MAPPING_MODE(3G)

NAME

mapping_mode − defines whether the mapping of the vdc extent to the viewport is isotropic (not distorted) or anisotropic (distorted).

SYNOPSIS

C SYNTAX

void mapping_mode(fildes,distort);
int fildes,distort;

FORTRAN77 SYNTAX

subroutine mapping_mode(fildes,distort)
integer*4 fildes,distort

PASCAL SYNTAX

procedure mapping_mode(fildes,distort:integer);

HP-UX COMPATIBILITY

Level: HP-UX/STANDARD

Origin: ANSI Computer Graphics Interface

DESCRIPTION

INPUT PARAMETERS

fildes
is an integer file descriptor returned by gopen when an I/O path to a graphic device is opened.
distort if TRUE (1), distorted mapping from virtual device coordinates to device coordinates is performed.
if FALSE (0), the mapping is not distorted.

DISCUSSION

When mapping mode is distorted (anisotropic), the viewport occupies the full physical region of interest (set by set_p1_p2), with no space left unused in the region. This is referred to as a 2-point scaling or "rubbering" and does not preserve aspect ratio. The numbers corresponding to vdc_extent span the entire physical region of interest.

When mapping mode is not distorted (isotropic), the viewport is calculated as the largest rectangle within the physical region of interest which preserves the aspect ration of the vdc_extent. Unless this matches the aspect ratio of the physical region of interest, some "white space" will be left unused outside the physical region of interest. By default, this white space will be distributed evenly on the two sides of the viewport; this can be modified by the viewport_justification. procedure.

This procedure changes the current vdc-to-device matrix. This means the matrix at the bottom of the matrix stack is changed and the matrix at the top of the matrix stack is changed if it was put there using the push_vdc_matrix procedure. No other matrices in the matrix stack are altered.

Changes to the mapping mode may not affect previously set values such as text size or tracking relationships. Mapping mode should be set before setting related values.

DEFAULTS

Isotropic

Museum

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