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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 "Frame.h"
#include "RenderStyle.h"
#include "Settings.h"
namespace WebCore {
namespace Style {
enum ESmartMinimumForFontSize { DoNotUseSmartMinimumForFontSize, UseSmartMinimumForFontFize };
static float computedFontSizeFromSpecifiedSize(float specifiedSize, bool isAbsoluteSize, float zoomFactor, ESmartMinimumForFontSize useSmartMinimumForFontSize, const Settings* 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 (fabsf(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 (!settings)
return 1.0f;
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.
if (zoomedSize < minSize)
zoomedSize = 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 (useSmartMinimumForFontSize && zoomedSize < minLogicalSize && (specifiedSize >= minLogicalSize || !isAbsoluteSize))
zoomedSize = 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->effectiveZoom();
if (Frame* frame = document.frame())
zoomFactor *= frame->textZoomFactor();
}
return computedFontSizeFromSpecifiedSize(specifiedSize, isAbsoluteSize, zoomFactor, UseSmartMinimumForFontFize, document.settings());
}
float computedFontSizeFromSpecifiedSizeForSVGInlineText(float specifiedSize, bool isAbsoluteSize, float zoomFactor, const Document& document)
{
return computedFontSizeFromSpecifiedSize(specifiedSize, isAbsoluteSize, zoomFactor, DoNotUseSmartMinimumForFontSize, document.settings());
}
const int fontSizeTableMax = 16;
const int fontSizeTableMin = 9;
const int totalKeywords = 8;
// WinIE/Nav4 table for font sizes. Designed to match the legacy font mapping system of HTML.
static const int quirksFontSizeTable[fontSizeTableMax - fontSizeTableMin + 1][totalKeywords] =
{
{ 9, 9, 9, 9, 11, 14, 18, 28 },
{ 9, 9, 9, 10, 12, 15, 20, 31 },
{ 9, 9, 9, 11, 13, 17, 22, 34 },
{ 9, 9, 10, 12, 14, 18, 24, 37 },
{ 9, 9, 10, 13, 16, 20, 26, 40 }, // fixed font default (13)
{ 9, 9, 11, 14, 17, 21, 28, 42 },
{ 9, 10, 12, 15, 17, 23, 30, 45 },
{ 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 const int strictFontSizeTable[fontSizeTableMax - fontSizeTableMin + 1][totalKeywords] =
{
{ 9, 9, 9, 9, 11, 14, 18, 27 },
{ 9, 9, 9, 10, 12, 15, 20, 30 },
{ 9, 9, 10, 11, 13, 17, 22, 33 },
{ 9, 9, 10, 12, 14, 18, 24, 36 },
{ 9, 10, 12, 13, 16, 20, 26, 39 }, // fixed font default (13)
{ 9, 10, 12, 14, 17, 21, 28, 42 },
{ 9, 10, 13, 15, 18, 23, 30, 45 },
{ 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 const float fontSizeFactors[totalKeywords] = { 0.60f, 0.75f, 0.89f, 1.0f, 1.2f, 1.5f, 2.0f, 3.0f };
float fontSizeForKeyword(unsigned keywordID, bool shouldUseFixedDefaultSize, const Document& document)
{
Settings* settings = document.settings();
if (!settings)
return 1.0f;
bool quirksMode = document.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 quirksMode ? quirksFontSizeTable[row][col] : strictFontSizeTable[row][col];
}
// Value is outside the range of the table. Apply the scale factor instead.
float minLogicalSize = std::max(settings->minimumLogicalFontSize(), 1);
return std::max(fontSizeFactors[keywordID - CSSValueXxSmall] * mediumSize, minLogicalSize);
}
template<typename T>
static int findNearestLegacyFontSize(int pixelFontSize, const T* table, int multiplier)
{
// Ignore table[0] because xx-small does not correspond to any legacy font size.
for (int i = 1; i < totalKeywords - 1; i++) {
if (pixelFontSize * 2 < (table[i] + table[i + 1]) * multiplier)
return i;
}
return totalKeywords - 1;
}
int legacyFontSizeForPixelSize(int pixelFontSize, bool shouldUseFixedDefaultSize, const Document& document)
{
Settings* settings = document.settings();
if (!settings)
return 1;
bool quirksMode = document.inQuirksMode();
int mediumSize = shouldUseFixedDefaultSize ? settings->defaultFixedFontSize() : settings->defaultFontSize();
if (mediumSize >= fontSizeTableMin && mediumSize <= fontSizeTableMax) {
int row = mediumSize - fontSizeTableMin;
return findNearestLegacyFontSize<int>(pixelFontSize, quirksMode ? quirksFontSizeTable[row] : strictFontSizeTable[row], 1);
}
return findNearestLegacyFontSize<float>(pixelFontSize, fontSizeFactors, mediumSize);
}
}
}
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