Division by zero in arcToSegments function

[ljadrbln]

Hello,

I have «Division by zero» error with next svg file:

[C:/App/vendor/phenx/php-svg-lib/src/Svg/Tag/Path.php:504] Base->{closure}()
[C:/App/vendor/phenx/php-svg-lib/src/Svg/Tag/Path.php:457] Svg\Tag\Path->arcToSegments()
[C:/App/vendor/phenx/php-svg-lib/src/Svg/Tag/Path.php:395] Svg\Tag\Path->drawArc()
[C:/App/vendor/phenx/php-svg-lib/src/Svg/Tag/AbstractTag.php:64] Svg\Tag\Path->start()
[C:/App/vendor/phenx/php-svg-lib/src/Svg/Document.php:357] Svg\Tag\AbstractTag->handle()
[C:/App/vendor/phenx/php-svg-lib/src/Svg/Document.php:225] xml_parse()
[C:/App/vendor/dompdf/dompdf/lib/Cpdf.php:5910] Svg\Document->render()
[C:/App/vendor/dompdf/dompdf/src/Adapter/CPDF.php:675] Dompdf\Cpdf->addSvgFromFile()
[C:/App/vendor/dompdf/dompdf/src/Renderer/Image.php:65] Dompdf\Adapter\CPDF->image()
[C:/App/vendor/dompdf/dompdf/src/Renderer.php:289] Dompdf\Renderer\Image->render()
[C:/App/vendor/dompdf/dompdf/src/Renderer.php:128] Dompdf\Renderer->_render_frame()
[C:/App/vendor/dompdf/dompdf/src/Renderer.php:195] Dompdf\Renderer->render()
[C:/App/vendor/dompdf/dompdf/src/Renderer.php:195] Dompdf\Renderer->render()
[C:/App/vendor/dompdf/dompdf/src/Renderer.php:195] Dompdf\Renderer->render()
[C:/App/vendor/dompdf/dompdf/src/FrameReflower/Page.php:149] Dompdf\Renderer->render()
[C:/App/vendor/dompdf/dompdf/src/Dompdf.php:765] Dompdf\FrameDecorator\AbstractFrameDecorator->reflow()

The rough workaround is to modify arcToSegments function in the Svg\Surface\SurfaceInterface\Path:

$ry = $ry ? $ry : 0.1;
$py = $py ? $py : 0.1;
$rx = $rx ? $rx : 0.1;
$px = $px ? $px : 0.1;

But maybe more elegant solution exists?

[christopheleblanc]

Hello,

We faced the same bug. The solution proposed by ljadrbln fixes the bug.

DomPDF is an excellent library and we hope that the definitive fix will be released soon :) .

[gvollant]

Thank you for found a solution.

We can wait somes week for a perfect rendering, but an exception "Division by zero" create global problem in a application

So, I think i'll be great and save headache if you create quickly an hotfix release

Thank you for your great work

[bsweeney]

The issue appears to be caused by a path command defining an arc where one or both of the radii are zero. You can reproduce the error with the following simple example:

<svg id="svg" xmlns="http://www.w3.org/2000/svg" width="200" height="200">
  <path d="M 25 25 a 5 0 5 0 0 50 50" stroke="orange" stroke-width="5" fill="none"/>
</svg>

Without a radius the arc is actually just a line. That makes for a simple solution to the issue, render a line instead of an arc.

---

Note that I would definitely not recommend using the suggested workaround. Changing a radius from 0 to .1 can have a significant impact on the rendering, as you can see when the radius in the above sample is changed.

<svg id="svg" xmlns="http://www.w3.org/2000/svg" width="200" height="200">
  <path d="M 25 25 a 5 .1 5 0 0 50 50" stroke="orange" stroke-width="5" fill="none"/>
</svg>