SVGFontFaceElement.cpp   [plain text]

/*
 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2008 Apple 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"

#if ENABLE(SVG_FONTS)
#include "SVGFontFaceElement.h"

#include "CSSFontFaceSrcValue.h"
#include "CSSParser.h"
#include "CSSPropertyNames.h"
#include "CSSStyleSheet.h"
#include "CSSValueKeywords.h"
#include "CSSValueList.h"
#include "Document.h"
#include "ElementIterator.h"
#include "FontCascade.h"
#include "SVGDocumentExtensions.h"
#include "SVGFontElement.h"
#include "SVGFontFaceSrcElement.h"
#include "SVGGlyphElement.h"
#include "SVGNames.h"
#include "StyleProperties.h"
#include "StyleResolver.h"
#include "StyleRule.h"
#include "StyleScope.h"
#include <math.h>

namespace WebCore {

using namespace SVGNames;

inline SVGFontFaceElement::SVGFontFaceElement(const QualifiedName& tagName, Document& document)
    : SVGElement(tagName, document)
    , m_fontFaceRule(StyleRuleFontFace::create(MutableStyleProperties::create(HTMLStandardMode)))
    , m_fontElement(nullptr)
{
    ASSERT(hasTagName(font_faceTag));
}

Ref<SVGFontFaceElement> SVGFontFaceElement::create(const QualifiedName& tagName, Document& document)
{
    return adoptRef(*new SVGFontFaceElement(tagName, document));
}

void SVGFontFaceElement::parseAttribute(const QualifiedName& name, const AtomicString& value)
{    
    CSSPropertyID propId = cssPropertyIdForSVGAttributeName(name);
    if (propId > 0) {
        // FIXME: Parse using the @font-face descriptor grammars, not the property grammars.
        m_fontFaceRule->mutableProperties().setProperty(propId, value, false);
        rebuildFontFace();
        return;
    }
    
    SVGElement::parseAttribute(name, value);
}

unsigned SVGFontFaceElement::unitsPerEm() const
{
    const AtomicString& value = attributeWithoutSynchronization(units_per_emAttr);
    if (value.isEmpty())
        return FontMetrics::defaultUnitsPerEm;

    return static_cast<unsigned>(ceilf(value.toFloat()));
}

int SVGFontFaceElement::xHeight() const
{
    return static_cast<int>(ceilf(attributeWithoutSynchronization(x_heightAttr).toFloat()));
}

int SVGFontFaceElement::capHeight() const
{
    return static_cast<int>(ceilf(attributeWithoutSynchronization(cap_heightAttr).toFloat()));
}

float SVGFontFaceElement::horizontalOriginX() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The X-coordinate in the font coordinate system of the origin of a glyph to be used when
    // drawing horizontally oriented text. (Note that the origin applies to all glyphs in the font.)
    // If the attribute is not specified, the effect is as if a value of "0" were specified.
    return m_fontElement->attributeWithoutSynchronization(horiz_origin_xAttr).toFloat();
}

float SVGFontFaceElement::horizontalOriginY() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The Y-coordinate in the font coordinate system of the origin of a glyph to be used when
    // drawing horizontally oriented text. (Note that the origin applies to all glyphs in the font.)
    // If the attribute is not specified, the effect is as if a value of "0" were specified.
    return m_fontElement->attributeWithoutSynchronization(horiz_origin_yAttr).toFloat();
}

float SVGFontFaceElement::horizontalAdvanceX() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The default horizontal advance after rendering a glyph in horizontal orientation. Glyph
    // widths are required to be non-negative, even if the glyph is typically rendered right-to-left,
    // as in Hebrew and Arabic scripts.
    return m_fontElement->attributeWithoutSynchronization(horiz_adv_xAttr).toFloat();
}

float SVGFontFaceElement::verticalOriginX() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The default X-coordinate in the font coordinate system of the origin of a glyph to be used when
    // drawing vertically oriented text. If the attribute is not specified, the effect is as if the attribute
    // were set to half of the effective value of attribute horiz-adv-x.
    const AtomicString& value = m_fontElement->attributeWithoutSynchronization(vert_origin_xAttr);
    if (value.isEmpty())
        return horizontalAdvanceX() / 2.0f;

    return value.toFloat();
}

float SVGFontFaceElement::verticalOriginY() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The default Y-coordinate in the font coordinate system of the origin of a glyph to be used when
    // drawing vertically oriented text. If the attribute is not specified, the effect is as if the attribute
    // were set to the position specified by the font's ascent attribute.             
    const AtomicString& value = m_fontElement->attributeWithoutSynchronization(vert_origin_yAttr);
    if (value.isEmpty())
        return ascent();

    return value.toFloat();
}

float SVGFontFaceElement::verticalAdvanceY() const
{
    if (!m_fontElement)
        return 0.0f;

    // Spec: The default vertical advance after rendering a glyph in vertical orientation. If the attribute is
    // not specified, the effect is as if a value equivalent of one em were specified (see units-per-em).                    
    const AtomicString& value = m_fontElement->attributeWithoutSynchronization(vert_adv_yAttr);
       if (value.isEmpty())
        return 1.0f;

    return value.toFloat();
}

int SVGFontFaceElement::ascent() const
{
    // Spec: Same syntax and semantics as the 'ascent' descriptor within an @font-face rule. The maximum
    // unaccented height of the font within the font coordinate system. If the attribute is not specified,
    // the effect is as if the attribute were set to the difference between the units-per-em value and the
    // vert-origin-y value for the corresponding font.
    const AtomicString& ascentValue = attributeWithoutSynchronization(ascentAttr);
    if (!ascentValue.isEmpty())
        return static_cast<int>(ceilf(ascentValue.toFloat()));

    if (m_fontElement) {
        const AtomicString& vertOriginY = m_fontElement->attributeWithoutSynchronization(vert_origin_yAttr);
        if (!vertOriginY.isEmpty())
            return static_cast<int>(unitsPerEm()) - static_cast<int>(ceilf(vertOriginY.toFloat()));
    }

    // Match Batiks default value
    return static_cast<int>(ceilf(unitsPerEm() * 0.8f));
}

int SVGFontFaceElement::descent() const
{
    // Spec: Same syntax and semantics as the 'descent' descriptor within an @font-face rule. The maximum
    // unaccented depth of the font within the font coordinate system. If the attribute is not specified,
    // the effect is as if the attribute were set to the vert-origin-y value for the corresponding font.
    const AtomicString& descentValue = attributeWithoutSynchronization(descentAttr);
    if (!descentValue.isEmpty()) {
        // 14 different W3C SVG 1.1 testcases use a negative descent value,
        // where a positive was meant to be used  Including:
        // animate-elem-24-t.svg, fonts-elem-01-t.svg, fonts-elem-02-t.svg (and 11 others)
        int descent = static_cast<int>(ceilf(descentValue.toFloat()));
        return descent < 0 ? -descent : descent;
    }

    if (m_fontElement) {
        const AtomicString& vertOriginY = m_fontElement->attributeWithoutSynchronization(vert_origin_yAttr);
        if (!vertOriginY.isEmpty())
            return static_cast<int>(ceilf(vertOriginY.toFloat()));
    }

    // Match Batiks default value
    return static_cast<int>(ceilf(unitsPerEm() * 0.2f));
}

String SVGFontFaceElement::fontFamily() const
{
    return m_fontFaceRule->properties().getPropertyValue(CSSPropertyFontFamily);
}

SVGFontElement* SVGFontFaceElement::associatedFontElement() const
{
    ASSERT(parentNode() == m_fontElement);
    ASSERT(!parentNode() || is<SVGFontElement>(*parentNode()));
    return m_fontElement;
}

void SVGFontFaceElement::rebuildFontFace()
{
    if (!isConnected()) {
        ASSERT(!m_fontElement);
        return;
    }

    // we currently ignore all but the first src element, alternatively we could concat them
    auto srcElement = childrenOfType<SVGFontFaceSrcElement>(*this).first();

    bool describesParentFont = is<SVGFontElement>(*parentNode());
    RefPtr<CSSValueList> list;

    if (describesParentFont) {
        m_fontElement = downcast<SVGFontElement>(parentNode());

        list = CSSValueList::createCommaSeparated();
        list->append(CSSFontFaceSrcValue::createLocal(fontFamily()));
    } else {
        m_fontElement = nullptr;
        if (srcElement)
            list = srcElement->srcValue();
    }

    if (!list || !list->length())
        return;

    // Parse in-memory CSS rules
    m_fontFaceRule->mutableProperties().addParsedProperty(CSSProperty(CSSPropertySrc, list));

    if (describesParentFont) {    
        // Traverse parsed CSS values and associate CSSFontFaceSrcValue elements with ourselves.
        RefPtr<CSSValue> src = m_fontFaceRule->properties().getPropertyCSSValue(CSSPropertySrc);
        CSSValueList* srcList = downcast<CSSValueList>(src.get());

        unsigned srcLength = srcList ? srcList->length() : 0;
        for (unsigned i = 0; i < srcLength; ++i) {
            if (CSSFontFaceSrcValue* item = downcast<CSSFontFaceSrcValue>(srcList->itemWithoutBoundsCheck(i)))
                item->setSVGFontFaceElement(this);
        }
    }

    document().styleScope().didChangeStyleSheetEnvironment();
}

Node::InsertionNotificationRequest SVGFontFaceElement::insertedInto(ContainerNode& rootParent)
{
    SVGElement::insertedInto(rootParent);
    if (!rootParent.isConnected()) {
        ASSERT(!m_fontElement);
        return InsertionDone;
    }
    document().accessSVGExtensions().registerSVGFontFaceElement(this);

    rebuildFontFace();
    return InsertionDone;
}

void SVGFontFaceElement::removedFrom(ContainerNode& rootParent)
{
    SVGElement::removedFrom(rootParent);

    if (rootParent.isConnected()) {
        m_fontElement = nullptr;
        document().accessSVGExtensions().unregisterSVGFontFaceElement(this);
        m_fontFaceRule->mutableProperties().clear();

        document().styleScope().didChangeStyleSheetEnvironment();
    } else
        ASSERT(!m_fontElement);
}

void SVGFontFaceElement::childrenChanged(const ChildChange& change)
{
    SVGElement::childrenChanged(change);
    rebuildFontFace();
}

} // namespace WebCore

#endif // ENABLE(SVG_FONTS)