Text and Fonts - PDF Explained - page 74

Text State
The text state parameters and the operators which modify them are summarized in
Table 6-1 .

Table 6-1. Text state parameters and their operators

Parame-
ter

Description Operands Operators Initial value

T c Character spacing charSpace Tc sets the character spacing to charSpace ,

expressed in unscaled text space units.

0

T w Word spacing wordSpace Tw sets the word spacing to wordSpace ,

expressed in unscaled text units.

0

T h Horizontal spacing scale Tz sets the horizontal scaling to ( scale / 100). 100 (normal spacing)

T l Leading leading TL sets the text leading to leading , expressed

in unscaled text space units.

0

T f , T fs Font, Font Size font, size Tf selects the font font at size size points. None. Must be specified.

T mode Rendering Mode render Tr sets the text rendering mode to render , an

integer.

0

T rise Rise rise Ts sets the text rise to rise , expressed in un-

scaled text space units.

0

We discuss the phrase “unscaled text space units” in “Text Space and Text Position-
ing” on page 75 . The text state is stored along with the graphics state, and manipu-
lated using the operators above. The current text state is affected by the stack operators
q and Q , just like the graphics state.

Printing Text
Printing text on the page requires:
1. Selecting a font.
2. Choosing position, size, and orientation.
3. Choosing spacing, color, text rendering mode, and other parameters.
4. Selecting characters from the font, and showing them on the page.

Text Sections
The operators BT (begin text) and ET (end text) form brackets around text sections .
Operators for showing text in a page's content stream may only appear between BT and
ET . Operators for altering text state, however, are not restricted in this way. Text sec-
tions may also contain other operators altering the general graphics state.