// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SVG <text> and <tspan> implementation
 *
 * Author:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *   bulia byak <buliabyak@users.sf.net>
 *   Jon A. Cruz <jon@joncruz.org>
 *   Abhishek Sharma
 *
 * Copyright (C) 1999-2002 Lauris Kaplinski
 * Copyright (C) 2000-2001 Ximian, Inc.
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */

/*
 * fixme:
 *
 * These subcomponents should not be items, or alternately
 * we have to invent set of flags to mark, whether standard
 * attributes are applicable to given item (I even like this
 * idea somewhat - Lauris)
 *
 */

#include <2geom/affine.h>
#include <libnrtype/FontFactory.h>
#include <libnrtype/font-instance.h>

#include <glibmm/i18n.h>
#include <glibmm/regex.h>

#include "svg/svg.h"
#include "display/drawing-text.h"
#include "attributes.h"
#include "document.h"
#include "preferences.h"
#include "desktop.h"
#include "sp-namedview.h"
#include "inkscape.h"
#include "xml/quote.h"
#include "mod360.h"

#include "sp-title.h"
#include "sp-desc.h"
#include "sp-text.h"

#include "sp-shape.h"
#include "sp-textpath.h"
#include "sp-tref.h"
#include "sp-tspan.h"
#include "sp-flowregion.h"

#include "text-editing.h"

// For SVG 2 text flow
#include "livarot/Shape.h"
#include "display/curve.h"

/*#####################################################
#  SPTEXT
#####################################################*/
SPText::SPText() : SPItem() {
}

SPText::~SPText()
{
    if (css) {
        sp_repr_css_attr_unref(css);
    }
};

void SPText::build(SPDocument *doc, Inkscape::XML::Node *repr) {
    this->readAttr( "x" );
    this->readAttr( "y" );
    this->readAttr( "dx" );
    this->readAttr( "dy" );
    this->readAttr( "rotate" );

    // textLength and friends
    this->readAttr( "textLength" );
    this->readAttr( "lengthAdjust" );
    SPItem::build(doc, repr);
    css = nullptr;
    this->readAttr( "sodipodi:linespacing" );    // has to happen after the styles are read
}

void SPText::release() {
    SPItem::release();
}

void SPText::set(SPAttributeEnum key, const gchar* value) {
    //std::cout << "SPText::set: " << sp_attribute_name( key ) << ": " << (value?value:"Null") << std::endl;

    if (this->attributes.readSingleAttribute(key, value, style, &viewport)) {
        this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
    } else {
        switch (key) {
            case SP_ATTR_SODIPODI_LINESPACING:
                // convert deprecated tag to css... but only if 'line-height' missing.
                if (value && !this->style->line_height.set) {
                    this->style->line_height.set = TRUE;
                    this->style->line_height.inherit = FALSE;
                    this->style->line_height.normal = FALSE;
                    this->style->line_height.unit = SP_CSS_UNIT_PERCENT;
                    this->style->line_height.value = this->style->line_height.computed = sp_svg_read_percentage (value, 1.0);
                }
                // Remove deprecated attribute
                this->setAttribute("sodipodi:linespacing", nullptr);

                this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_TEXT_LAYOUT_MODIFIED_FLAG);
                break;

            default:
                SPItem::set(key, value);
                break;
        }
    }
}

void SPText::child_added(Inkscape::XML::Node *rch, Inkscape::XML::Node *ref) {
    SPItem::child_added(rch, ref);

    this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_TEXT_CONTENT_MODIFIED_FLAG | SP_TEXT_LAYOUT_MODIFIED_FLAG);
}

void SPText::remove_child(Inkscape::XML::Node *rch) {
    SPItem::remove_child(rch);

    this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_TEXT_CONTENT_MODIFIED_FLAG | SP_TEXT_LAYOUT_MODIFIED_FLAG);
}


void SPText::update(SPCtx *ctx, guint flags) {

    unsigned childflags = (flags & SP_OBJECT_MODIFIED_CASCADE);
    if (flags & SP_OBJECT_MODIFIED_FLAG) {
        childflags |= SP_OBJECT_PARENT_MODIFIED_FLAG;
    }

    // Create temporary list of children
    std::vector<SPObject *> l;
    for (auto& child: children) {
        sp_object_ref(&child, this);
        l.push_back(&child);
    }

    for (auto child:l) {
        if (childflags || (child->uflags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))) {
            /* fixme: Do we need transform? */
            child->updateDisplay(ctx, childflags);
        }
        sp_object_unref(child, this);
    }

    // update ourselves after updating children
    SPItem::update(ctx, flags);

    if (flags & ( SP_OBJECT_STYLE_MODIFIED_FLAG |
                  SP_OBJECT_CHILD_MODIFIED_FLAG |
                  SP_TEXT_LAYOUT_MODIFIED_FLAG   ) )
    {

        SPItemCtx const *ictx = reinterpret_cast<SPItemCtx const *>(ctx);

        double const w = ictx->viewport.width();
        double const h = ictx->viewport.height();
        double const em = style->font_size.computed;
        double const ex = 0.5 * em;  // fixme: get x height from pango or libnrtype.

        attributes.update( em, ex, w, h );

        // Set inline_size computed value if necessary (i.e. if unit is %).
        if (has_inline_size()) {
            if (style->inline_size.unit == SP_CSS_UNIT_PERCENT) {
                if (is_horizontal()) {
                    style->inline_size.computed = style->inline_size.value * ictx->viewport.width();
                } else {
                    style->inline_size.computed = style->inline_size.value * ictx->viewport.height();
                }
            }
        }

        /* fixme: It is not nice to have it here, but otherwise children content changes does not work */
        /* fixme: Even now it may not work, as we are delayed */
        /* fixme: So check modification flag everywhere immediate state is used */
        this->rebuildLayout();

        Geom::OptRect paintbox = this->geometricBounds();

        for (SPItemView* v = this->display; v != nullptr; v = v->next) {
            Inkscape::DrawingGroup *g = dynamic_cast<Inkscape::DrawingGroup *>(v->arenaitem);
            this->_clearFlow(g);
            g->setStyle(this->style, this->parent->style);
            // pass the bbox of this as paintbox (used for paintserver fills)
            this->layout.show(g, paintbox);
        }
    }
}

void SPText::modified(guint flags) {
//	SPItem::onModified(flags);

    guint cflags = (flags & SP_OBJECT_MODIFIED_CASCADE);

    if (flags & SP_OBJECT_MODIFIED_FLAG) {
        cflags |= SP_OBJECT_PARENT_MODIFIED_FLAG;
    }

    // FIXME: all that we need to do here is to call setStyle, to set the changed
    // style, but there's no easy way to access the drawing glyphs or texts corresponding to a
    // text this. Therefore we do here the same as in _update, that is, destroy all items
    // and create new ones. This is probably quite wasteful.
    if (flags & ( SP_OBJECT_STYLE_MODIFIED_FLAG )) {
        Geom::OptRect paintbox = this->geometricBounds();

        for (SPItemView* v = this->display; v != nullptr; v = v->next) {
            Inkscape::DrawingGroup *g = dynamic_cast<Inkscape::DrawingGroup *>(v->arenaitem);
            this->_clearFlow(g);
            g->setStyle(this->style, this->parent->style);
            this->layout.show(g, paintbox);
        }
    }

    // Create temporary list of children
    std::vector<SPObject *> l;
    for (auto& child: children) {
        sp_object_ref(&child, this);
        l.push_back(&child);
    }

    for (auto child:l) {
        if (cflags || (child->mflags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))) {
            child->emitModified(cflags);
        }
        sp_object_unref(child, this);
    }
}

Inkscape::XML::Node *SPText::write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags) {
    if (flags & SP_OBJECT_WRITE_BUILD) {
        if (!repr) {
            repr = xml_doc->createElement("svg:text");
        }

        std::vector<Inkscape::XML::Node *> l;

        for (auto& child: children) {
            if (SP_IS_TITLE(&child) || SP_IS_DESC(&child)) {
                continue;
            }

            Inkscape::XML::Node *crepr = nullptr;

            if (SP_IS_STRING(&child)) {
                crepr = xml_doc->createTextNode(SP_STRING(&child)->string.c_str());
            } else {
                crepr = child.updateRepr(xml_doc, nullptr, flags);
            }

            if (crepr) {
                l.push_back(crepr);
            }
        }

        for (auto i=l.rbegin();i!=l.rend();++i) {
            repr->addChild(*i, nullptr);
            Inkscape::GC::release(*i);
        }
    } else {
        for (auto& child: children) {
            if (SP_IS_TITLE(&child) || SP_IS_DESC(&child)) {
                continue;
            }

            if (SP_IS_STRING(&child)) {
                child.getRepr()->setContent(SP_STRING(&child)->string.c_str());
            } else {
                child.updateRepr(flags);
            }
        }
    }

    this->attributes.writeTo(repr);
    this->rebuildLayout();  // copied from update(), see LP Bug 1339305

    SPItem::write(xml_doc, repr, flags);

    return repr;
}


void
SPText::shape_changed (Inkscape::XML::Node *repr, char const *key, char const *oldval,
                       char const *newval, bool is_interactive, void* data) {

    SPText* text = static_cast<SPText*>(data);
    if (text) {
        text->updateRepr(); // Why is this necessary, it is definitely overkill!
        // text->rebuildLayout();
    } else {
        std::cerr << "SPText::shape_changed: no text object!" << std::endl;
    }
}


Geom::OptRect SPText::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
    Geom::OptRect bbox = SP_TEXT(this)->layout.bounds(transform);

    // FIXME this code is incorrect
    if (bbox && type == SPItem::VISUAL_BBOX && !this->style->stroke.isNone()) {
        double scale = transform.descrim();
        bbox->expandBy(0.5 * this->style->stroke_width.computed * scale);
    }

    return bbox;
}

Inkscape::DrawingItem* SPText::show(Inkscape::Drawing &drawing, unsigned /*key*/, unsigned /*flags*/) {
    Inkscape::DrawingGroup *flowed = new Inkscape::DrawingGroup(drawing);
    flowed->setPickChildren(false);
    flowed->setStyle(this->style, this->parent->style);

    // pass the bbox of the text object as paintbox (used for paintserver fills)
    this->layout.show(flowed, this->geometricBounds());

    return flowed;
}


void SPText::hide(unsigned int key) {
    for (SPItemView* v = this->display; v != nullptr; v = v->next) {
        if (v->key == key) {
            Inkscape::DrawingGroup *g = dynamic_cast<Inkscape::DrawingGroup *>(v->arenaitem);
            this->_clearFlow(g);
        }
    }
}

const char* SPText::displayName() const {
    if (has_inline_size()) {
        return _("Auto-wrapped text");
    } else if (has_shape_inside()) {
        return _("Text in-a-shape");
    } else {
        return _("Text");
    }
}

gchar* SPText::description() const {

    SPStyle *style = this->style;

    char *n = xml_quote_strdup( style->font_family.value );

    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
    int unit = prefs->getInt("/options/font/unitType", SP_CSS_UNIT_PT);
    Inkscape::Util::Quantity q = Inkscape::Util::Quantity(style->font_size.computed, "px");
    q.quantity *= this->i2doc_affine().descrim();
    Glib::ustring xs = q.string(sp_style_get_css_unit_string(unit));

    char const *trunc = "";
    Inkscape::Text::Layout const *layout = te_get_layout((SPItem *) this);

    if (layout && layout->inputTruncated()) {
        trunc = _(" [truncated]");
    }

    char *ret = ( SP_IS_TEXT_TEXTPATH(this)
      ? g_strdup_printf(_("on path%s (%s, %s)"), trunc, n, xs.c_str())
      : g_strdup_printf(_("%s (%s, %s)"),        trunc, n, xs.c_str()) );
    return ret;
}

void SPText::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
    if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_TEXT_BASELINE)) {
        // Choose a point on the baseline for snapping from or to, with the horizontal position
        // of this point depending on the text alignment (left vs. right)
        Inkscape::Text::Layout const *layout = te_get_layout(this);

        if (layout != nullptr && layout->outputExists()) {
            boost::optional<Geom::Point> pt = layout->baselineAnchorPoint();

            if (pt) {
                p.emplace_back((*pt) * this->i2dt_affine(), Inkscape::SNAPSOURCE_TEXT_ANCHOR, Inkscape::SNAPTARGET_TEXT_ANCHOR);
            }
        }
    }
}

void SPText::hide_shape_inside()
{
    SPText *text = dynamic_cast<SPText *>(this);
    SPObject *object = dynamic_cast<SPObject *>(this);
    SPStyle *item_style = this->style;
    if (item_style && text && item_style->shape_inside.set) {
        SPCSSAttr *css_unset = sp_css_attr_from_style(item_style, SP_STYLE_FLAG_IFSET);
        css = sp_css_attr_from_style(item_style, SP_STYLE_FLAG_IFSET);
        sp_repr_css_unset_property(css_unset, "shape-inside");
        sp_repr_css_attr_unref(css_unset);
        this->changeCSS(css_unset, "style");
    } else {
        css = nullptr;
    }
}

void SPText::show_shape_inside()
{
    SPText *text = dynamic_cast<SPText *>(this);
    SPObject *object = dynamic_cast<SPObject *>(this);
    if (text && css) {
        this->changeCSS(css, "style");
    }
}

Geom::Affine SPText::set_transform(Geom::Affine const &xform) {
    // See if 'shape-inside' has rectangle
    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
    if (prefs->getBool("/tools/text/use_svg2", true)) {
        Inkscape::XML::Node* rectangle = get_first_rectangle();
        if (rectangle) {
            return xform;
        }
    }
    // we cannot optimize textpath because changing its fontsize will break its match to the path
    
    if (SP_IS_TEXT_TEXTPATH (this)) {
        if (!this->_optimizeTextpathText) {
            return xform;
        } else {
            this->_optimizeTextpathText = false;
        }
    }

    // we cannot optimize text with textLength because it may show different size than specified
    if (this->attributes.getTextLength()->_set)
        return xform;

    /* This function takes care of scaling & translation only, we return whatever parts we can't
       handle. */

// TODO: pjrm tried to use fontsize_expansion(xform) here and it works for text in that font size
// is scaled more intuitively when scaling non-uniformly; however this necessitated using
// fontsize_expansion instead of expansion in other places too, where it was not appropriate
// (e.g. it broke stroke width on copy/pasting of style from horizontally stretched to vertically
// stretched shape). Using fontsize_expansion only here broke setting the style via font
// dialog. This needs to be investigated further.
    double const ex = xform.descrim();
    if (ex == 0) {
        return xform;
    }

    Geom::Affine ret(Geom::Affine(xform).withoutTranslation());
    ret[0] /= ex;
    ret[1] /= ex;
    ret[2] /= ex;
    ret[3] /= ex;

    // Adjust x/y, dx/dy
    this->_adjustCoordsRecursive (this, xform * ret.inverse(), ex);

    // Adjust font size
    this->_adjustFontsizeRecursive (this, ex);

    // Adjust stroke width
    this->adjust_stroke_width_recursive (ex);

    // Adjust pattern fill
    this->adjust_pattern(xform * ret.inverse());

    // Adjust gradient fill
    this->adjust_gradient(xform * ret.inverse());

    return ret;
}

void SPText::print(SPPrintContext *ctx) {
    Geom::OptRect pbox, bbox, dbox;
    pbox = this->geometricBounds();
    bbox = this->desktopVisualBounds();
    dbox = Geom::Rect::from_xywh(Geom::Point(0,0), this->document->getDimensions());

    Geom::Affine const ctm (this->i2dt_affine());

    this->layout.print(ctx,pbox,dbox,bbox,ctm);
}

/*
 * Member functions
 */

void SPText::_buildLayoutInit()
{

    layout.strut.reset();
    layout.wrap_mode = Inkscape::Text::Layout::WRAP_NONE; // Default to SVG 1.1

    if (style) {

        // Strut
        font_instance *font = font_factory::Default()->FaceFromStyle( style );
        if (font) {
            font->FontMetrics(layout.strut.ascent, layout.strut.descent, layout.strut.xheight);
            font->Unref();
        }
        layout.strut *= style->font_size.computed;
        if (style->line_height.normal ) {
            layout.strut.computeEffective( Inkscape::Text::Layout::LINE_HEIGHT_NORMAL );
        } else if (style->line_height.unit == SP_CSS_UNIT_NONE) {
            layout.strut.computeEffective( style->line_height.computed );
        } else {
            if( style->font_size.computed > 0.0 ) {
                layout.strut.computeEffective( style->line_height.computed/style->font_size.computed );
            }
        }


        // To do: follow SPItem clip_ref/mask_ref code
        if (style->shape_inside.set ) {

            layout.wrap_mode = Inkscape::Text::Layout::WRAP_SHAPE_INSIDE;

            // Find union of all exclusion shapes
            Shape *exclusion_shape = nullptr;
            if(style->shape_subtract.set) {
                exclusion_shape = _buildExclusionShape();
            }

            // Find inside shape curves
            for (auto shape_id : style->shape_inside.shape_ids) {

                    SPShape *shape = dynamic_cast<SPShape *>(document->getObjectById( shape_id ));
                    if ( shape ) {

                        // This code adapted from sp-flowregion.cpp: GetDest()
                        if (!(shape->_curve)) {
                            shape->set_shape();
                        }
                        SPCurve *curve = shape->getCurve();

                        if ( curve ) {
                            Path *temp = new Path;
                            Path *padded = new Path;
                            temp->LoadPathVector( curve->get_pathvector(), shape->transform, true );
                            if( style->shape_padding.set ) {
                                // std::cout << "  padding: " << style->shape_padding.computed << std::endl;
                                temp->OutsideOutline ( padded, style->shape_padding.computed, join_round, butt_straight, 20.0 );
                            } else {
                                // std::cout << "  no padding" << std::endl;
                                padded->Copy( temp );
                            }
                            padded->Convert( 0.25 );  // Convert to polyline
                            Shape* sh = new Shape;
                            padded->Fill( sh, 0 );
                            // for( unsigned i = 0; i < temp->pts.size(); ++i ) {
                            //   std::cout << " ........ " << temp->pts[i].p << std::endl;
                            // }
                            // std::cout << " ...... shape: " << sh->numberOfPoints() << std::endl;
                            Shape *uncross = new Shape;
                            uncross->ConvertToShape( sh );

                            // Subtract exclusion shape
                            if(style->shape_subtract.set) {
                                Shape *copy = new Shape;
                                if (exclusion_shape && exclusion_shape->hasEdges()) {
                                    copy->Booleen(uncross, const_cast<Shape*>(exclusion_shape), bool_op_diff);
                                } else {
                                    copy->Copy(uncross);
                                }
                                layout.appendWrapShape( copy );
                                //delete exclusion_shape;
                                continue;
                            }

                            layout.appendWrapShape( uncross );

                            delete temp;
                            delete padded;
                            delete sh;
                            // delete uncross;
                        } else {
                            std::cerr << "SPText::_buildLayoutInit(): Failed to get curve." << std::endl;
                        }
                }
            }

        } else if (has_inline_size()) {

            layout.wrap_mode = Inkscape::Text::Layout::WRAP_INLINE_SIZE;

            // If both shape_inside and inline_size are set, shape_inside wins out.

            // We construct a rectangle with one dimension set by the computed value of 'inline-size'
            // and the other dimension set to infinity. Text is laid out starting at the 'x' and 'y'
            // attribute values. This is handled elsewhere.

            Geom::OptRect opt_frame = get_frame();
            Geom::Rect frame = *opt_frame;

            Shape *shape = new Shape;
            shape->Reset();
            int v0 = shape->AddPoint(frame.corner(0));
            int v1 = shape->AddPoint(frame.corner(1));
            int v2 = shape->AddPoint(frame.corner(2));
            int v3 = shape->AddPoint(frame.corner(3));
            shape->AddEdge(v0, v1);
            shape->AddEdge(v1, v2);
            shape->AddEdge(v2, v3);
            shape->AddEdge(v3, v0);
            Shape *uncross = new Shape;
            uncross->ConvertToShape( shape );

            layout.appendWrapShape( uncross );

            delete shape;

        } else if (style->white_space.value == SP_CSS_WHITE_SPACE_PRE     ||
                   style->white_space.value == SP_CSS_WHITE_SPACE_PREWRAP ||
                   style->white_space.value == SP_CSS_WHITE_SPACE_PRELINE ) {
            layout.wrap_mode = Inkscape::Text::Layout::WRAP_WHITE_SPACE;
        }

    } // if (style)
}

unsigned SPText::_buildLayoutInput(SPObject *object, Inkscape::Text::Layout::OptionalTextTagAttrs const &parent_optional_attrs, unsigned parent_attrs_offset, bool in_textpath)
{
    unsigned length = 0;
    int child_attrs_offset = 0;
    Inkscape::Text::Layout::OptionalTextTagAttrs optional_attrs;

    // Per SVG spec, an object with 'display:none' doesn't contribute to text layout.
    if (object->style->display.computed == SP_CSS_DISPLAY_NONE) {
        return 0;
    }

    if (SP_IS_TEXT(object)) {

        bool use_xy = true;
        bool use_dxdyrotate = true;

        // SVG 2 Text wrapping.
        if (layout.wrap_mode == Inkscape::Text::Layout::WRAP_SHAPE_INSIDE ||
            layout.wrap_mode == Inkscape::Text::Layout::WRAP_INLINE_SIZE) {
            use_xy = false;
            use_dxdyrotate = false;
        }

        SP_TEXT(object)->attributes.mergeInto(&optional_attrs, parent_optional_attrs, parent_attrs_offset, use_xy, use_dxdyrotate);

        // SVG 2 Text wrapping
        if (layout.wrap_mode == Inkscape::Text::Layout::WRAP_INLINE_SIZE) {

            // For horizontal text:
            //   'x' is used to calculate the left/right edges of the rectangle but is not
            //   needed later. If not deleted here, it will cause an incorrect positioning
            //   of the first line.
            //   'y' is used to determine where the first line box is located and is needed
            //   during the output stage.
            // For vertical text:
            //   Follow above but exchange 'x' and 'y'.
            // The SVG 2 spec currently says use the 'x' and 'y' from the <text> element,
            // if not defined in the <text> element, use the 'x' and 'y' from the first child.
            // We only look at the <text> element. (Doing otherwise means tracking if
            // we've found 'x' and 'y' and then creating the Shape at the end.)
            if (is_horizontal()) {
                // Horizontal text
                SVGLength* y = _getFirstYLength();
                if (y) {
                    optional_attrs.y.push_back(*y);
                } else {
                    std::cerr << "SPText::_buildLayoutInput: No 'y' attribute value with horizontal 'inline-size'!" << std::endl;
                }
            } else {
                // Vertical text
                SVGLength* x = _getFirstXLength();
                if (x) {
                    optional_attrs.x.push_back(*x);
                } else {
                    std::cerr << "SPText::_buildLayoutInput: No 'x' attribute value with vertical 'inline-size'!" << std::endl;
                }
            }
        }

        // set textLength on the entire layout, see note in TNG-Layout.h
        if (SP_TEXT(object)->attributes.getTextLength()->_set) {
            layout.textLength._set = true;
            layout.textLength.value = SP_TEXT(object)->attributes.getTextLength()->value;
            layout.textLength.computed = SP_TEXT(object)->attributes.getTextLength()->computed;
            layout.textLength.unit = SP_TEXT(object)->attributes.getTextLength()->unit;
            layout.lengthAdjust = (Inkscape::Text::Layout::LengthAdjust) SP_TEXT(object)->attributes.getLengthAdjust();
        }
    }

    else if (SP_IS_TSPAN(object)) {
        SPTSpan *tspan = SP_TSPAN(object);

        // x, y attributes are stripped from some tspans marked with role="line" as we do our own line layout.
        // This should be checked carefully, as it can undo line layout in imported SVG files.
        bool use_xy = !in_textpath && (tspan->role == SP_TSPAN_ROLE_UNSPECIFIED || !tspan->attributes.singleXYCoordinates());
        bool use_dxdyrotate = true;

        // SVG 2 Text wrapping: see comment above.
        if (layout.wrap_mode == Inkscape::Text::Layout::WRAP_SHAPE_INSIDE ||
            layout.wrap_mode == Inkscape::Text::Layout::WRAP_INLINE_SIZE) {
            use_xy = false;
            use_dxdyrotate = false;
        }

        tspan->attributes.mergeInto(&optional_attrs, parent_optional_attrs, parent_attrs_offset, use_xy, use_dxdyrotate);
    }

    else if (SP_IS_TREF(object)) {
        SP_TREF(object)->attributes.mergeInto(&optional_attrs, parent_optional_attrs, parent_attrs_offset, true, true);
    }

    else if (SP_IS_TEXTPATH(object)) {
        in_textpath = true;
        SP_TEXTPATH(object)->attributes.mergeInto(&optional_attrs, parent_optional_attrs, parent_attrs_offset, false, true);
        optional_attrs.x.clear();
        optional_attrs.y.clear();
    }

    else {
        optional_attrs = parent_optional_attrs;
        child_attrs_offset = parent_attrs_offset;
    }


    if (SP_IS_TSPAN(object)) {
        if (SP_TSPAN(object)->role != SP_TSPAN_ROLE_UNSPECIFIED) {
            // we need to allow the first line not to have role=line, but still set the source_cookie to the right value
            SPObject *prev_object = object->getPrev();
            if (prev_object && SP_IS_TSPAN(prev_object)) {
                if (!layout.inputExists()) {
                    layout.appendText("", prev_object->style, prev_object, &optional_attrs);
                }
                layout.appendControlCode(Inkscape::Text::Layout::PARAGRAPH_BREAK, prev_object);
            }
            if (!object->hasChildren()) {
                layout.appendText("", object->style, object, &optional_attrs);
            }
            length++;     // interpreting line breaks as a character for the purposes of x/y/etc attributes
                          // is a liberal interpretation of the svg spec, but a strict reading would mean
                          // that if the first line is empty the second line would take its place at the
                          // start position. Very confusing.
            child_attrs_offset--;
        }
    }

    for (auto& child: object->children) {
        SPString *str = dynamic_cast<SPString *>(&child);
        if (str) {
            Glib::ustring const &string = str->string;
            // std::cout << "  Appending: >" << string << "<" << std::endl;
            layout.appendText(string, object->style, &child, &optional_attrs, child_attrs_offset + length);
            length += string.length();
        } else if (!sp_repr_is_meta_element(child.getRepr())) {
            /*      ^^^^ XML Tree being directly used here while it shouldn't be.*/
            length += _buildLayoutInput(&child, optional_attrs, child_attrs_offset + length, in_textpath);
        }
    }

    return length;
}

Shape* SPText::_buildExclusionShape() const
{
    Shape *result = new Shape(); // Union of all exclusion shapes
    Shape *shape_temp = new Shape();

    for(auto shape_id : style->shape_subtract.shape_ids) {

            SPShape *shape = dynamic_cast<SPShape *>(document->getObjectById( shape_id ));
            if ( shape ) {
                // This code adapted from sp-flowregion.cpp: GetDest()
                if (!(shape->_curve)) {
                    shape->set_shape();
                }
                SPCurve *curve = shape->getCurve();

                if ( curve ) {
                    Path *temp = new Path;
                    Path *margin = new Path;
                    temp->LoadPathVector( curve->get_pathvector(), shape->transform, true );

                    if( shape->style->shape_margin.set ) {
                        temp->OutsideOutline ( margin, -shape->style->shape_margin.computed, join_round, butt_straight, 20.0 );
                    } else {
                        margin->Copy( temp );
                    }

                    margin->Convert( 0.25 );  // Convert to polyline
                    Shape* sh = new Shape;
                    margin->Fill( sh, 0 );

                    Shape *uncross = new Shape;
                    uncross->ConvertToShape( sh );

                    if (result->hasEdges()) {
                        shape_temp->Booleen(result, uncross, bool_op_union);
                        std::swap(result, shape_temp);
                    } else {
                        result->Copy(uncross);
                    }
                }
            }
    }
    return result;
}


// SVG requires one to use the first x/y value found on a child element if x/y not given on text
// element. TODO: Recurse.
SVGLength*
SPText::_getFirstXLength()
{
    SVGLength* x = attributes.getFirstXLength();

    if (!x) {
        for (auto& child: children) {
            if (SP_IS_TSPAN(&child)) {
                SPTSpan *tspan = SP_TSPAN(&child);
                x = tspan->attributes.getFirstXLength();
                break;
            }
        }
    }

    return x;
}


SVGLength*
SPText::_getFirstYLength()
{
    SVGLength* y = attributes.getFirstYLength();

    if (!y) {
        for (auto& child: children) {
            if (SP_IS_TSPAN(&child)) {
                SPTSpan *tspan = SP_TSPAN(&child);
                y = tspan->attributes.getFirstYLength();
                break;
            }
        }
    }

    return y;
}


void SPText::rebuildLayout()
{
    layout.clear();
    _buildLayoutInit();

    Inkscape::Text::Layout::OptionalTextTagAttrs optional_attrs;
    _buildLayoutInput(this, optional_attrs, 0, false);

    layout.calculateFlow();

    for (auto& child: children) {
        if (SP_IS_TEXTPATH(&child)) {
            SPTextPath const *textpath = SP_TEXTPATH(&child);
            if (textpath->originalPath != nullptr) {
#if DEBUG_TEXTLAYOUT_DUMPASTEXT
                g_print("%s", layout.dumpAsText().c_str());
#endif
                layout.fitToPathAlign(textpath->startOffset, *textpath->originalPath);
            }
        }
    }
#if DEBUG_TEXTLAYOUT_DUMPASTEXT
    g_print("%s", layout.dumpAsText().c_str());
#endif

    // set the x,y attributes on role:line spans
    for (auto& child: children) {
        if (SP_IS_TSPAN(&child)) {
            SPTSpan *tspan = SP_TSPAN(&child);
            if ((tspan->role != SP_TSPAN_ROLE_UNSPECIFIED)
                 && tspan->attributes.singleXYCoordinates() ) {
                Inkscape::Text::Layout::iterator iter = layout.sourceToIterator(tspan);
                Geom::Point anchor_point = layout.chunkAnchorPoint(iter);
                tspan->attributes.setFirstXY(anchor_point);
                // repr needs to be updated but if we do it here we get a loop.
            }
        }
    }
}


void SPText::_adjustFontsizeRecursive(SPItem *item, double ex, bool is_root)
{
    SPStyle *style = item->style;

    if (style && !Geom::are_near(ex, 1.0)) {
        if (!style->font_size.set && is_root) {
            style->font_size.set = 1;
        }
        style->font_size.type = SP_FONT_SIZE_LENGTH;
        style->font_size.computed *= ex;
        style->letter_spacing.computed *= ex;
        style->word_spacing.computed *= ex;
        if (style->line_height.unit != SP_CSS_UNIT_NONE &&
            style->line_height.unit != SP_CSS_UNIT_PERCENT &&
            style->line_height.unit != SP_CSS_UNIT_EM &&
            style->line_height.unit != SP_CSS_UNIT_EX) {
            // No unit on 'line-height' property has special behavior.
            style->line_height.computed *= ex;
        }
        item->updateRepr();
    }

    for(auto& o: item->children) {
        if (SP_IS_ITEM(&o))
            _adjustFontsizeRecursive(SP_ITEM(&o), ex, false);
    }
}

void SPText::_adjustCoordsRecursive(SPItem *item, Geom::Affine const &m, double ex, bool is_root)
{
    if (SP_IS_TSPAN(item))
        SP_TSPAN(item)->attributes.transform(m, ex, ex, is_root);
              // it doesn't matter if we change the x,y for role=line spans because we'll just overwrite them anyway
    else if (SP_IS_TEXT(item))
        SP_TEXT(item)->attributes.transform(m, ex, ex, is_root);
    else if (SP_IS_TEXTPATH(item))
        SP_TEXTPATH(item)->attributes.transform(m, ex, ex, is_root);
    else if (SP_IS_TREF(item)) {
        SP_TREF(item)->attributes.transform(m, ex, ex, is_root);
    }

    for(auto& o: item->children) {
        if (SP_IS_ITEM(&o))
            _adjustCoordsRecursive(SP_ITEM(&o), m, ex, false);
    }
}


void SPText::_clearFlow(Inkscape::DrawingGroup *in_arena)
{
    in_arena->clearChildren();
}

bool SPText::is_horizontal() const
{
    unsigned mode = style->writing_mode.computed;
    return (mode == SP_CSS_WRITING_MODE_LR_TB || mode == SP_CSS_WRITING_MODE_RL_TB);
}

bool SPText::has_inline_size() const
{
    // If inline size is '0' it is as if it is not set.
    return (style->inline_size.set && style->inline_size.value != 0);
}

bool SPText::has_shape_inside() const
{
    return (style->shape_inside.set);
}

// Gets rectangle defined by <text> x, y and inline-size ("infinite" in one direction).
Geom::OptRect SPText::get_frame()
{
    Geom::OptRect opt_frame;
    Geom::Rect frame;

    if (has_inline_size()) {
        double inline_size = style->inline_size.computed;
        unsigned mode      = style->writing_mode.computed;
        unsigned anchor    = style->text_anchor.computed;
        unsigned direction = style->direction.computed;

        if (is_horizontal()) {
            // horizontal
            frame = Geom::Rect::from_xywh(attributes.firstXY()[Geom::X], -100000, inline_size, 200000);
            if (anchor == SP_CSS_TEXT_ANCHOR_MIDDLE) {
                frame *= Geom::Translate (-inline_size/2.0, 0 );
            } else if ( (direction == SP_CSS_DIRECTION_LTR && anchor == SP_CSS_TEXT_ANCHOR_END  ) ||
                        (direction == SP_CSS_DIRECTION_RTL && anchor == SP_CSS_TEXT_ANCHOR_START) ) {
                frame *= Geom::Translate (-inline_size, 0);
            }
        } else {
            // vertical
            frame = Geom::Rect::from_xywh(-100000, attributes.firstXY()[Geom::Y], 200000, inline_size);
            if (anchor == SP_CSS_TEXT_ANCHOR_MIDDLE) {
                frame *= Geom::Translate (0, -inline_size/2.0);
            } else if (anchor == SP_CSS_TEXT_ANCHOR_END) {
                frame *= Geom::Translate (0, -inline_size);
            }
        }

        opt_frame = frame;

    } else {
        // See if 'shape-inside' has rectangle
        Inkscape::XML::Node* rectangle = get_first_rectangle();

        if (rectangle) {
            double x = 0.0;
            double y = 0.0;
            double width = 0.0;
            double height = 0.0;
            sp_repr_get_double (rectangle, "x",      &x);
            sp_repr_get_double (rectangle, "y",      &y);
            sp_repr_get_double (rectangle, "width",  &width);
            sp_repr_get_double (rectangle, "height", &height);
            frame = Geom::Rect::from_xywh( x, y, width, height);
            opt_frame = frame;
        }
    }

    return opt_frame;
}

// Find the node of the first rectangle (if it exists) in 'shape-inside'.
Inkscape::XML::Node* SPText::get_first_rectangle()
{
    Inkscape::XML::Node* first_rectangle = nullptr;

    Inkscape::XML::Node *our_ref = getRepr();

    if (style->shape_inside.set && style->shape_inside.value) {

        std::vector<Glib::ustring> shapes = get_shapes();

        for (auto shape: shapes) {

            Inkscape::XML::Node *item =
                sp_repr_lookup_descendant (our_ref->root(), "id", shape.c_str());

            if (item && strncmp("svg:rect", item->name(), 8) == 0) {
                return item;
                break;
            }
        }
    }

    return first_rectangle;
}

// Get a list of shape in 'shape-inside' as a vector of strings.
std::vector<Glib::ustring> SPText::get_shapes() const
{
    std::vector<Glib::ustring> shapes;
    if (style->shape_inside.set && style->shape_inside.value) {

        static Glib::RefPtr<Glib::Regex> regex = Glib::Regex::create("url\\(#([A-z0-9#]*)\\)");
        Glib::MatchInfo matchInfo;
        regex->match(style->shape_inside.value, matchInfo);

        while (matchInfo.matches()) {
            shapes.push_back(matchInfo.fetch(1));
            matchInfo.next();
        }
    }

    return shapes;
}


SPItem *create_text_with_inline_size (SPDesktop *desktop, Geom::Point p0, Geom::Point p1)
{
    SPDocument *doc = desktop->getDocument();

    Inkscape::XML::Document *xml_doc = doc->getReprDoc();
    Inkscape::XML::Node *text_repr = xml_doc->createElement("svg:text");
    text_repr->setAttribute("xml:space", "preserve"); // we preserve spaces in the text objects we create

    SPText *text_object = dynamic_cast<SPText *>(desktop->currentLayer()->appendChildRepr(text_repr));
    g_assert(text_object != nullptr);

    // Invert coordinate system?
    p0 *= desktop->dt2doc();
    p1 *= desktop->dt2doc();

    // Pixels to user units
    p0 *= SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();
    p1 *= SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();

    sp_repr_set_svg_double( text_repr, "x", p0[Geom::X]);
    sp_repr_set_svg_double( text_repr, "y", p0[Geom::Y]);

    double inline_size = p1[Geom::X] - p0[Geom::X];

    text_object->style->inline_size.setDouble( inline_size );
    text_object->style->inline_size.set = true;

    Inkscape::XML::Node *text_node = xml_doc->createTextNode("");
    text_repr->appendChild(text_node);

    SPItem *item = dynamic_cast<SPItem *>(desktop->currentLayer());
    g_assert(item != nullptr);

    // text_object->transform = item->i2doc_affine().inverse();

    text_object->updateRepr();

    SPCSSAttr* css = sp_repr_css_attr (text_repr, "style");

    Inkscape::GC::release(text_repr);
    Inkscape::GC::release(text_node);

    return text_object;
}

SPItem *create_text_with_rectangle (SPDesktop *desktop, Geom::Point p0, Geom::Point p1)
{
    SPDocument *doc = desktop->getDocument();

    Inkscape::XML::Document *xml_doc = doc->getReprDoc();
    Inkscape::XML::Node *text_repr = xml_doc->createElement("svg:text");
    text_repr->setAttribute("xml:space", "preserve"); // we preserve spaces in the text objects we create

    SPText *text_object = dynamic_cast<SPText *>(desktop->currentLayer()->appendChildRepr(text_repr));
    g_assert(text_object != nullptr);

    // Invert coordinate system?
    p0 *= desktop->dt2doc();
    p1 *= desktop->dt2doc();

    // Pixels to user units
    p0 *= SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();
    p1 *= SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();

    // Create rectangle
    Inkscape::XML::Node *rect_repr = xml_doc->createElement("svg:rect");
    sp_repr_set_svg_double( rect_repr, "x", p0[Geom::X]);
    sp_repr_set_svg_double( rect_repr, "y", p0[Geom::Y]);
    sp_repr_set_svg_double( rect_repr, "width",  abs(p1[Geom::X]-p0[Geom::X]));
    sp_repr_set_svg_double( rect_repr, "height", abs(p1[Geom::Y]-p0[Geom::Y]));

    // Find defs, if does not exist, create.
    Inkscape::XML::Node *defs_repr = sp_repr_lookup_name (xml_doc->root(), "svg:defs");
    if (defs_repr == nullptr) {
        defs_repr = xml_doc->createElement("svg:defs");
        xml_doc->root()->addChild(defs_repr, nullptr);
    }

    // Add rectangle to defs.
    defs_repr->addChild(rect_repr, nullptr);

    // Link rectangle to text
    std::string value("url(#");
    value += rect_repr->attribute("id");
    value += ")";
    SPCSSAttr* css = sp_repr_css_attr (text_repr, "style");
    sp_repr_css_set_property (css, "shape-inside", value.c_str());
    sp_repr_css_set(text_repr, css, "style");
    sp_repr_css_attr_unref(css);

    /* Create <tspan> */
    Inkscape::XML::Node *rtspan = xml_doc->createElement("svg:tspan");
    rtspan->setAttribute("sodipodi:role", "line"); // otherwise, why bother creating the tspan?
    Inkscape::XML::Node *text_node = xml_doc->createTextNode("");
    rtspan->appendChild(text_node);
    text_repr->appendChild(rtspan);

    SPItem *item = dynamic_cast<SPItem *>(desktop->currentLayer());
    g_assert(item != nullptr);

    Inkscape::GC::release(rtspan);
    Inkscape::GC::release(text_repr);
    Inkscape::GC::release(text_node);
    Inkscape::GC::release(defs_repr);
    Inkscape::GC::release(rect_repr);

    return text_object;
}

/*
 * TextTagAttributes implementation
 */

// Not used.
// void TextTagAttributes::readFrom(Inkscape::XML::Node const *node)
// {
//     readSingleAttribute(SP_ATTR_X, node->attribute("x"));
//     readSingleAttribute(SP_ATTR_Y, node->attribute("y"));
//     readSingleAttribute(SP_ATTR_DX, node->attribute("dx"));
//     readSingleAttribute(SP_ATTR_DY, node->attribute("dy"));
//     readSingleAttribute(SP_ATTR_ROTATE, node->attribute("rotate"));
//     readSingleAttribute(SP_ATTR_TEXTLENGTH, node->attribute("textLength"));
//     readSingleAttribute(SP_ATTR_LENGTHADJUST, node->attribute("lengthAdjust"));
// }

bool TextTagAttributes::readSingleAttribute(unsigned key, gchar const *value, SPStyle const *style, Geom::Rect const *viewport)
{
    // std::cout << "TextTagAttributes::readSingleAttribute: key: " << key
    //           << "  value: " << (value?value:"Null") << std::endl;
    std::vector<SVGLength> *attr_vector;
    bool update_x = false;
    bool update_y = false;
    switch (key) {
        case SP_ATTR_X:      attr_vector = &attributes.x;  update_x = true; break;
        case SP_ATTR_Y:      attr_vector = &attributes.y;  update_y = true; break;
        case SP_ATTR_DX:     attr_vector = &attributes.dx; update_x = true; break;
        case SP_ATTR_DY:     attr_vector = &attributes.dy; update_y = true; break;
        case SP_ATTR_ROTATE: attr_vector = &attributes.rotate; break;
        case SP_ATTR_TEXTLENGTH:
            attributes.textLength.readOrUnset(value);
            return true;
            break;
        case SP_ATTR_LENGTHADJUST:
            attributes.lengthAdjust = (value && !strcmp(value, "spacingAndGlyphs")?
                                        Inkscape::Text::Layout::LENGTHADJUST_SPACINGANDGLYPHS :
                                        Inkscape::Text::Layout::LENGTHADJUST_SPACING); // default is "spacing"
            return true;
            break;
        default: return false;
    }

    // FIXME: sp_svg_length_list_read() amalgamates repeated separators. This prevents unset values.
    *attr_vector = sp_svg_length_list_read(value);

    if( (update_x || update_y) && style != nullptr && viewport != nullptr ) {
        double const w = viewport->width();
        double const h = viewport->height();
        double const em = style->font_size.computed;
        double const ex = em * 0.5;
        for(auto & it : *attr_vector) {
            if( update_x )
                it.update( em, ex, w );
            if( update_y )
                it.update( em, ex, h );
        }
    }
    return true;
}

void TextTagAttributes::writeTo(Inkscape::XML::Node *node) const
{
    writeSingleAttributeVector(node, "x", attributes.x);
    writeSingleAttributeVector(node, "y", attributes.y);
    writeSingleAttributeVector(node, "dx", attributes.dx);
    writeSingleAttributeVector(node, "dy", attributes.dy);
    writeSingleAttributeVector(node, "rotate", attributes.rotate);

    writeSingleAttributeLength(node, "textLength", attributes.textLength);

    if (attributes.textLength._set) {
        if (attributes.lengthAdjust == Inkscape::Text::Layout::LENGTHADJUST_SPACING) {
            node->setAttribute("lengthAdjust", "spacing");
        } else if (attributes.lengthAdjust == Inkscape::Text::Layout::LENGTHADJUST_SPACINGANDGLYPHS) {
            node->setAttribute("lengthAdjust", "spacingAndGlyphs");
        }
    }
}

void TextTagAttributes::update( double em, double ex, double w, double h )
{
    for(auto & it : attributes.x) {
        it.update( em, ex, w );
    }
    for(auto & it : attributes.y) {
        it.update( em, ex, h );
    }
    for(auto & it : attributes.dx) {
        it.update( em, ex, w );
    }
    for(auto & it : attributes.dy) {
        it.update( em, ex, h );
    }
}

void TextTagAttributes::writeSingleAttributeLength(Inkscape::XML::Node *node, gchar const *key, const SVGLength &length)
{
    if (length._set) {
        node->setAttribute(key, length.write().c_str());
    } else
        node->setAttribute(key, nullptr);
}

void TextTagAttributes::writeSingleAttributeVector(Inkscape::XML::Node *node, gchar const *key, std::vector<SVGLength> const &attr_vector)
{
    if (attr_vector.empty())
        node->setAttribute(key, nullptr);
    else {
        Glib::ustring string;

        // FIXME: this has no concept of unset values because sp_svg_length_list_read() can't read them back in
        for (auto it : attr_vector) {
            if (!string.empty()) string += ' ';
            string += it.write();
        }
        node->setAttribute(key, string.c_str());
    }
}

bool TextTagAttributes::singleXYCoordinates() const
{
    return attributes.x.size() <= 1 && attributes.y.size() <= 1;
}

bool TextTagAttributes::anyAttributesSet() const
{
    return !attributes.x.empty() || !attributes.y.empty() || !attributes.dx.empty() || !attributes.dy.empty() || !attributes.rotate.empty();
}

Geom::Point TextTagAttributes::firstXY() const
{
    Geom::Point point;
    if (attributes.x.empty()) point[Geom::X] = 0.0;
    else point[Geom::X] = attributes.x[0].computed;
    if (attributes.y.empty()) point[Geom::Y] = 0.0;
    else point[Geom::Y] = attributes.y[0].computed;
    return point;
}

void TextTagAttributes::setFirstXY(Geom::Point &point)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (attributes.x.empty())
        attributes.x.resize(1, zero_length);
    if (attributes.y.empty())
        attributes.y.resize(1, zero_length);
    attributes.x[0] = point[Geom::X];
    attributes.y[0] = point[Geom::Y];
}

SVGLength* TextTagAttributes::getFirstXLength()
{
    if (!attributes.x.empty()) {
        return &attributes.x[0];
    } else {
        return nullptr;
    }
}

SVGLength* TextTagAttributes::getFirstYLength()
{
    if (!attributes.y.empty()) {
        return &attributes.y[0];
    } else {
        return nullptr;
    }
}

// Instance of TextTagAttributes contains attributes as defined by text/tspan element.
// output: What will be sent to the rendering engine.
// parent_attrs: Attributes collected from all ancestors.
// parent_attrs_offset: Where this element fits into the parent_attrs.
// copy_xy: Should this elements x, y attributes contribute to output (can preserve set values but not use them... kind of strange).
// copy_dxdxrotate: Should this elements dx, dy, rotate attributes contribute to output.
void TextTagAttributes::mergeInto(Inkscape::Text::Layout::OptionalTextTagAttrs *output, Inkscape::Text::Layout::OptionalTextTagAttrs const &parent_attrs, unsigned parent_attrs_offset, bool copy_xy, bool copy_dxdyrotate) const
{
    mergeSingleAttribute(&output->x,      parent_attrs.x,      parent_attrs_offset, copy_xy ? &attributes.x : nullptr);
    mergeSingleAttribute(&output->y,      parent_attrs.y,      parent_attrs_offset, copy_xy ? &attributes.y : nullptr);
    mergeSingleAttribute(&output->dx,     parent_attrs.dx,     parent_attrs_offset, copy_dxdyrotate ? &attributes.dx : nullptr);
    mergeSingleAttribute(&output->dy,     parent_attrs.dy,     parent_attrs_offset, copy_dxdyrotate ? &attributes.dy : nullptr);
    mergeSingleAttribute(&output->rotate, parent_attrs.rotate, parent_attrs_offset, copy_dxdyrotate ? &attributes.rotate : nullptr);
    if (attributes.textLength._set) { // only from current node, this is not inherited from parent
        output->textLength.value = attributes.textLength.value;
        output->textLength.computed = attributes.textLength.computed;
        output->textLength.unit = attributes.textLength.unit;
        output->textLength._set = attributes.textLength._set;
        output->lengthAdjust = attributes.lengthAdjust;
    }
}

void TextTagAttributes::mergeSingleAttribute(std::vector<SVGLength> *output_list, std::vector<SVGLength> const &parent_list, unsigned parent_offset, std::vector<SVGLength> const *overlay_list)
{
    output_list->clear();
    if (overlay_list == nullptr) {
        if (parent_list.size() > parent_offset)
        {
            output_list->reserve(parent_list.size() - parent_offset);
            std::copy(parent_list.begin() + parent_offset, parent_list.end(), std::back_inserter(*output_list));
        }
    } else {
        output_list->reserve(std::max((int)parent_list.size() - (int)parent_offset, (int)overlay_list->size()));
        unsigned overlay_offset = 0;
        while (parent_offset < parent_list.size() || overlay_offset < overlay_list->size()) {
            SVGLength const *this_item;
            if (overlay_offset < overlay_list->size()) {
                this_item = &(*overlay_list)[overlay_offset];
                overlay_offset++;
                parent_offset++;
            } else {
                this_item = &parent_list[parent_offset];
                parent_offset++;
            }
            output_list->push_back(*this_item);
        }
    }
}

void TextTagAttributes::erase(unsigned start_index, unsigned n)
{
    if (n == 0) return;
    if (!singleXYCoordinates()) {
        eraseSingleAttribute(&attributes.x, start_index, n);
        eraseSingleAttribute(&attributes.y, start_index, n);
    }
    eraseSingleAttribute(&attributes.dx, start_index, n);
    eraseSingleAttribute(&attributes.dy, start_index, n);
    eraseSingleAttribute(&attributes.rotate, start_index, n);
}

void TextTagAttributes::eraseSingleAttribute(std::vector<SVGLength> *attr_vector, unsigned start_index, unsigned n)
{
    if (attr_vector->size() <= start_index) return;
    if (attr_vector->size() <= start_index + n)
        attr_vector->erase(attr_vector->begin() + start_index, attr_vector->end());
    else
        attr_vector->erase(attr_vector->begin() + start_index, attr_vector->begin() + start_index + n);
}

void TextTagAttributes::insert(unsigned start_index, unsigned n)
{
    if (n == 0) return;
    if (!singleXYCoordinates()) {
        insertSingleAttribute(&attributes.x, start_index, n, true);
        insertSingleAttribute(&attributes.y, start_index, n, true);
    }
    insertSingleAttribute(&attributes.dx, start_index, n, false);
    insertSingleAttribute(&attributes.dy, start_index, n, false);
    insertSingleAttribute(&attributes.rotate, start_index, n, false);
}

void TextTagAttributes::insertSingleAttribute(std::vector<SVGLength> *attr_vector, unsigned start_index, unsigned n, bool is_xy)
{
    if (attr_vector->size() <= start_index) return;
    SVGLength zero_length;
    zero_length = 0.0;
    attr_vector->insert(attr_vector->begin() + start_index, n, zero_length);
    if (is_xy) {
        double begin = start_index == 0 ? (*attr_vector)[start_index + n].computed : (*attr_vector)[start_index - 1].computed;
        double diff = ((*attr_vector)[start_index + n].computed - begin) / n;   // n tested for nonzero in insert()
        for (unsigned i = 0 ; i < n ; i++)
            (*attr_vector)[start_index + i] = begin + diff * i;
    }
}

void TextTagAttributes::split(unsigned index, TextTagAttributes *second)
{
    if (!singleXYCoordinates()) {
        splitSingleAttribute(&attributes.x, index, &second->attributes.x, false);
        splitSingleAttribute(&attributes.y, index, &second->attributes.y, false);
    }
    splitSingleAttribute(&attributes.dx, index, &second->attributes.dx, true);
    splitSingleAttribute(&attributes.dy, index, &second->attributes.dy, true);
    splitSingleAttribute(&attributes.rotate, index, &second->attributes.rotate, true);
}

void TextTagAttributes::splitSingleAttribute(std::vector<SVGLength> *first_vector, unsigned index, std::vector<SVGLength> *second_vector, bool trimZeros)
{
    second_vector->clear();
    if (first_vector->size() <= index) return;
    second_vector->resize(first_vector->size() - index);
    std::copy(first_vector->begin() + index, first_vector->end(), second_vector->begin());
    first_vector->resize(index);
    if (trimZeros)
        while (!first_vector->empty() && (!first_vector->back()._set || first_vector->back().value == 0.0))
            first_vector->resize(first_vector->size() - 1);
}

void TextTagAttributes::join(TextTagAttributes const &first, TextTagAttributes const &second, unsigned second_index)
{
    if (second.singleXYCoordinates()) {
        attributes.x = first.attributes.x;
        attributes.y = first.attributes.y;
    } else {
        joinSingleAttribute(&attributes.x, first.attributes.x, second.attributes.x, second_index);
        joinSingleAttribute(&attributes.y, first.attributes.y, second.attributes.y, second_index);
    }
    joinSingleAttribute(&attributes.dx, first.attributes.dx, second.attributes.dx, second_index);
    joinSingleAttribute(&attributes.dy, first.attributes.dy, second.attributes.dy, second_index);
    joinSingleAttribute(&attributes.rotate, first.attributes.rotate, second.attributes.rotate, second_index);
}

void TextTagAttributes::joinSingleAttribute(std::vector<SVGLength> *dest_vector, std::vector<SVGLength> const &first_vector, std::vector<SVGLength> const &second_vector, unsigned second_index)
{
    if (second_vector.empty())
        *dest_vector = first_vector;
    else {
        dest_vector->resize(second_index + second_vector.size());
        if (first_vector.size() < second_index) {
            std::copy(first_vector.begin(), first_vector.end(), dest_vector->begin());
            SVGLength zero_length;
            zero_length = 0.0;
            std::fill(dest_vector->begin() + first_vector.size(), dest_vector->begin() + second_index, zero_length);
        } else
            std::copy(first_vector.begin(), first_vector.begin() + second_index, dest_vector->begin());
        std::copy(second_vector.begin(), second_vector.end(), dest_vector->begin() + second_index);
    }
}

void TextTagAttributes::transform(Geom::Affine const &matrix, double scale_x, double scale_y, bool extend_zero_length)
{
    SVGLength zero_length;
    zero_length = 0.0;

    /* edge testcases for this code:
       1) moving text elements whose position is done entirely with transform="...", no x,y attributes
       2) unflowing multi-line flowtext then moving it (it has x but not y)
    */
    unsigned points_count = std::max(attributes.x.size(), attributes.y.size());
    if (extend_zero_length && points_count < 1)
        points_count = 1;
    for (unsigned i = 0 ; i < points_count ; i++) {
        Geom::Point point;
        if (i < attributes.x.size()) point[Geom::X] = attributes.x[i].computed;
        else point[Geom::X] = 0.0;
        if (i < attributes.y.size()) point[Geom::Y] = attributes.y[i].computed;
        else point[Geom::Y] = 0.0;
        point *= matrix;
        if (i < attributes.x.size())
            attributes.x[i] = point[Geom::X];
        else if (point[Geom::X] != 0.0 && extend_zero_length) {
            attributes.x.resize(i + 1, zero_length);
            attributes.x[i] = point[Geom::X];
        }
        if (i < attributes.y.size())
            attributes.y[i] = point[Geom::Y];
        else if (point[Geom::Y] != 0.0 && extend_zero_length) {
            attributes.y.resize(i + 1, zero_length);
            attributes.y[i] = point[Geom::Y];
        }
    }
    for (auto & it : attributes.dx)
        it = it.computed * scale_x;
    for (auto & it : attributes.dy)
        it = it.computed * scale_y;
}

double TextTagAttributes::getDx(unsigned index)
{
    if( attributes.dx.empty()) {
        return 0.0;
    }
    if( index < attributes.dx.size() ) {
        return attributes.dx[index].computed;
    } else {
        return 0.0; // attributes.dx.back().computed;
    }
}


double TextTagAttributes::getDy(unsigned index)
{
    if( attributes.dy.empty() ) {
        return 0.0;
    }
    if( index < attributes.dy.size() ) {
        return attributes.dy[index].computed;
    } else {
        return 0.0; // attributes.dy.back().computed;
    }
}


void TextTagAttributes::addToDx(unsigned index, double delta)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (attributes.dx.size() < index + 1) attributes.dx.resize(index + 1, zero_length);
    attributes.dx[index] = attributes.dx[index].computed + delta;
}

void TextTagAttributes::addToDy(unsigned index, double delta)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (attributes.dy.size() < index + 1) attributes.dy.resize(index + 1, zero_length);
    attributes.dy[index] = attributes.dy[index].computed + delta;
}

void TextTagAttributes::addToDxDy(unsigned index, Geom::Point const &adjust)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (adjust[Geom::X] != 0.0) {
        if (attributes.dx.size() < index + 1) attributes.dx.resize(index + 1, zero_length);
        attributes.dx[index] = attributes.dx[index].computed + adjust[Geom::X];
    }
    if (adjust[Geom::Y] != 0.0) {
        if (attributes.dy.size() < index + 1) attributes.dy.resize(index + 1, zero_length);
        attributes.dy[index] = attributes.dy[index].computed + adjust[Geom::Y];
    }
}

double TextTagAttributes::getRotate(unsigned index)
{
    if( attributes.rotate.empty() ) {
        return 0.0;
    }
    if( index < attributes.rotate.size() ) {
        return attributes.rotate[index].computed;
    } else {
        return attributes.rotate.back().computed;
    }
}


void TextTagAttributes::addToRotate(unsigned index, double delta)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (attributes.rotate.size() < index + 2) {
        if (attributes.rotate.empty())
            attributes.rotate.resize(index + 2, zero_length);
        else
            attributes.rotate.resize(index + 2, attributes.rotate.back());
    }
    attributes.rotate[index] = mod360(attributes.rotate[index].computed + delta);
}


void TextTagAttributes::setRotate(unsigned index, double angle)
{
    SVGLength zero_length;
    zero_length = 0.0;

    if (attributes.rotate.size() < index + 2) {
        if (attributes.rotate.empty())
            attributes.rotate.resize(index + 2, zero_length);
        else
            attributes.rotate.resize(index + 2, attributes.rotate.back());
    }
    attributes.rotate[index] = mod360(angle);
}


/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
