1 /* 2 * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org) 3 * (C) 2004-2005 Allan Sandfeld Jensen (kde (at) carewolf.com) 4 * Copyright (C) 2006, 2007 Nicholas Shanks (webkit (at) nickshanks.com) 5 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved. 6 * Copyright (C) 2007 Alexey Proskuryakov <ap (at) webkit.org> 7 * Copyright (C) 2007, 2008 Eric Seidel <eric (at) webkit.org> 8 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/) 9 * Copyright (c) 2011, Code Aurora Forum. All rights reserved. 10 * Copyright (C) Research In Motion Limited 2011. All rights reserved. 11 * Copyright (C) 2012 Google Inc. All rights reserved. 12 * 13 * This library is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU Library General Public 15 * License as published by the Free Software Foundation; either 16 * version 2 of the License, or (at your option) any later version. 17 * 18 * This library is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 * Library General Public License for more details. 22 * 23 * You should have received a copy of the GNU Library General Public License 24 * along with this library; see the file COPYING.LIB. If not, write to 25 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 26 * Boston, MA 02110-1301, USA. 27 */ 28 29 #include "config.h" 30 #include "core/css/FontSize.h" 31 32 #include "CSSValueKeywords.h" 33 #include "core/dom/Document.h" 34 #include "core/frame/Settings.h" 35 36 namespace WebCore { 37 38 float FontSize::getComputedSizeFromSpecifiedSize(const Document* document, float zoomFactor, bool isAbsoluteSize, float specifiedSize, ESmartMinimumForFontSize useSmartMinimumForFontSize) 39 { 40 // Text with a 0px font size should not be visible and therefore needs to be 41 // exempt from minimum font size rules. Acid3 relies on this for pixel-perfect 42 // rendering. This is also compatible with other browsers that have minimum 43 // font size settings (e.g. Firefox). 44 if (fabsf(specifiedSize) < std::numeric_limits<float>::epsilon()) 45 return 0.0f; 46 47 // We support two types of minimum font size. The first is a hard override that applies to 48 // all fonts. This is "minSize." The second type of minimum font size is a "smart minimum" 49 // that is applied only when the Web page can't know what size it really asked for, e.g., 50 // when it uses logical sizes like "small" or expresses the font-size as a percentage of 51 // the user's default font setting. 52 53 // With the smart minimum, we never want to get smaller than the minimum font size to keep fonts readable. 54 // However we always allow the page to set an explicit pixel size that is smaller, 55 // since sites will mis-render otherwise (e.g., http://www.gamespot.com with a 9px minimum). 56 57 Settings* settings = document->settings(); 58 if (!settings) 59 return 1.0f; 60 61 int minSize = settings->minimumFontSize(); 62 int minLogicalSize = settings->minimumLogicalFontSize(); 63 float zoomedSize = specifiedSize * zoomFactor; 64 65 // Apply the hard minimum first. We only apply the hard minimum if after zooming we're still too small. 66 if (zoomedSize < minSize) 67 zoomedSize = minSize; 68 69 // Now apply the "smart minimum." This minimum is also only applied if we're still too small 70 // after zooming. The font size must either be relative to the user default or the original size 71 // must have been acceptable. In other words, we only apply the smart minimum whenever we're positive 72 // doing so won't disrupt the layout. 73 if (useSmartMinimumForFontSize && zoomedSize < minLogicalSize && (specifiedSize >= minLogicalSize || !isAbsoluteSize)) 74 zoomedSize = minLogicalSize; 75 76 // Also clamp to a reasonable maximum to prevent insane font sizes from causing crashes on various 77 // platforms (I'm looking at you, Windows.) 78 return std::min(maximumAllowedFontSize, zoomedSize); 79 } 80 81 const int fontSizeTableMax = 16; 82 const int fontSizeTableMin = 9; 83 const int totalKeywords = 8; 84 85 // WinIE/Nav4 table for font sizes. Designed to match the legacy font mapping system of HTML. 86 static const int quirksFontSizeTable[fontSizeTableMax - fontSizeTableMin + 1][totalKeywords] = 87 { 88 { 9, 9, 9, 9, 11, 14, 18, 28 }, 89 { 9, 9, 9, 10, 12, 15, 20, 31 }, 90 { 9, 9, 9, 11, 13, 17, 22, 34 }, 91 { 9, 9, 10, 12, 14, 18, 24, 37 }, 92 { 9, 9, 10, 13, 16, 20, 26, 40 }, // fixed font default (13) 93 { 9, 9, 11, 14, 17, 21, 28, 42 }, 94 { 9, 10, 12, 15, 17, 23, 30, 45 }, 95 { 9, 10, 13, 16, 18, 24, 32, 48 } // proportional font default (16) 96 }; 97 // HTML 1 2 3 4 5 6 7 98 // CSS xxs xs s m l xl xxl 99 // | 100 // user pref 101 102 // Strict mode table matches MacIE and Mozilla's settings exactly. 103 static const int strictFontSizeTable[fontSizeTableMax - fontSizeTableMin + 1][totalKeywords] = 104 { 105 { 9, 9, 9, 9, 11, 14, 18, 27 }, 106 { 9, 9, 9, 10, 12, 15, 20, 30 }, 107 { 9, 9, 10, 11, 13, 17, 22, 33 }, 108 { 9, 9, 10, 12, 14, 18, 24, 36 }, 109 { 9, 10, 12, 13, 16, 20, 26, 39 }, // fixed font default (13) 110 { 9, 10, 12, 14, 17, 21, 28, 42 }, 111 { 9, 10, 13, 15, 18, 23, 30, 45 }, 112 { 9, 10, 13, 16, 18, 24, 32, 48 } // proportional font default (16) 113 }; 114 // HTML 1 2 3 4 5 6 7 115 // CSS xxs xs s m l xl xxl 116 // | 117 // user pref 118 119 // For values outside the range of the table, we use Todd Fahrner's suggested scale 120 // factors for each keyword value. 121 static const float fontSizeFactors[totalKeywords] = { 0.60f, 0.75f, 0.89f, 1.0f, 1.2f, 1.5f, 2.0f, 3.0f }; 122 123 float FontSize::fontSizeForKeyword(const Document* document, int keyword, bool shouldUseFixedDefaultSize) 124 { 125 const Settings* settings = document->settings(); 126 if (!settings) 127 return 1.0f; 128 129 bool quirksMode = document->inQuirksMode(); 130 int mediumSize = shouldUseFixedDefaultSize ? settings->defaultFixedFontSize() : settings->defaultFontSize(); 131 if (mediumSize >= fontSizeTableMin && mediumSize <= fontSizeTableMax) { 132 // Look up the entry in the table. 133 int row = mediumSize - fontSizeTableMin; 134 int col = (keyword - CSSValueXxSmall); 135 return quirksMode ? quirksFontSizeTable[row][col] : strictFontSizeTable[row][col]; 136 } 137 138 // Value is outside the range of the table. Apply the scale factor instead. 139 float minLogicalSize = std::max(settings->minimumLogicalFontSize(), 1); 140 return std::max(fontSizeFactors[keyword - CSSValueXxSmall] * mediumSize, minLogicalSize); 141 } 142 143 144 145 template<typename T> 146 static int findNearestLegacyFontSize(int pixelFontSize, const T* table, int multiplier) 147 { 148 // Ignore table[0] because xx-small does not correspond to any legacy font size. 149 for (int i = 1; i < totalKeywords - 1; i++) { 150 if (pixelFontSize * 2 < (table[i] + table[i + 1]) * multiplier) 151 return i; 152 } 153 return totalKeywords - 1; 154 } 155 156 int FontSize::legacyFontSize(const Document* document, int pixelFontSize, bool shouldUseFixedDefaultSize) 157 { 158 const Settings* settings = document->settings(); 159 if (!settings) 160 return 1; 161 162 bool quirksMode = document->inQuirksMode(); 163 int mediumSize = shouldUseFixedDefaultSize ? settings->defaultFixedFontSize() : settings->defaultFontSize(); 164 if (mediumSize >= fontSizeTableMin && mediumSize <= fontSizeTableMax) { 165 int row = mediumSize - fontSizeTableMin; 166 return findNearestLegacyFontSize<int>(pixelFontSize, quirksMode ? quirksFontSizeTable[row] : strictFontSizeTable[row], 1); 167 } 168 169 return findNearestLegacyFontSize<float>(pixelFontSize, fontSizeFactors, mediumSize); 170 } 171 172 } // namespace WebCore 173
