imagediff

README

Imagediff

Overview

ImageDiff is a Go package for comparing images and visually highlighting their differences. It is useful for tasks like automated testing, where verifying the correctness of image outputs is crucial. The package provides a straightforward API to compare two images, generating a third image that visually marks the differences.

Features

Compare two images and highlight differences. Supports different color coding for various levels of differences. Handles images of different sizes. Outputs a new image marking areas present in one image but not the other.

Installation

To install the command-line tool:

go install codeberg.org/slaxor/imagediff/cmd/imagediff@master

Usage

Import the package in your Go file:

import "codeberg.org/slaxor/imagediff"

Basic usage involves calling the CompareFiles function with the paths of the two images to compare and the output file path:

equal, err := imagediff.CompareFiles("path/to/image1.png", "path/to/image2.png", "path/to/result.png")
if err != nil {
    log.Fatalf("Error comparing images: %v", err)
}
if !equal {
    fmt.Println("Images are different, see image1_png_image2_png_diff.png for details.")
} else {
    fmt.Println("Images are identical.")
}

Command-Line Tool

After installation, you can use the imagediff command to compare images:

imagediff image1.png image2.png

If the images differ it will return a message telling you and save a file (image1_png_image2_png_diff.png in our case) marking the differences. You can use it as an overlay on your originals with any graphics program of your choosing.

As an example consider:

## Contributing

Contributions are welcome. Please open an issue or submit a pull request with your improvements.

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for more details.

Documentation

Index

• Variables
• func Compare(a, b image.Image) (image.Image, bool, error)
• func CompareFiles(aFile, bFile, resultFile string) (bool, error)
• func Merge(images ...image.Image) image.Image

Variables

var (
	Palette = color.Palette{
		palColors["sameColor"],
		palColors["diffColor1"],
		palColors["diffColor2"],
		palColors["diffColor3"],
		palColors["diffColor4"],
		palColors["diffColor5"],
		palColors["diffColor6"],
		palColors["diffColor7"],
		palColors["diffColor8"],
		palColors["aOnlyColor"],
		palColors["bOnlyColor"],
	}
)

Functions

func Compare

func Compare(a, b image.Image) (image.Image, bool, error)

Compare takes 2 imgs compares them and returns a result img the combined size of the 2 with all differences marked as 50% red and a only as 50% cyan b only as 50% orange a boolean telling if the imgs differ

func CompareFiles

func CompareFiles(aFile, bFile, resultFile string) (bool, error)

CompareFiles takes 2 input and an output filename as argument compares them and write the difference to the resultFile returns a bool telling if differences have been found and an error which we hope is nil.

func Merge

func Merge(images ...image.Image) image.Image