontSize : settings.defaultFontSize;
if (mediumSize >= fontSizeTableMin && mediumSize <= fontSizeTableMax) {
// Look up the entry in the table.
int row = mediumSize - fontSizeTableMin;
int col = (keywordID - CSSValueXxSmall);
return inQuirksMode ? quirksFontSizeTable[row][col] : strictFontSizeTable[row][col];
}
// Value is outside the range of the table. Apply the scale factor instead.
float minLogicalSize = std::max<float>(settings.minimumLogicalFontSize, 1);
return std::max(fontSizeFactors[keywordID - CSSValueXxSmall] * mediumSize, minLogicalSize);
}
float fontSizeForKeyword(unsigned keywordID, bool shouldUseFixedDefaultSize, const Document& document)
{
return fontSizeForKeyword(keywordID, shouldUseFixedDefaultSize, document.settingsValues(), document.inQuirksMode());
}
template<typename T, std::size_t Extent>
static int findNearestLegacyFontSize(int pixelFontSize, std::span<const T, Extent> table, int multiplier)
{
// Ignore table[0] because xx-small does not correspond to any legacy font size.
for (size_t i = 1; i < table.size() - 1; ++i) {
if (pixelFontSize * 2 < (table[i] + table[i + 1]) * multiplier)
return i;
}
return table.size() - 1;
}
int legacyFontSizeForPixelSize(int pixelFontSize, bool shouldUseFixedDefaultSize, const Document& document)
{
bool quirksMode = document.inQuirksMode();
int mediumSize = shouldUseFixedDefaultSize ? document.settings().defaultFixedFontSize() : document.settings().defaultFontSize();
if (mediumSize >= fontSizeTableMin && mediumSize <= fontSizeTableMax) {
int row = mediumSize - fontSizeTableMin;
return findNearestLegacyFontSize(pixelFontSize, std::span { quirksMode ? quirksFontSizeTable[row] : strictFontSizeTable[row] }, 1);
}
return findNearestLegacyFontSize(pixelFontSize, std::span { fontSizeFactors }, mediumSize);
}
static float adjustedFontSize(float size, float sizeAdjust, float metricValue)
{
if (!size)
return 0;
float aspectValue = metricValue / size;
return size * (sizeAdjust / aspectValue);
}
float adjustedFontSize(float size, const FontSizeAdjust& sizeAdjust, const FontMetrics& metrics)
{
// FIXME: The behavior for missing metrics has yet to be defined.
// https://github.com/w3c/csswg-drafts/issues/6384
switch (sizeAdjust.metric) {
case FontSizeAdjust::Metric::CapHeight:
return metrics.capHeight() ? adjustedFontSize(size, *sizeAdjust.value, *metrics.capHeight()) : size;
case FontSizeAdjust::Metric::ChWidth:
return metrics.zeroWidth() ? adjustedFontSize(size, *sizeAdjust.value, *metrics.zeroWidth()) : size;
// FIXME: Are ic-height and ic-width the same? Gecko treats them the same.
case FontSizeAdjust::Metric::IcWidth:
case FontSizeAdjust::Metric::IcHeight:
return metrics.ideogramWidth() ? adjustedFontSize(size, *sizeAdjust.value, *metrics.ideogramWidth()) : size;
case FontSizeAdjust::Metric::ExHeight:
default:
return metrics.xHeight() ? adjustedFontSize(size, *sizeAdjust.value, *metrics.xHeight()) : size;
}
ASSERT_NOT_REACHED();
}
} // namespace Style
} // namespace WebCore
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