# TWO-DIMENSIONAL GEOMETRIC SOLVER

From the geometric point of view, any drawing can be presented as a set
of plane objects, i.e. points, lines, segments, arcs, ellipses, and
spline curves. However, not every arbitrary set of flat geometric
objects is a drawing. In any drawing, geometric objects always depend on
interrelations that determine the positions of some objects in respect
to other ones. Such interrelations are always assumed to exist, no
matter whether we draw a sketch by a pencil on paper or simulate it on
the computer. As for computer-aided drawing, such interrelations are set
by *geometric constraints*, that include *logical constraints*, such as
coincidence, parallelism/perpendicularity, tangency, horizontality,
verticality, symmetry, and *dimensional constraints* that set various
*linear and angular dimensions*, as well as curve length or radius. A
sketch/drawing that has at least one dimensional constraint is called a
*parametric* one.

The 2D geometric solver permits to calculate the positions of geometric
objects meeting all the given constraints and sketch dimensions. If the
positions of objects during drawing conform to given constraints and
dimensions, then this process is called *parametric drawing*.

```{toctree}

subsections/EN/Assignment_of_GCE_Geometric_Solver
subsections/EN/Embedding_in_an_Application
subsections/EN/Supported_Geometry_Types
subsections/EN/Types_of_Geometric_Constraints_and_Dimensions
subsections/EN/Basic_Data_Types_of_GCE_Solver_API
subsections/EN/Geometric_Constraint_System
subsections/EN/Representation_of_Geometric_Objects
subsections/EN/Degree_of_Freedom
subsections/EN/Add_and_Delete_Geometric_Objects
subsections/EN/Fixing_and_Freezing_Geometric_Objects
subsections/EN/Geometric_Object_Control_Points
subsections/EN/Scalar_Variables
subsections/EN/Linear_Equation
subsections/EN/API_Call_Journalling
subsections/EN/Callback_functions
```