svgrootinlinebox.cpp

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/*
 * This file is part of the WebKit project.
 *
 * Copyright (C) 2006 Oliver Hunt <[e-mail]>
 *           (C) 2006 Apple Computer Inc.
 *           (C) 2007 Nikolas Zimmermann <[e-mail]>
 *
 * 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 "SVGRootInlineBox.h"

#include "Editor.h"
#include "Frame.h"
#include "GraphicsContext.h"
#include "RenderBlock.h"
#include "RenderSVGRoot.h"
#include "SVGInlineFlowBox.h"
#include "SVGInlineTextBox.h"
#include "SVGFontElement.h"
#include "SVGPaintServer.h"
#include "SVGRenderStyleDefs.h"
#include "SVGRenderSupport.h"
#include "SVGResourceFilter.h"
#include "SVGTextPositioningElement.h"
#include "SVGURIReference.h"
#include "Text.h"
#include "UnicodeRange.h"

#include <float.h>

// Text chunk creation is complex and the whole process
// can easily be traced by setting this variable > 0.
#define DEBUG_CHUNK_BUILDING 0

namespace WebCore {

static inline bool isVerticalWritingMode(const SVGRenderStyle* style)
{
    return style->writingMode() == WM_TBRL || style->writingMode() == WM_TB; 
}

static inline EAlignmentBaseline dominantBaselineToShift(bool isVerticalText, const RenderObject* text, const Font& font)
{
    ASSERT(text);

    const SVGRenderStyle* style = text->style() ? text->style()->svgStyle() : 0;
    ASSERT(style);

    const SVGRenderStyle* parentStyle = text->parent() && text->parent()->style() ? text->parent()->style()->svgStyle() : 0;

    EDominantBaseline baseline = style->dominantBaseline();
    if (baseline == DB_AUTO) {
        if (isVerticalText)
            baseline = DB_CENTRAL;
        else
            baseline = DB_ALPHABETIC;
    }

    switch (baseline) {
    case DB_USE_SCRIPT:
        // TODO: 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:
    {
        if (parentStyle)
            return dominantBaselineToShift(isVerticalText, text->parent(), font);

        ASSERT_NOT_REACHED();
        return AB_AUTO;
    }
    case DB_RESET_SIZE:
    {
        if (parentStyle)
            return dominantBaselineToShift(isVerticalText, text->parent(), font);

        ASSERT_NOT_REACHED();
        return AB_AUTO;    
    }
    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;
    }
}

static inline float alignmentBaselineToShift(bool isVerticalText, const RenderObject* text, const Font& font)
{
    ASSERT(text);

    const SVGRenderStyle* style = text->style() ? text->style()->svgStyle() : 0;
    ASSERT(style);

    const SVGRenderStyle* parentStyle = text->parent() && text->parent()->style() ? text->parent()->style()->svgStyle() : 0;

    EAlignmentBaseline baseline = style->alignmentBaseline();
    if (baseline == AB_AUTO) {
        if (parentStyle && style->dominantBaseline() == DB_AUTO)
            baseline = dominantBaselineToShift(isVerticalText, text->parent(), font);
        else
            baseline = dominantBaselineToShift(isVerticalText, text, font);

        ASSERT(baseline != AB_AUTO);    
    }

    // Note: http://wiki.apache.org/xmlgraphics-fop/LineLayout/AlignmentHandling
    switch (baseline) {
    case AB_BASELINE:
    {
        if (parentStyle)
            return dominantBaselineToShift(isVerticalText, text->parent(), font);

        return 0.0f;
    }
    case AB_BEFORE_EDGE:
    case AB_TEXT_BEFORE_EDGE:
        return font.ascent();
    case AB_MIDDLE:
        return font.xHeight() / 2.0f;
    case AB_CENTRAL:
        // Not needed, we're taking this into account already for vertical text!
        // return (font.ascent() - font.descent()) / 2.0f;
        return 0.0f;
    case AB_AFTER_EDGE:
    case AB_TEXT_AFTER_EDGE:
    case AB_IDEOGRAPHIC:
        return font.descent();
    case AB_ALPHABETIC:
        return 0.0f;
    case AB_HANGING:
        return font.ascent() * 8.0f / 10.0f;
    case AB_MATHEMATICAL:
        return font.ascent() / 2.0f;
    default:
        ASSERT_NOT_REACHED();
        return 0.0f;
    }
}

static inline float glyphOrientationToAngle(const SVGRenderStyle* svgStyle, bool isVerticalText, const UChar& character)
{
    switch (isVerticalText ? svgStyle->glyphOrientationVertical() : svgStyle->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 90.0f;

        return 0.0f;
    }
    case GO_90DEG:
        return 90.0f;
    case GO_180DEG:
        return 180.0f;
    case GO_270DEG:
        return 270.0f;
    case GO_0DEG:
    default:
        return 0.0f;
    }
}

static inline bool glyphOrientationIsMultiplyOf180Degrees(float orientationAngle)
{
    return fabsf(fmodf(orientationAngle, 180.0f)) == 0.0f;
}

static inline float calculateGlyphAdvanceAndShiftRespectingOrientation(bool isVerticalText, float orientationAngle, float glyphWidth, float glyphHeight, const Font& font, SVGChar& svgChar, float& xOrientationShift, float& yOrientationShift)
{
    bool orientationIsMultiplyOf180Degrees = glyphOrientationIsMultiplyOf180Degrees(orientationAngle);

    // 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) {
        if (orientationAngle == 0.0f) {
            xOrientationShift = -glyphWidth / 2.0f;
            yOrientationShift = font.ascent();
        } else if (orientationAngle == 90.0f) {
            xOrientationShift = -glyphHeight;
            yOrientationShift = font.descent();
            svgChar.orientationShiftY = -font.ascent();
        } else if (orientationAngle == 270.0f) {
            xOrientationShift = glyphHeight;
            yOrientationShift = font.descent();
            svgChar.orientationShiftX = -glyphWidth;
            svgChar.orientationShiftY = -font.ascent();
        } else if (orientationAngle == 180.0f) {
            yOrientationShift = font.ascent();
            svgChar.orientationShiftX = -glyphWidth / 2.0f;
            svgChar.orientationShiftY = font.ascent() - font.descent();
        }

        // vertical advance calculation
        if (orientationAngle != 0.0f && !orientationIsMultiplyOf180Degrees)
            return glyphWidth;

        return glyphHeight; 
    }

    // horizontal orientation handling
    if (orientationAngle == 90.0f) {
        xOrientationShift = glyphWidth / 2.0f;
        yOrientationShift = -font.descent();
        svgChar.orientationShiftX = -glyphWidth / 2.0f - font.descent(); 
        svgChar.orientationShiftY = font.descent();
    } else if (orientationAngle == 270.0f) {
        xOrientationShift = -glyphWidth / 2.0f;
        yOrientationShift = -font.descent();
        svgChar.orientationShiftX = -glyphWidth / 2.0f + font.descent();
        svgChar.orientationShiftY = glyphHeight;
    } else if (orientationAngle == 180.0f) {
        xOrientationShift = glyphWidth / 2.0f;
        svgChar.orientationShiftX = -glyphWidth / 2.0f;
        svgChar.orientationShiftY = font.ascent() - font.descent();
    }

    // horizontal advance calculation
    if (orientationAngle != 0.0f && !orientationIsMultiplyOf180Degrees)
        return glyphHeight;

    return glyphWidth;
}

static inline void startTextChunk(SVGTextChunkLayoutInfo& info)
{
    info.chunk.boxes.clear();
    info.chunk.boxes.append(SVGInlineBoxCharacterRange());

    info.chunk.start = info.it;
    info.assignChunkProperties = true;
}

static inline void closeTextChunk(SVGTextChunkLayoutInfo& info)
{
    ASSERT(!info.chunk.boxes.last().isOpen());
    ASSERT(info.chunk.boxes.last().isClosed());

    info.chunk.end = info.it;
    ASSERT(info.chunk.end >= info.chunk.start);

    info.svgTextChunks.append(info.chunk);
}

RenderSVGRoot* findSVGRootObject(RenderObject* start)
{
    // Find associated root inline box
    while (start && !start->isSVGRoot())
        start = start->parent();

    ASSERT(start);
    ASSERT(start->isSVGRoot());

    return static_cast<RenderSVGRoot*>(start);
}

static inline FloatPoint topLeftPositionOfCharacterRange(Vector<SVGChar>& chars)
{
    return topLeftPositionOfCharacterRange(chars.begin(), chars.end());
}

FloatPoint topLeftPositionOfCharacterRange(Vector<SVGChar>::iterator it, Vector<SVGChar>::iterator end)
{
    float lowX = FLT_MAX, lowY = FLT_MAX;
    for (; it != end; ++it) {
        if (it->isHidden())
            continue;

        float x = (*it).x;
        float y = (*it).y;

        if (x < lowX)
            lowX = x;

        if (y < lowY)
            lowY = y;
    }

    return FloatPoint(lowX, lowY);
}

// Helper function
static float calculateKerning(RenderObject* item)
{
    const Font& font = item->style()->font();
    const SVGRenderStyle* svgStyle = item->style()->svgStyle();

    float kerning = 0.0f;
    if (CSSPrimitiveValue* primitive = static_cast<CSSPrimitiveValue*>(svgStyle->kerning())) {
        kerning = primitive->getFloatValue();

        if (primitive->primitiveType() == CSSPrimitiveValue::CSS_PERCENTAGE && font.pixelSize() > 0)
            kerning = kerning / 100.0f * font.pixelSize();
    }

    return kerning;
}

// Helper class for paint()
struct SVGRootInlineBoxPaintWalker {
    SVGRootInlineBoxPaintWalker(SVGRootInlineBox* rootBox, SVGResourceFilter* rootFilter, RenderObject::PaintInfo paintInfo, int tx, int ty)
        : m_rootBox(rootBox)
        , m_chunkStarted(false)
        , m_paintInfo(paintInfo)
        , m_savedInfo(paintInfo)
        , m_boundingBox(tx + rootBox->x(), ty + rootBox->y(), rootBox->width(), rootBox->height())
        , m_filter(0)
        , m_rootFilter(rootFilter)
        , m_fillPaintServer(0)
        , m_strokePaintServer(0)
        , m_fillPaintServerObject(0)
        , m_strokePaintServerObject(0)
        , m_tx(tx)
        , m_ty(ty)
    {
    }

    ~SVGRootInlineBoxPaintWalker()
    {
        ASSERT(!m_filter);
        ASSERT(!m_fillPaintServer);
        ASSERT(!m_fillPaintServerObject);
        ASSERT(!m_strokePaintServer);
        ASSERT(!m_strokePaintServerObject);
        ASSERT(!m_chunkStarted);
    }

    void teardownFillPaintServer()
    {
        if (!m_fillPaintServer)
            return;

        m_fillPaintServer->teardown(m_paintInfo.context, m_fillPaintServerObject, ApplyToFillTargetType, true);

        m_fillPaintServer = 0;
        m_fillPaintServerObject = 0;
    }

    void teardownStrokePaintServer()
    {
        if (!m_strokePaintServer)
            return;

        m_strokePaintServer->teardown(m_paintInfo.context, m_strokePaintServerObject, ApplyToStrokeTargetType, true);

        m_strokePaintServer = 0;
        m_strokePaintServerObject = 0;
    }

    void chunkStartCallback(InlineBox* box)
    {
        ASSERT(!m_chunkStarted);
        m_chunkStarted = true;

        InlineFlowBox* flowBox = box->parent();

        // Initialize text rendering
        RenderObject* object = flowBox->renderer();
        ASSERT(object);

        m_savedInfo = m_paintInfo;
        m_paintInfo.context->save();

        if (!flowBox->isRootInlineBox())
            m_paintInfo.context->concatCTM(m_rootBox->renderer()->localTransform());

        m_paintInfo.context->concatCTM(object->localTransform());

        if (!flowBox->isRootInlineBox()) {
            prepareToRenderSVGContent(object, m_paintInfo, m_boundingBox, m_filter, m_rootFilter);
            m_paintInfo.rect = object->localTransform().inverse().mapRect(m_paintInfo.rect);
        }
    }

    void chunkEndCallback(InlineBox* box)
    {
        ASSERT(m_chunkStarted);
        m_chunkStarted = false;

        InlineFlowBox* flowBox = box->parent();

        RenderObject* object = flowBox->renderer();
        ASSERT(object);

        // Clean up last used paint server
        teardownFillPaintServer();
        teardownStrokePaintServer();