Figure: Normalization and Workstation Transformations.
Figure: Normalization and Workstation Transformations.
+----------------------------------------+
|CALL ISWKWN (KWKID,XMIN,XMAX,YMIN,YMAX) |
+----------------------------------------+
Action: This routine defines a workstation window in the normalized device
coordinates space. It sets the (requested) workstation window on a
previously opened workstation. The workstation window, specified in
normalized device coordinates (i.e., 0.-1. by 0.-1.) is the portion of
normalized device coordinates space that the application wishes to appear
on the given workstation. This permits primitives which are created when
multiple workstations are active to be clipped and scaled differently on
the different workstations.
The workstation window (together with the workstation viewport and the
rule that the aspect ratio of the workstation window must be preserved)
determines the mapping (uniform scale with translation) from normalized
device coordinates to device coordinates.
The requested workstation window becomes the current workstation window
either during the invocation of ISWKWN (if the display surface is empty or
if it does not cause an implicit regeneration) or at some later time (for
example, during an invocation of ICLRWK).
Parameter Description:
+----------------------------------------+
|CALL ISWKVP (KWKID,XMIN,XMAX,YMIN,YMAX) |
+----------------------------------------+
Action: This routine sets the (requested) workstation viewport on a
previously opened workstation. The workstation viewport, specified in
device coordinates, is the portion of the maximum available display
surface that the application wishes to use (see section
[more info]).
The workstation viewport (together with the workstation window and the
rule that aspect ratios must be preserved) also determines the mapping
(uniform scaling with translation) from normalized device coordinates to
device coordinates.
The requested workstation viewport becomes the current workstation
viewport either during the invocation of ISWKVP (if the display surface is
empty or if it does not cause an implicit regeneration) or at some later
time (for example, during an invocation of ICLRWK). The device
coordinates region specified by the parameters must be contained in or
equal to the maximum available display surface. The initial requested
workstation viewport is the entire display surface.
Parameter Description:
+------------------------------------+
| CALL ISWN (NT,XMIN,XMAX,YMIN,YMAX) |
+------------------------------------+
Action: This routine sets the boundaries of the window of a normalization
transformation. The window must be specified in world coordinates. The
boundaries of the window, together with the boundaries of the viewport
(which are in normalized device coordinates) determine a transformation
from world coordinates to normalized device coordinates consisting of
separate X and Y scale factors and a translation in two dimensions. The
normalization transformation is selected by using routine ISELNT.
Parameter Description:
+------------------------------------+
| CALL ISVP (NT,XMIN,XMAX,YMIN,YMAX) |
+------------------------------------+
Action: This routine sets the boundaries of the viewport of a
normalization transformation. The viewport must be specified in normalized
device coordinates. The boundaries of the viewport have two roles:
+------------------+
| CALL ISELNT (NT) |
+------------------+
Action: This routine selects the normalization transformation to be used
when world coordinates must be mapped to or from normalized device
coordinates (NDC). These mappings usually take place during invocations of
primitives ( IFA, IPL, IPM, and ITX) and during graphics input ( IRQLC).
Transformation 0 always has a window and a viewport that are the unit
square (0.-1. by 0.-1.) and cannot be changed with ISVP or ISWN.
Transformation 0 is selected by default.
Parameter Description:
+--------------------------+
| CALL IGRNG (XSIZE,YSIZE) |
+--------------------------+
Action: This routine is used to determine the physical dimensions (in
centimeter) and to optimize the aspect ratio and the centering of a
picture. If the X or Y dimension of output device are smaller than XSIZE
or YSIZE, a scaling factor is applied to the final size of the picture but
the aspect ratio is kept. When an Encapsulated PostScript workstation is
active, a call to this routine is mandatory in order to define the size of
the picture (e.g the PostScript BoundingBox).
Parameter Description: