17521 2012-06-16 22:47:55 +0000 Revise of background-attachment: fixed and transforms [editorial] 2012-10-19 19:46:20 +0000 1 1 1 Unclassified CSS Transforms unspecified PC All RESOLVED FIXED P2 normal --- 1 smfr smfr ayg cmarrin dbaron dino dschulze eoconnor smfr sylvaing public-css-bugzilla oldest_to_newest 69158 0 smfr 2012-06-16 22:47:55 +0000 The spec describes a behavior for background-attachment:fixed where the transformed element behaves as if it were a "porthole" through which the fixed background shows. This is tricky, but implementable for 2D transforms, but very difficult for implementors of 3D transforms. We may wish to punt and just say that any background-attachment:fixed on an element that is transformed, or has a transformed container, behaves like background-attachment:scroll. 69161 1 ayg 2012-06-17 09:53:30 +0000 I'm okay with this if implementers agree. What do other implementers think? If it's easy for some implementers but not others, and if we agree that the proposed behavior is a punt and not really correct, I'd say we should leave the spec more "correct" for now even though we know not all implementations will be able to make it -- much like for intersections. 69293 2 dbaron 2012-06-20 17:03:53 +0000 Another option is to say that you draw the same piece of background as though there were no transforms, and then you transform it. 69294 3 1145 smfr 2012-06-20 17:05:06 +0000 Created attachment 1145 Testcase 69323 4 sylvaing 2012-06-21 14:21:28 +0000 IE10 Release Preview does what David suggests i.e.: 1. Render the fixed background as if there were no transform 2. Transform the result from #1 As a result: - Subsequent adjustments to the position of the element preserves the 'porthole'-like behavior of background-attachment:fixed i.e. as the element moves around its background continues to adjust - But any transform applied to the element applies to the rendering of the fixed background within that element. 69427 5 dbaron 2012-06-26 18:34:07 +0000 (In reply to comment #2) > Another option is to say that you draw the same piece of background as though > there were no transforms, and then you transform it. This is also what we already do (although we don't get the invalidation right when scrolling), and it's our preference as well. 69456 6 smfr 2012-06-27 17:01:07 +0000 Proposal at <http://lists.w3.org/Archives/Public/www-style/2012Jun/0635.html> 69900 7 smfr 2012-07-12 18:12:46 +0000 Consensus is to follow my proposal. One final question: for an element with a transform or transformed ancestor, what's the computed value for background-attachment, if the specified value is 'fixed'? 69901 8 smfr 2012-07-12 18:28:06 +0000 https://dvcs.w3.org/hg/csswg/rev/8039e489eeb0 Leaving bug open for the computed style issue. 69906 9 dbaron 2012-07-12 19:11:52 +0000 My inclination is that it's better for the computed value not to change (i.e., still be 'fixed' even if it won't actually be fixed). 71130 10 sylvaing 2012-07-18 22:25:42 +0000 I would also background-attachment's computed value to remain 'fixed' in thie case; the property's computed value is 'as specified' and I'd rather leave it that way. We're only changing the used value. 76698 11 dschulze 2012-10-19 15:08:25 +0000 *** Bug 19636 has been marked as a duplicate of this bug. *** 76711 12 smfr 2012-10-19 17:13:45 +0000 We resolved that the computed values are not affected. 76714 13 dschulze 2012-10-19 17:20:08 +0000 Do we need to state this on the spec? 76715 14 dschulze 2012-10-19 17:26:53 +0000 What about this sentence at the end of the paragraph, right before the issue text: "The computed style of 'background-attached' is not affected." If it is ok, I go ahead and do the change. 76716 15 smfr 2012-10-19 17:42:59 +0000 The same issue applies to transform-style when combined with opacity. I think it's fine to say that the computed value of the property is not affected. 76744 16 dschulze 2012-10-19 19:46:20 +0000 Fixed after 177d757a1f34. 1145 2012-06-20 17:05:06 +0000 2012-06-20 17:05:06 +0000 Testcase background-fixed-transformed.html text/html 1766 smfr PCFET0NUWVBFIGh0bWw+Cgo8aHRtbD4KPGhlYWQ+CiAgPHN0eWxlPgogICAgYm9keSB7CiAgICAg IGhlaWdodDogMjAwMHB4OwogICAgfQogICAgCiAgICAuZXhhbXBsZSB7CiAgICAgIGRpc3BsYXk6 IGlubGluZS1ibG9jazsKICAgICAgaGVpZ2h0OiA0MDBweDsKICAgICAgd2lkdGg6IDQwMHB4Owog ICAgICBtYXJnaW46IDEwcHg7CiAgICAgIGJvcmRlcjogMXB4IHNvbGlkIGJsYWNrOwogICAgfQog ICAgLmJveCB7CiAgICAgIHdpZHRoOiAzMDBweDsKICAgICAgaGVpZ2h0OiAzMDBweDsKICAgICAg bWFyZ2luOiAxMHB4OwogICAgICBiYWNrZ3JvdW5kLWNvbG9yOiBzaWx2ZXI7CiAgICAgIGJhY2tn cm91bmQtaW1hZ2U6IHVybChodHRwOi8vd3d3LmxpYi51dGV4YXMuZWR1L21hcHMvbmF0aW9uYWxf cGFya3Mvb2x5bXBpY19tYXAuanBnKTsKICAgICAgYmFja2dyb3VuZC1yZXBlYXQ6IHJlcGVhdDsK ICAgICAgYmFja2dyb3VuZC1hdHRhY2htZW50OiBmaXhlZDsKICAgIH0KICAgIAogICAgLnRyYW5z Zm9ybWVkIHsKICAgICAgLXdlYmtpdC10cmFuc2Zvcm06IHRyYW5zbGF0ZVgoMTBweCk7CiAgICAg IC1tb3otdHJhbnNmb3JtOiB0cmFuc2xhdGVYKDEwcHgpOwogICAgICAtbXMtdHJhbnNmb3JtOiB0 cmFuc2xhdGVYKDEwcHgpOwogICAgICAtby10cmFuc2Zvcm06IHRyYW5zbGF0ZVgoMTBweCk7CiAg ICAgIHRyYW5zZm9ybTogdHJhbnNsYXRlWCgxMHB4KTsKICAgIH0KICAgIAogICAgLnJvdGF0ZWQg ewogICAgICAtd2Via2l0LXRyYW5zZm9ybTogcm90YXRlKDQ1ZGVnKTsKICAgICAgLW1vei10cmFu c2Zvcm06IHJvdGF0ZSg0NWRlZyk7CiAgICAgIC1tcy10cmFuc2Zvcm06IHJvdGF0ZSg0NWRlZyk7 CiAgICAgIC1vLXRyYW5zZm9ybTogcm90YXRlKDQ1ZGVnKTsKICAgICAgdHJhbnNmb3JtOiByb3Rh dGUoNDVkZWcpOwogICAgfQogICAgCiAgICAucGVyc3BlY3RpdmUgewogICAgICAtd2Via2l0LXBl cnNwZWN0aXZlOiA1MDBweDsKICAgICAgLW1vei1wZXJzcGVjdGl2ZTogNTAwcHg7CiAgICAgIC1t cy1wZXJzcGVjdGl2ZTogNTAwcHg7CiAgICAgIC1vLXBlcnNwZWN0aXZlOiA1MDBweDsKICAgICAg cGVyc3BlY3RpdmU6IDUwMHB4OwogICAgfQogICAgCiAgICAueHJvdGF0ZWQgewogICAgICAtd2Vi a2l0LXRyYW5zZm9ybTogcm90YXRlWSg0NWRlZyk7CiAgICAgIC1tb3otdHJhbnNmb3JtOiByb3Rh dGVZKDQ1ZGVnKTsKICAgICAgLW1zLXRyYW5zZm9ybTogcm90YXRlWSg0NWRlZyk7CiAgICAgIC1v LXRyYW5zZm9ybTogcm90YXRlWSg0NWRlZyk7CiAgICAgIHRyYW5zZm9ybTogcm90YXRlWSg0NWRl Zyk7CiAgICB9CiAgPC9zdHlsZT4KPC9oZWFkPgo8Ym9keT4KCjxkaXYgY2xhc3M9ImV4YW1wbGUi PgogIDxoMj5Ob3JtYWw8L2gyPgogIDxkaXYgY2xhc3M9ImJveCI+PC9kaXY+CjwvZGl2PgoKPGRp diBjbGFzcz0iZXhhbXBsZSI+CiAgPGgyPlRyYW5zZm9ybWVkOiB0cmFuc2xhdGU8L2gyPgogIDxk aXYgY2xhc3M9InRyYW5zZm9ybWVkIGJveCI+PC9kaXY+CjwvZGl2PgoKPGRpdiBjbGFzcz0iZXhh bXBsZSI+CiAgPGgyPlRyYW5zZm9ybWVkOiByb3RhdGU8L2gyPgogIDxkaXYgY2xhc3M9InJvdGF0 ZWQgYm94Ij48L2Rpdj4KPC9kaXY+Cgo8ZGl2IGNsYXNzPSJleGFtcGxlIj4KICA8aDI+VHJhbnNm b3JtZWQ6IDNkPC9oMj4KICA8ZGl2IGNsYXNzPSJwZXJzcGVjdGl2ZSI+CiAgICA8ZGl2IGNsYXNz PSJ4cm90YXRlZCBib3giPjwvZGl2PgogIDwvZGl2Pgo8L2Rpdj4KCjwvYm9keT4KPC9odG1sPgo=