One of the intended uses of Wisej is to migrate LOB applications, that were originally developed under VB6, Windows Forms, other desktop platforms, or even Visual WebGUI. Those environments use raster image icons, namely PNG.
Up to now I’ve used PNG icons on my Wisej test applications.
The first version of our themes were all done using png icons. We then enhanced qooxdoo to support SVG icons and dynamic colors on the xml definition.
the problem with png icons is that you need several versions of each and they don’t scale well on hi def displays. When using SVG icons their main color can be changed depending on the state instead of changing the actual icon.
All images are preloaded and cached. SVG icons are cached as XML elements and the their fill color is updated when setting the icon. The fill color can be the color of the widget or set in the theme.
I forgot to add that Wisej themes also support border images and slicing: