Aquileo | SimplifyPolygons fails to merge horizontal edges

Tue, 03 Aug 2021 15:33:07 -0000

Hi,

SimplifyPolygons has a problem when processing horizontal joins. The polygon merging done for the first join modifies the polygon points in a way that the second join can not be processed afterwards (the GetOverlap no longer detects an overlap and ignores it). That's why the following examples return more than one result polygon:

int main()
{
    Paths paths({
        { {110,50}, {110,100}, {90,100} },
        { {10,100}, {100,100}, {100,190} },
        { {40,50}, {40,100}, {20,100} },
    });

    Paths simplifiedPaths;
    SimplifyPolygons(paths, simplifiedPaths, ClipperLib::pftPositive);

    cout << "simplified:" << endl;
    cout << simplifiedPaths << endl;
}

Second example:

    Paths paths({
        { {90,100}, {80,100}, {85,60} },
        { {10,100}, {90,100}, {50,190} },
        { {110,100}, {85,100}, {97,60} },
        { {105,100}, {115,100}, {110,140} }
    });

I've attached two images for visualization.

Aquileo | Recent changes to 208: SimplifyPolygons fails to merge horizontal edges

Aquileo | SimplifyPolygons fails to merge horizontal edges