The backend is the “canvas” on which a schematic is drawn. Schemdraw supports two backends: Matplotlib, and SVG.
By default, all schematics are drawn on a Matplotlib axis.
A new Matplotlib Figure and Axis will be created, with no frame or borders.
A schematic may be added to an existing Axis by using the
The Matplotlib backend renders text labels as primative lines and arcs rather than text elements by default. This has the downside that SVG editors, such as Inkscape, cannot perform textual searches on the SVGs. The upside is that there is no dependence on installed fonts on the hosts that open the SVGs.
To configure Matplotlib to render labels as SVG text elements:
import matplotlib matplotlib.rcParams['svg.fonttype'] = 'none'
Schematics can also be drawn on directly to an SVG image backend. The SVG backend can be enabled for all drawings by calling:
The backend can be changed at any time. Alternatively, the backend can be set individually on each Drawing:
with schemdraw.Drawing(backend='svg') as d: ...
Use additional Python libraries, such as pycairo, to convert the SVG output into other image formats.
The SVG backend has basic math text support, including greek symbols, subscripts, and superscripts. However, if ziamath and latex2mathml packages are installed, they will be used for full Latex math support.
The SVG backend can produce searchable-text SVGs by setting:
schemdraw.svgconfig.text = 'text'
However, text mode does not support full Latex compatibility. To switch back to rendering text as SVG paths:
schemdraw.svgconfig.text = 'path'
Some SVG renderers are not fully compatible with SVG2.0. For better compatibility with SVG1.x, use
schemdraw.svgconfig.svg2 = False
The decimal precision of SVG elements can be set using
schemdraw.svgconfig.precision = 2
Reasons to choose the SVG backend include:
No Matplotlib/Numpy dependency required (huge file size savings if bundling an executable).
Speed. The SVG backend draws 4-10x faster than Matplotlib, depending on the circuit complexity.
Reasons to use Matplotlib backend:
To customize the schematic after drawing it by using other Matplotlib functionality.
To render directly in other, non-SVG, image formats, with no additional code.