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Update user manual
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Simon Giraudot
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@ -20,18 +20,17 @@ on, \cgal provides a 3D point set structure to make it easier for the
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user to handle additional properties (such as normal vectors, colors,
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labels...) and to call \cgal algorithms on them.
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The point set data structure is based on a set of `std::vector`
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objects that each stores one property. When created, a
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`CGAL::Point_set_3<Gt>` object only contains 2 properties:
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`CGAL::Point_set_3<Gt>` is a vector based data structure that
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contains, by default, only 2 properties:
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- The "point" property (with `CGAL::Point_3<Gt>` type)
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- The _point_ property (with `CGAL::Point_3<Gt>` type)
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- The "index" property (with `std::size_t` type) used to easily change
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- The _index_ property (with `std::size_t` type) used to easily change
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the order of the points without having to move all the properties.
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Any property the user needs can be easily added, modified and
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removed. A property is identified by a unique name and a
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type. Convenience methods are provided to handle the property "normal"
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type. Convenience methods are provided to handle the property _normal_
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of type `CGAL::Vector_3<Gt>` that is a very common property on point
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sets.
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@ -59,8 +58,8 @@ normal property, set the normal values, add or remove an item, etc.
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\section Point_set_3_Properties Using Additional Properties
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Every information in the point set is a property. A raw point set
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comes with "index" and "point" properties. As we saw in the previous
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section, the user can easily add a "normal" property. But this
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comes with _index_ and _point_ properties. As we saw in the previous
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section, the user can easily add a _normal_ property. But this
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mechanism is generalized to any type of property.
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The following example shows how to define a color property and an
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@ -81,7 +80,7 @@ applying \cgal algorithms to it is straightforward.
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When adding a new property to the point set, the associated property
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map is returned and can then be used as a standard property map. For
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points and normals, the property maps can recovered using the methods
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`point_pmap()` and `normal_pmap()`.
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`point_map()` and `normal_map()`.
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The following example shows how to apply some algorithms from the
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\cgal library using a point set object:
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@ -108,13 +107,13 @@ property maps:
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- `CGAL::Point_set_3::index_back_inserter()` is used as an output iterator that creates
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new item
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- `CGAL::Point_set_3::point_push_pmap()` is a property map that is allowed to create a
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- `CGAL::Point_set_3::point_push_map()` is a property map that is allowed to create a
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new item if it was not yet created by the back inserter
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- `CGAL::Point_set_3::normal_push_pmap()` works similarly
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- `CGAL::Point_set_3::normal_push_map()` works similarly
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Such "push property maps" are also available for other user-defined
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properties (see `CGAL::Point_set_3::push_pmap()`).
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Such _push property maps_ are also available for other user-defined
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properties (see `CGAL::Point_set_3::push_map()`).
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The following example shows how to read a point set in the XYZ format
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(it also normalizes and inverses the normal vectors and write the
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@ -137,7 +136,7 @@ For example, if the following line is found in the PLY header:
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> property uchar red
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Then a property named "red" and with type `boost::uint8_t` (`boost`
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Then a property named _red_ and with type `boost::uint8_t` (`boost`
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types are used because of their fixed memory size) will be
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instanciated in the point set and filled with the corresponding
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values.
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@ -145,10 +144,10 @@ values.
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Only points and normals are recovered as properties with complex class
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types (namely `CGAL::Point_3` and `CGAL::Vector_3`). Other properties
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are stored with simple number types. For example, if a color is given
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with integer red, green and blue values, 3 integer properties "red",
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"green" and "blue" will be instanciated. A user-defined interpreter
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with integer red, green and blue values, 3 integer properties _red_,
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_green_ and _blue_ will be instanciated. A user-defined interpreter
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must be implemented if such properties should be stored all together
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(a unique property "color" of type `CGAL::cpp11::array` for example).
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(a unique property _color_ of type `CGAL::cpp11::array` for example).
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The following example shows how to use this interpreter and how to
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recover a specific property afterwards:
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@ -156,6 +155,18 @@ recover a specific property afterwards:
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\cgalExample{Point_set_3/point_set_read_ply.cpp}
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\section Point_set_3_History History
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This package has been created to fill the need for a practical data
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structure that handles points with a user-defined set of
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properties. This property behavior was already implemented in the
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\ref Chapter_3D_Surface_mesh "Surface Mesh" package: all the classes
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dedicated to the management of properties were extracted so that they
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can be used in this _3D Point Set_ package. `CGAL::Surface_mesh<P>`
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and `CGAL::Point_set_3<P>` follow a similar API for property
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management.
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