US Letter has incorrect size

[grinay]

Hello. I'm trying to create pdf out of json file.
I'm looking for a way to set the custom page size, but unable to find it and start looking into standard sizes provided with parameter paper. And I found what I'm looking for. Format "Letter", however standard of letter has dimensions of 612x792 but in pdfcpu it has size 612x791. May you advice is that a bug?
And is there any way to set the custom size?

Also would be interesting to know, how to set media box.

Here is my json

{
  "origin": "UpperLeft",
  "paper": "Letter",
  "pages": {
    "1": {
      "paper": "Letter",
      "content": {
        "paper": "Letter",
        "width": 612,
        "height": 792,
        "image": [
          {
            "src": "image.png",
            "pos": [
              0,
              0
            ],
            "width": 612,
            "height": 792
          }
        ]

and later there is only pure text create with absolute position.
And in log I see

WRITE: 2024/04/07 15:16:11 writePagesDict: writing pageDict for obj=2 page=1
<<
        <Count, 1>
        <Kids, [(6 0 R)]>
        <MediaBox, [0.00 0.00 595.00 842.00]>
        <Type, Pages>
>>
WRITE: 2024/04/07 15:16:11 addToObjectStream begin, obj#:2 gen#:0
TRACE: 2024/04/07 15:16:11 FindTableEntry: obj#:8 gen:0 
TRACE: 2024/04/07 15:16:11 FindTableEntry: obj#:2 gen:0 
TRACE: 2024/04/07 15:16:11 AddObject end : ObjCount:3 prolog = <6 0 4 243 2 315> Content = <<</Contents 5 0 R/CropBox[0.000000000000 0.000000000000 612.000000000000 791.000000000000]/MediaBox[0.000000000000 0.000000000000 612.000000000000 791.000000000000]/Parent 2 0 R/Resources<</Font<</F0 4 0 R>>/XObject<</Im0 3 0 R>>>>/Type/Page>><</BaseFont/Helvetica/Encoding/WinAnsiEncoding/Subtype/Type1/Type/Font>><</Count 1/Kids[6 0 R]/MediaBox[0.000000000000 0.000000000000 595.000000000000 842.000000000000]/Type/Pages>>>

I don't understand where is this media box comes from <MediaBox, [0.00 0.00 595.00 842.00]>, as I have another sizes. I'm trying to solve the issue of correctly positioning text, but my text for some reasons misaligned originally it must be around 15 point lower, trying to recreate pdf after OCR.

[grinay]

Small update, I was able to put text on its place by adding height into Y position.
The only questions left about the custom sizes, and media boxes.

[hhrutter]

papersize is corrected.
thanks for discovering this!

As far as the PDF creation via JSON:
Did you check the samples at https://github.com/pdfcpu/pdfcpu/tree/master/pkg/testdata/json/create ?