fitmethod-auto-manual.php

<?php
function determineFittingFontScale(
    $pdfLib,
    int $textFlow,
    array $fitTextFlowOptions,
    array $maxDims
): float {
    $fontScale = 1.0;

    while ($fontScale >= 0.3) {
        $pdfLib->fit_textflow(
            $textFlow,
            0, 0,
            $maxDims['width'], $maxDims['height'],
            implode(' ', array_merge(
                $fitTextFlowOptions,
                [
                    "fontscale=$fontScale",
                    'blind',
                    'rewind=1',
                ]
            ))
        );

        $textWidth =  $pdfLib->info_textflow($textFlow, 'textwidth');
        $textHeight =  $pdfLib->info_textflow($textFlow, 'textheight');

        if ($maxDims['width'] >= $textWidth && $maxDims['height'] >= $textHeight)
            return $fontScale;

        $fontScale *= 0.99;
    }

    return max(0.3, $fontScale);
}

$p = new PDFlib();
$p->set_option("stringformat=utf8");
$p->begin_document("", "");

/* Create an A4 Landscape page */
$p->begin_page_ext(0, 0, "width=a4.height height=a4.width");

$createTextFlowOptList = [
    'hyphenchar=none',
    'fontname=Helvetica',
    'encoding=unicode',
    'fontsize=32',
    'leftindent=0',
    'adjustmethod=nofit',
    'charclass={letter .}',
];

$fitTextFlowOpts = ['fitmethod=auto', 'showborder'];

$boxDims = ['width' => 200, 'height' => 100];
$boxPos = ['llx' => 10, 'lly' => 200];

$lines = [
    'bar@example.com',
    'second line',
    'third line',
    'fourth line',
];

$textFlow = $p->create_textflow(implode(PHP_EOL, $lines), implode(' ', $createTextFlowOptList));

$fontScale = determineFittingFontScale($p, $textFlow, $fitTextFlowOpts, $boxDims);

$res = $p->fit_textflow(
    $textFlow,
    $boxPos['llx'], $boxPos['lly'],
    $boxPos['llx'] + $boxDims['width'],
    $boxPos['lly'] + $boxDims['height'],
    implode(' ', array_merge($fitTextFlowOpts, ["fontscale=$fontScale", 'rewind=1']))
);

$p->end_page_ext("");

$p->end_document("");

$buf = $p->get_buffer();
$len = strlen($buf);

header("Content-type: application/pdf");
header("Content-Length: $len");
header("Content-Disposition: inline; filename=fitmethod-auto.pdf");
print $buf;