svg_painter

The code generator for the svg_painter library. This package is responsible for parsing SVG files and generating the corresponding Flutter CustomPainter code.

Usage

This package is intended to be used as a dev_dependency alongside build_runner.

1. Add svg_painter to your dev_dependencies.
2. Add svg_painter_annotation to your dependencies.
3. Annotate your classes with @SvgPainter.file(...) or @SvgPainter.code(...).
4. Run dart run build_runner build.

Features

• Fast & Lightweight: Generates optimized CustomPainter code with zero runtime parsing.

• Dynamic Properties: Expose SVG fills and strokes as constructor arguments for runtime recoloring.

• Intelligent Grouping: Automatically group shared styles into indexed properties (e.g., fill1, fill2).

• Semantic Renaming: Map generic names to semantic ones (e.g., fill1 -> background).

• Style Inheritance: Overriding a group's property automatically propagates to all children that inherit from it.

• SVG Support: Comprehensive support for shapes, paths, transforms, and gradients.

Customizing your SVG

The power of svg_painter lies in its ability to turn static SVGs into customizable Flutter components.

1. Exposure Modes

Control which properties are exposed in the generated constructor using SvgExposureMode:

• none (Default): The painter is static. No properties are exposed.

• id: Only elements with an id attribute are exposed (e.g., <circle id="eye"/> -> eyeFill).

• indexed: Group shared colors/styles and expose them as fill1, fill2, etc.

• mixed: Expose both ID-based and indexed properties.

@SvgPainter.file('assets/logo.svg', exposureMode: SvgExposureMode.mixed)

class LogoPainter extends _$LogoPainter {}

2. Property Renaming

Use propertyMapping to give your properties semantic names. This is especially useful with indexed mode.

For a German flag (Black, Red, Gold):

@SvgPainter.code(

  germanFlagSvg,

  exposureMode: SvgExposureMode.indexed,

  propertyMapping: {

    'fill1': 'topColor',

    'fill2': 'middleColor',

    'fill3': 'bottomColor',

  },

)

class GermanFlagPainter extends _$GermanFlagPainter {}



// Usage: Turn Germany into Netherlands!

const flag = GermanFlagPainter(

  topColor: Colors.red,

  middleColor: Colors.white,

  bottomColor: Colors.blue,

);

3. Dynamic Style Inheritance

svg_painter respects SVG inheritance rules. If you expose a property for a group (<g>), overriding that property will affect all children that inherit from it.

<g id="header" fill="red">

  <circle cx="10" cy="10" r="5" /> <!-- Inherits headerFill -->

  <rect x="20" y="20" width="10" height="10" /> <!-- Inherits headerFill -->

</g>

@SvgPainter.code(svg, exposureMode: SvgExposureMode.id)

class MyPainter extends _$MyPainter {}



// Both the circle and rect will turn green:

const painter = MyPainter(headerFill: Colors.green);