MWE using Gaussian blur filter

[enricofacca]

Can someone provide a Minimal Working Example where a Gaussian filter is applied to blur the edges of a shape?
Like the filter described here.

I tried using the Filter and FilterItem classes but I did not succeed.

Thank you in advance.

Enrico

[cduck]

This is a good question. Filters can be a bit tricky. Here is that example translated to drawsvg:

d = draw.Drawing(230, 120)

# Circle
d.append(draw.Circle(60, 60, 50, fill='green'))

# Blurred circle
blur = draw.Filter()
blur.append(draw.FilterItem('feGaussianBlur', in_='SourceGraphic', stdDeviation=5))
d.append(draw.Circle(170, 60, 50, fill='green', filter=blur))

d.save_svg('out.svg')
d

SVG file content (from print(d.as_svg())):

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
     width="230" height="120" viewBox="0 0 230 120">
<defs>
<filter id="d0">
<feGaussianBlur in="SourceGraphic" stdDeviation="5"></feGaussianBlur>
</filter>
</defs>
<circle cx="60" cy="60" r="50" fill="green" />
<circle cx="170" cy="60" r="50" fill="green" filter="url(#d0)" />
</svg>

Notes:

• You need to use the keyword argument in_ instead of in because in is a reserved keyword in Python. Adding an underscore to the end also works when you need to use the SVG class="" or other attriributes.
• d.raster(), d.save_mp3(), etc. will ignore any filter effects because the CairoSVG library does not support them. Only .svg file output will show the blur effect.
• When you ask questions like this in the future, it is helpful if you include a short example of the code you tried and its output.

[enricofacca]

Thank you very much for the nice and fast response.
You also answered to my second question on why the filter was not applied in the svg to png conversion.