`pdf_to_image`

Render PDF pages to images using the native pdfium library at runtime.

Parameters

pathstringone of path or source_key: File path to the PDF; supports ${ctx.key} interpolation.
source_keystringone of path or source_key: Context key whose value is the file path (must be a string).
pagesstringdefault "all": Page specification: "all", a single page "3", a range "1-5", or a combination "1-3,7,9-11". Pages are 1-based.
formatstringdefault "png": Image format: "png", "jpeg", or "jpg".
dpinumberdefault 150.0: Resolution in dots per inch for rendering.
output_keystringdefault "images": Context key where the array of rendered image objects is stored.

Providing both path and source_key is an error. Requires the pdfium native library. Set PDFIUM_LIB_PATH env var, place libpdfium in the working directory, or install it system-wide.

Context Output

<output_key> (default images) — an array of objects, one per rendered page, each containing:
- page — 1-based page number.
- width — rendered image width in pixels.
- height — rendered image height in pixels.
- format — the image format ("png", "jpeg", or "jpg").
- image_base64 — base64-encoded image data.
page_count — total number of pages in the PDF document.

Example

local flow = Flow.new("render_pdf_pages")

flow:step("render", nodes.pdf_to_image({
    path = "/data/document.pdf",
    pages = "1-3",
    format = "png",
    dpi = 200,
    output_key = "images"
}))

flow:step("done", nodes.log({
    message = "Rendered ${ctx.page_count} total pages, got ${ctx.images} image(s)"
})):depends_on("render")

return flow

Limits

pdf_to_image reads the PDF into memory and stores rendered images as base64 in workflow context. The following process limits are enforced:

IRONFLOW_MAX_PDF_BYTES — maximum PDF file size, default 104857600.
IRONFLOW_MAX_PDF_RENDER_PAGES — maximum pages rendered by one node call, default 25.
IRONFLOW_MAX_PDF_RENDER_PIXELS — maximum pixels per rendered page, default 25000000.
IRONFLOW_MAX_PDF_DPI — maximum accepted DPI, default 300.