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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 "third_party/blink/renderer/core/css/font_size_functions.h"
#include "third_party/blink/renderer/core/css_value_keywords.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/frame/settings.h"
namespace blink {
float FontSizeFunctions::GetComputedSizeFromSpecifiedSize(
const Document* document,
float zoom_factor,
bool is_absolute_size,
float specified_size,
ApplyMinimumFontSize apply_minimum_font_size) {
// 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(specified_size) < std::numeric_limits<float>::epsilon())
return 0.0f;
Settings* settings = document->GetSettings();
if (apply_minimum_font_size && settings) {
// We support two types of minimum font size. The first is a hard override
// that applies to all fonts. This is "min_size." 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).
int min_size = settings->GetMinimumFontSize();
int min_logical_size = settings->GetMinimumLogicalFontSize();
// Apply the hard minimum first.
if (specified_size < min_size)
specified_size = min_size;
// Now apply the "smart minimum". 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 (specified_size < min_logical_size && !is_absolute_size)
specified_size = min_logical_size;
}
// 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(kMaximumAllowedFontSize, specified_size * zoom_factor);
}
const int kFontSizeTableMax = 16;
const int kDefaultMediumFontSize = 12;
const int kFontSizeTableMin = 9;
const int kTotalKeywords = 8;
// WinIE/Nav4 table for font sizes. Designed to match the legacy font mapping
// system of HTML.
static const int kQuirksFontSizeTable[kFontSizeTableMax - kFontSizeTableMin +
1][kTotalKeywords] = {
{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 kStrictFontSizeTable[kFontSizeTableMax - kFontSizeTableMin +
1][kTotalKeywords] = {
{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 kFontSizeFactors[kTotalKeywords] = {
0.60f, 0.75f, 0.89f, 1.0f, 1.2f, 1.5f, 2.0f, 3.0f};
static int inline RowFromMediumFontSizeInRange(const Settings* settings,
bool quirks_mode,
bool is_monospace,
int& medium_size) {
medium_size = settings ? (is_monospace ? settings->GetDefaultFixedFontSize()
: settings->GetDefaultFontSize())
: kDefaultMediumFontSize;
if (medium_size >= kFontSizeTableMin && medium_size <= kFontSizeTableMax)
return medium_size - kFontSizeTableMin;
return -1;
}
float FontSizeFunctions::FontSizeForKeyword(const Document* document,
unsigned keyword,
bool is_monospace) {
DCHECK_GE(keyword, 1u);
DCHECK_LE(keyword, 8u);
const Settings* settings = document ? document->GetSettings() : nullptr;
bool quirks_mode = document ? document->InQuirksMode() : false;
int medium_size = 0;
int row = RowFromMediumFontSizeInRange(settings, quirks_mode, is_monospace,
medium_size);
if (row >= 0) {
int col = (keyword - 1);
return quirks_mode ? kQuirksFontSizeTable[row][col]
: kStrictFontSizeTable[row][col];
}
// Value is outside the range of the table. Apply the scale factor instead.
float min_logical_size =
settings ? std::max(settings->GetMinimumLogicalFontSize(), 1) : 1;
return std::max(kFontSizeFactors[keyword - 1] * medium_size,
min_logical_size);
}
template <typename T>
static int FindNearestLegacyFontSize(int pixel_font_size,
const T* table,
int multiplier) {
// Ignore table[0] because xx-small does not correspond to any legacy font
// size.
for (int i = 1; i < kTotalKeywords - 1; i++) {
if (pixel_font_size * 2 < (table[i] + table[i + 1]) * multiplier)
return i;
}
return kTotalKeywords - 1;
}
int FontSizeFunctions::LegacyFontSize(const Document* document,
int pixel_font_size,
bool is_monospace) {
const Settings* settings = document->GetSettings();
if (!settings)
return 1;
bool quirks_mode = document->InQuirksMode();
int medium_size = 0;
int row = RowFromMediumFontSizeInRange(settings, quirks_mode, is_monospace,
medium_size);
if (row >= 0) {
return FindNearestLegacyFontSize<int>(
pixel_font_size,
quirks_mode ? kQuirksFontSizeTable[row] : kStrictFontSizeTable[row], 1);
}
return FindNearestLegacyFontSize<float>(pixel_font_size, kFontSizeFactors,
medium_size);
}
} // namespace blink
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