118495 2013-07-09 01:10:12 -0700 Page zoom/scale causes javascript auto scroll not work 2013-07-09 01:12:12 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) All All UNCONFIRMED P2 Major --- 0 chenzx webkit-unassigned oldest_to_newest 907026 0 chenzx 2013-07-09 01:10:12 -0700 When set page zoom/scale factor to a value < 1, then the JS code `element.content.scrollTop++` will be affected by this And the page auto scroll will not work. This problem exists in both newest Chrome 27 and Firefox 22. Reason for this: (1)In fact, zoom/scale operator should NOT apply to the point/position type, but only to the length type; (2)Or maybe we can change the internal DOM layput impl's type from int to double? (3)I had to say, the testcase expects a "continuous" style changing behavor, while discretized int-type values should always give a gap; void Element::setScrollTop(int newTop) { document()->updateLayoutIgnorePendingStylesheets(); if (RenderBox* rend = renderBox()) rend->setScrollTop(static_cast<int>(newTop * rend->style()->effectiveZoom())); //<--- } 907028 1 206298 chenzx 2013-07-09 01:12:12 -0700 Created attachment 206298 Testcase for this bug report Load this page, and change the page zoom to <1 value, then the auto scroll will stop working 206298 2013-07-09 01:12:12 -0700 2013-07-09 01:12:12 -0700 Testcase for this bug report index.html text/html 1135 chenzx PGh0bWw+DQo8aGVhZD4NCjx0aXRsZT5zY3JvbGwgdGVzdDwvdGl0bGU+DQo8L2hlYWQ+DQo8Ym9k eT4KPGRpdj4KPHVsIGlkPSJkZW1vIiBzdHlsZT0ib3ZlcmZsb3c6aGlkZGVuOyBoZWlnaHQ6OTZw eDsiPgogPGxpID4xMTExMTExMTExMTExMTExMTE8L2xpPgogPGxpID4yMjIyMjIyMjIyMjIyMjIy MjI8L2xpPgogPGxpID4zMzMzMzMzMzMzMzMzMzMzMzM8L2xpPgogPGxpID40NDQ0NDQ0NDQ0NDQ0 NDQ0NDQ8L2xpPgogPGxpID41NTU1NTU1NTU1NTU1NTU1NTU8L2xpPgogPGxpID42NjY2NjY2NjY2 NjY2NjY2NjY8L2xpPgogPGxpID43Nzc3Nzc3Nzc3Nzc3Nzc3Nzc8L2xpPgogPGxpID44ODg4ODg4 ODg4ODg4ODg4ODg8L2xpPgogPGxpID45OTk5OTk5OTk5OTk5OTk5OTk8L2xpPgo8L3VsPgo8L2Rp dj4KCjxzY3JpcHQgdHlwZT0idGV4dC9qYXZhc2NyaXB0Ij4KZnVuY3Rpb24gTWFycXVlZShjb250 ZW50LCBzcGVlZCl7CiAgICAKICAgIHRoaXMuc3BlZWQgPSBzcGVlZCB8fCA4MDsgLy9kZWZhdWx0 IHZhbHVlCiAgICB0aGlzLmNvbnRlbnQgPSBjb250ZW50OwogICAgdGhpcy5jb250ZW50LmlubmVy SFRNTCArPSB0aGlzLmNvbnRlbnQuaW5uZXJIVE1MOwogICAgdGhpcy5jb250ZW50LnNjcm9sbFRv cCA9IDE7CiAgICB0aGlzLnRocmVhZFNjcm9sbCA9IG51bGw7Cn0KTWFycXVlZS5wcm90b3R5cGU9 IHsKICAgIHN0YXJ0OiBmdW5jdGlvbigpewogICAgICAgICBpZihwYXJzZUludCh0aGlzLmNvbnRl bnQuc2Nyb2xsVG9wKSA+PSAocGFyc2VJbnQodGhpcy5jb250ZW50LnNjcm9sbEhlaWdodCkgLyAy KSApCiAgICAgICAgIHsKICAgICAgICAgICAgdGhpcy5jb250ZW50LnNjcm9sbFRvcCA9IDA7CiAg ICAgICAgIH0KICAgICAgICB0aGlzLmNvbnRlbnQuc2Nyb2xsVG9wICsrOwogICAgfSwKICAgIGF1 dG9TY3JvbGw6IGZ1bmN0aW9uKCl7CiAgICAgICAgdmFyIHNlbGYgPSB0aGlzOwogICAgICAgIHRo aXMudGhyZWFkU2Nyb2xsID0gc2V0SW50ZXJ2YWwoZnVuY3Rpb24oKXtzZWxmLnN0YXJ0KCl9LCB0 aGlzLnNwZWVkKTsKICAgIH0KfQpuZXcgTWFycXVlZShkb2N1bWVudC5nZXRFbGVtZW50QnlJZCgi ZGVtbyIpKS5hdXRvU2Nyb2xsKCk7DQo8L3NjcmlwdD4NCjwvYm9keT4NCjwvaHRtbD4NCg==