pdf module

The glu.pdf module

The glu.pdf module provides low-level access to PDF generation using the baseline-pdf library. It allows direct control over PDF objects, streams, fonts, and images.

For most use cases, the glu.frontend module is recommended. The glu.pdf module is useful when you need fine-grained control over the PDF output.

local pdf = require("glu.pdf")

Module functions

Name	Parameters	Returns	Description
`pdf.new()`	filename (string)	PDFWriter	Create a new PDF writer

PDFWriter

local pdf = require("glu.pdf")
local pw = pdf.new("output.pdf")

Attributes

Name	R/W	Type	Description
`default_page_width`	R/W	number	Default width for new pages (points)
`default_page_height`	R/W	number	Default height for new pages (points)
`default_offset_x`	R/W	number	Default horizontal offset
`default_offset_y`	R/W	number	Default vertical offset
`size`	R	number	Size of the PDF document in bytes

Methods

Name	Parameters	Returns	Description
`new_object()`	-	Object	Create a new PDF object
`add_page()`	stream	Page	Add a page with the given stream
`load_face()`	filename, [index]	Face	Load a font face
`load_image()`	filename, [page], [box]	Image	Load an image file
`finish()`	-	-	Finalize and write the PDF

Example:

local pw = pdf.new("output.pdf")
pw.default_page_width = 595   -- A4 width in points
pw.default_page_height = 842  -- A4 height in points

-- Create content stream
local stream = pw:new_object()
stream.force_stream = true
stream:write("BT /F1 24 Tf 100 700 Td (Hello PDF) Tj ET")

-- Add page
local page = pw:add_page(stream)

pw:finish()

Object

PDF objects represent the building blocks of a PDF file.

local obj = pw:new_object()

Attributes

Name	R/W	Type	Description
`object_number`	R	number	The PDF object number
`force_stream`	R/W	boolean	Always write as stream object
`dict`	R/W	table	Dictionary entries
`array`	R/W	table	Array data

Methods

Name	Parameters	Returns	Description
`write()`	string	-	Write data to the object stream
`save()`	-	-	Save the object to the PDF
`set_compression()`	level	-	Set compression level (0-9)

Example:

local stream = pw:new_object()
stream.force_stream = true
stream:set_compression(9)
stream:write("BT /F1 12 Tf 72 720 Td (Hello) Tj ET")
stream:save()

Page

local page = pw:add_page(stream)

Attributes

Name	R/W	Type	Description
`width`	R/W	number	Page width in points
`height`	R/W	number	Page height in points
`offset_x`	R/W	number	Horizontal offset
`offset_y`	R/W	number	Vertical offset
`object_number`	R/W	number	PDF object number
`faces`	R/W	table	List of Face objects used
`images`	R/W	table	List of Image objects used
`dict`	R/W	table	Additional dictionary entries

Face

Font face objects for PDF text rendering.

local face = pw:load_face("fonts/MyFont.ttf", 0)

Attributes

Name	R/W	Type	Description
`internal_name`	R	string	PDF internal font name
`postscript_name`	R	string	PostScript name of the font
`units_per_em`	R	number	Font units per em
`filename`	R	string	Path to the font file
`face_id`	R	number	Internal face ID

Methods

Name	Parameters	Returns	Description
`codepoint()`	rune	number	Get codepoint for a character
`codepoints()`	runes (table)	table	Get codepoints for characters
`register_codepoint()`	codepoint	-	Register codepoint for subsetting
`register_codepoints()`	codepoints (table)	-	Register multiple codepoints

Example:

local face = pw:load_face("fonts/CrimsonPro-Regular.ttf")
local cps = face:codepoints({"H", "e", "l", "o"})
face:register_codepoints(cps)

Image

local img = pw:load_image("image.png")
local pdf_page = pw:load_image("document.pdf", 1, "/MediaBox")

Attributes

Name	R/W	Type	Description
`internal_name`	R	string	PDF internal image name
`page_number`	R	number	Page number (for PDF images)

Methods

Name	Parameters	Returns	Description
`close()`	-	-	Close and free memory
`get_pdf_box_dimensions()`	page, box	table	Get box dimensions

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