SVG to Dart Widget Converter

svg2dart is a command-line tool that converts SVG files into pure Dart code. It generates performant Flutter widgets that use LeafRenderObjectWidget and a pre-recorded ui.Picture for rendering.

This approach allows you to use your vector graphics directly in your Flutter application without runtime dependencies like flutter_svg, which can lead to better performance and a smaller dependency tree.

The conversion process is powered by the vector_graphics_compiler and vector_graphics_codec packages.

Features

• Pure Dart code: Generates widgets based on LeafRenderObjectWidget and a pre-recorded ui.Picture, minimizing runtime overhead.
• Optimizations: Includes an optional optimizations flag that uses pathops for path simplification and Tessellator for direct GPU rendering.
• Core SVG Support: Converts paths, fills, strokes, and basic gradients.
• Batch Processing: Supports processing both single files and entire directories, preserving the source directory structure.
• build_runner Integration: Automates code generation within your development workflow.

Limitations

Currently, the tool does not support the following SVG features:

• Raster images (<image>)
• Advanced SVG features (like filters, patterns, etc.)

Files containing unsupported elements (like <image>) will be skipped during generation.

Installation

To use svg2dart from the command line, install it globally using pub:

dart pub global activate svg2dart

Usage

Once activated, you can use the svg2dart command from anywhere in your terminal.

svg2dart [options]

Options

Flag	Abbreviation	Description	Required
--input	-i	Path to the input SVG file or directory.	Yes
--output	-o	Path to the output Dart file or directory.	Yes
--optimizations		Enable optimizations (path simplification and tessellation).	No
--help	-h	Показать справочное сообщение.	No

Examples

1. Converting a Single File

To convert a single SVG file into a Dart widget:

svg2dart --input assets/icons/cloud.svg --output lib/icons/

This command will read assets/icons/cloud.svg and generate a Cloud widget inside lib/icons/cloud.dart.

2. Converting an Entire Directory

To convert all .svg files within a directory (and its subdirectories):

svg2dart --input assets/icons/ --output lib/generated/icons/

Alternative: Usage with build_runner

For automatic code generation that integrates with your development workflow, you can use svg2dart as a builder.

1. Add dependencies to your project's pubspec.yaml:

   dev_dependencies:
     build_runner: ^2.9.0 # or latest
     svg2dart: ^0.0.7 # or latest
   

2. Run the builder:

   To generate the Dart files once:

   dart run build_runner build --delete-conflicting-outputs
   

   To watch for file changes and regenerate automatically:

   dart run build_runner watch --delete-conflicting-outputs
   

By default, the builder processes .svg files from the assets/svg directory and places the generated .dart files into lib/generated/svg. You can customize these paths by creating a build.yaml file in your project's root.

Here is an example of a build.yaml file that changes the default input and output directories:

targets:
  $default:
    builders:
      svg2dart:
        options:
          # Default is "assets/svg"
          input: "assets/my_icons"
          # Default is "lib/generated/svg"
          output: "lib/generated/icons"          
          # Default is false
          optimizations: true

Using the Generated Widget

After generation, you can import the Dart file and use the widget like any other Flutter widget. You can override the original SVG dimensions by providing width and height properties.

import 'package:my_app/generated/icons/cloud.gen.dart';

class MyScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: Center(
        // Use the generated widget with a custom size
        child: CloudSvg(
          width: 100,
          height: 100,
          colorFilter: ColorFilter.mode(Colors.yellow, BlendMode.srcIn)
        ),
      ),
    );
  }
}