Comment 5 for bug 1353550

Mirco Müller (macslow) wrote :

The observed rendering-glitches are due to bugs in Qt's SVG-renderer. There are many bugs filed upstream against Qt's SVG-render-engine. Too many to list here. A further note that has to be made, is that Qt only supports "SVG 1.2 Tiny" and the two icons in question...

/usr/share/icons/ubuntu-mobile/apps/scalable/calendar.svg
/usr/share/icons/ubuntu-mobile/apps/scalable/contacts-app.svg

... are "SVG 1.1. Full". One major problem this exposes is the clipPath-feature used in these two icons not being supported by the "SVG 1.2 Tiny" standard, thus not handled by Qt/QML... hence the rendering glitches.

Despite the shortcomings of Qt's SVG-render-engine, we should not be using SVGs with embedded bitmap-data being several hundered kilobytes (up to a few megabytes in some cases) in size as icons. That is hurting rendering performance. The same file saved as PNG in the native resolution is in general about four times smaller in size.

calendar.svg -> calendar.png: 727289 KBytes -> 197988 KBytes
contacts-app.svg -> contacts-app.png: 855552 KBytes -> 263874 KBytes

I marked this as "Won't fix".

What we need to do is convert all SVGs of our typical icon-themes ("suru", "ubuntu-mobile") to PNGs.