Ticket #5358: shrinkbug.cpp

#include <assert.h>
#include <vector>
#include <boost/polygon/polygon.hpp>

using namespace std;

namespace gtl = boost::polygon;

typedef gtl::rectangle_data<int> Rectangle;
typedef gtl::polygon_data<int> Polygon;
typedef gtl::polygon_traits<Polygon>::point_type Point;

// Input polygon.
typedef int ipt[2];
const ipt data[] = {
    {645748,684196},{643709,684196},{643555,684196},{628872,684196},{620334,656269},
    {620287,656115},{620287,408944},{619486,406744},{618271,403405},{616244,402234},
    {613165,400457},{610860,400863},{607359,401480},{605855,403274},{603570,405996},
    {603570,409551},{603570,411892},{605855,414615},{607359,416409},{610860,417026},
    {613165,417432},{616244,415655},{618271,414484},{619486,411144},{620287,408944},
    {620287,656115},{620193,655807},{577589,516454},{577589,455256},{577589,452945},
    {577589,408071},{575971,408071},{553957,408071},{553957,391468},{552602,389122},
    {543288,372991},{539122,365774},{536413,365774},{509453,365774},{508099,368120},
    {504184,374899},{494618,391468},{504184,408037},{505287,409946},{509453,417162},
    {536413,417162},{539122,417162},{543288,409946},{544391,408037},{553957,391468},
    {553957,408071},{552658,408071},{552291,408712},{552193,408880},{543267,424341},
    {505308,424341},{505263,424263},{495915,408071},{494666,408071},{470986,408071},
    {470986,452945},{470986,455256},{573398,455256},{573838,455256},{576276,455256},
    {577589,455256},{577589,516454},{577551,516330},{576511,512929},{557642,512929},
    {554870,512929},{554870,465743},{553540,465743},{493705,465743},{493705,512929},
    {492687,512929},{492428,512929},{492426,512929},{492254,512929},{491889,512929},
    {491246,512929},{490218,512929},{488757,512929},{487077,512929},{485840,512929},
    {485696,512929},{445525,512929},{445525,408944},{444724,406744},{443509,403405},
    {441482,402234},{438403,400457},{436097,400863},{432598,401480},{431092,403274},
    {428807,405996},{428807,409551},{428807,411892},{431092,414615},{432598,416409},
    {436097,417026},{438403,417432},{441482,415655},{443509,414484},{444724,411144},
    {445525,408944},{445525,512929},{444596,512929},{427449,512929},{426805,512929},
    {426742,512929},{426552,512906},{426470,512895},{423088,512486},{423071,512480},
    {422987,512447},{416980,510169},{416891,510108},{411608,506461},{411537,506381},
    {407278,501575},{407228,501480},{404244,495794},{404223,495708},{402827,490045},
    {402827,487257},{402827,398779},{403269,395139},{403270,395123},{405547,389119},
    {405585,389020},{409234,383733},{409295,383645},{414100,379387},{414181,379316},
    {419867,376331},{419962,376282},{419957,376283},{420039,376263},{425528,374910},
    {425675,374874},{425711,374865},{425852,374865},{426520,374865},{427317,374865},
    {427900,374865},{487792,374865},{489490,374865},{490971,374865},{492014,374865},
    {492669,374865},{495915,374865},{505263,358674},{505317,358581},{505309,358595},
    {543267,358595},{552290,374223},{552658,374865},{559086,374865},{560783,374865},
    {562028,374865},{562164,374865},{621126,374865},{621770,374865},{621834,374865},
    {625167,375270},{625468,375306},{625489,375308},{631158,377458},{631274,377502},
    {631398,377549},{631594,377624},{636880,381272},{636968,381333},{641226,386138},
    {641297,386219},{644282,391905},{644332,392000},{645727,397662},{645748,397748},
    {645748,510126},{645748,675973},{645748,679096},{645748,679662},{645748,683732},
    {645748,683932},
};

void psvg(const char* name, const vector<Polygon>& pset)
{
    Rectangle ext;
    gtl::extents(ext, pset);
    float x0 = gtl::xl(ext), y0 = gtl::yl(ext);
    float xlen = gtl::xh(ext) - x0;
    float ylen = gtl::yh(ext) - y0;
    float scale = 600 / max(xlen, ylen);
    FILE* f = fopen(name, "w");
    fprintf(f, "<svg width='%f' height='%f'>\n", 40+xlen*scale, 40+ylen*scale);
    for(unsigned int i=0; i<pset.size(); i++) {
        for(Polygon::iterator_type j=++pset[i].begin(); j!=pset[i].end(); j++) {
            const Point& a = *(j-1);
            const Point& b = *j;
            fprintf(f, "<line x1='%f' y1='%f' x2='%f' y2='%f'"
                    " stroke='black' stroke-width='1'/>\n",
                    20+(gtl::x(a)-x0)*scale, 20+(gtl::y(a)-y0)*scale,
                    20+(gtl::x(b)-x0)*scale, 20+(gtl::y(b)-y0)*scale);
        }
    }
    fprintf(f, "</svg>\n");
    fclose(f);
}

int main()
{
    //
    // Create a polygon_set from the above data.  Store in
    // "before.svg" for visual inspection.
    //
    vector<Point> points;
    for(unsigned int i=0; i<sizeof(data)/sizeof(data[0]); i++)
        points.push_back(Point(data[i][0], data[i][1]));
    Polygon p;
    gtl::set_points(p, points.begin(), points.end());
    vector<Polygon> pset;
    pset.push_back(p);
    psvg("before.svg", pset);

    Rectangle r1;
    gtl::extents(r1, pset);
    printf("r1 extents: X: (%d - %d), Y: (%d - %d)\n",
           gtl::xl(r1), gtl::xh(r1), gtl::yl(r1), gtl::yh(r1));

    //
    // Shrink it (and store in "after.svg"): clearly this should not
    // *increase* the extents of the polygon...
    //
    gtl::resize(pset, -874);
    psvg("after.svg", pset);

    Rectangle r2;
    gtl::extents(r2, pset);
    printf("r2 extents: X: (%d - %d), Y: (%d - %d)\n",
           gtl::xl(r2), gtl::xh(r2), gtl::yl(r2), gtl::yh(r2));

    //
    // ... but it does!
    //
    assert(gtl::contains(r2, gtl::ll(r1)));
    assert(gtl::contains(r2, gtl::lr(r1)));
    assert(gtl::contains(r2, gtl::ul(r1)));
    assert(gtl::contains(r2, gtl::ul(r1)));

    return 0;
}