KernelCAD Documentation

Defines a non persistent transformation in 2D space.
This transformation is a general transformation.
It can be a Trsf2d from package gp, an affinity, or you can
define your own transformation giving the corresponding
matrix of transformation.

With a GTrsf2d you can transform only a doublet of coordinates
XY. It is not possible to transform other geometric objects
because these transformations can change the nature of non-
elementary geometric objects.
A GTrsf2d is represented with a 2 rows * 3 columns matrix :

V1 V2 T XY XY
| a11 a12 a14 | | x | | x'|
| a21 a22 a24 | | y | | y'|
| 0 0 1 | | 1 | | 1 |

Query IKO_Standard_Object from this interface to create a copy or obtain the type name

Methods

Init

_CSFDB_Getgp_GTrsf2dmatrix

_CSFDB_Getgp_GTrsf2dloc

_CSFDB_Getgp_GTrsf2dshape

_CSFDB_Setgp_GTrsf2dshape

_CSFDB_Getgp_GTrsf2dscale

_CSFDB_Setgp_GTrsf2dscale

HRESULT Init()

returns identity transformation.

HRESULT Init1(IKO_gp_Trsf2d* T)

Converts the gp_Trsf2d transformation T into a
general transformation.

HRESULT Init2(IKO_gp_Mat2d* M, KC2D* V)

Creates a transformation based on the matrix M and the
vector V where M defines the vectorial part of the
transformation, and V the translation part.

HRESULT SetAffinity(IKO_gp_Ax2d* A, double Ratio)

HRESULT SetValue(int Row, int Col, double Value)

Replaces the coefficient (Row, Col) of the matrix representing
this transformation by Value,
Raises OutOfRange if Row 1 or Row 2 or Col 1 or Col 3

HRESULT SetTranslationPart(KC2D* Coord)

HRESULT SetTrsf2d(IKO_gp_Trsf2d* T)

Assigns the vectorial and translation parts of T to this transformation.

HRESULT SetVectorialPart(IKO_gp_Mat2d* Matrix)

Replaces the vectorial part of this transformation by Matrix.

HRESULT IsNegative(VARIANT_BOOL* ret)

Returns true if the determinant of the vectorial part of
this transformation is negative.

HRESULT IsSingular(VARIANT_BOOL* ret)

Returns true if this transformation is singular (and
therefore, cannot be inverted).
Note: The Gauss LU decomposition is used to invert the
transformation matrix. Consequently, the transformation
is considered as singular if the largest pivot found is less
than or equal to gp::Resolution().
Warning
If this transformation is singular, it cannot be inverted.

HRESULT Form(gp_TrsfFormKO* ret)

Returns the nature of the transformation. It can be
an identity transformation, a rotation, a translation, a mirror
transformation (relative to a point or axis), a scaling
transformation, a compound transformation or some
other type of transformation.

HRESULT TranslationPart(KC2D* ret)

Returns the translation part of the GTrsf2d.

HRESULT VectorialPart(IKO_gp_Mat2d** ret)

Computes the vectorial part of the GTrsf2d. The returned
Matrix is a 2*2 matrix.

HRESULT Value(int Row, int Col, double* ret)

Returns the coefficients of the global matrix of transformation.
Raised OutOfRange if Row 1 or Row 2 or Col 1 or Col 3

HRESULT Invert()

HRESULT Inverted(IKO_gp_GTrsf2d** ret)

Computes the reverse transformation.
Raised an exception if the matrix of the transformation
is not inversible.

HRESULT Multiply(IKO_gp_GTrsf2d* T)

HRESULT Multiplied(IKO_gp_GTrsf2d* T, IKO_gp_GTrsf2d** ret)

Computes the transformation composed with T and me.
In a C++ implementation you can also write Tcomposed = this * T.
Example :
GTrsf2d T1, T2, Tcomp; ...............
//composition :
Tcomp = T2.Multiplied(T1); // or (Tcomp = T2 * T1)
// transformation of a point
XY P(10.,3.);
XY P1(P);
Tcomp.Transforms(P1); //using Tcomp
XY P2(P);
T1.Transforms(P2); //using T1 then T2
T2.Transforms(P2); // P1 = P2 !!!

HRESULT PreMultiply(IKO_gp_GTrsf2d* T)

HRESULT Power(int N)

HRESULT Powered(int N, IKO_gp_GTrsf2d** ret)

Computes the following composition of transformations
this * this * .......* me, N time.
if N = 0 this = Identity
if N 0 this = me.Inverse() *...........* me.Inverse().

HRESULT Transforms(KC2D* Coord)

HRESULT Transformed(KC2D* Coord, KC2D* ret)

HRESULT Transforms1(double* X, double* Y)

Applies this transformation to the coordinates:
- of the number pair Coord, or
- X and Y.

Note:
- Transforms modifies X, Y, or the coordinate pair Coord, while
- Transformed creates a new coordinate pair.

HRESULT Trsf2d(IKO_gp_Trsf2d** ret)

HRESULT _CSFDB_Getgp_GTrsf2dmatrix(IKO_gp_Mat2d** ret)

HRESULT _CSFDB_Getgp_GTrsf2dloc(KC2D* ret)

HRESULT _CSFDB_Getgp_GTrsf2dshape(gp_TrsfFormKO* ret)

HRESULT _CSFDB_Setgp_GTrsf2dshape(gp_TrsfFormKO p)

HRESULT _CSFDB_Getgp_GTrsf2dscale(double* ret)

HRESULT _CSFDB_Setgp_GTrsf2dscale(double p)