Various issues with HTML tables (and padding and page-breaks) in concise proof-of-concept [closed]

Problems with proof-of-concept test-case:

A. First output:

1. Why is there green visible? I.e. why does the inner table get a left indent outside its parent cell? How can this be prevented? Can someone provide a proof of concept with this addressed?
2. Why is there red visible? I.e. why is there spacing around the inner table cells while they have the exact same width as their parent cell? Can someone provide a proof of concept with this addressed?

B. Second output, where a page-break is within play:

1. Where to start.. The page-break has some disastrous consequences. I have started working in HTML because it was claimed the page-break issue for variable content cells that should not be broken was solved and fixed, but I think this proof of concept example speaks for itself. I have added nobr where I needed it, and the first output proves it is feasable to stick together. How can this be fixed?

   1. Also note how the left column with “row-label” gets misaligned on a new “row”

   2. Also note how the order of images changes: the ones that were supposed to fit on the 1st page, get put after the page-break after the last image. Same goes for the cell to its left (from question B2).

Note that for my case, it is not feasable (by memory) to render in a clone first to calculate height, as we need to render 250-300mb PDFs containing hundreds of pages.

I have also verified that the units in mm are fully supported; changing it to px yields the same issues.

I have also considered using tc-lib-pdf as TCPDF is not maintained any more, but it is still only 60% complete.

Proof of concept test case code:

$pdf = new TCPDF();
$pdf->setPrintHeader(false);
$pdf->setPrintFooter(false);
$outputTestCase = function (TCPDF $pdf, int $y) {
    $pdf->AddPage();
    $pdf->setY($y);
    $pdf->writeHTMLCell($pdf->getPageWidth(), 0, null, null, '
<table nobr="true" style="background-color:yellow;">
  <tr style="color:#f4f4f4;background-color:#0041aa;">
    <td style="width:68mm;line-height:13px;"></td>
    <td style="width:102mm;line-height:13px;">Header 1</td>
  </tr>
  <tr>
    <td style="width:68mm;line-height:13px;">&nbsp;</td>
    <td style="width:102mm;line-height:13px;">Header 2</td>
  </tr>
  <tr nobr="true">
    <td style="width:68mm;line-height:13px;font-size:11px;font-weight:bold;">Row-label</td>
    <td style="width:102mm;line-height:13px;vertical-align:baseline;background-color:green;">
      <table style="background-color:red;">
        <tr><td style="width:102mm;"><img width="102mm" height="76mm" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACQAAAAkCAIAAABuYg/PAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAA1SURBVFhH7c0xDQAgEAAx3LxMpIOJhoFc0r3r7HmmjCgjyogyoowoI8qIMqKMKCPKiF+zPReVflPJ9AfYpgAAAABJRU5ErkJggg=="/></td></tr>
        <tr><td style="width:102mm;"><img width="102mm" height="67mm" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACQAAAAkCAYAAADhAJiYAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsIAAA7CARUoSoAAAABGSURBVFhH7c6hAYAwEMDAhwHYfyWmKqaa2Io7E5trvc+ag9y7xzBUDBVDxVAxVAwVQ8VQMVQMFUPFUDFUDBVDxVAx9G/mA651Ax2hOeJbAAAAAElFTkSuQmCC"/></td></tr>
        <tr><td style="width:102mm;"><img width="102mm" height="68mm" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACQAAAAkCAIAAABuYg/PAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAA1SURBVFhH7c0xDQAgEAAx3LxMpIOJhoFc0r3r7HmmjCgjyogyoowoI8qIMqKMKCPKiF+zPReVflPJ9AfYpgAAAABJRU5ErkJggg=="/></td></tr>
      </table>
    </td>
  </tr>
</table>');
};
$outputTestCase($pdf, 10);
$outputTestCase($pdf, 70);
$pdf->Output();
exit;