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fix: encode native signature stamps as WinAnsi #8236

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fix: encode native signature stamps as WinAnsi #8236

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28 changes: 18 additions & 10 deletions lib/Service/SignatureStampPreview/SignatureStampAppearanceBuilder.php
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Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ public function buildXObject(
$nameY = $nameStartY;
$estimatedCharWidth = $nameFontSize * 0.52;
foreach ($nameLines as $nameLine) {
$lineWidth = strlen($nameLine) * $estimatedCharWidth;
$lineWidth = mb_strlen($nameLine) * $estimatedCharWidth;
$nameX = max($leftPadding, ($leftHalfW - $lineWidth) / 2.0);
$escaped = $this->escapePdfText($nameLine);
$stream .= "BT\n";
Expand Down Expand Up @@ -105,6 +105,7 @@ public function buildXObject(
'Type' => '/Font',
'Subtype' => '/Type1',
'BaseFont' => '/Helvetica',
'Encoding' => '/WinAnsiEncoding',
],
],
],
Expand All @@ -122,7 +123,7 @@ public function wrapTextForPdf(string $line, float $availableWidth, float $fontS

$estimatedCharWidth = max(1.0, $fontSize * 0.52);
$maxChars = max(1, (int)floor($availableWidth / $estimatedCharWidth));
if (strlen($trimmed) <= $maxChars) {
if (mb_strlen($trimmed) <= $maxChars) {
return [$trimmed];
}

Expand All @@ -134,7 +135,7 @@ public function wrapTextForPdf(string $line, float $availableWidth, float $fontS
}

$candidate = $current === '' ? $word : $current . ' ' . $word;
if (strlen($candidate) <= $maxChars) {
if (mb_strlen($candidate) <= $maxChars) {
$current = $candidate;
continue;
}
Expand All @@ -144,9 +145,9 @@ public function wrapTextForPdf(string $line, float $availableWidth, float $fontS
$current = '';
}

while (strlen($word) > $maxChars) {
$result[] = substr($word, 0, $maxChars);
$word = substr($word, $maxChars);
while (mb_strlen($word) > $maxChars) {
$result[] = mb_substr($word, 0, $maxChars);
$word = mb_substr($word, $maxChars);
}

$current = $word;
Expand All @@ -160,10 +161,17 @@ public function wrapTextForPdf(string $line, float $availableWidth, float $fontS
}

public function escapePdfText(string $value): string {
$value = str_replace('\\', '\\\\', $value);
$value = str_replace('(', '\\(', $value);
$value = str_replace(')', '\\)', $value);
$encoded = mb_convert_encoding($value, 'Windows-1252', 'UTF-8');
if (mb_convert_encoding($encoded, 'UTF-8', 'Windows-1252') !== $value) {
throw new \InvalidArgumentException(
'signature stamp contains characters that cannot be represented by WinAnsiEncoding',
);
}

$encoded = str_replace('\\', '\\\\', $encoded);
$encoded = str_replace('(', '\\(', $encoded);
$encoded = str_replace(')', '\\)', $encoded);

return $value;
return $encoded;
}
}
54 changes: 54 additions & 0 deletions tests/php/Unit/Service/SignatureStampPreview/SignatureStampAppearanceBuilderTest.php
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Original file line number Diff line number Diff line change
@@ -0,0 +1,54 @@
<?php

declare(strict_types=1);
/**
* SPDX-FileCopyrightText: 2026 LibreCode coop and contributors
* SPDX-License-Identifier: AGPL-3.0-or-later
*/

namespace OCA\Libresign\Tests\Unit\Service\SignatureStampPreview;

use OCA\Libresign\Service\SignatureStampPreview\SignatureStampAppearanceBuilder;
use OCA\Libresign\Service\SignatureTextService;
use OCA\Libresign\Service\SignerElementsService;

final class SignatureStampAppearanceBuilderTest extends \OCA\Libresign\Tests\Unit\TestCase {
public function testBuildXObjectEncodesTextAsWinAnsi(): void {
$signatureTextService = $this->createMock(SignatureTextService::class);
$signatureTextService->method('parse')->willReturn([
'parsed' => 'Signé par Renée',
'templateFontSize' => 10.0,
]);
$builder = new SignatureStampAppearanceBuilder($signatureTextService);

$xObject = $builder->buildXObject(
100,
50,
SignerElementsService::RENDER_MODE_DESCRIPTION_ONLY,
);

$this->assertSame('/WinAnsiEncoding', $xObject->resources['Font']['F1']['Encoding']);
$this->assertStringContainsString("(Sign\xE9 par Ren\xE9e) Tj", $xObject->stream);
$this->assertStringNotContainsString('Signé par Renée', $xObject->stream);
}

public function testWrapTextForPdfDoesNotSplitMultibyteCharacters(): void {
$signatureTextService = $this->createMock(SignatureTextService::class);
$builder = new SignatureStampAppearanceBuilder($signatureTextService);

$this->assertSame(
['éé', 'éé'],
$builder->wrapTextForPdf('éééé', 15.0, 10.0),
);
}

public function testEscapePdfTextRejectsCharactersOutsideWinAnsi(): void {
$signatureTextService = $this->createMock(SignatureTextService::class);
$builder = new SignatureStampAppearanceBuilder($signatureTextService);

$this->expectException(\InvalidArgumentException::class);
$this->expectExceptionMessage('signature stamp contains characters that cannot be represented by WinAnsiEncoding');

$builder->escapePdfText('Signed by 😀');
}
}