CGAL users discussion list

[Sebastien Loriot <>]

region_map()

https://doc.cgal.org/latest/Shape_detection/classCGAL_1_1Shape__detection_1_1Region__growing.html#a60adecff409f4025585c64cd3bd70110

Provides a property map associating indicating the region index for each 
input element. The key of the map depends on your instantiation. But
everything should be documented in the documentation of your model.

Best,

Sebastien.

On 9/13/23 09:56, Claus Volko ( via cgal-discuss 
Mailing List) wrote:
> OK, it seems I've found it out myself by now:
>
>    for (Region_growing::Primitive_and_region region : regions)
>    {
>        Line_3* l = new Line_3(Point_3(0, -10, 0), Point_3(0, +10, 0));
>
>        if (CGAL::intersection(region.first, *l))
>        {
>            std::cout << "Region has point on it" << std::endl;
>            break;
>        }
>    }
>
> Am Mi., 13. Sept. 2023 um 09:39 Uhr schrieb Claus Volko 
> < <>>:
>
>     OK, I've realized by now that the code I posted was not wrong but
>     that what I really need is to check if a line intersects with a
>     region, as I don't know the y coordinate of the point I'm looking
>     for. How can that be done?
>
>     Am Mi., 13. Sept. 2023 um 07:04 Uhr schrieb Claus Volko
>     < <>>:
>
>         I would like to find the region that contains a given point
>         after using the region growing algorithm for shape detection. I
>         tried this code but it does not seem to work:
>
>            for (Region_growing::Primitive_and_region region : regions)
>            {
>                Point_3 *point = new Point_3(0, 0, 0);
>                if (region.first.has_on(*point))
>                    std::cout << "Region has zero point on it" << std::endl;
>            }
>
>         Also, if I found a region, how can I access the information
>         about the boundaries of the region?
>
>         -- 
>         Dipl.-Ing. Dr. Claus D. Volko, BSc
>         http://www.cdvolko.net/ <http://www.cdvolko.net/>
>
>
>
>
>
>     -- 
>     Dipl.-Ing. Dr. Claus D. Volko, BSc
>     http://www.cdvolko.net/ <http://www.cdvolko.net/>
>
>
>
>
>
> --
> Dipl.-Ing. Dr. Claus D. Volko, BSc
> http://www.cdvolko.net/ <http://www.cdvolko.net/>
>
>
>
>
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