msdfgen/ext/import-svg.cpp

#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include "import-svg.h"

#ifndef MSDFGEN_DISABLE_SVG

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <tinyxml2.h>

#ifdef MSDFGEN_USE_SKIA
#include <skia/core/SkPath.h>
#include <skia/utils/SkParsePath.h>
#include <skia/pathops/SkPathOps.h>
#endif

#include "../core/arithmetics.hpp"

#define ARC_SEGMENTS_PER_PI 2
#define ENDPOINT_SNAP_RANGE_PROPORTION (::msdfgen::real(1)/::msdfgen::real(16384))

namespace msdfgen {

#if defined(_DEBUG) || !NDEBUG
#define REQUIRE(cond) { if (!(cond)) { fprintf(stderr, "SVG Parse Error (%s:%d): " #cond "\n", __FILE__, __LINE__); return false; } }
#else
#define REQUIRE(cond) { if (!(cond)) return false; }
#endif

MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_FAILURE = 0x00;
MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_SUCCESS_FLAG = 0x01;
MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_PARTIAL_FAILURE_FLAG = 0x02;
MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_INCOMPLETE_FLAG = 0x04;
MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG = 0x08;
MSDFGEN_EXT_PUBLIC const int SVG_IMPORT_TRANSFORMATION_IGNORED_FLAG = 0x10;

static void skipExtraChars(const char *&pathDef) {
    while (*pathDef == ',' || *pathDef == ' ' || *pathDef == '\t' || *pathDef == '\r' || *pathDef == '\n')
        ++pathDef;
}

static bool readNodeType(char &output, const char *&pathDef) {
    skipExtraChars(pathDef);
    char nodeType = *pathDef;
    if (nodeType && nodeType != '+' && nodeType != '-' && nodeType != '.' && nodeType != ',' && (nodeType < '0' || nodeType > '9')) {
        ++pathDef;
        output = nodeType;
        return true;
    }
    return false;
}

static bool readCoord(Point2 &output, const char *&pathDef) {
    skipExtraChars(pathDef);
    int shift;
    double x, y;
    if (sscanf(pathDef, "%lf%lf%n", &x, &y, &shift) == 2 || sscanf(pathDef, "%lf , %lf%n", &x, &y, &shift) == 2) {
        output.x = x;
        output.y = y;
        pathDef += shift;
        return true;
    }
    return false;
}

static bool readReal(real &output, const char *&pathDef) {
    skipExtraChars(pathDef);
    int shift;
    double v;
    if (sscanf(pathDef, "%lf%n", &v, &shift) == 1) {
        pathDef += shift;
        output = v;
        return true;
    }
    return false;
}

static bool readBool(bool &output, const char *&pathDef) {
    skipExtraChars(pathDef);
    int shift;
    int v;
    if (sscanf(pathDef, "%d%n", &v, &shift) == 1) {
        pathDef += shift;
        output = v != 0;
        return true;
    }
    return false;
}

static real arcAngle(Vector2 u, Vector2 v) {
    return real(nonZeroSign(crossProduct(u, v)))*acos(clamp(dotProduct(u, v)/(u.length()*v.length()), real(-1), real(+1)));
}

static Vector2 rotateVector(Vector2 v, Vector2 direction) {
    return Vector2(direction.x*v.x-direction.y*v.y, direction.y*v.x+direction.x*v.y);
}

static void addArcApproximate(Contour &contour, Point2 startPoint, Point2 endPoint, Vector2 radius, real rotation, bool largeArc, bool sweep) {
    if (endPoint == startPoint)
        return;
    if (radius.x == real(0) || radius.y == real(0))
        return contour.addEdge(new LinearSegment(startPoint, endPoint));

    radius.x = fabs(radius.x);
    radius.y = fabs(radius.y);
    Vector2 axis(cos(rotation), sin(rotation));

    Vector2 rm = rotateVector(real(.5)*(startPoint-endPoint), Vector2(axis.x, -axis.y));
    Vector2 rm2 = rm*rm;
    Vector2 radius2 = radius*radius;
    real radiusGap = rm2.x/radius2.x+rm2.y/radius2.y;
    if (radiusGap > real(1)) {
        radius *= sqrt(radiusGap);
        radius2 = radius*radius;
    }
    real dq = (radius2.x*rm2.y+radius2.y*rm2.x);
    real pq = radius2.x*radius2.y/dq-1;
    real q = (largeArc == sweep ? real(-1) : real(+1))*sqrt(max(pq, real(0)));
    Vector2 rc(q*radius.x*rm.y/radius.y, -q*radius.y*rm.x/radius.x);
    Point2 center = real(.5)*(startPoint+endPoint)+rotateVector(rc, axis);

    real angleStart = arcAngle(Vector2(1, 0), (rm-rc)/radius);
    real angleExtent = arcAngle((rm-rc)/radius, (-rm-rc)/radius);
    if (!sweep && angleExtent > real(0))
        angleExtent -= real(2*M_PI);
    else if (sweep && angleExtent < real(0))
        angleExtent += real(2*M_PI);

    int segments = (int) ceil(real(ARC_SEGMENTS_PER_PI)/real(M_PI)*fabs(angleExtent));
    real angleIncrement = angleExtent/segments;
    real cl = real(4)/real(3)*sin(real(.5)*angleIncrement)/(real(1)+cos(real(.5)*angleIncrement));

    Point2 prevNode = startPoint;
    real angle = angleStart;
    for (int i = 0; i < segments; ++i) {
        Point2 controlPoint[2];
        Vector2 d(cos(angle), sin(angle));
        controlPoint[0] = center+rotateVector(Vector2(d.x-cl*d.y, d.y+cl*d.x)*radius, axis);
        angle += angleIncrement;
        d.set(cos(angle), sin(angle));
        controlPoint[1] = center+rotateVector(Vector2(d.x+cl*d.y, d.y-cl*d.x)*radius, axis);
        Point2 node = i == segments-1 ? endPoint : center+rotateVector(d*radius, axis);
        contour.addEdge(new CubicSegment(prevNode, controlPoint[0], controlPoint[1], node));
        prevNode = node;
    }
}

#define FLAGS_FINAL(flags) (((flags)&(SVG_IMPORT_SUCCESS_FLAG|SVG_IMPORT_INCOMPLETE_FLAG|SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG)) == (SVG_IMPORT_SUCCESS_FLAG|SVG_IMPORT_INCOMPLETE_FLAG|SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG))

static void findPathByForwardIndex(tinyxml2::XMLElement *&path, int &flags, int &skips, tinyxml2::XMLElement *parent, bool hasTransformation) {
    for (tinyxml2::XMLElement *cur = parent->FirstChildElement(); cur && !FLAGS_FINAL(flags); cur = cur->NextSiblingElement()) {
        if (!strcmp(cur->Name(), "path")) {
            if (!skips--) {
                path = cur;
                flags |= SVG_IMPORT_SUCCESS_FLAG;
                if (hasTransformation || cur->Attribute("transform"))
                    flags |= SVG_IMPORT_TRANSFORMATION_IGNORED_FLAG;
            } else if (flags&SVG_IMPORT_SUCCESS_FLAG)
                flags |= SVG_IMPORT_INCOMPLETE_FLAG;
        } else if (!strcmp(cur->Name(), "g"))
            findPathByForwardIndex(path, flags, skips, cur, hasTransformation || cur->Attribute("transform"));
        else if (!strcmp(cur->Name(), "rect") || !strcmp(cur->Name(), "circle") || !strcmp(cur->Name(), "ellipse") || !strcmp(cur->Name(), "polygon"))
            flags |= SVG_IMPORT_INCOMPLETE_FLAG;
        else if (!strcmp(cur->Name(), "mask") || !strcmp(cur->Name(), "use"))
            flags |= SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG;
    }
}

static void findPathByBackwardIndex(tinyxml2::XMLElement *&path, int &flags, int &skips, tinyxml2::XMLElement *parent, bool hasTransformation) {
    for (tinyxml2::XMLElement *cur = parent->LastChildElement(); cur && !FLAGS_FINAL(flags); cur = cur->PreviousSiblingElement()) {
        if (!strcmp(cur->Name(), "path")) {
            if (!skips--) {
                path = cur;
                flags |= SVG_IMPORT_SUCCESS_FLAG;
                if (hasTransformation || cur->Attribute("transform"))
                    flags |= SVG_IMPORT_TRANSFORMATION_IGNORED_FLAG;
            } else if (flags&SVG_IMPORT_SUCCESS_FLAG)
                flags |= SVG_IMPORT_INCOMPLETE_FLAG;
        } else if (!strcmp(cur->Name(), "g"))
            findPathByBackwardIndex(path, flags, skips, cur, hasTransformation || cur->Attribute("transform"));
        else if (!strcmp(cur->Name(), "rect") || !strcmp(cur->Name(), "circle") || !strcmp(cur->Name(), "ellipse") || !strcmp(cur->Name(), "polygon"))
            flags |= SVG_IMPORT_INCOMPLETE_FLAG;
        else if (!strcmp(cur->Name(), "mask") || !strcmp(cur->Name(), "use"))
            flags |= SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG;
    }
}

bool buildShapeFromSvgPath(Shape &shape, const char *pathDef, real endpointSnapRange) {
    char nodeType = '\0';
    char prevNodeType = '\0';
    Point2 prevNode(0, 0);
    bool nodeTypePreread = false;
    while (nodeTypePreread || readNodeType(nodeType, pathDef)) {
        nodeTypePreread = false;
        Contour &contour = shape.addContour();
        bool contourStart = true;

        Point2 startPoint;
        Point2 controlPoint[2];
        Point2 node;

        while (*pathDef) {
            switch (nodeType) {
                case 'M': case 'm':
                    if (!contourStart) {
                        nodeTypePreread = true;
                        goto NEXT_CONTOUR;
                    }
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 'm')
                        node += prevNode;
                    startPoint = node;
                    --nodeType; // to 'L' or 'l'
                    break;
                case 'Z': case 'z':
                    REQUIRE(!contourStart);
                    goto NEXT_CONTOUR;
                case 'L': case 'l':
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 'l')
                        node += prevNode;
                    contour.addEdge(new LinearSegment(prevNode, node));
                    break;
                case 'H': case 'h':
                    REQUIRE(readReal(node.x, pathDef));
                    if (nodeType == 'h')
                        node.x += prevNode.x;
                    contour.addEdge(new LinearSegment(prevNode, node));
                    break;
                case 'V': case 'v':
                    REQUIRE(readReal(node.y, pathDef));
                    if (nodeType == 'v')
                        node.y += prevNode.y;
                    contour.addEdge(new LinearSegment(prevNode, node));
                    break;
                case 'Q': case 'q':
                    REQUIRE(readCoord(controlPoint[0], pathDef));
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 'q') {
                        controlPoint[0] += prevNode;
                        node += prevNode;
                    }
                    contour.addEdge(new QuadraticSegment(prevNode, controlPoint[0], node));
                    break;
                case 'T': case 't':
                    if (prevNodeType == 'Q' || prevNodeType == 'q' || prevNodeType == 'T' || prevNodeType == 't')
                        controlPoint[0] = node+node-controlPoint[0];
                    else
                        controlPoint[0] = node;
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 't')
                        node += prevNode;
                    contour.addEdge(new QuadraticSegment(prevNode, controlPoint[0], node));
                    break;
                case 'C': case 'c':
                    REQUIRE(readCoord(controlPoint[0], pathDef));
                    REQUIRE(readCoord(controlPoint[1], pathDef));
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 'c') {
                        controlPoint[0] += prevNode;
                        controlPoint[1] += prevNode;
                        node += prevNode;
                    }
                    contour.addEdge(new CubicSegment(prevNode, controlPoint[0], controlPoint[1], node));
                    break;
                case 'S': case 's':
                    if (prevNodeType == 'C' || prevNodeType == 'c' || prevNodeType == 'S' || prevNodeType == 's')
                        controlPoint[0] = node+node-controlPoint[1];
                    else
                        controlPoint[0] = node;
                    REQUIRE(readCoord(controlPoint[1], pathDef));
                    REQUIRE(readCoord(node, pathDef));
                    if (nodeType == 's') {
                        controlPoint[1] += prevNode;
                        node += prevNode;
                    }
                    contour.addEdge(new CubicSegment(prevNode, controlPoint[0], controlPoint[1], node));
                    break;
                case 'A': case 'a':
                    {
                        Vector2 radius;
                        real angle;
                        bool largeArg;
                        bool sweep;
                        REQUIRE(readCoord(radius, pathDef));
                        REQUIRE(readReal(angle, pathDef));
                        REQUIRE(readBool(largeArg, pathDef));
                        REQUIRE(readBool(sweep, pathDef));
                        REQUIRE(readCoord(node, pathDef));
                        if (nodeType == 'a')
                            node += prevNode;
                        angle *= real(M_PI)/real(180);
                        addArcApproximate(contour, prevNode, node, radius, angle, largeArg, sweep);
                    }
                    break;
                default:
                    REQUIRE(!"Unknown node type");
            }
            contourStart &= nodeType == 'M' || nodeType == 'm';
            prevNode = node;
            prevNodeType = nodeType;
            readNodeType(nodeType, pathDef);
        }
    NEXT_CONTOUR:
        // Fix contour if it isn't properly closed
        if (!contour.edges.empty() && prevNode != startPoint) {
            if ((contour.edges.back()->point(1)-contour.edges[0]->point(0)).length() < endpointSnapRange)
                contour.edges.back()->moveEndPoint(contour.edges[0]->point(0));
            else
                contour.addEdge(new LinearSegment(prevNode, startPoint));
        }
        prevNode = startPoint;
        prevNodeType = '\0';
    }
    return true;
}

bool loadSvgShape(Shape &output, const char *filename, int pathIndex, Vector2 *dimensions) {
    tinyxml2::XMLDocument doc;
    if (doc.LoadFile(filename))
        return false;
    tinyxml2::XMLElement *root = doc.FirstChildElement("svg");
    if (!root)
        return false;

    tinyxml2::XMLElement *path = NULL;
    int flags = 0;
    int skippedPaths = abs(pathIndex)-(pathIndex != 0);
    if (pathIndex > 0)
        findPathByForwardIndex(path, flags, skippedPaths, root, false);
    else
        findPathByBackwardIndex(path, flags, skippedPaths, root, false);
    if (!path)
        return false;
    const char *pd = path->Attribute("d");
    if (!pd)
        return false;

    double left, bottom;
    double width = root->DoubleAttribute("width"), height = root->DoubleAttribute("height");
    const char *viewBox = root->Attribute("viewBox");
    if (viewBox)
        (void) sscanf(viewBox, "%lf %lf %lf %lf", &left, &bottom, &width, &height);
    if (dimensions)
        *dimensions = Vector2(width, height);
    output.contours.clear();
    output.inverseYAxis = true;
    return buildShapeFromSvgPath(output, pd, ENDPOINT_SNAP_RANGE_PROPORTION*Vector2(width, height).length());
}

#ifndef MSDFGEN_USE_SKIA

int loadSvgShape(Shape &output, Shape::Bounds &viewBox, const char *filename) {
    tinyxml2::XMLDocument doc;
    if (doc.LoadFile(filename))
        return SVG_IMPORT_FAILURE;
    tinyxml2::XMLElement *root = doc.FirstChildElement("svg");
    if (!root)
        return SVG_IMPORT_FAILURE;

    tinyxml2::XMLElement *path = NULL;
    int flags = 0;
    int skippedPaths = 0;
    findPathByBackwardIndex(path, flags, skippedPaths, root, false);
    if (!(path && (flags&SVG_IMPORT_SUCCESS_FLAG)))
        return SVG_IMPORT_FAILURE;
    const char *pd = path->Attribute("d");
    if (!pd)
        return SVG_IMPORT_FAILURE;

    double left = 0, bottom = 0;
    double width = root->DoubleAttribute("width"), height = root->DoubleAttribute("height");
    const char *viewBoxStr = root->Attribute("viewBox");
    if (viewBoxStr)
        (void) sscanf(viewBoxStr, "%lf %lf %lf %lf", &left, &bottom, &width, &height);
    viewBox.l = left;
    viewBox.b = bottom;
    viewBox.r = left+width;
    viewBox.t = bottom+height;
    output.contours.clear();
    output.inverseYAxis = true;
    if (!buildShapeFromSvgPath(output, pd, ENDPOINT_SNAP_RANGE_PROPORTION*Vector2(width, height).length()))
        return SVG_IMPORT_FAILURE;
    return flags;
}

#else

void shapeFromSkiaPath(Shape &shape, const SkPath &skPath); // defined in resolve-shape-geometry.cpp

static bool readTransformationOp(SkScalar dst[6], int &count, const char *&str, const char *name) {
    int nameLen = int(strlen(name));
    if (!memcmp(str, name, nameLen)) {
        const char *curStr = str+nameLen;
        skipExtraChars(curStr);
        if (*curStr == '(') {
            skipExtraChars(++curStr);
            count = 0;
            while (*curStr && *curStr != ')') {
                real x;
                if (!(count < 6 && readReal(x, curStr)))
                    return false;
                dst[count++] = SkScalar(x);
                skipExtraChars(curStr);
            }
            if (*curStr == ')') {
                str = curStr+1;
                return true;
            }
        }
    }
    return false;
}

static SkMatrix parseTransformation(int &flags, const char *str) {
    SkMatrix transformation;
    skipExtraChars(str);
    while (*str) {
        SkScalar values[6];
        int count;
        SkMatrix partial;
        if (readTransformationOp(values, count, str, "matrix") && count == 6) {
            partial.setAll(values[0], values[2], values[4], values[1], values[3], values[5], SkScalar(0), SkScalar(0), SkScalar(1));
        } else if (readTransformationOp(values, count, str, "translate") && (count == 1 || count == 2)) {
            if (count == 1)
                values[1] = SkScalar(0);
            partial.setTranslate(values[0], values[1]);
        } else if (readTransformationOp(values, count, str, "scale") && (count == 1 || count == 2)) {
            if (count == 1)
                values[1] = values[0];
            partial.setScale(values[0], values[1]);
        } else if (readTransformationOp(values, count, str, "rotate") && (count == 1 || count == 3)) {
            if (count == 3)
                partial.setRotate(values[0], values[1], values[2]);
            else
                partial.setRotate(values[0]);
        } else if (readTransformationOp(values, count, str, "skewX") && count == 1) {
            partial.setSkewX(tan(SkScalar(M_PI)/SkScalar(180)*values[0]));
        } else if (readTransformationOp(values, count, str, "skewY") && count == 1) {
            partial.setSkewY(tan(SkScalar(M_PI)/SkScalar(180)*values[0]));
        } else {
            flags |= SVG_IMPORT_PARTIAL_FAILURE_FLAG;
            break;
        }
        transformation = transformation*partial;
        skipExtraChars(str);
    }
    return transformation;
}

static SkMatrix combineTransformation(int &flags, const SkMatrix &parentTransformation, const char *transformationString, const char *transformationOriginString) {
    if (transformationString) {
        SkMatrix transformation = parseTransformation(flags, transformationString);
        if (transformationOriginString) {
            Point2 origin;
            if (readCoord(origin, transformationOriginString))
                transformation = SkMatrix::Translate(SkScalar(origin.x), SkScalar(origin.y))*transformation*SkMatrix::Translate(SkScalar(-origin.x), SkScalar(-origin.y));
            else
                flags |= SVG_IMPORT_PARTIAL_FAILURE_FLAG;
        }
        return parentTransformation*transformation;
    }
    return parentTransformation;
}

static void gatherPaths(SkPath &fullPath, int &flags, tinyxml2::XMLElement *parent, const SkMatrix &transformation) {
    for (tinyxml2::XMLElement *cur = parent->FirstChildElement(); cur && !FLAGS_FINAL(flags); cur = cur->NextSiblingElement()) {
        if (!strcmp(cur->Name(), "g"))
            gatherPaths(fullPath, flags, cur, combineTransformation(flags, transformation, cur->Attribute("transform"), cur->Attribute("transform-origin")));
        else if (!strcmp(cur->Name(), "mask") || !strcmp(cur->Name(), "use"))
            flags |= SVG_IMPORT_UNSUPPORTED_FEATURE_FLAG;
        else {
            SkPath curPath;
            if (!strcmp(cur->Name(), "path")) {
                const char *pd = cur->Attribute("d");
                if (!(pd && SkParsePath::FromSVGString(pd, &curPath))) {
                    flags |= SVG_IMPORT_PARTIAL_FAILURE_FLAG;
                    continue;
                }
            } else if (!strcmp(cur->Name(), "rect")) {
                SkScalar x = SkScalar(cur->DoubleAttribute("x")), y = SkScalar(cur->DoubleAttribute("y"));
                SkScalar width = SkScalar(cur->DoubleAttribute("width")), height = SkScalar(cur->DoubleAttribute("height"));
                SkScalar rx = SkScalar(cur->DoubleAttribute("rx")), ry = SkScalar(cur->DoubleAttribute("ry"));
                if (!(width && height))
                    continue;
                SkRect rect = SkRect::MakeLTRB(x, y, x+width, y+height);
                if (rx || ry) {
                    SkScalar radii[] = { rx, ry, rx, ry, rx, ry, rx, ry };
                    curPath.addRoundRect(rect, radii);
                } else
                    curPath.addRect(rect);
            } else if (!strcmp(cur->Name(), "circle")) {
                SkScalar cx = SkScalar(cur->DoubleAttribute("cx")), cy = SkScalar(cur->DoubleAttribute("cy"));
                SkScalar r = SkScalar(cur->DoubleAttribute("r"));
                if (!r)
                    continue;
                curPath.addCircle(cx, cy, r);
            } else if (!strcmp(cur->Name(), "ellipse")) {
                SkScalar cx = SkScalar(cur->DoubleAttribute("cx")), cy = SkScalar(cur->DoubleAttribute("cy"));
                SkScalar rx = SkScalar(cur->DoubleAttribute("rx")), ry = SkScalar(cur->DoubleAttribute("ry"));
                if (!(rx && ry))
                    continue;
                curPath.addOval(SkRect::MakeLTRB(cx-rx, cy-ry, cx+rx, cy+ry));
            } else if (!strcmp(cur->Name(), "polygon")) {
                const char *pd = cur->Attribute("points");
                if (!pd) {
                    flags |= SVG_IMPORT_PARTIAL_FAILURE_FLAG;
                    continue;
                }
                Point2 point;
                if (!readCoord(point, pd))
                    continue;
                curPath.moveTo(SkScalar(point.x), SkScalar(point.y));
                if (!readCoord(point, pd))
                    continue;
                do {
                    curPath.lineTo(SkScalar(point.x), SkScalar(point.y));
                } while (readCoord(point, pd));
                curPath.close();
            } else
                continue;
            curPath.transform(combineTransformation(flags, transformation, cur->Attribute("transform"), cur->Attribute("transform-origin")));
            if (Op(fullPath, curPath, kUnion_SkPathOp, &fullPath))
                flags |= SVG_IMPORT_SUCCESS_FLAG;
            else
                flags |= SVG_IMPORT_PARTIAL_FAILURE_FLAG;
        }
    }
}

int loadSvgShape(Shape &output, Shape::Bounds &viewBox, const char *filename) {
    tinyxml2::XMLDocument doc;
    if (doc.LoadFile(filename))
        return SVG_IMPORT_FAILURE;
    tinyxml2::XMLElement *root = doc.FirstChildElement("svg");
    if (!root)
        return SVG_IMPORT_FAILURE;

    SkPath fullPath;
    int flags = 0;
    gatherPaths(fullPath, flags, root, SkMatrix());
    if (!((flags&SVG_IMPORT_SUCCESS_FLAG) && Simplify(fullPath, &fullPath)))
        return SVG_IMPORT_FAILURE;
    shapeFromSkiaPath(output, fullPath);
    output.inverseYAxis = true;
    output.orientContours();

    double left = 0, bottom = 0;
    double width = root->DoubleAttribute("width"), height = root->DoubleAttribute("height");
    const char *viewBoxStr = root->Attribute("viewBox");
    if (viewBoxStr)
        (void) sscanf(viewBoxStr, "%lf %lf %lf %lf", &left, &bottom, &width, &height);
    viewBox.l = left;
    viewBox.b = bottom;
    viewBox.r = left+width;
    viewBox.t = bottom+height;
    return flags;
}

#endif

}

#endif