svg-helpers 0.4.0

No project description provided

SVG helpers

Tools to help make SVG graphics with python.

pip install svg-helpers

import svg_helpers

width = 150
height = width * 2 / 3
r = height * 3 / 10

# this will make a japanese flag:
svg = svg_helpers.make_svg(width=width, height=height)
svg.add_element("rect", width=width, height=height, fill="white", stroke="#eee")
svg.add_element("circle", cx=width/2, cy=height/2, r=r, fill="#bc002d")
print(svg)

Though with something as simple as this, consider just using f-string formatting. It can sometimes be difficult to get the quotes right, though.

print(f"""
<svg xmlns="http://www.w3.org/2000/svg" width="{width}" height="{height}">
  <rect width="{width}" height="{height}" fill="white" stroke="#eee" />
  <circle cx="{width/2}" cy="{height/2}" r="{r}" fill="#bc002d" />
</svg>
""")

Names always match the SVG names. For example, svg rect elements have an x and y property, so use x and y to make a rect. Underscores in attribute names become dashes (stroke_width=1 → stroke-width="1"), and a trailing underscore is stripped so you can escape Python keywords (class_="hi" → class="hi").

Adding raw markup

Adding elements from strings can be helpful for text, especially when it has <tspan> elements in it:

from svg_helpers import make_svg

size = 400
noun = "banana"

svg = make_svg(width=size, height=size)
svg.add_from_string("""
<style>
  .small {
    font: italic 12px serif;
  }
  .small > tspan {
    font: bold 10px sans-serif;
    fill: red;
  }
</style>
""")
svg.add_element("rect", width=size, height=size, fill="white", stroke="#eee")
svg.add_from_string(
    f'<text x="{size/2}" y="{size/2}" class="small">'
    f'You are <tspan>not</tspan> a {noun}!'
    '</text>'
)
print(svg)

Shapes from shapely

If you have shapely installed, you can pass any geometry directly to add_shape and it'll be drawn as a <path> (or a group of paths for compound shapes):

import shapely
from svg_helpers import make_svg

svg = make_svg(width=200, height=200)
svg.add_element("rect", width=200, height=200, fill="white")

# any shapely geometry: Point, LineString, Polygon, MultiPolygon, ...
circle = shapely.Point(100, 100).buffer(50)
svg.add_shape(circle, fill="none", stroke="black", stroke_width=2)

print(svg)

For shapes with many points, pass precision=N to round coordinates and strip trailing zeros:

svg.add_shape(big_polygon, precision=2, fill="red")

Multi-line text

add_text is a convenience for laying out multi-line text using <tspan> children, with vertical_align of "top", "middle", or "bottom":

svg.add_text(
    "first line\nsecond line\nthird line",
    x=100, y=100,
    vertical_align="middle",
    font_family="sans-serif",
)

Alternatives

This is really just a few small functions. If you want something more comprehensive:

• svg.py
• drawsvg
• svg_ultralight
• svgwrite
• vsketch

Goals

• friendly syntax that's easy to read and remember. Trying to be as close as is practical to simply writing SVG directly.
• no baggage. no dependencies. can import just about anywhere, and other projects can import without importing fifteen billion other packages.
• low maintenance.

Anti-goals

• comprehensive: it's ok if there are things missing.
• opinionated: it should not coerce using in a particular way.

License

MIT.