[flutter_svg] Flutter - how add custom font for svg image? #158691

Imported from dnfield/flutter_svg#680

Original report by @FetFrumos on Mar 11, 2022

I have svg image(export from Adobe Xd). For the correct display of this file, I need to install an additional font in the system(MAC or Windows) - then the picture is displayed correctly, without this font it is incorrect. but I need to display this drawing in application. I using flutter_svg plugin. I download ttf of font, add in assets and pubspec. But after that it doesn't work either. how add custom font for svg image(with flutter_svg)?

Comment by @dnfield on Mar 13, 2022
I'd find it helpful if you shared a small but complete example of the issue.

Some places where this could possibly go wrong:

• The font isn't getting included in the pubspec correctly (see https://docs.flutter.dev/cookbook/design/fonts).
• The font is getting included as a plain asset and you need to use font loading API to load it (https://api.flutter.dev/flutter/dart-ui/loadFontFromList.html).
• For some reason the SVG is getting parsed and rendered to a picture before the font is loaded.
• The SVG is not specifying the correct font family information to resolve to your custom font.
• The flutter_svg package is not making the right use of font rendering attributes to get the custom font to be used.

Obviously if it's that last point, there's a bug in this package. A reproduction case would be able to narrow this down.

Comment by @L4hibYoussef on Mar 15, 2023
Is there any updates on this. I am appearing to have the same issue. Font is loaded before image is rendered and font is available for use in the app. I am building the app for web using canvaskit.

Comment by @devalev on Jul 12, 2023

Is there any updates on this. I am appearing to have the same issue. Font is loaded before image is rendered and font is available for use in the app. I am building the app for web using canvaskit.

You need to load the font when executing the application.

void main() async {
  runApp(const MyApp());
}

void loadFont() async {
  var fontLoader = FontLoader("FontName");
  fontLoader.addFont(rootBundle.load('fonts/FontName.ttf'));
  await fontLoader.load();
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    loadFont();
    return Container();
  }
}

Please note that sometimes the font-family is specified in extra quotes in the svg file

font-family="FontName"

and

font-family="'FontName'"

these are different things, and, accordingly, you need to import different fonts

var fontLoader = FontLoader("FontName");

var fontLoader = FontLoader("'FontName'");