image_white_background 0.1.1

Composite a transparent image onto a solid (white) background with optional padding or a fixed canvas size. Handy before sending images to OCR / vision models that prefer an opaque background.

🖼️ image_white_background

Composite a transparent image onto a solid background

Useful before sending images to OCR / vision models, which often read more reliably against an opaque background than a transparent one.

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Features

• 🧱 Padding mode — image plus a coloured border on every side
• 🎯 Fixed-canvas mode — center the image on a canvas of an exact size
• 🎨 Any background colour (defaults to white)
• 🖼️ Returns PNG bytes (Uint8List) ready to upload or display
• 🪶 Tiny, dart:ui-only

Install

dependencies:
  image_white_background: ^0.1.1

or flutter pub add image_white_background.

Usage

import 'package:image_white_background/image_white_background.dart';

// Padding mode: image + a white border on every side.
final padded = await ImageWhiteBackground.apply(
  pngBytes,
  padding: const EdgeInsets.all(24),
);

// Fixed-canvas mode: center the image on a white canvas of an exact size.
final framed = await ImageWhiteBackground.apply(
  pngBytes,
  canvasSize: const Size(1024, 1024),
);

// Any background colour you like.
final onBlack = await ImageWhiteBackground.apply(
  pngBytes,
  background: const Color(0xFF000000),
);

apply returns PNG bytes you can upload, display with Image.memory, or hand to a vision API.

Related

Part of the Flutter Grading Toolkit — pairs with handwriting_answer_pad (capture) and ai_rubric_grader (grade).

Contributing

Issues and PRs welcome. Run flutter test before submitting.

License

MIT © 2026 Muhammad Ali