NAME

SET VIEW TRANSFORMATION INPUT PRIORITY − assign relative priority of a view representation to be used when transforming input values

SYNOPSIS

C Syntax

void
pset_view_tran_in_pri ( ws, index, ref_index, priority )
Pintws;workstation identifier
Pintindex;view index
Pintref_index;reference view index
Prel_pripriority;relative priority

Required PHIGS Operating States

(PHOP, WSOP, ∗, ∗)

DESCRIPTION

Purpose

SET VIEW TRANSFORMATION INPUT PRIORITY assigns a relative priority to an entry in the workstation’s view table, to be used when transforming LOCATOR or STROKE operator input coordinates from Device Coordinates (DC) to World Coordinates (WC). 

C Input Parameters

wsThe identifier of the workstation for which the view transformation input priority is being set. 

indexThe priority is being set for this view index. 

ref_index
The priority of index is set just higher or lower than that of this reference view index. 

priority
The relative priority for index, relative to the ref_index; one of the enumerated values:

PPRI_HIGHERHigher
PPRI_LOWERLower

Execution

SET VIEW TRANSFORMATION INPUT PRIORITY assigns a relative priority to a view representation entry in the workstation’s view table, to be used when transforming LOCATOR or STROKE operator input coordinates from DC to WC.  The priority of view index is set just higher or just lower than the priority of the reference view index. 

LOCATOR or STROKE operator input data are transformed by the inverse viewing pipeline, from DC to WC.  First, the inverse workstation transformation (in effect when the input is generated) maps the DC values to Normalized Projection Coordinates (NPC), always resulting in values in the NPC unit cube.  Then, the NPC positions need to be mapped to WC by the inverse of one of the viewing transformations; the relative priority order of the viewing transformations is used to determine which viewing transformation inverse to apply. 

Views with lower priority than view 0’s will never be used to map input data.  View 0 is the identity transformation encompassing the entire NPC space cube and cannot be changed.  Therefore, any input position is necessarily in view 0, and lower priority views are effectively disabled.  The initial ordering, when a workstation is opened, gives view number 0 the highest priority, view 1 the next highest, and so on.  All views except 0 are disabled. 

If the view index is the same as the reference view index, the function has no effect. 

The relative view transformation input priorities may be obtained using INQUIRE LIST OF VIEW INDICES. 

ERRORS

003Ignoring function, function requires state (PHOP, WSOP, ∗, ∗)

054Ignoring function, the specified workstation is not open

057Ignoring function, specified workstation is of category MI

114Ignoring function, the view index value is less than zero

101Ignoring function, the specified representation has not been defined

SEE ALSO

SET VIEW REPRESENTATION 3 (3P)
INQUIRE LIST OF VIEW INDICES (3P)

September 02, 1992