Adobe Acrobat SDK
Multimedia Features (Chapter 9 in PDF Reference)
Adobe® Supplement to the ISO 32000
9.5.6 Persistence of 3D Measurements and Markups 67
The following figure illustrates the parameters associated with the perpendicular dimension.
FIGURE 9.21
FIGURE 9.21
shows the measure markup and parameters. All the markup items are drawn on the
annotation plane (as defined by
AP
). The text layout is defined in a similar manner as for linear dimensions.
The lower-left corner of the text box is positioned at the text anchor point (
TP
), and the text's X-axis is
aligned with the measure line. The text will flow in the direction defined by a vector from
A1
to
A2
. The
text's up direction is defined as the cross product of the annotation plane normal and the text X-axis, in the
direction defined by the
TY
parameter.
In addition to controlling text position, the text anchor point (
TP
) also controls the lengths of the leader
lines and the placement of the measure line. Because the leader lines are parallel and the measure line
must be perpendicular to both leader lines, the intersection of the leader lines and the measure line is
easily computed.
If the text position
TP
is outside the area between
A1
and
A2
, an extension line collinear to the measure
line connecting
TP
to the closest anchor point is generated.
There are three parts to the text string displayed with the measurement: a numeric value (
V
), a units string
(
U
), and an optional user string (
UT
). The display of the numeric value field number is also controlled by the
precision value (
P
), which indicates how many digits to display to the right of the decimal point. The
viewer should convert the numeric value to a string and combine it with the units string and user text as
appropriate. This process is viewer dependent.
3D Angular Dimension Measurement
An
angular measurement
is used to denote the angle between two linear entities, as shown here.
UT
text string
(
Optional; ExtensionLevel 3
) A string defined by the user that is
appended to the end of the measurement value string. If omitted, no
string is appended.
S
dictionary
(
Optional; ExtensionLevel 3
) A comment reference is an
indirect reference
to a projection annotation that may be associated with this 3D
measurement. See
“3D Measurements and Projection Annotations” on
page 75
.
TABLE 9.39c Additional entries in a 3D measurement/markup dictionary
for a 3D perpendicular dimension measurement
KEY
TYPE
VALUE
!
!
6ALUE
40TEXTANCHORPOINT
$
49
!0ANNOTATIONPLANENORMAL
-EASURE,INE
,EADER,INE
