path: root/Source/WebCore/rendering/svg/SVGRootInlineBox.cpp

/*
 * Copyright (C) 2006 Oliver Hunt <ojh16@student.canterbury.ac.nz>
 * Copyright (C) 2006 Apple Inc.
 * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
 * Copyright (C) 2011 Torch Mobile (Beijing) CO. Ltd. 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"
#include "SVGRootInlineBox.h"

#include "GraphicsContext.h"
#include "RenderSVGText.h"
#include "RenderSVGTextPath.h"
#include "SVGInlineFlowBox.h"
#include "SVGInlineTextBox.h"
#include "SVGNames.h"
#include "SVGRenderingContext.h"
#include "SVGTextPositioningElement.h"

namespace WebCore {

SVGRootInlineBox::SVGRootInlineBox(RenderSVGText& renderSVGText)
    : RootInlineBox(renderSVGText)
    , m_logicalHeight(0)
{
}

RenderSVGText& SVGRootInlineBox::renderSVGText()
{
    return downcast<RenderSVGText>(blockFlow());
}

void SVGRootInlineBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit, LayoutUnit)
{
    ASSERT(paintInfo.phase == PaintPhaseForeground || paintInfo.phase == PaintPhaseSelection);
    ASSERT(!paintInfo.context().paintingDisabled());

    bool isPrinting = renderSVGText().document().printing();
    bool hasSelection = !isPrinting && selectionState() != RenderObject::SelectionNone;
    bool shouldPaintSelectionHighlight = !(paintInfo.paintBehavior & PaintBehaviorSkipSelectionHighlight);

    PaintInfo childPaintInfo(paintInfo);
    if (hasSelection && shouldPaintSelectionHighlight) {
        for (InlineBox* child = firstChild(); child; child = child->nextOnLine()) {
            if (is<SVGInlineTextBox>(*child))
                downcast<SVGInlineTextBox>(*child).paintSelectionBackground(childPaintInfo);
            else if (is<SVGInlineFlowBox>(*child))
                downcast<SVGInlineFlowBox>(*child).paintSelectionBackground(childPaintInfo);
        }
    }

    SVGRenderingContext renderingContext(renderSVGText(), paintInfo, SVGRenderingContext::SaveGraphicsContext);
    if (renderingContext.isRenderingPrepared()) {
        for (InlineBox* child = firstChild(); child; child = child->nextOnLine())
            child->paint(paintInfo, paintOffset, 0, 0);
    }
}

void SVGRootInlineBox::computePerCharacterLayoutInformation()
{
    auto& textRoot = downcast<RenderSVGText>(blockFlow());

    Vector<SVGTextLayoutAttributes*>& layoutAttributes = textRoot.layoutAttributes();
    if (layoutAttributes.isEmpty())
        return;

    if (textRoot.needsReordering())
        reorderValueLists(layoutAttributes);

    // Perform SVG text layout phase two (see SVGTextLayoutEngine for details).
    SVGTextLayoutEngine characterLayout(layoutAttributes);
    layoutCharactersInTextBoxes(this, characterLayout);

    // Perform SVG text layout phase three (see SVGTextChunkBuilder for details).
    characterLayout.finishLayout();

    // Perform SVG text layout phase four
    // Position & resize all SVGInlineText/FlowBoxes in the inline box tree, resize the root box as well as the RenderSVGText parent block.
    FloatRect childRect;
    layoutChildBoxes(this, &childRect);
    layoutRootBox(childRect);
}

void SVGRootInlineBox::layoutCharactersInTextBoxes(InlineFlowBox* start, SVGTextLayoutEngine& characterLayout)
{
    for (InlineBox* child = start->firstChild(); child; child = child->nextOnLine()) {
        if (is<SVGInlineTextBox>(*child)) {
            ASSERT(is<RenderSVGInlineText>(child->renderer()));
            characterLayout.layoutInlineTextBox(downcast<SVGInlineTextBox>(*child));
        } else {
            // Skip generated content.
            Node* node = child->renderer().node();
            if (!node)
                continue;

            auto& flowBox = downcast<SVGInlineFlowBox>(*child);
            bool isTextPath = node->hasTagName(SVGNames::textPathTag);
            if (isTextPath) {
                // Build text chunks for all <textPath> children, using the line layout algorithm.
                // This is needeed as text-anchor is just an additional startOffset for text paths.
                SVGTextLayoutEngine lineLayout(characterLayout.layoutAttributes());
                layoutCharactersInTextBoxes(&flowBox, lineLayout);

                characterLayout.beginTextPathLayout(downcast<RenderSVGTextPath>(child->renderer()), lineLayout);
            }

            layoutCharactersInTextBoxes(&flowBox, characterLayout);

            if (isTextPath)
                characterLayout.endTextPathLayout();
        }
    }
}

void SVGRootInlineBox::layoutChildBoxes(InlineFlowBox* start, FloatRect* childRect)
{
    for (InlineBox* child = start->firstChild(); child; child = child->nextOnLine()) {
        FloatRect boxRect;
        if (is<SVGInlineTextBox>(*child)) {
            ASSERT(is<RenderSVGInlineText>(child->renderer()));

            auto& textBox = downcast<SVGInlineTextBox>(*child);
            boxRect = textBox.calculateBoundaries();
            textBox.setX(boxRect.x());
            textBox.setY(boxRect.y());
            textBox.setLogicalWidth(boxRect.width());
            textBox.setLogicalHeight(boxRect.height());
        } else {
            // Skip generated content.
            if (!child->renderer().node())
                continue;

            auto& flowBox = downcast<SVGInlineFlowBox>(*child);
            layoutChildBoxes(&flowBox);

            boxRect = flowBox.calculateBoundaries();
            flowBox.setX(boxRect.x());
            flowBox.setY(boxRect.y());
            flowBox.setLogicalWidth(boxRect.width());
            flowBox.setLogicalHeight(boxRect.height());
        }
        if (childRect)
            childRect->unite(boxRect);
    }
}

void SVGRootInlineBox::layoutRootBox(const FloatRect& childRect)
{
    RenderSVGText& parentBlock = renderSVGText();

    // Finally, assign the root block position, now that all content is laid out.
    LayoutRect boundingRect = enclosingLayoutRect(childRect);
    parentBlock.setLocation(boundingRect.location());
    parentBlock.setSize(boundingRect.size());

    // Position all children relative to the parent block.
    for (InlineBox* child = firstChild(); child; child = child->nextOnLine()) {
        // Skip generated content.
        if (!child->renderer().node())
            continue;
        child->adjustPosition(-childRect.x(), -childRect.y());
    }

    // Position ourselves.
    setX(0);
    setY(0);
    setLogicalWidth(childRect.width());
    setLogicalHeight(childRect.height());
    setLineTopBottomPositions(0, boundingRect.height(), 0, boundingRect.height());
}

InlineBox* SVGRootInlineBox::closestLeafChildForPosition(const LayoutPoint& point)
{
    InlineBox* firstLeaf = firstLeafChild();
    InlineBox* lastLeaf = lastLeafChild();
    if (firstLeaf == lastLeaf)
        return firstLeaf;

    // FIXME: Check for vertical text!
    InlineBox* closestLeaf = nullptr;
    for (InlineBox* leaf = firstLeaf; leaf; leaf = leaf->nextLeafChild()) {
        if (!leaf->isSVGInlineTextBox())
            continue;
        if (point.y() < leaf->y())
            continue;
        if (point.y() > leaf->y() + leaf->virtualLogicalHeight())
            continue;

        closestLeaf = leaf;
        if (point.x() < leaf->left() + leaf->logicalWidth())
            return leaf;
    }

    return closestLeaf ? closestLeaf : lastLeaf;
}

bool SVGRootInlineBox::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit lineTop, LayoutUnit lineBottom, HitTestAction hitTestAction)
{
    for (InlineBox* leaf = firstLeafChild(); leaf; leaf = leaf->nextLeafChild()) {
        if (!leaf->isSVGInlineTextBox())
            continue;
        if (leaf->nodeAtPoint(request, result, locationInContainer, accumulatedOffset, lineTop, lineBottom, hitTestAction))
            return true;
    }

    return false;
}

static inline void swapItemsInLayoutAttributes(SVGTextLayoutAttributes* firstAttributes, SVGTextLayoutAttributes* lastAttributes, unsigned firstPosition, unsigned lastPosition)
{
    SVGCharacterDataMap::iterator itFirst = firstAttributes->characterDataMap().find(firstPosition + 1);
    SVGCharacterDataMap::iterator itLast = lastAttributes->characterDataMap().find(lastPosition + 1);
    bool firstPresent = itFirst != firstAttributes->characterDataMap().end();
    bool lastPresent = itLast != lastAttributes->characterDataMap().end();
    if (!firstPresent && !lastPresent)
        return;

    if (firstPresent && lastPresent) {
        std::swap(itFirst->value, itLast->value);
        return;
    }

    if (firstPresent && !lastPresent) {
        lastAttributes->characterDataMap().set(lastPosition + 1, itFirst->value);
        return;
    }

    // !firstPresent && lastPresent
    firstAttributes->characterDataMap().set(firstPosition + 1, itLast->value);
}

static inline void findFirstAndLastAttributesInVector(Vector<SVGTextLayoutAttributes*>& attributes, RenderSVGInlineText* firstContext, RenderSVGInlineText* lastContext,
                                                      SVGTextLayoutAttributes*& first, SVGTextLayoutAttributes*& last)
{
    first = nullptr;
    last = nullptr;

    unsigned attributesSize = attributes.size();
    for (unsigned i = 0; i < attributesSize; ++i) {
        SVGTextLayoutAttributes* current = attributes[i];
        if (!first && firstContext == &current->context())
            first = current;
        if (!last && lastContext == &current->context())
            last = current;
        if (first && last)
            break;
    }

    ASSERT(first);
    ASSERT(last);
}

static inline void reverseInlineBoxRangeAndValueListsIfNeeded(void* userData, Vector<InlineBox*>::iterator first, Vector<InlineBox*>::iterator last)
{
    ASSERT(userData);
    Vector<SVGTextLayoutAttributes*>& attributes = *reinterpret_cast<Vector<SVGTextLayoutAttributes*>*>(userData);

    // This is a copy of std::reverse(first, last). It additionally assures that the metrics map within the renderers belonging to the InlineBoxes are reordered as well.
    while (true)  {
        if (first == last || first == --last)
            return;

        if (!is<SVGInlineTextBox>(**last) || !is<SVGInlineTextBox>(**first)) {
            InlineBox* temp = *first;
            *first = *last;
            *last = temp;
            ++first;
            continue;
        }

        auto& firstTextBox = downcast<SVGInlineTextBox>(**first);
        auto& lastTextBox = downcast<SVGInlineTextBox>(**last);

        // Reordering is only necessary for BiDi text that is _absolutely_ positioned.
        if (firstTextBox.len() == 1 && firstTextBox.len() == lastTextBox.len()) {
            RenderSVGInlineText& firstContext = firstTextBox.renderer();
            RenderSVGInlineText& lastContext = lastTextBox.renderer();

            SVGTextLayoutAttributes* firstAttributes = nullptr;
            SVGTextLayoutAttributes* lastAttributes = nullptr;
            findFirstAndLastAttributesInVector(attributes, &firstContext, &lastContext, firstAttributes, lastAttributes);
            swapItemsInLayoutAttributes(firstAttributes, lastAttributes, firstTextBox.start(), lastTextBox.start());
        }

        InlineBox* temp = *first;
        *first = *last;
        *last = temp;

        ++first;
    }
}

void SVGRootInlineBox::reorderValueLists(Vector<SVGTextLayoutAttributes*>& attributes)
{
    Vector<InlineBox*> leafBoxesInLogicalOrder;
    collectLeafBoxesInLogicalOrder(leafBoxesInLogicalOrder, reverseInlineBoxRangeAndValueListsIfNeeded, &attributes);
}

} // namespace WebCore