bild

bild

A collection of parallel image processing algorithms in pure Go.

The aim of this project is simplicity in use and development over absolute high performance, but most algorithms are designed to be efficient and make use of parallelism when available.

It uses packages from the standard library whenever possible to reduce dependency use and development abstractions.

All operations return image types from the standard library.

Documentation

The documentation for the various packages is available here.

CLI usage

Download and compile from sources:

go get github.com/anthonynsimon/bild

Or get the pre-compiled binaries for your platform on the releases page

…

For example, to apply a median effect with a radius of 1.5 on the image input.png, writing the result into a new file called output.png:

bild effect median --radius 1.5 input.png output.png

To resize an image to 800x600 using the lanczos filter:

bild transform resize --width 800 --height 600 --filter lanczos input.png output.png

To rotate an image 90 degrees clockwise, expanding bounds to fit:

bild transform rotate --angle 90 --resize-bounds input.png output.png

To crop an image to a specific region:

bild transform crop --rect 0x0+512x256 input.png output.png

To convert an image to another format (the encoder is chosen from the output extension):

bild imgio encode input.png output.webp

Install package

bild requires Go version 1.25 or greater.

go get github.com/anthonynsimon/bild/...

Basic package usage example:

package main

import (
    "github.com/anthonynsimon/bild/effect"
    "github.com/anthonynsimon/bild/imgio"
    "github.com/anthonynsimon/bild/transform"
)

func main() {
    img, err := imgio.Open("input.jpg")
    if err != nil {
        fmt.Println(err)
        return
    }

    inverted := effect.Invert(img)
    resized := transform.Resize(inverted, 800, 800, transform.Linear)
    rotated := transform.Rotate(resized, 45, nil)

    if err := imgio.Save("output.png", rotated, imgio.PNGEncoder()); err != nil {
        fmt.Println(err)
        return
    }
}

Supported formats

imgio.Open decodes PNG, JPEG, BMP and WebP images. The following encoders are available:

• imgio.PNGEncoder()
• imgio.JPEGEncoder(quality)
• imgio.BMPEncoder()
• imgio.WEBPEncoder(options) — pass nil for defaults

The CLI selects the encoder from the output file extension (.png, .jpg/.jpeg, .bmp, .webp).

Output examples

Adjustment

import "github.com/anthonynsimon/bild/adjust"

Brightness

result := adjust.Brightness(img, 0.25)

Contrast

result := adjust.Contrast(img, -0.5)

Gamma

result := adjust.Gamma(img, 2.2)

Hue

result := adjust.Hue(img, -42)

Saturation

result := adjust.Saturation(img, 0.5)

Blend modes

import "github.com/anthonynsimon/bild/blend"

result := blend.Multiply(bg, fg)

Add	Color Burn	Color Dodge
Darken	Difference	Divide
Exclusion	Lighten	Linear Burn
Linear Light	Multiply	Normal
Opacity	Overlay	Screen
Soft Light	Subtract

Blur

import "github.com/anthonynsimon/bild/blur"

Box Blur

result := blur.Box(img, 3.0)

Gaussian Blur

result := blur.Gaussian(img, 3.0)

Channel

import "github.com/anthonynsimon/bild/channel"

Extract Channels

result := channel.Extract(img, channel.Alpha)

Extract Multiple Channels

result := channel.ExtractMultiple(img, channel.Red, channel.Alpha)

Effect

import "github.com/anthonynsimon/bild/effect"

Dilate

result := effect.Dilate(img, 3)

Edge Detection

result := effect.EdgeDetection(img, 1.0)

Emboss

result := effect.Emboss(img)

Erode

result := effect.Erode(img, 3)

Grayscale

result := effect.Grayscale(img)

Invert

result := effect.Invert(img)

Median

result := effect.Median(img, 10.0)

Sepia

result := effect.Sepia(img)

Sharpen

result := effect.Sharpen(img)

Sobel

result := effect.Sobel(img)

Unsharp Mask

result := effect.UnsharpMask(img, 0.6, 1.2)

Histogram

import "github.com/anthonynsimon/bild/histogram"

RGBA Histogram

hist := histogram.NewRGBAHistogram(img)
result := hist.Image()

Noise

import "github.com/anthonynsimon/bild/noise"

Uniform colored

result := noise.Generate(280, 280, &noise.Options{Monochrome: false, NoiseFn: noise.Uniform})

Binary monochrome

result := noise.Generate(280, 280, &noise.Options{Monochrome: true, NoiseFn: noise.Binary})

Gaussian monochrome

result := noise.Generate(280, 280, &noise.Options{Monochrome: true, NoiseFn: noise.Gaussian})

Perlin Noise

result := noise.GeneratePerlin(280, 280, 0.25)

Paint

import "github.com/anthonynsimon/bild/paint"

Flood Fill

// Fuzz is the percentage of maximum color distance that is tolerated
result := paint.FloodFill(img, image.Point{240, 0}, color.RGBA{255, 0, 0, 255}, 15)

Segmentation

import "github.com/anthonynsimon/bild/segment"

Threshold

result := segment.Threshold(img, 128)

Transform

import "github.com/anthonynsimon/bild/transform"

Crop

// Source image is 280x280
result := transform.Crop(img, image.Rect(70,70,210,210))

FlipH

result := transform.FlipH(img)

FlipV

result := transform.FlipV(img)

Resize Resampling Filters

result := transform.Resize(img, 280, 280, transform.Linear)

Nearest Neighbor	Linear	Gaussian
Mitchell Netravali	Catmull Rom	Lanczos

Rotate

// Options set to nil will use defaults (ResizeBounds set to false, Pivot at center)
result := transform.Rotate(img, -45.0, nil)

// If ResizeBounds is set to true, the full rotation bounding area is used
result := transform.Rotate(img, -45.0, &transform.RotationOptions{ResizeBounds: true})

// Pivot coordinates are set from the top-left corner
// Notice ResizeBounds being set to default (false)
result := transform.Rotate(img, -45.0, &transform.RotationOptions{Pivot: &image.Point{0, 0}})

Shear Horizontal

result := transform.ShearH(img, 30)

Shear Vertical

result := transform.ShearV(img, 30)

Translate

result := transform.Translate(img, 80, 0)

Zoom

// Zoom in 2x, preserving the image size (out-of-bounds pixels are cropped)
result := transform.Zoom(img, 2.0, nil)

// Zoom in 2x, expanding the canvas to fit the full zoomed image
result := transform.Zoom(img, 2.0, &transform.ZoomOptions{ResizeBounds: true})

// Zoom with a custom pivot point
result := transform.Zoom(img, 2.0, &transform.ZoomOptions{Pivot: &image.Point{0, 0}})

Contribute

Want to hack on the project? Any kind of contribution is welcome!
Simply follow the next steps:

• Fork the project.
• Create a new branch.
• Make your changes and write tests when practical.
• Commit your changes to the new branch.
• Send a pull request, it will be reviewed shortly.

In case you want to add a feature, please create a new issue and briefly explain what the feature would consist of. For bugs or requests, before creating an issue please check if one has already been created for it.

Changelog

Please see the changelog for more details.

License

This project is licensed under the MIT license. Please read the LICENSE file.