198291 2019-05-28 03:49:29 -0700 Zoom affects maximum element size 2023-04-21 05:22:36 -0700 1 1 1 Unclassified WebKit Layout and Rendering WebKit Nightly Build Unspecified Unspecified NEW InRadar P2 Normal --- 1 andyearnshaw webkit-unassigned ahmad.saleem792 bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 1539525 0 370724 andyearnshaw 2019-05-28 03:49:29 -0700 Created attachment 370724 Repro case (ResizeObserver support required to view) Steps to reproduce the problem: 1. Create a div at height 33554428px 2. Zoom in 3. Observe the change in div height As the zoom level increases, the height of the div decreases. This behaviour is not observed in Firefox or EdgeHTML. The impact it has is on virtual scrolling solutions where the total scrollable area is greater than the maximum permitted element height. In this situation, we apply a multiplier to the scroll position to get the virtual scroll position. Chrome and Safari's behaviour means that we need to observe resizes of an element at maximum height/width so we can adjust our scaling accordingly (see 195158 for more info on that). 1539674 1 simon.fraser 2019-05-28 11:42:35 -0700 By "zoom" do you mean pinch-zoom or Command-+? 1539911 2 andyearnshaw 2019-05-29 00:39:36 -0700 Command-+ on macOS Safari, sorry I should have been more clear on this. I'm not sure about pinch-zoom on iPad/iPhone as I am unable to test it currently. 1880202 3 webkit-bug-importer 2022-07-01 15:30:36 -0700 <rdar://problem/96317811> 1950320 4 ahmad.saleem792 2023-04-21 05:22:36 -0700 Chrome Canary 114 and Safari Technology Preview 168 matches each other and changes DIV height while Firefox Nightly 114 does not. Just wanted to share updated testing result. Thanks! 370724 2019-05-28 03:49:29 -0700 2019-05-28 03:49:29 -0700 Repro case (ResizeObserver support required to view) zoom-element-resize.html text/html 1068 andyearnshaw PCFET0NUWVBFIGh0bWw+CjxodG1sPgo8Ym9keT4KICAgIDxkaXYgaWQ9InRlc3QiPjwvZGl2Pgog ICAgPHNjcmlwdD4KICAgICAgY29uc3QgTUFYX0VMRU1FTlRfU0laRSA9ICgoKSA9PiB7CiAgICAg ICAgY29uc3QgZGl2ID0gZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgnZGl2Jyk7CiAgICAgICAgbGV0 IG1pbiA9IDA7CiAgICAgICAgbGV0IG1heCA9IDEwMDAwMDAwMDsKCiAgICAgICAgZGl2LnN0eWxl LnBvc2l0aW9uID0gJ2Fic29sdXRlJzsKICAgICAgICBkaXYuc3R5bGUud2lkdGggPSAnMXB4JzsK ICAgICAgICBkb2N1bWVudC5ib2R5LmFwcGVuZENoaWxkKGRpdik7CgogICAgICAgIHdoaWxlICht aW4gPCBtYXgpIHsKICAgICAgICAgIGNvbnN0IG1pZGRsZSA9IE1hdGguZmxvb3IoKG1pbiArIG1h eCkgLyAyKTsKICAgICAgICAgIGRpdi5zdHlsZS5oZWlnaHQgPSBgJHttaWRkbGV9cHhgOwoKICAg ICAgICAgIGlmIChkaXYub2Zmc2V0SGVpZ2h0ICE9PSAwICYmIGRpdi5vZmZzZXRIZWlnaHQgPCBt aWRkbGUpIHsKICAgICAgICAgICAgbWluID0gZGl2Lm9mZnNldEhlaWdodDsKICAgICAgICAgICAg YnJlYWs7CiAgICAgICAgICB9CiAgICAgICAgICBpZiAoZGl2Lm9mZnNldEhlaWdodCA9PT0gMCkg ewogICAgICAgICAgICBtYXggPSBtaWRkbGUgLSAxOwogICAgICAgICAgfSBlbHNlIHsKICAgICAg ICAgICAgbWluID0gbWlkZGxlOwogICAgICAgICAgfQogICAgICAgIH0KCiAgICAgICAgZG9jdW1l bnQuYm9keS5yZW1vdmVDaGlsZChkaXYpOwogICAgICAgIHJldHVybiBtaW47CiAgICAgIH0pKCk7 CgogICAgICBmdW5jdGlvbiB1cGRhdGUoKSB7CiAgICAgICAgdGVzdC50ZXh0Q29udGVudCA9IGBU aGlzIGRpdiBpcyAke3Rlc3Qub2Zmc2V0SGVpZ2h0fXB4IGluIGhlaWdodGA7CiAgICAgIH0KICAg ICAgY29uc3QgcmVzaXplID0gbmV3IFJlc2l6ZU9ic2VydmVyKHVwZGF0ZSk7CiAgICAgIHJlc2l6 ZS5vYnNlcnZlKHRlc3QpOwoKICAgICAgdGVzdC5zdHlsZS5oZWlnaHQgPSBgJHtNQVhfRUxFTUVO VF9TSVpFfXB4YDsKICAgIDwvc2NyaXB0Pgo8L2JvZHk+CjwvaHRtbD4K