lwout_svg.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2001-2003 Refractions Research Inc.
 *
 **********************************************************************/
 
 
#include "liblwgeom_internal.h"
#include "stringbuffer.h"
 
 
static void
assvg_geom(stringbuffer_t* sb, const LWGEOM *geom, int relative, int precision);
 
 
static void
pointArray_svg_rel(stringbuffer_t* sb, const POINTARRAY *pa, int close_ring, int precision, int start_at_index)
{
        int i, end;
        const POINT2D *pt;
 
        double f = 1.0;
        double dx, dy, x, y, accum_x, accum_y;
 
        char sx[OUT_DOUBLE_BUFFER_SIZE];
        char sy[OUT_DOUBLE_BUFFER_SIZE];
 
        if (precision >= 0)
        {
                f = pow(10, precision);
        }
 
        end = close_ring ? pa->npoints : pa->npoints - 1;
 
        /* Starting point */
        pt = getPoint2d_cp(pa, start_at_index);
 
        x = round(pt->x*f)/f;
        y = round(pt->y*f)/f;
 
        lwprint_double(x, precision, sx);
        lwprint_double(-y, precision, sy);
 
        stringbuffer_aprintf(sb, "%s %s l", sx, sy);
 
        /* accum */
        accum_x = x;
        accum_y = y;
 
        /* All the following ones */
        for (i = (start_at_index + 1); i < end; i++)
        {
                pt = getPoint2d_cp(pa, i);
 
                x = round(pt->x*f)/f;
                y = round(pt->y*f)/f;
 
                dx = x - accum_x;
                dy = y - accum_y;
 
                accum_x += dx;
                accum_y += dy;
 
                lwprint_double(dx, precision, sx);
                lwprint_double(-dy, precision, sy);
                stringbuffer_aprintf(sb, " %s %s", sx, sy);
        }
}
 
 
static void
pointArray_svg_abs(stringbuffer_t* sb, const POINTARRAY *pa, int close_ring, int precision, int start_at_index)
{
        int i, end;
        const POINT2D* pt;
        char sx[OUT_DOUBLE_BUFFER_SIZE];
        char sy[OUT_DOUBLE_BUFFER_SIZE];
 
        end = close_ring ? pa->npoints : pa->npoints - 1;
 
        for (i = start_at_index; i < end; i++)
        {
                pt = getPoint2d_cp(pa, i);
 
                if (i == 1)
                {
                        if (start_at_index > 0 ){
                                        stringbuffer_append(sb, "L ");
                        }
                        else {
                                        stringbuffer_append(sb, " L ");
                        }
                }
                else if (i) stringbuffer_append(sb, " ");
 
                lwprint_double(pt->x, precision, sx);
                lwprint_double(-(pt->y), precision, sy);
 
                stringbuffer_aprintf(sb, "%s %s", sx, sy);
        }
}
 
 
static void
assvg_point(stringbuffer_t* sb, const LWPOINT *point, int circle, int precision)
{
        char sx[OUT_DOUBLE_BUFFER_SIZE];
        char sy[OUT_DOUBLE_BUFFER_SIZE];
        if ( !lwgeom_is_empty((LWGEOM*)point) ){
                const POINT2D* pt = getPoint2d_cp(point->point, 0);
                lwprint_double(pt->x, precision, sx);
                lwprint_double(-(pt->y), precision, sy);
 
                stringbuffer_aprintf(sb,
                        circle ? "x=\"%s\" y=\"%s\"" : "cx=\"%s\" cy=\"%s\"",
                        sx, sy);
        }
}
 
 
static void
assvg_line(stringbuffer_t* sb, const LWLINE *line, int relative, int precision)
{
        /* Start path with SVG MoveTo */
        stringbuffer_append(sb, "M ");
        if (relative)
                pointArray_svg_rel(sb, line->points, 1, precision, 0);
        else
                pointArray_svg_abs(sb, line->points, 1, precision, 0);
}
 
static void pointArray_svg_arc(stringbuffer_t* sb, const POINTARRAY *pa, int close_ring, int relative,  int precision)
{
        uint32_t i; //, end;
        char sx[OUT_DOUBLE_BUFFER_SIZE];
        char sy[OUT_DOUBLE_BUFFER_SIZE];
 
        LWDEBUG(2, "pointArray_svg_arc called.");
 
        for (i = 2; i < pa->npoints; i+=2)
        {
                LWDEBUGF(3, "assvg_circstring: arc ending at point %d", i);
                int largeArcFlag, sweepFlag, clockwise;
                int is_circle = LW_FALSE;
                double a1, a3;
                double radius; /* Arc radius */
                double total_angle;
                POINT2D center;
                const POINT2D *t1;
                const POINT2D *t2;
                const POINT2D *t3;
                int p2_side = 0;
                t1 = getPoint2d_cp(pa, i - 2);
                t2 = getPoint2d_cp(pa, i - 1);
                t3 = getPoint2d_cp(pa, i);
                radius = lw_arc_center(t1, t2, t3, &center);
                if ( t1->x == t3->x && t1->y == t3->y ){
                        is_circle = LW_TRUE;
                }
                p2_side = lw_segment_side(t1, t3, t2);
                if ( p2_side == -1 )
                        clockwise = LW_TRUE;
                else
                        clockwise = LW_FALSE;
                /* Angles of each point that defines the arc section */
                a1 = atan2(t1->y - center.y, t1->x - center.x)*180/M_PI;
                //a2 = atan2(t2->y - center.y, t2->x - center.x)*180/M_PI;
                a3 = atan2(t3->y - center.y, t3->x - center.x)*180/M_PI;
 
                LWDEBUGF(2, " center is POINT(%.15g %.15g) - radius:%g", center.x, center.y, radius);
 
                total_angle = clockwise ? a1 - a3 : a3 - a1;
                if (total_angle < 0 ){
                        total_angle += 360;
                }
 
                //stringbuffer_aprintf(sb, "angles (a1 a2 a3): %g %g %g is_circle: %d, total_angle: %g, t1.x: %f, t3.x: %f, t1.y: %f, t3.y: %f ", a1, a2, a3, is_circle, total_angle, t1->x, t3->x, t1->y, t3->y);
 
                largeArcFlag = (total_angle <= 180)? 0 : 1;
                /* The side of the t1/t3 line that t2 falls on dictates the sweep
                direction from t1 to t3. */
                sweepFlag = (p2_side == -1) ? 1 : 0;
                if ( (i == 2) && !is_circle ){
                        lwprint_double(t1->x, precision, sx);
                        lwprint_double(-(t1->y), precision, sy);
                        stringbuffer_aprintf(sb, "%s %s", sx, sy);
                }
                if ( (i == 2) && is_circle){
                        lwprint_double(center.x, precision, sx);
                        lwprint_double(-(center.y), precision, sy);
                        stringbuffer_aprintf(sb, "%s %s", sx, sy);
                }
                lwprint_double(radius, precision, sx);
                lwprint_double(0, precision, sy);
                if (is_circle){
                        //https://stackoverflow.com/questions/5737975/circle-drawing-with-svgs-arc-path
                        lwprint_double(radius*2, precision, sy);
                        stringbuffer_aprintf(sb, " m %s 0 a %s %s 0 1 0 -%s 0", sx, sx, sx, sy);
                        stringbuffer_aprintf(sb, " a %s %s 0 1 0 %s 0", sx, sx, sy);
                }
                else {
                        /* Arc radius radius 0 arcflag swipeflag */
                        if (relative){
                                stringbuffer_aprintf(sb, " a %s %s 0 %d %d ", sx, sx, largeArcFlag, sweepFlag);
                        }
                        else {
                                stringbuffer_aprintf(sb, " A %s %s 0 %d %d ", sx, sx, largeArcFlag, sweepFlag);
                        }
                        lwprint_double(t3->x, precision, sx);
                        lwprint_double(-(t3->y), precision, sy);
                        /* end point */
                        stringbuffer_aprintf(sb, "%s %s", sx, sy);
                }
        }
}
 
static void
assvg_circstring(stringbuffer_t* sb, const LWCIRCSTRING *icurve, int relative, int precision)
{
        /* Start path with SVG MoveTo */
        stringbuffer_append(sb, "M ");
        pointArray_svg_arc(sb, icurve->points, 1, relative, precision);
}
 
static void
assvg_compound(stringbuffer_t* sb, const LWCOMPOUND *icompound, int relative, int precision)
{
        uint32_t i;
        LWGEOM *geom;
        LWCIRCSTRING *tmpc = NULL;
        LWLINE *tmpl = NULL;
        /* Start path with SVG MoveTo */
        stringbuffer_append(sb, "M ");
 
        for (i = 0; i < icompound->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, " ");  /* SVG whitespace Separator */
                geom = icompound->geoms[i];
 
                switch (geom->type)
                {
                        case CIRCSTRINGTYPE:
                                tmpc = (LWCIRCSTRING *)geom;
                                pointArray_svg_arc(sb, tmpc->points, 1, relative, precision);
                                break;
 
                        case LINETYPE:
                                tmpl = (LWLINE *)geom;
 
                                if (i){
                                        if (relative)
                                                pointArray_svg_rel(sb, tmpl->points, 1, precision, 1);
                                        else
                                                pointArray_svg_abs(sb, tmpl->points, 1, precision, 1);
                                }
                                else {
                                        if (relative)
                                                pointArray_svg_rel(sb, tmpl->points, 1, precision, 0);
                                        else
                                                pointArray_svg_abs(sb, tmpl->points, 1, precision, 0);
                                }
                                break;
 
                        default:
                                break; 
                }
        }
}
 
static void
assvg_polygon(stringbuffer_t* sb, const LWPOLY *poly, int relative, int precision)
{
        uint32_t i;
 
        for (i = 0; i<poly->nrings; i++)
        {
                if (i) stringbuffer_append(sb, " ");    /* Space between each ring */
                stringbuffer_append(sb, "M ");          /* Start path with SVG MoveTo */
 
                if (relative)
                {
                        pointArray_svg_rel(sb, poly->rings[i], 0, precision, 0);
                        stringbuffer_append(sb, " z");  /* SVG closepath */
                }
                else
                {
                        pointArray_svg_abs(sb, poly->rings[i], 0, precision, 0);
                        stringbuffer_append(sb, " Z");  /* SVG closepath */
                }
        }
}
 
static void
assvg_multipoint(stringbuffer_t* sb, const LWMPOINT *mpoint, int relative, int precision)
{
        const LWPOINT *point;
        uint32_t i;
 
        for (i = 0; i<mpoint->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, ",");  /* Arbitrary comma separator */
                point = mpoint->geoms[i];
                assvg_point(sb, point, relative, precision);
        }
}
 
 
static void
assvg_multiline(stringbuffer_t* sb, const LWMLINE *mline, int relative, int precision)
{
        const LWLINE *line;
        uint32_t i;
 
        for (i = 0; i<mline->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, " ");  /* SVG whitespace Separator */
                line = mline->geoms[i];
                assvg_line(sb, line, relative, precision);
        }
}
 
static void
assvg_multipolygon(stringbuffer_t* sb, const LWMPOLY *mpoly, int relative, int precision)
{
        const LWPOLY *poly;
        uint32_t i;
 
        for (i = 0; i<mpoly->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, " ");  /* SVG whitespace Separator */
                poly = mpoly->geoms[i];
                assvg_polygon(sb, poly, relative, precision);
        }
}
 
static void
assvg_multicurve(stringbuffer_t* sb, const LWMCURVE *mcurve, int relative, int precision)
{
        uint32_t i;
        LWGEOM *geom;
        const LWCIRCSTRING *tmpc = NULL;
        const LWLINE *tmpl = NULL;
 
        for (i = 0; i < mcurve->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, " ");  /* SVG whitespace Separator */
                geom = mcurve->geoms[i];
 
                switch (geom->type)
                {
                        case CIRCSTRINGTYPE:
                                tmpc = (LWCIRCSTRING *)geom;
                                assvg_circstring(sb, tmpc, relative, precision);
                                break;
 
                        case LINETYPE:
                                tmpl = (LWLINE *)geom;
                                assvg_line(sb, tmpl, relative, precision);
                                break;
 
                        default:
                                break; 
                }
        }
}
 
static void
assvg_curvepoly(stringbuffer_t* sb, const LWCURVEPOLY *curvepoly, int relative, int precision)
{
        uint32_t i;
        LWGEOM *tmp;
 
        for (i = 0; i < curvepoly->nrings; i++)
        {
                if (i) stringbuffer_append(sb, " ");    /* Space between each ring */
                tmp = curvepoly->rings[i];
                switch (tmp->type)
                {
                        case CIRCSTRINGTYPE:
                                assvg_circstring(sb, (LWCIRCSTRING *)tmp, relative, precision);
                                break;
 
                        case LINETYPE:
                                assvg_line(sb, (LWLINE *)tmp, relative, precision);
                                break;
 
                        case COMPOUNDTYPE:
                                assvg_compound(sb, (LWCOMPOUND *)tmp, relative, precision);
                                break;
 
                        default:
                                break; 
                }
                if (relative)
                {
                        stringbuffer_append(sb, " z");  /* SVG closepath */
                }
                else
                {
                        stringbuffer_append(sb, " Z");  /* SVG closepath */
                }
        }
}
 
static void
assvg_multisurface(stringbuffer_t* sb, const LWMSURFACE *msurface, int relative, int precision)
{
        LWGEOM *geom;
        uint32_t i;
        const LWPOLY *poly;
        const LWCURVEPOLY *curvepoly;
 
        for (i = 0; i < msurface->ngeoms; i++)
        {
                if (i) stringbuffer_append(sb, " ");  /* SVG whitespace Separator */
                geom = msurface->geoms[i];
                switch (geom->type)
                {
                        case CURVEPOLYTYPE:
                                curvepoly = (LWCURVEPOLY *) geom;
                                assvg_curvepoly(sb, curvepoly, relative, precision);
                                break;
                        case POLYGONTYPE:
                                poly = (LWPOLY *) geom;
                                assvg_polygon(sb, poly, relative, precision);
                                break;
                        default:
                                break; 
                }
        }
}
 
static void
assvg_collection(stringbuffer_t* sb, const LWCOLLECTION *col, int relative, int precision)
{
        uint32_t i; uint32_t j = 0;
        const LWGEOM *subgeom;
 
        /* EMPTY GEOMETRYCOLLECTION */
        if (col->ngeoms == 0) return;
 
        for (i = 0; i<col->ngeoms; i++)
        {
                subgeom = col->geoms[i];
                if (!lwgeom_is_empty(subgeom) ){
                        if (j) stringbuffer_append(sb, ";");
                        j++;
                        assvg_geom(sb, subgeom, relative, precision);
                }
        }
 
}
 
 
 
static void
assvg_geom(stringbuffer_t* sb, const LWGEOM *geom, int relative, int precision)
{
    int type = geom->type;
 
        switch (type)
        {
        case POINTTYPE:
                assvg_point(sb, (LWPOINT*)geom, relative, precision);
                break;
 
        case LINETYPE:
                assvg_line(sb, (LWLINE*)geom, relative, precision);
                break;
 
        case POLYGONTYPE:
                assvg_polygon(sb, (LWPOLY*)geom, relative, precision);
                break;
 
        case MULTIPOINTTYPE:
                assvg_multipoint(sb, (LWMPOINT*)geom, relative, precision);
                break;
 
        case MULTILINETYPE:
                assvg_multiline(sb, (LWMLINE*)geom, relative, precision);
                break;
 
        case MULTIPOLYGONTYPE:
                assvg_multipolygon(sb, (LWMPOLY*)geom, relative, precision);
                break;
 
        case CIRCSTRINGTYPE:
                assvg_circstring(sb, (LWCIRCSTRING*)geom, relative, precision);
                break;
 
        case COMPOUNDTYPE:
                assvg_compound(sb, (LWCOMPOUND*)geom, relative, precision);
                break;
 
        case CURVEPOLYTYPE:
                assvg_curvepoly(sb, (LWCURVEPOLY*)geom, relative, precision);
                break;
 
        case MULTICURVETYPE:
                assvg_multicurve(sb, (LWMCURVE*)geom, relative, precision);
                break;
 
        case MULTISURFACETYPE:
                assvg_multisurface(sb, (LWMSURFACE*)geom, relative, precision);
                break;
 
        default:
                lwerror("assvg_geom_buf: '%s' geometry type not supported.",
                        lwtype_name(type));
        }
 
}
 
lwvarlena_t *
lwgeom_to_svg(const LWGEOM *geom, int precision, int relative)
{
        stringbuffer_t sb;
        int type = geom->type;
 
        /* Empty varlena for empties */
        if(lwgeom_is_empty(geom))
        {
                lwvarlena_t *v = lwalloc(LWVARHDRSZ);
                LWSIZE_SET(v->size, LWVARHDRSZ);
                return v;
        }
 
        stringbuffer_init_varlena(&sb);
 
        switch (type)
        {
        case POINTTYPE:
                assvg_point(&sb, (LWPOINT*)geom, relative, precision);
                break;
        case LINETYPE:
                assvg_line(&sb, (LWLINE*)geom, relative, precision);
                break;
        case POLYGONTYPE:
                assvg_polygon(&sb, (LWPOLY*)geom, relative, precision);
                break;
        case CIRCSTRINGTYPE:
                assvg_circstring(&sb, (LWCIRCSTRING*)geom, relative, precision);
                break;
        case COMPOUNDTYPE:
                assvg_compound(&sb, (LWCOMPOUND*)geom, relative, precision);
                break;
        case CURVEPOLYTYPE:
                assvg_curvepoly(&sb, (LWCURVEPOLY*)geom, relative, precision);
                break;
        case MULTIPOINTTYPE:
                assvg_multipoint(&sb, (LWMPOINT*)geom, relative, precision);
                break;
        case MULTILINETYPE:
                assvg_multiline(&sb, (LWMLINE*)geom, relative, precision);
                break;
        case MULTICURVETYPE:
                assvg_multicurve(&sb, (LWMCURVE*)geom, relative, precision);
                break;
        case MULTIPOLYGONTYPE:
                assvg_multipolygon(&sb, (LWMPOLY*)geom, relative, precision);
                break;
        case MULTISURFACETYPE:
                assvg_multisurface(&sb, (LWMSURFACE*)geom, relative, precision);
                break;
        case COLLECTIONTYPE:
                assvg_collection(&sb, (LWCOLLECTION*)geom, relative, precision);
                break;
 
        default:
                lwerror("lwgeom_to_svg: '%s' geometry type not supported", lwtype_name(type));
        }
 
        return stringbuffer_getvarlena(&sb);
}