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/*
* Copyright (C) Research In Motion Limited 2010. 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)
#include "SVGTextLayoutEngineBaseline.h"
#include "Font.h"
#include "RenderObject.h"
#include "SVGRenderStyle.h"
#include "SVGTextMetrics.h"
#include "UnicodeRange.h"
namespace WebCore {
SVGTextLayoutEngineBaseline::SVGTextLayoutEngineBaseline(const Font& font)
: m_font(font)
{
}
float SVGTextLayoutEngineBaseline::calculateBaselineShift(const SVGRenderStyle* style, SVGElement* lengthContext) const
{
if (style->baselineShift() == BS_LENGTH) {
SVGLength baselineShiftValueLength = style->baselineShiftValue();
if (baselineShiftValueLength.unitType() == LengthTypePercentage)
return baselineShiftValueLength.valueAsPercentage() * m_font.pixelSize();
return baselineShiftValueLength.value(lengthContext);
}
switch (style->baselineShift()) {
case BS_BASELINE:
return 0;
case BS_SUB:
return -m_font.height() / 2;
case BS_SUPER:
return m_font.height() / 2;
default:
ASSERT_NOT_REACHED();
return 0;
}
}
EAlignmentBaseline SVGTextLayoutEngineBaseline::dominantBaselineToAlignmentBaseline(bool isVerticalText, const RenderObject* textRenderer) const
{
ASSERT(textRenderer);
ASSERT(textRenderer->style());
ASSERT(textRenderer->parent());
ASSERT(textRenderer->parent()->style());
const SVGRenderStyle* style = textRenderer->style()->svgStyle();
ASSERT(style);
EDominantBaseline baseline = style->dominantBaseline();
if (baseline == DB_AUTO) {
if (isVerticalText)
baseline = DB_CENTRAL;
else
baseline = DB_ALPHABETIC;
}
switch (baseline) {
case DB_USE_SCRIPT:
// FIXME: The dominant-baseline and the baseline-table components are set by determining the predominant script of the character data content.
return AB_ALPHABETIC;
case DB_NO_CHANGE:
return dominantBaselineToAlignmentBaseline(isVerticalText, textRenderer->parent());
case DB_RESET_SIZE:
return dominantBaselineToAlignmentBaseline(isVerticalText, textRenderer->parent());
case DB_IDEOGRAPHIC:
return AB_IDEOGRAPHIC;
case DB_ALPHABETIC:
return AB_ALPHABETIC;
case DB_HANGING:
return AB_HANGING;
case DB_MATHEMATICAL:
return AB_MATHEMATICAL;
case DB_CENTRAL:
return AB_CENTRAL;
case DB_MIDDLE:
return AB_MIDDLE;
case DB_TEXT_AFTER_EDGE:
return AB_TEXT_AFTER_EDGE;
case DB_TEXT_BEFORE_EDGE:
return AB_TEXT_BEFORE_EDGE;
default:
ASSERT_NOT_REACHED();
return AB_AUTO;
}
}
float SVGTextLayoutEngineBaseline::calculateAlignmentBaselineShift(bool isVerticalText, const RenderObject* textRenderer) const
{
ASSERT(textRenderer);
ASSERT(textRenderer->style());
ASSERT(textRenderer->style()->svgStyle());
ASSERT(textRenderer->parent());
const RenderObject* textRendererParent = textRenderer->parent();
ASSERT(textRendererParent);
EAlignmentBaseline baseline = textRenderer->style()->svgStyle()->alignmentBaseline();
if (baseline == AB_AUTO) {
baseline = dominantBaselineToAlignmentBaseline(isVerticalText, textRendererParent);
ASSERT(baseline != AB_AUTO);
}
// Note: http://wiki.apache.org/xmlgraphics-fop/LineLayout/AlignmentHandling
switch (baseline) {
case AB_BASELINE:
return dominantBaselineToAlignmentBaseline(isVerticalText, textRendererParent);
case AB_BEFORE_EDGE:
case AB_TEXT_BEFORE_EDGE:
return m_font.ascent();
case AB_MIDDLE:
return m_font.xHeight() / 2;
case AB_CENTRAL:
return (m_font.ascent() - m_font.descent()) / 2;
case AB_AFTER_EDGE:
case AB_TEXT_AFTER_EDGE:
case AB_IDEOGRAPHIC:
return m_font.descent();
case AB_ALPHABETIC:
return 0;
case AB_HANGING:
return m_font.ascent() * 8 / 10.f;
case AB_MATHEMATICAL:
return m_font.ascent() / 2;
default:
ASSERT_NOT_REACHED();
return 0;
}
}
float SVGTextLayoutEngineBaseline::calculateGlyphOrientationAngle(bool isVerticalText, const SVGRenderStyle* style, const UChar& character) const
{
ASSERT(style);
switch (isVerticalText ? style->glyphOrientationVertical() : style->glyphOrientationHorizontal()) {
case GO_AUTO: {
// Spec: Fullwidth ideographic and fullwidth Latin text will be set with a glyph-orientation of 0-degrees.
// Text which is not fullwidth will be set with a glyph-orientation of 90-degrees.
unsigned int unicodeRange = findCharUnicodeRange(character);
if (unicodeRange == cRangeSetLatin || unicodeRange == cRangeArabic)
return 90;
return 0;
}
case GO_90DEG:
return 90;
case GO_180DEG:
return 180;
case GO_270DEG:
return 270;
case GO_0DEG:
default:
return 0;
}
}
static inline bool glyphOrientationIsMultiplyOf180Degrees(float orientationAngle)
{
return !fabsf(fmodf(orientationAngle, 180));
}
float SVGTextLayoutEngineBaseline::calculateGlyphAdvanceAndOrientation(bool isVerticalText, SVGTextMetrics& metrics, float angle, float& xOrientationShift, float& yOrientationShift) const
{
bool orientationIsMultiplyOf180Degrees = glyphOrientationIsMultiplyOf180Degrees(angle);
// The function is based on spec requirements:
//
// Spec: If the 'glyph-orientation-horizontal' results in an orientation angle that is not a multiple of
// of 180 degrees, then the current text position is incremented according to the vertical metrics of the glyph.
//
// Spec: If if the 'glyph-orientation-vertical' results in an orientation angle that is not a multiple of
// 180 degrees, then the current text position is incremented according to the horizontal metrics of the glyph.
// Vertical orientation handling.
if (isVerticalText) {
float ascentMinusDescent = m_font.ascent() - m_font.descent();
if (!angle) {
xOrientationShift = (ascentMinusDescent - metrics.width()) / 2;
yOrientationShift = m_font.ascent();
} else if (angle == 180)
xOrientationShift = (ascentMinusDescent + metrics.width()) / 2;
else if (angle == 270) {
yOrientationShift = metrics.width();
xOrientationShift = ascentMinusDescent;
}
// Vertical advance calculation.
if (angle && !orientationIsMultiplyOf180Degrees)
return metrics.width();
return metrics.height();
}
// Horizontal orientation handling.
if (angle == 90)
yOrientationShift = -metrics.width();
else if (angle == 180) {
xOrientationShift = metrics.width();
yOrientationShift = -m_font.ascent();
} else if (angle == 270)
xOrientationShift = metrics.width();
// Horizontal advance calculation.
if (angle && !orientationIsMultiplyOf180Degrees)
return metrics.height();
return metrics.width();
}
}
#endif // ENABLE(SVG)
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