PDF Render Tool

Getting started

This service takes the plain, fixed-width text your system already prints and renders it as a PDF, optionally on your own letterhead. It changes nothing about the application producing the text. You keep printing to a file or a spool queue exactly as you do now, and the PDF is built from that.

There are two parts. The page you are on is a settings tool: load a sample of your output, adjust until the preview looks right, then take those settings away. The API is the part you actually integrate with, and it is where the rendering happens.

The quickest possible start, using the free tier with no sign-up:

curl -F "[email protected]" \
  https://pdf.tachytelic.net/api/render-raw -o report.pdf

That gives you a plain PDF with default settings. Everything below is about making it match your stationery exactly.

How the layout works

Fixed-width output is a grid. Every character occupies the same width and every line sits the same distance below the last, which is exactly how a line printer behaved. The renderer reproduces that grid rather than trying to reflow anything, so columns stay lined up.

Two numbers control it:

• Line spacing (vertSpace) is the distance between one row and the next, in points. 12 points gives six lines per inch, the line-printer standard.
• Point size (pointSize) is how big the characters are. It does not affect row positions, only how the text looks within them.

A row's position is simply topmargin + (row number × vertSpace), measured from the top of the page. So if you are matching pre-printed stationery, work out those two numbers first and the rest follows. Nudging topmargin and leftmargin shifts the whole block without disturbing the alignment between rows.

All measurements are in points, where 72 points is one inch. A4 is 595 by 842 points, LETTER is 612 by 792.

Where pages break

This is the part that most often needs thought. Legacy files divide into pages in one of three ways, and the renderer supports all three. They can be combined, and whichever break comes first wins.

1. Form feeds

Most spool files contain a form feed character (0x0C) at each page boundary. This is handled automatically, and formFeeds is on by default. If your file has them, you usually need to do nothing else.

2. A fixed number of lines

Some files have no form feeds but a consistent page depth, often 66 or 72 lines. Set lines to that number.

3. A marker line

The awkward case: no form feeds, and pages that vary in length. What these files do have is a header line that repeats at the top of every page. Put some of that line in splitOn and a new page starts wherever it appears.

The marker line becomes the first line of the new page, because that is what it is. To hide it, set skipEachPage to 1, which blanks it while leaving every other row exactly where it was. If the header carries something you want printed, such as an order number or a date, leave skipEachPage alone and it stays visible.

splitOn is a plain piece of text by default, so a marker like INVOICE (CONT.) needs no special treatment. Tick Split on is a regex when you need to be more precise. For example, ^pic\s+\d+ matches a header line whatever order number follows it, where the literal text would only ever match one document.

Skip lines, or skip each page?

Two similarly named options that do different jobs:

• skipLines blanks the first N lines of the whole document. Use it for a one-off control line at the very top of the file.
• skipEachPage blanks the first N lines of every page. Use it for a header that repeats.

Both blank the lines in place rather than deleting them, so nothing below shifts up and your alignment survives.

Every option

All options are optional. The defaults suit ordinary fixed-width output. In the API, names are PascalCase (PointSize); the tool shows the friendly label.

The pages option accepts all, first, last, a single number, a range such as 1-3, an open range such as 2- or -3, or a list such as 1,3,5-7. Page numbers stay stable whichever subset you ask for, so you can render the same file more than once with different letterheads and merge the results afterwards.

Common problems

My box-drawing characters are garbage

Set Encoding to cp850, or cp437 on older US systems. Files from DOS and Unix systems of that era are almost never UTF-8. You will also need to upload a monospace font file, because the three built-in fonts cannot draw those characters.

Every other page is blank

Your lines value is smaller than the real page depth, so each source page overflows onto a second one. Set lines to the actual form depth, commonly 66 or 72.

A control line is showing at the top of every page

Set skipEachPage to 1. For a line at the very start of the file only, use skipLines instead.

Everything sits slightly too low or too far right

Adjust topmargin and leftmargin. These shift the whole block and will not disturb the spacing between rows.

The columns drift further out of line further down the page

That is vertSpace, not the margins. A small error per row accumulates down the page. Fractional values are allowed and often needed, for example 12.083.

My file has no form feeds and pages of different lengths

Use splitOn, described in Where pages break.

Strange characters appear where control codes were

Leave Strip control codes ticked. It removes embedded printer escape sequences that would otherwise render as visible junk.

Calling the API

There are two endpoints. Both do the same rendering and differ only in how you hand over the data.

Multipart, returns a PDF directly

The simplest to use from a shell script or a legacy box with curl on it.

curl -F "[email protected]" \
     -F "[email protected]" \
     -F 'options={"paper":"A4","lines":66,"skipEachPage":1}' \
     https://pdf.tachytelic.net/api/render-raw -o report.pdf

Form fields: text (required), background, fontFile, and options as a JSON string using the lower-case names from the table above. The response body is the PDF itself.

JSON, returns base64

Better suited to Power Automate, Logic Apps and similar tools, which prefer JSON both ways.

POST https://pdf.tachytelic.net/api/render
Content-Type: application/json

{
  "TextFileContent": "<base64 of your text file>",
  "BackgroundPdfContent": "<base64 of your letterhead PDF>",
  "Paper": "A4",
  "Lines": 66,
  "SkipEachPage": 1
}

Options use PascalCase here and sit at the top level of the object rather than in a nested options field. The response is {"PdfFileContent": "<base64 of the PDF>"}. Use the Copy as curl box on the Tool tab to get this filled in with your current settings.

What comes back when something is wrong

Power Automate

There is a Power Platform connector, so you do not need to build the HTTP request yourself. Add the Render text to PDF action and fill in the fields. The options are the same ones described above, shown with their friendly names.

Do not base64 anything yourself

This is the one thing that catches people out, and it fails quietly rather than with an error.

TextFileContent, BackgroundPdfContent and FontFileContent are declared as binary fields. Power Automate encodes them for you. If you wrap the value in a base64() expression first, it gets encoded a second time, and what arrives is one enormous single line of base64 rather than your document.

The result is a PDF containing your letterhead and no text at all, because that single line is then blanked by Skip lines or Skip each page. Nothing errors, you just get an empty page.

Feed the output of Get file content straight into the field instead. The service now rejects double-encoded text with a clear message rather than returning a blank page, but the fix is to remove the base64() call.

Text or Text file content?

• Use Text when you already have the document as a string in the flow. It is the simplest option and avoids the encoding question entirely.
• Use Text file content when the bytes matter, typically a legacy code page such as cp850 with box-drawing characters, where you need the original bytes preserved and decoded with the Encoding option rather than guessed at.

Supply one or the other. If both are present, TextFileContent wins.

Getting the PDF back

The action returns PdfFileContent. Pass it straight to Create file or an email attachment. Power Automate handles the decoding, so again, no base64ToBinary() is needed in the ordinary case.

Limits and API keys

The service is free to use with no sign-up, limited per IP address:

• 60 requests per minute
• 150 requests per day

That is plenty for evaluating it and for light day-to-day use. Go over it and you get a 429 with a short explanation.

If you are running something in production, an API key removes the shared limit and gives you your own daily allowance. Send it as a header:

curl -F "[email protected]" \
     -H "x-api-key: your-key-here" \
     https://pdf.tachytelic.net/api/render-raw -o report.pdf

Keys also mean your usage is not affected by anyone else sharing your outbound IP address, which matters if you are behind a corporate NAT or calling from a cloud service.

To get one, or to talk about anything unusual in your output, get in touch. If you are working with SCO OpenServer specifically, there is a full walkthrough for that platform.