User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/602.1 (KHTML, like Gecko) Version/8.0 Safari/602.1 elementary OS/0.4 (Loki) Epiphany/3.18.5 Steps to reproduce: On a HiDPI display on Ubuntu (i.e. the 15" 4K System76 Oryx Pro) with a scaling factor of 2 Actual results: all theme assets emulated in web pages (i.e. default text entries, dropdowns, check boxes, etc.) are using lodpi assets instead of hidpi. The Ambiance GTK theme itself properly supports HiDPI 2x scaling. Expected results: Instead, the emulated GTK widgets should be rendered using the HiDPI assets when being used on a machine with a scaling factor of 2.
Thanks for the report. With Adwaita 3.18, data:text/html,<input type="text"> renders as expected, but data:text/html,<input type="checkbox"> does not. -gtk-icon-source: -gtk-scaled(url("assets/checkbox-unchecked.png"), url("assets/checkbox -firstname.lastname@example.org")); I wonder whether perhaps the -gtk-scaled implementation is only looking at the device scale and not the transformation matrix. If so, a well placed cairo_surface_set_device_scale() in nsNativeThemeGTK::DrawWidgetBackground() should fix this. With Adwaita 3.20, a checkbox looks OK, but a check does not.
Jan is working on the Gtk/HiDPI issues right now.