NAME

SCALE − calculate a 2D transformation matrix to perform a specified scaling

SYNOPSIS

C Syntax

void
pscale ( scale_vector, error_ind, m )
Pvec∗scale_vector;scale factor vector
Pint∗error_ind;OUT error indicator
Pmatrixm;OUT transformation matrix

Required PHIGS Operating States

(PHOP, ∗, ∗, ∗)

DESCRIPTION

Purpose

Use SCALE to generate a 2D homogeneous (3 × 3) transformation matrix that performs a 2D scaling. 

The returned matrix can be passed as an argument to SET LOCAL TRANSFORMATION or SET GLOBAL TRANSFORMATION to modify the modelling transformation that is applied to output primitives during traversal. 

C Input Parameter

scale_vector
A pointer to a Pvec data structure containing the scale factors to be applied to the x and y dimensions.  Pvec is defined in phigs.h as follows:

typedef struct  {
Pfloatdelta_x;/∗ x coordinate ∗/
Pfloatdelta_y;/∗ y coordinate ∗/
} Pvec;

C Output Parameters

error_ind
A pointer to the location to store the error number of any error detected by this function.

mThe 3 × 3 homogeneous transformation matrix that performs the specified scaling.  Pmatrix is defined in phigs.h as follows:

typedef  Pfloat  Pmatrix[3][3];

Execution

SCALE returns a 2D homogeneous (3 × 3) transformation matrix that performs the scaling specified by scale factor vector.  The scaling is relative to the origin of the current modelling coordinate system. 

The scale factor vector specifies sx and sy scaling factors that control scaling in the x and y directions. 

ERRORS

002Ignoring function, function requires state (PHOP, ∗, ∗, ∗)

SEE ALSO

SET LOCAL TRANSFORMATION (3P)
BUILD TRANSFORMATION MATRIX (3P)
COMPOSE MATRIX (3P)
SCALE 3 (3P)
TRANSFORM POINT (3P)

September 02, 1992