Unlock the Power of SVG in Your Flutter App
When it comes to building a Flutter application, choosing the right image format is crucial. That’s where Scalable Vector Graphics (SVG) comes in – offering several advantages over bitmap files, especially when it comes to retaining image quality while scaling.
Why SVG Matters
SVG is widely used in applications due to its ability to maintain image quality regardless of size. However, Flutter’s 2D graphics library, Skia, can only serialize images into SVG files, making it impossible to decode or render SVG images directly. Fortunately, the community has developed a fantastic Dart-native package called flutter_svg that renders and decodes SVG quickly.
Introducing flutter_svg
The flutter_svg package implements a picture cache that stores a ui:Picture class, which records specific SVG rendering commands in binary mode. This approach avoids repeatedly parsing XML files and consumes minimal memory.
Adding flutter_svg to Your Project
To add this package to your Flutter dependencies, simply run flutter pub add flutter_svg or add it to your pubspec.yaml file. Once installed, import the package in your Dart code where you want to use it.
Using flutter_svg in Your App
There are several ways to use this package:
- Load an SVG from an internal file stored in the asset folder
- Load an SVG file from a URL
- Load an SVG from SVG code
Customizing Your SVG
Once you’ve loaded your SVG file, you can change the color or tint of the image, add a semantics label to enhance accessibility, and even replace the default placeholder with a custom widget.
Checking SVG Compatibility
While the flutter_svg library doesn’t support all SVG features, it provides a helper method to ensure you don’t render a broken image due to unsupported features.
Optimizing Your SVG Files
To get the most out of flutter_svg with Adobe Illustrator, follow these recommendations:
- Choose presentation attributes instead of inline CSS
- Embed images instead of linking to another file
- Use layer names to add a name to every layer for SVG tags
Rendering SVG Files in Another Canvas
If you need to render your SVG into another canvas, SVGPicture makes it easy.
The Bottom Line
Using SVG files can be a great addition to your Flutter app, but it’s crucial to observe your use cases and measure your app and SVG performance continuously. Although Flutter doesn’t support SVG natively, the flutter_svg package provides excellent performant and fast support for SVG files.