Name

DHTTST − Performs a pick operation on an output workstation when the application is using the X11[R] event queue. 

Operating States: PHOP, WSOP, ∗, ∗
Digital PHIGS extension function
 

Syntax

DHTTST (WKID, X, Y, DIST, ORDER, IFS, IFL, EFS, EFL, IPPD, STAT,
PPD, PP)

Argument     Data Type      Access    Description
---------------------------------------------------------------------------
WKID         Integer        Read      Workstation identifier
X, Y         Reals          Read      Point in local device coordinates
DIST         Real           Read      Pick aperture in local device
                                      coordinates
ORDER        Integer        Read      Return path order
IFS          Integer        Read      Inclusion filter size
IFL          Array of       Read      Inclusion filter list
             integers
EFS          Integer        Read      Exclusion filter size
EFL          Array of       Read      Exclusion filter list
             integers
IPPD         Integer        Read      Depth of pick path to return
STAT         Integer        Write     Status
PPD          Integer        Write     Depth of actual pick path
PP(3)        Array of       Write     Pick path
             integers
---------------------------------------------------------------------------

Constants

Defined Argument      Constant      Description
---------------------------------------------------------------------------
ORDER                 PPOTOP        Top first.
                      PPOBOT        Bottom first.
STAT                  PNONE         User performed a break action.
                      POK           User picked a primitive.
                      PNPICK        User triggered the device, but did not
                                    make a selection.
---------------------------------------------------------------------------

Description

DHTTST performs a pick operation on an output workstation when the application is using the X11[R] event queue (generally with workstation types 2n2 and 2n3, where n is either 3 or 4).  Using this function, the application can get X11 cursor events, transform them from X11 coordinates to device coordinates in Digital PHIGS, and then get a pick path back from Digital PHIGS. 

To transform X11 coordinates to Digital PHIGS device coordinates, you must do the following:

•Convert to floating point numbers. 

•The X11 origin is at the upper-left of the window, while the Digital PHIGS origin is at the lower-left of the window.  To change from X11 points to Digital PHIGS points, use the following equation:

y = y_max - y

See Also

PGTPK
PRQPK
PSMPK