Created attachment 242844 [details] Test case Open the following SVG in WebKit: <svg xmlns="http://www.w3.org/2000/svg"> <filter id="f1" x="0" y="0" width="100" height="100" filterUnits="userSpaceOnUse"> <!-- Create a green square at x=0. --> <feFlood result="red" x="100" y="0" flood-color="red"/> <feFlood result="green" flood-color="green"/> <!-- Attempt to offset the red square left to cover up the green square. However, this filter's filter region should clip away the red square, and only transparent pixels should be offset left, leaving the green square intact. --> <feOffset result="red" in="SourceGraphic" dx="-100" x="0" y="0" width="200" height="100"/> <feMerge> <feMergeNode in="green"/> <feMergeNode in="red"/> </feMerge> </filter> <rect x="0" y="0" width="100" height="100" filter="url(#f1)"/> </svg> Result: Nothing is drawn. Expected: A 100 x 100 green rectangle. A black rectangle is drawn at (0,0). The filter f1 has a red rectangle drawn at (100,0). This rectangle should be completely clipped since it outside the rectangle area of the target element. When offsetting this rectangle with dx=-1, this should not have any effect because it clipped when it was first drawn. Merging this empty rectangle with a green rectangle should result in a green rectangle at (0,0) NOTE: FireFox and Chrome both render this SVG as expected. NOTE: This test is an imported test from Mozilla SVG test suite but is modified a little to narrow down the problem.
<rdar://problem/19180719>
IIRC there is a dupe for this one already.
These tests are flaky (sometimes pass) on GTK, passing more often now that we've enabled threaded compositor. Updating expectations accordingly.
I am able to reproduce this bug in Safari Technology Preview 155 as well, where nothing is draw while both Chrome Canary 108 and Firefox Nightly 107 have "green" square. Thanks!
(In reply to Ahmad Saleem from comment #4) > I am able to reproduce this bug in Safari Technology Preview 155 as well, > where nothing is draw while both Chrome Canary 108 and Firefox Nightly 107 > have "green" square. Thanks! With LBSE turned on using WebKit ToT (minibrowser), it does show 'black' rectangle compared to 'green' of other browsers. So LBSE slightly progresses this.