A gem to draw shapes and text

Can someone point me to a good graphing library in RoR to draw shapes
and text mostly? I am aware of RMagick, but it looks like it is
heavyweight and consumes a lot of memory. Is that right? Other
packages such as scruffy and Gruff seem mostly for drawing charts.

Also, is there a neat way to render SVG graphics on a webpage using
RoR? Or is it necessary that the graphics be converted to a commonly
used format such as png/jgp/bmp, etc.?