DLI Implementation and Reference Guide - Datalogics

5.8 DLI Implementation and Reference Guide
dlpdftextadvance
The most common use for making new text areas from portions of a DLPDFTEXT area
Concepts and Facilities: Guide to the DL Pager Composition System
is to copyfit text to composed lines. The dlpdftextadvance function call is used to
supply the width and height change for a string of text, and accounts for character
shaping and combining, as well as horizontal reading direction. The
dlpdfcontentwidetextwidth function call may be used to get a rough estimate
of the width or height change for a string. The dlpdfcontentwidetextwidth call
does not take character shaping or combining into account, and assumes a left-toright
line data orientation. The dlpdftextadvance call looks much like the
dlpdfcontentwidetextwidth calls, but with some enhancements.
void dlpdftextadvance (DLPDFTEXT *, DLPDFFONT *,
PDEGraphicState *,
PDETextState *,
ASFixed, ASFixed,
dlpdftext_X,
ASFixed, ASFixedPoint *)
• The first argument is a DLPDFTEXT area that contains text to be set...
• ...in the indicated DLPDFFONT...
• ...using the supplied graphics of PDEGraphicState...
• ...and text states of PDETextState.
• The fifth argument describes the point size of the font;
• the sixth argument describes the set width of the font;
• the seventh argument, the dlpdftext_X parameter, is one of
DLPDFTEXT_X_LEFT or DLPDFTEXT_X_RIGHT, used to indicate whether the
starting location is the left or right end (respectively) of the text, distinguishing a
left-to-right line order (e.g. English) from a right-to-left line order (e.g. Arabic);
• the eighth argument indicates the angle of text (in counterclockwise degrees),
supplied as an ASFixed value;
• the ninth argument is a pointer to an ASFixedPoint; the X and Y position change
resulting from this call is returned in ASFixed units in this ASFixedPoint.
An exception will be raised for invalid parameters, or if the text advance could not be
calculated.