piwodlaiwo/triangle

Triangle is a tool to create image arts using the delaunay triangulation technique. It takes an image as input and it converts to abstract image composed of tiles of triangles.

The technique

First the image is blured out to smothen the sharp pixel edges. The more blured an image is the more diffused the generated output will be.
Second the resulted image is converted to grayscale mode.
Then a sobel filter operator is applied on the grayscaled image to obtain the image edges. An optional threshold value is applied to filter out the representative pixels of the resulting image.
Lastly we apply the delaunay algorithm on the pixels obtained from the previous step.

blur = tri.Stackblur(img, uint32(width), uint32(height), uint32(*blurRadius))
gray = tri.Grayscale(blur)
sobel = tri.SobelFilter(gray, float64(*sobelThreshold))
points = tri.GetEdgePoints(sobel, *pointsThreshold, *maxPoints)

triangles = delaunay.Init(width, height).Insert(points).GetTriangles()

Installation and usage

$ go get github.com/esimov/triangle/cmd/triangle
$ go install

MacOS (Brew) install

The library can be installed via Homebrew too or by downloading the binary file from the releases folder.

$ brew tap esimov/triangle
$ brew install triangle

Supported commands

$ triangle --help

The following flags are supported:

Flag	Default	Description
`in`	n/a	Input file
`out`	n/a	Output file
`blur`	4	Blur radius
`max`	2500	Maximum number of points
`noise`	0	Noise factor
`points`	20	Points threshold
`sobel`	10	Sobel filter threshold
`solid`	false	Solid line color
`wireframe`	0	Wireframe mode (without,with,both)
`stroke`	1	Stroke width
`gray`	false	Convert to grayscale
`svg`	false	Save as SVG
`web`	false	Output SVG in browser

Output as image or SVG

By default the output is saved to an image file, but setting the -svg flag as true you can export the resulted vertices even to an SVG file, being the perfect candidate for large poster images. Using a small image as input source, exporting to an *.svg file will generate a very low processing footprint whitout quality loss.

$ triangle -in samples/input.jpg -out output.png -svg=1

Using the -svg together with -web flag you can access the svg result on the web browser.

$ triangle -in samples/input.jpg -out output.png -svg=1 -web=1

Multiple image processing with a single command

You can transform even multiple images from a specific folder with a single command by declaring as -in flag the source folder and as -out flag the destination folder.

$ triangle -in ./samples/ -out ./ouput -wireframe=0 -max=3500 -stroke=2 -blur=2 -noise=4

Tweaks

Setting a lower points threshold, the resulted image will be more like a cubic painting. You can even add a noise factor, generating a more artistic, grainy image.

Here are some examples you can experiment with:

$ triangle -in samples/input.jpg -out output.png -wireframe=0 -max=3500 -stroke=2 -blur=2
$ triangle -in samples/input.jpg -out output.png -wireframe=2 -max=5500 -stroke=1 -blur=10