SVG Filters

SVG elements act as layers when they are used in sequence. The use of filters rasterizes them
They can be merged together, forming an image which is also a bitmap.

Note how close the blur is to the image; one usually adds an offset filter to create a shadow.

https://plnkr.co/edit/M7xRZFMPVN8q7ofGvnxU?p=info

https://plnkr.co/edit/N85w4WIZs4jRe7KMJ59b


sources:

http://apike.ca/prog_svg_filtering.html

https://developer.mozilla.org/en-US/docs/Web/SVG/Element/filter