User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:104.0) Gecko/20100101 Firefox/104.0

Steps to reproduce:

This HTML of a green circle with a blue drop-shadow that ends up partially off-screen:

<div style="filter: drop-shadow( -120px 0px 10px blue )">
<svg width="500" height="500">
<circle cx="130" cy="50" r="50" fill="green"/>
</svg>
</div>

(Note: SVG is not required to reproduce this issue, it was just easier to see what was going on with a circle )

Actual results:

When a drop-shadow ends up off screen, the item casting the shadow is rendered incorrectly. In the example below, the shadow is partially off the left side of the screen, and the left-most column of pixels in the item casting the shadow is stretched to the left. See screenshot comparing FF (above) to Chrome (below).

Expected results:

The green circle should render the same regardless of whether its drop shadow ends up off-screen.

The Bugbug bot thinks this bug should belong to the 'Core::SVG' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

This issue can be reproduced without SVG, here's an example with a CSS circle instead:

<div style="filter: drop-shadow( -120px 0px 10px blue )">
  <div style="position: absolute; left: 80; width: 100; height: 100; background: green; border-radius: 50%">
  </div>
</div>

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c6f1243c3ba45a4ad3cfd1cacdbf12ad377b4a81&tochange=fc2b3d6448bcc3575fffb1abc923e7e703aeef54

:gw, since you are the author of the regressor, bug 1749380, could you take a look? Also, could you set the severity field?

For more information, please visit auto_nag documentation.

Example of this in the wild at https://lysto.gg/quest/Lysto-Mini-Quest-1. The white boxes above the "COMPLETE NOW" buttons are glitches which go away on interaction but reappear every time the section is expanded. Traced it down to Bug 1749380 using mozregression and does not happen with drop-shadow disabled.