langolf / vrt-runner

VRT runner and result generator for images

@magiclab/vrt-runner

VRT runner and result generator for images

CLI

npx @magiclab/vrt-runner --cwd path_to_diff_images --output result_output

It expects the files to have a simple folder syntax

path_to_diff_images
├── baseline
│   ├── 1.png
│   └── 2.png
└── test
    ├── 1.png
    └── 2.png

Change options via CLI, e.g. comparison diff threshold

    npx @magiclab/vrt-runner --cwd path_to_diff_images --output result_output --matchingThreshold 0.25

Variable Name	Description
--ignoreChange	If true, error will not be thrown when image change detected. Default true
--matchingThreshold	Matching threshold, ranges from 0 to 1. Smaller values make the comparison more sensitive. 0.05 by default. 0 by default for reg-cli.
--thresholdRate	Rate threshold for detecting change. When the difference ratio of the image is larger than the set rate detects the change. Applied after matchingThreshold.
--thresholdPixel	Pixel threshold for detecting change. When the difference pixel of the image is larger than the set pixel detects the change. This value takes precedence over thresholdRate. Applied after matchingThreshold.
--concurrency	How many processes launches in parallel. If omitted 4
--enableAntialias	Enable antialias. If omitted true
--additionalDetection	Enable additional difference detection(highly experimental). Select "none" or "client" (default: none).

Node

You can also use it as a node module

import runVrt from '@magiclab/vrt-runner';

runVrt({
    cwd,
    output,
    teamcity, // boolean flag to know if we should log teamcity friendly output
    options, // optional: parameters for reg-cli
});

Hooks

Currently we support onVrtComplete hook, which allows you to get results of comparison and timing of comparison.

One of the ways to use this data is the following:

(async function() {
    try {
        // define action
        const onVrtCompleteAction: onVrtCompleteType = (result, cmpTime) => {
            const info = showResults({
                failedItems: result.failedItems.length + result.deletedItems.length,
                passed: result.passedItems.length + result.newItems.length,
                diffTime: cmpTime / 1000,
            });

            return info;
        };

        // save data after runVrt
        const info = await runVrt({
            cwd,
            output,
            teamcity, // boolean flag to know if we should log teamcity friendly output
            onVrtComplete: onVrtCompleteAction
        });

        // work with data
        console.log(info);
    }
    process.exit(0);
})();

How to change options for reg-cli instance

You might want to change the different comparison options in instances of vrt-runner. You can do it via options, which are are aligned with pixelmatch API

Change comparison diff threshold in Node

    const options = {
        matchingThreshold: 0.2
    };

    const vrtIntance01 = runVrt({
        cwd,
        output,
        teamcity, // boolean flag to know if we should log teamcity friendly output
        options,
    });

    const optionsSecondType = {
        matchingThreshold: 0.2
    };

    const vrtIntance03 = runVrt({
        cwd,
        output,
        teamcity, // boolean flag to know if we should log teamcity friendly output
        optionsSecondType,
    });

    const vrtIntance03 = runVrt({
        cwd,
        output,
        teamcity, // boolean flag to know if we should log teamcity friendly output
    });
})();

Assets

CSS files for the report page are generated. If you need to make changes to it, update src/report-assets/css/vrt.scss and run the following command:

    yarn styles