html_to_image_flutter

Flutter plugin to convert HTML content or HTML asset files to PNG image bytes using WebView on Android and WKWebView on iOS.

Requirements

Android: Minimum SDK Version 21
iOS: Minimum Deployment Target 11.0

Usage

Convert to Image from HTML content

Future<Uint8List> convertToImage(String content, Duration delay,int? width)

final imageBytes = await HtmlToImage.convertToImage(
  content: content,
);
final image = Image.memory(imageBytes);

Convert to Image from HTML asset

Future<Uint8List> convertToImageFromAsset(String asset, Duration delay,int? width)

final imageBytes = await HtmlToImage.convertToImageFromAsset(
  asset: 'assets/example.html',
);
final image = Image.memory(imageBytes);

Offline support

html_to_image_flutter renders HTML passed from Dart directly inside the native WebView, so plain HTML strings and bundled Flutter assets can be converted while the device is offline.

For fully offline output, keep all required CSS, fonts, and images available locally:

final imageBytes = await HtmlToImage.convertToImage(
  content: '''
    <div style="padding:16px;font-family:Arial;background:white;color:#111">
      <h1>Offline receipt</h1>
      <p>This HTML does not require network access.</p>
    </div>
  ''',
  width: 360,
);

Recommended offline patterns:

Inline critical CSS in the HTML.
Use convertToImageFromAsset for bundled HTML templates.
Use base64/data URI images or local asset content injected into the HTML.
Avoid depending on remote image, font, or stylesheet URLs when deterministic offline captures are required.
Default delay is 200 milliseconds
Default width is device width