generateImage method

Future<Uint8List?> generateImage(String mermaidSyntax)

Implementation

Future<Uint8List?> generateImage(String mermaidSyntax) async {
  final fileName = mermaidSyntax.hashCode;

  final tempDir = Directory('.tmp_superdeck');

  final tempFile = File(p.join(tempDir.path, '$fileName.mmd'));
  final outputFile = File(p.join(tempDir.path, '$fileName.png'));

  if (!await tempDir.exists()) {
    await tempDir.create(recursive: true);
  }

  try {
    mermaidSyntax = mermaidSyntax.trim().replaceAll(r'\n', '\n');

    await tempFile.writeAsString(mermaidSyntax);

    final imageSizeParams = '--scale 2'.split(' ');
    final params =
        '-t dark -b transparent -i ${tempFile.path} -o ${outputFile.path} '
            .split(' ');

    // Check if can execute mmdc before executing command
    final mmdcResult = await Process.run('mmdc', ['--version']);

    if (mmdcResult.exitCode != 0) {
      log(
        '"mmdc" not found. You need mermaid cli installed to process mermaid syntax',
      );

      return null;
    }

    final result = await Process.run('mmdc', [...params, ...imageSizeParams]);

    if (result.exitCode != 0) {
      log('Error while processing mermaid syntax');
      log(result.stderr);
      return null;
    }

    return outputFile.readAsBytes();
  } catch (e) {
    log('Error while processing mermaid syntax: $e');
    return null;
  } finally {
    if (await tempDir.exists()) {
      await tempDir.delete(recursive: true);
    }
  }
}