PDFlib Text Extraction Toolkit (TET) Manual

width may be zero for non-spacing characters. On the other hand, the outline may
actually be wider than the glyph’s width value, e.g. for slanted text.
The width will be 0 for artificial characters.
> The angle alpha provides the direction of inline text progression, specified as the deviation
from the standard direction. The standard direction is 0˚ for horizontal writing
mode, and -90˚ for vertical writing mode (see below for more details on vertical
writing mode). Therefore, the angle alpha will be 0˚ for standard horizontal text as
well as for standard vertical text.
> The angle beta specifies any skewing which has been applied to the text, e.g. for
slanted (italicized) text. The angle will be measured against the perpendicular of
alpha. It will be 0˚ for standard upright text (for both horizontal and vertical writing
mode). If the absolute value of beta is greater than 90˚ the text will be mirrored at
the baseline.
> The fontid field contains the pCOS ID of the font used for the glyph. It can be used to
retrieve detailed font information, such as the font name, embedding status, writing
mode (horizontal/vertical), etc. Section 9.1, »Simple pCOS Examples«, page 105 shows
sample code for retrieving font details.
> The fontsize field specifies the size of the text in points. It will be normalized, and
therefore always be positive.
> The textrendering field specifies the kind of rendering for a glyph, e.g. stroked, filled,
or invisible. It will reflect the numerical text rendering mode as defined for PDF page
descriptions (see Table 10.10, page 144). Invisible text will be extracted by default, but
this can be changed with the ignoreinvisibletext option of TET_open_page( ).
End points of glyphs and words. In order to do proper highlighting you need the end
position of the last character in a word. Using x, y, width, and alpha returned by TET_get_
char_info( ) you can determine the end point of a glyph in horizontal writing mode:
x end = x + width * cos(alpha)
y end = y + width * sin(alpha)
In the common case of horizontally oriented text (i.e. alpha=0) this reduces to
x end = x + width
y end = y
For CJK text with vertical writing mode the end point calculation works as follows:
x end = x
y end = y - fontsize
66 Chapter 6: Text Extraction