File Formats: Portable Document Format (PDF)

Portable Document Format (PDF)

Portable Document Format (PDF). PDF was developed by the Adobe Corporation to allow the exchange and viewing of electronic documents easily and reliably, independent of the environment in which they were created. This format lets you compress large documents to a size small enough to download very quickly. It is also becoming a powerful format for reproducing documents over the web.

LEAD supports versions 1.2, 1.3 and 1.4 of this format. LEAD also supports loading and saving multi-page files in this format.

The PDF Filter loads AI (Adobe Illustrator) files from version 7 to version 10, which only have PDF data.

This filter can also save large images by setting the ESO_PDF_SAVE_LOW_MEMORY_USAGE flag in the SAVEFILEOPTION structure. It can also load files that are stored in memory (memory files). It can both load and save PDF files that are JPEG, LZW, CCITT G1 1D, CCITT G3 2D, or CCITT G4 compressed, or are uncompressed. In addition, this filter supports JBIG2 compressed PDF files. (Note that not all flavors of JBIG2 decompression are supported.)

This filter can load files that are stored in memory (memory files). In addition, it supports an option that disables the cropping of files, by setting the PDF_DISABLE_CROPPING flag in the FILEPDFOPTIONS structure, and an option that disables the use of CIE colors, by setting the PDF_DISABLE_CIECOLORS flag in the FILEPDFOPTIONS structure. Disabling the use of CIE colors will result in faster loading of PDF files.

Support for this format is available in the Barcode PDF modules and the PDF Plug in. For more information on the available products, refer to Products and Licensing. Support for this file format can be unlocked using one of the following support constants: L_KEY_PDF, L_KEY_PDF_SAVE, L_KEY_OCR_PDF_OUTPUT, L_KEY_BARCODES_PDF_READ, or L_KEY_BARCODES_PDF_WRITE.

For saving JBIG2 compressed PDF files, the user should unlock this capability using L_KEY_JBIG2.

The file constants associated with this file format are:

Constant	Read Support	Write Support	Description
FILE_RAS_PDF	Yes*	1, 2, 4, 8, 24 BPP	[146] Raster PDF uncompressed.
FILE_RAS_PDF_JBIG2	N/A*	1 BPP	[188] Raster PDF with JBIG2 Compression.
FILE_RAS_PDF_G3_1D	N/A*	1 BPP	[147] Raster PDF with G3 1D Compression.
FILE_RAS_PDF_G3_2D	N/A*	1 BPP	[148] Raster PDF with G3 2D Compression.
FILE_RAS_PDF_G4	N/A*	1 BPP	[149] Raster PDF with G4 Compression.
FILE_RAS_PDF_LZW	N/A*	1, 2, 4, 8, 24 BPP	[179] Raster PDF with LZW Compression.
FILE_RAS_PDF_JPEG	N/A*	8 BPP (Grayscale) 24 BPP	[150] Raster PDF with JPEG 4:4:4 Compression.
FILE_RAS_PDF_JPEG_422	N/A*	24 BPP	[151] Raster PDF with JPEG 4:2:2 Compression.
FILE_RAS_PDF_JPEG_411	N/A*	24 BPP	[152] Raster PDF with JPEG 4:1:1 Compression.
FILE_RAS_PDF_CMYK	N/A*	24 BPP	[333] Raster PDF with uncompressed CMYK data.
FILE_RAS_PDF_LZW_CMYK	N/A*	24 BPP	[334] Raster PDF with LZW Compressed CMYK data.

Required DLL: LFPDF. The files required for reading PDF and writing PDF are different . For a listing of the exact DLLs needed, based on the toolkit version, refer to Files To Be Included With Your Application.

*NOTE: When you request file information on a PDF file, FILE_RAS_PDF will always be returned for the file format, regardless of the composition of the PDF file. LEADTOOLS can read PDF documents that are made up of both text and images. The text and images are rasterized into one raster image for each page of the document. LEADTOOLS can write PDF documents that are made up of raster images only.