DLI Implementation and Reference Guide - Datalogics

11.2 DLI Implementation and Reference Guide
Overview
Concepts and Facilities: Guide to the DL Pager Composition System
Inclusion of graphics is accomplished in two ways. The first is an image, in the sense
of a PDF or PostScript Image Operator. The second is a Encapsulated PostScript (EPS)
file. Note that images included as EPS will not appear in PDF pages on-screen (e.g.
when displayed by Adobe Reader or Adobe Acrobat), but will appear in both
PostScript pages and Adobe PDF PostScript pages. Adobe Normalizer, also available
from Datalogics, can be used to distill EPS images to PDF format in order to make
EPS sources visible in PDF output.
The interfaces provided in DLI for images are intentionally very low-level. They
presume that any graphics conversions have already been completed. Public-domain
packages for the conversion of graphics from common formats (PNG, GIF, TIFF, etc.)
are readily available and can create data in the form these interfaces expect.
Graphic Image Structures
DLI manages graphics via the structure DLPDFIMAGE. This structure is used for both
image and EPS data.
There are four functions to create images depending on the format (Bitmap, EPS, PDF,
and a convenience function for several other graphic formats), and one function to use
an image (dlpdfcontentreferenceimage).
NOTE: Encapsulated PostScript (EPS) is not a valid graphic format for PDF. The EPS
function available through DLI will enable you to embed the EPS image in the PDF
document, but it will not be visible until the document is printed. (Adobe
Normalizer, also available from Datalogics, can be used to distill EPS images to PDF
format in order to make EPS sources visible in PDF output.)
Image structures are created on a per-document basis. If the same image is used in
multiple documents, multiple copies of that image must be created. Images are tracked
within the document and all images are destroyed when the document is destroyed.