298725 2025-09-11 09:39:40 -0700 [CG] radius of CGGaussianBlurStyle is not in the BaseCTM coordinates 2025-09-12 11:14:31 -0700 1 1 1 Unclassified WebKit Layout and Rendering WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 sabouhallawa sabouhallawa bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 2142373 0 476698 sabouhallawa 2025-09-11 09:39:40 -0700 Created attachment 476698 test case 1. Lunch ToT WebKit on a Retina display 2. Enable the internal feature "GraphicsContext Blur Filter Rendering" 3. Open the attached test case. 4. "Disable Full Page Accelerated Drawing" From Debug/Drawing Compositing Flags 5. Compare the display of the accelerated drawing versus the unaccelerated drawing Results: The unaccelerated drawing is incorrect. The blur radius is doubled for unaccelerated drawing. In /299740@main, the radius of the CGGaussianBlurStyle was scaled by the device scale factor as a work around for a CG bug on accelerated drawing. The radius should not be scaled by the device scale factor. In other words it should be in the BaseCTM coordinates. This is the behavior of the unaccelerated drawing. So the workaround should stay for the accelerated drawing only till the CG bug is fixed. 2142376 1 webkit-bug-importer 2025-09-11 09:40:15 -0700 <rdar://problem/160383014> 2142378 2 sabouhallawa 2025-09-11 09:49:57 -0700 Pull request: https://github.com/WebKit/WebKit/pull/50609 2142633 3 ews-feeder 2025-09-12 11:14:29 -0700 Committed 299903@main (763d74646247): <https://commits.webkit.org/299903@main> Reviewed commits have been landed. Closing PR #50609 and removing active labels. 476698 2025-09-11 09:39:40 -0700 2025-09-11 09:39:40 -0700 test case test-blur.html text/html 865 sabouhallawa PGh0bWw+CjxzdHlsZT4KICAgIC5ib3ggewogICAgICAgIHdpZHRoOiAxNTBweDsKICAgICAgICBo ZWlnaHQ6IDEwMHB4OwogICAgICAgIGRpc3BsYXk6IGlubGluZS1ibG9jazsKICAgICAgICBtYXJn aW46IDEwcHg7CiAgICB9Cjwvc3R5bGU+Cjxib2R5PgogICAgPGRpdiBzdHlsZT0iZmlsdGVyOiBi bHVyKDApOyI+CiAgICAgICAgPGRpdiBjbGFzcz0iYm94IiBzdHlsZT0iYmFja2dyb3VuZC1jb2xv cjogcmVkOyI+PC9kaXY+CiAgICAgICAgPGRpdiBjbGFzcz0iYm94IiBzdHlsZT0iYmFja2dyb3Vu ZC1jb2xvcjogZ3JlZW47Ij48L2Rpdj4KICAgIDwvZGl2PgogICAgPGRpdiBzdHlsZT0iZmlsdGVy OiBibHVyKDJweCk7Ij4KICAgICAgICA8ZGl2IGNsYXNzPSJib3giIHN0eWxlPSJiYWNrZ3JvdW5k LWNvbG9yOiByZWQ7Ij48L2Rpdj4KICAgICAgICA8ZGl2IGNsYXNzPSJib3giIHN0eWxlPSJiYWNr Z3JvdW5kLWNvbG9yOiBncmVlbjsiPjwvZGl2PgogICAgPC9kaXY+CiAgICA8ZGl2IHN0eWxlPSJm aWx0ZXI6IGJsdXIoM3B4KTsiPgogICAgICAgIDxkaXYgY2xhc3M9ImJveCIgc3R5bGU9ImJhY2tn cm91bmQtY29sb3I6IHJlZDsiPjwvZGl2PgogICAgICAgIDxkaXYgY2xhc3M9ImJveCIgc3R5bGU9 ImJhY2tncm91bmQtY29sb3I6IGdyZWVuOyI+PC9kaXY+CiAgICA8L2Rpdj4KICAgIDxkaXYgc3R5 bGU9ImZpbHRlcjogYmx1cigxMHB4KTsiPgogICAgICAgIDxkaXYgY2xhc3M9ImJveCIgc3R5bGU9 ImJhY2tncm91bmQtY29sb3I6IHJlZDsiPjwvZGl2PgogICAgICAgIDxkaXYgY2xhc3M9ImJveCIg c3R5bGU9ImJhY2tncm91bmQtY29sb3I6IGdyZWVuOyI+PC9kaXY+CiAgICA8L2Rpdj4KPC9ib2R5 Pgo8L2h0bWw+Cg==