PHP SVG Optimizer

php-svg-optimizer is a lightweight PHP library designed to optimize SVG files by applying various transformations and cleanup operations. The library ensures that the optimized SVG files are compliant with SVG 2.0 specifications.

The tool strives to optimize as much as possible without losing any data that could distort the image's quality, ensuring the resulting SVG remains visually identical to the original while being more efficient in terms of size and performance.

Versions & Dependencies

Version	PHP	Documentation
^7.1	^8.3	current

Requirements

• ext-dom: Required PHP extension for XML handling.
• ext-libxml: Required PHP extension for XML error handling.
• ext-mbstring: Required PHP extension for multibyte string handling.

Installation

To install the library, run:

composer require mathiasreker/php-svg-optimizer

Using the Library

You can use this library either as a command-line tool (CLI) or as a standalone package.

---

CLI tool

Usage

vendor/bin/svg-optimizer [options] process <path1> <path2> ...

Options:
-h , --help               Display help for the command.
-c , --config             Path to a JSON file with custom optimization rules. If not provided, all default optimizations will be applied.
-d , --dry-run            Only calculate potential savings without modifying the files.
-q , --quiet              Suppress all output except errors.
-v , --version            Display the version of the library.

Commands:
Process                   Provide a list of directories or files to process.

Examples:

vendor/bin/svg-optimizer --dry-run process /path/to/svgs
vendor/bin/svg-optimizer --config=config.json process /path/to/file.svg
vendor/bin/svg-optimizer --config='{"removeUnsafeElements": true}' process /path/to/file.svg
vendor/bin/svg-optimizer --quiet process /path/to/file.svg

Config file example:

{
    "convertColorsToHex": true,
    "convertEmptyTagsToSelfClosing": true,
    "flattenGroups": false,
    "minifySvgCoordinates": true,
    "minifyTransformations": true,
    "removeComments": true,
    "removeDefaultAttributes": true,
    "removeDeprecatedAttributes": true,
    "removeDoctype": true,
    "removeEnableBackgroundAttribute": true,
    "removeEmptyAttributes": true,
    "removeInkscapeFootprints": true,
    "removeInvisibleCharacters": true,
    "removeMetadata": true,
    "removeTitleAndDesc": true,
    "removeUnnecessaryWhitespace": true,
    "removeUnsafeElements": false,
    "removeUnusedNamespaces": true,
    "sortAttributes": true
}

Package

To ensure robustness when using the library, it's crucial to handle exceptions, as invalid or malformed SVG files could lead to runtime errors. Catching these exceptions will allow you to manage potential issues gracefully and prevent your application from crashing.

Example specifying rules

<?php

declare(strict_types=1);

require_once __DIR__ . '/vendor/autoload.php';

use MathiasReker\PhpSvgOptimizer\Service\Facade\SvgOptimizerFacade;

try {
    $svgOptimizer = SvgOptimizerFacade::fromFile('path/to/source.svg')
        ->withRules(
            convertColorsToHex: true,
            convertEmptyTagsToSelfClosing: true,
            flattenGroups: false,
            minifySvgCoordinates: true,
            minifyTransformations: true,
            removeComments: true,
            removeDefaultAttributes: true,
            removeDeprecatedAttributes: true,
            removeDoctype: true,
            removeEmptyAttributes: true,
            removeEnableBackgroundAttribute: true,
            removeInkscapeFootprints: true,
            removeMetadata: true,
            removeTitleAndDesc: true,
            removeUnnecessaryWhitespace: true,
            removeUnsafeElements: false,
            removeUnusedNamespaces: true,
            sortAttributes: true,
        )
        ->optimize()
        ->saveToFile('path/to/output.svg');
} catch (\Exception $exception) {
    echo $exception->getMessage();
}

Example parsing from a file and saving to a file using default rules

<?php

declare(strict_types=1);

require_once __DIR__ . '/vendor/autoload.php';

use MathiasReker\PhpSvgOptimizer\Service\Facade\SvgOptimizerFacade;

try {
    $svgOptimizer = SvgOptimizerFacade::fromFile('path/to/source.svg')
        ->optimize()
        ->saveToFile('path/to/output.svg');

    $metaData = $svgOptimizer->getMetaData();

    echo sprintf('Optimized size: %d bytes%s', $metaData->getOptimizedSize(), \PHP_EOL);
    echo sprintf('Original size: %d bytes%s', $metaData->getOriginalSize(), \PHP_EOL);
    echo sprintf('Size reduction: %d bytes%s', $metaData->getSavedBytes(), \PHP_EOL);
    echo sprintf('Reduction percentage: %s %%%s', $metaData->getSavedPercentage(), \PHP_EOL);
} catch (\Exception $exception) {
    echo $exception->getMessage();
}

Example parsing from a file and returning the content using default rules

<?php

declare(strict_types=1);

require_once __DIR__ . '/vendor/autoload.php';

use MathiasReker\PhpSvgOptimizer\Service\Facade\SvgOptimizerFacade;

try {
    $svgOptimizer = SvgOptimizerFacade::fromFile('path/to/source.svg')
        ->optimize();

    echo sprintf('Get content: ', $svgOptimizer->getContent(), \PHP_EOL);

    $metaData = $svgOptimizer->getMetaData();

    echo sprintf('Optimized size: %d bytes%s', $metaData->getOptimizedSize(), \PHP_EOL);
    echo sprintf('Original size: %d bytes%s', $metaData->getOriginalSize(), \PHP_EOL);
    echo sprintf('Size reduction: %d bytes%s', $metaData->getSavedBytes(), \PHP_EOL);
    echo sprintf('Reduction percentage: %s %%%s', $metaData->getSavedPercentage(), \PHP_EOL);
} catch (\Exception $exception) {
    echo $exception->getMessage();
}

Example parsing from a string and returning the content using default rules

<?php

declare(strict_types=1);

require_once __DIR__ . '/vendor/autoload.php';

use MathiasReker\PhpSvgOptimizer\Service\Facade\SvgOptimizerFacade;

try {
    $svgOptimizer = SvgOptimizerFacade::fromString('<svg>...</svg>')
        ->optimize();

    echo sprintf('Content: ', $svgOptimizer->getContent(), \PHP_EOL);

    $metaData = $svgOptimizer->getMetaData();

    echo sprintf('Optimized size: %d bytes%s', $metaData->getOptimizedSize(), \PHP_EOL);
    echo sprintf('Original size: %d bytes%s', $metaData->getOriginalSize(), \PHP_EOL);
    echo sprintf('Size reduction: %d bytes%s', $metaData->getSavedBytes(), \PHP_EOL);
    echo sprintf('Reduction percentage: %s %%%s', $metaData->getSavedPercentage(), \PHP_EOL);
} catch (\Exception $exception) {
    echo $exception->getMessage();
}

Documentation

Static factory method to create SvgOptimizerFacade from a file path.

$svgOptimizer = SvgOptimizerFacade::fromFile('path/to/source.svg');

Static factory method to create SvgOptimizerFacade from a string.

$svgOptimizer = SvgOptimizerFacade::fromString('<svg>...</svg>');

withRules Method

Configure which SVG optimization rules to apply. The method accepts boolean parameters that determine whether specific rules should be enabled or disabled.

Parameters:

Converts rgb() color values to hexadecimal format:

$svgOptimizer->withRules(convertColorsToHex: true);

Converts empty tags to self-closing tags:

$svgOptimizer->withRules(convertEmptyTagsToSelfClosing: true);

Flattens nested <g> elements, moving their child elements up to the parent node:

$svgOptimizer->withRules(flattenGroups: true);

Minifies coordinate values by removing unnecessary precision:

$svgOptimizer->withRules(minifySvgCoordinates: true);

Minifies transformation attributes by removing redundant values:

$svgOptimizer->withRules(minifyTransformations: true);

Removes all comments from the SVG:

$svgOptimizer->withRules(removeComments: true);

Removes default attribute values that match common defaults:

$svgOptimizer->withRules(removeDefaultAttributes: true);

Removes deprecated attributes from the SVG:

$svgOptimizer->withRules(removeDeprecatedAttributes: true);

Removes the SVG doctype declaration:

$svgOptimizer->withRules(removeDoctype: true);

Removes empty attributes from the SVG:

$svgOptimizer->withRules(removeEmptyAttributes: true);

Removes the enable-background attribute from the SVG:

$svgOptimizer->withRules(removeEnableBackgroundAttribute: true);

Removes Inkspace-specific footprints from the SVG:

$svgOptimizer->withRules(removeInkscapeFootprints: true);

Removes invisible characters from the SVG:

$svgOptimizer->withRules(removeInvisibleCharacters: true);

Removes <metadata> tags from the SVG:

$svgOptimizer->withRules(removeMetadata: true);

Removes <title> and <desc> tags from the SVG:

$svgOptimizer->withRules(removeTitleAndDesc: true);

Cleans up unnecessary whitespace in the SVG:

$svgOptimizer->withRules(removeUnnecessaryWhitespace: true);

Removes unused namespaces from the SVG:

$svgOptimizer->withRules(removeUnusedNamespaces: true);

Removes unsafe elements from the SVG (risky):

$svgOptimizer->withRules(removeUnsafeElements: true);

Sorts attributes within each element:

$svgOptimizer->withRules(sortAttributes: true);

Below you see the default configuration. You can configure each rule individually by passing the desired values to it:

$svgOptimizer->withRules(
    convertColorsToHex: true,
    convertEmptyTagsToSelfClosing: true,
    flattenGroups: false,
    minifySvgCoordinates: true,
    minifyTransformations: true,
    removeComments: true,
    removeDefaultAttributes: true,
    removeDeprecatedAttributes: true,
    removeDoctype: true,
    removeEmptyAttributes: true,
    removeEnableBackgroundAttribute: true,
    removeInkscapeFootprints: true,
    removeMetadata: true,
    removeTitleAndDesc: true,
    removeUnnecessaryWhitespace: true,
    removeUnsafeElements: false,
    removeUnusedNamespaces: true,
    sortAttributes: true,
);

optimize Method

Finalizes the optimization process and generates the optimized SVG file.

$svgOptimizer->optimize();

saveToFile Method

Saves the optimized SVG file to the specified path.

$svgOptimizer->saveToFile('path/to/output.svg');

getContent Method

Returns the optimized SVG content.

$svgOptimizer->getContent();

getOptimizedSize Method

Returns the size of the optimized SVG file.

$svgOptimizer->getMetaData()->getOptimizedSize();

getOriginalSize Method

Returns the size of the original SVG file.

$svgOptimizer->getMetaData()->getOriginalSize();

getSavedBytes Method

Returns the number of bytes saved by the optimization process.

$svgOptimizer->getMetaData()->getSavedBytes();

getSavedPercentage Method

Returns the percentage of bytes saved by the optimization process.

$svgOptimizer->getMetaData()->getSavedPercentage();

Roadmap

For a complete list of proposed features and known issues, see the open issues.

Contributing

We welcome all contributions! If you have ideas for improvements, feel free to fork the repository and submit a pull request. You can also open an issue. If you find this project helpful, don’t forget to give it a star!

Library Structure and Contribution Guide

The library implements the Strategy Pattern, where strategies are encapsulated as "rules" located in the /src/Service/Rule directory.

Adding a New Rule

1. Create the Rule

Create a new final readonly class in the /src/Service/Rule directory and implement the SvgOptimizerRuleInterface. This interface will define the logic for your rule.

2. Write Tests

Write comprehensive unit tests for your rule in the /tests/Unit/Service/Rule directory. Ensure the tests cover various scenarios to verify the correct behavior and edge cases for your rule.

3. Integrate the Rule

• Register the rule in the SVG optimizer builder located at /src/Service/Facade/SvgOptimizerFacade.php.
• Add your rule to the rule enum in /src/Type/Rule.php.
• Include the rule in the processor by updating /src/Processor/SvgFileProcessor.php.

4. Update Documentation

Document the functionality and purpose of your rule in the README.md to ensure users understand its behavior and usage.

Docker

To use the project with Docker, you can start the container using:

docker-compose up -d

Then, access the container:

docker exec -it php-svg-optimizer bash

Tools

Run static analysis:

composer analyze:all

Run tests:

composer test

Fix code style:

composer lint:all

Build badges:

composer build:badges

License

This project is licensed under the MIT License. See the LICENSE file for more information.

Disclaimer

Although the tool has been thoroughly tested and is built in a way that avoids risky changes, its use is at your own risk. We cannot guarantee that it will be fully compatible with all SVG files or workflows. It is highly recommended to test the tool with sample SVG files and ensure compatibility with your specific use case before using it in a production environment.