PDFlib Text Extraction Toolkit (TET) Manual

Fig. 6.2
Configuring coordinate display in Acrobat; use View, Cursor Coordinates to display cursor coordinates.
constructed by determining the union of all rectangles specified in the includebox option,
and subtracting the union of all rectangles specified in the excludebox option. A
character is considered inside the clipping area if its reference point is inside the clipping
area. This means that a character could be considered inside the clipping area even
if parts of it extend beyond the clipping area, or vice versa.
Glyph metrics. Using TET_get_char_info( ) you can retrieve font and metrics information
for the characters which are returned for a particular glyph. The following values
are available for each character in the output (see Figure 6.3 and Table 10.15):
> The uv value contains the UTF-32 Unicode value of the current character, i.e. the character
for which details are retrieved. This field will always contain UTF-32, even in
language bindings that can deal only with UTF-16 strings in their native Unicode
strings. Accessing the uv field allows applications to deal with characters outside the
BMP without having to interpret surrogate pairs. Since surrogate pairs are reported
as two separate characters, the uv field of the leading surrogate value will contain the
actual Unicode value (larger than U+FFFF). The uv field of the trailing surrogate value
is treated as an artificial character, and has a uv value of 0.
> The type field specifies how the character was created. There are two groups: real and
artificial characters. The group of real characters comprises normal characters (i.e.
the complete result of a single glyph) and characters which start a multi-character
sequence that corresponds to a single glyph (e.g. the first character of a ligature). The
74 Chapter 6: Text Extraction