dpi
Specifies the expected number of pixels per inch on a display device
type: double, default: 96.0, minimum: 0.0
For bitmap output, dpi guarantees that text rendering will be done more
accurately, both in size and in placement.
For SVG output, dpi guarantees the dimensions in the output correspond to
the correct number of points or inches.
- Graphs
Note: bitmap output, svg only.