Command-line tool which takes a 4-channel RGBA image and generates a signed distance field. The bitmask is determined by pixels with alpha over 128 and any RGB channel over 128.
# install the tool
npm install image-sdf -g
# apply the effect on an image
# and pipe it to a new file
image-sdf atlas.png --spread 32 --downscale 2 > atlas-sdf.pngThe code has been adpated from libgdx.
PRs welcome. This could be split into more modules (generating a bit mask, computing SDF, better image support, etc).
image-sdf input.png [opt]
Options:
-o, --output output file
-s, --spread distance spread amount, default 1
-d, --downscale amount to downscale the output, default 1
-a, --alphaonly Alpha only, if 1 then only look at alpha not RGB. default 0
-x, --gridwidth Grid cell width in px. If present, SDFs will be generated within grid cells. default -1
-y, --gridheight Grid cell height in px. If present, SDFs will be generated within grid cells. default -1
-c, --color output color, accepts css strings. If it is "S" then it will use the same color replacing alpha, default #fff
-h Show help
Examples:
image-sdf input.png -c "rgb(128,255,20)" -s 10 -o output.png
image-sdf input.png --spread 2 --downscale 2 > output.png
image-sdf input.png --color black -o build/output.png
image-sdf input.png --color S -o build/output.png -x 16 -y 16 -a 1
The programmatic API may evolve into their own modules, i.e. for custom bitmasks.
MIT, see LICENSE.md for details.