I need help - I can help - Render Checkbox Stream

I'm using activex rev 1613 on windows 2012 R2 server.

I face something I cannot explain.

I draw some formfield into new pdf, then I render the page into a png.

text field, or button or signature are shown but no checkbox

just like if the fonction UpdateAppearanceStream had no effect on checkbox

I followed the recommandations here :

https://www.debenu.com/kb/appearance-streams-pdf-form-fields/

(where it is said that generation of appearance streams is (...) supported for (...), checkbox)

and set SetNeedAppearances(0) then generate Appearance streams in a loop. but nothing helps.

checkboxes are not shown until I set SetNeedAppearances(1) , open the pdf with acrobat, save it and renderpagetofile

Any Idea is welcomed

here below a sample code :

<?php

$qp = new COM('DebenuPDFLibrary64AX1613.PDFLibrary');

if ($qp->UnlockKey('xxxxxxxxxxxxxxxxxxxxxxxxxxxx') != 1){

echo ('PDF License validation failed!');

die();

}

$qp->SetOrigin(1);

$qp->SetMeasurementUnits(0);

$qp->SetNeedAppearances(0);

//direct text to test renderoption(3,1)

$qp->DrawText(20,20, "pipopipo");

//text box is ok

$fftx_index= $qp->NewFormField("newtextfield", 1);

$qp->SetFormFieldBounds($fftx_index, 20, 40 ,30, 15);

$qp->SetFormFieldValue($fftx_index, "text1");

//checkbox is never shown using page render

$ffcb_index= $qp->NewFormField("newcheckbox", 3);

$qp->SetFormFieldPrintable($ffcb_index,1);

$qp->SetFormFieldCheckStyle($ffcb_index, 2, 1);

$qp->SetFormFieldBounds($ffcb_index, 20, 60 ,30, 15);

$qp->SetFormFieldValue($ffcb_index, "Yes");

// with or without this block does not change anything

$qp->AddStandardFont(0);

$qp->SetFormFieldStandardFont($ffcb_index,0);

$qp->SetFormFieldBorderColorGray($ffcb_index, 0.5);

$qp->SetFormFieldBorderStyle($ffcb_index,2,0,0,0);

$qp->SetFormFieldBackgroundColor($ffcb_index,1.0,0.0,0.0);

$qp->SetFormFieldAlignment($ffcb_index, 1);

$qp->SetFormFieldTextSize($ffcb_index, 24);

$qp->SetFormFieldVisible($ffcb_index, 1);

// end of with or without this block does not change anything

$retour ='';

for ($i = 1; $i <= $qp->FormFieldCount();$i++){

if (1== $qp->UpdateAppearanceStream($i)){

$retour .= ' ok';

}

print_r ($retour);

$qp->SaveToFile('./testfile.pdf');

$qp->SetRenderOptions(1, 1);

//$qp->SetRenderOptions(3, 1); //does not help, checkbox

$retour = $qp->RenderPageToFile(72, 1, 5, './rendertest.PNG');

echo '<img src="./rendertest.PNG"/>';