Name

peval_view_map_matrix − Creates a view mapping matrix. 

Operating States: PHOP, ∗, ∗, ∗
PHIGS standard function

Syntax

void peval_view_map_matrix (
  const Pview_map  ∗mapping,    /∗ (I) View mapping ∗/
  Pint             ∗error_ind,  /∗ (O) Error indicator ∗/
  Pmatrix           matrix      /∗ (O) View mapping matrix ∗/
)

Data Structures

typedef struct {
    Plimit    win;      /∗ window limits ∗/
    Plimit    proj_vp;  /∗ projection viewport limits ∗/
} Pview_map;
    typedef struct {
        Pfloat   x_min;    /∗ x minimum ∗/
        Pfloat   x_max;    /∗ x maximum ∗/
        Pfloat   y_min;    /∗ y minimum ∗/
        Pfloat   y_max;    /∗ y maximum ∗/
    } Plimit;
typedef Pfloat Pmatrix[3][3];

Description

peval_view_map_matrix creates a view mapping matrix, which can be passed as input to the pset_view_rep function.  (This transforms the PHIGS coordinate system from view reference coordinate points to normalized projection coordinate points.) 

To create the view mapping matrix, use the following procedure:
 

•Specify window limits within view reference coordinate space in the order UMIN, UMAX, VMIN, VMAX. 

The following restrictions apply:

UMIN < UMAX

VMIN < VMAX

The formation of the v- and u-axes in the view reference coordinate system is described in Getting Started with DEC PHIGS. 

•Specify projection viewport limits (view clipping limits) within normalized projection coordinate space in the order XMIN, XMAX, YMIN, YMAX. 

The following restrictions apply:

XMIN < XMAX

YMIN < YMAX

XMIN, XMAX, YMIN, and YMAX must be in the range [0,1],
inclusive.

Projection and the normalized projection coordinate system are described in Getting Started with DEC PHIGS and DEC PHIGS Developer’s Guide. 

If the view mapping parameters are consistent and well defined (that is, if they conform to the specified rules and restrictions), a call to this function returns the 3 x 3 view mapping matrix.  Otherwise, a nonzero error indicator is returned. 

See Also

peval_view_map_matrix3
peval_view_ori_matrix
pinq_view_facs
pe_inq_ext_view_rep3
pset_view_ind
pset_view_rep