printMultipleColumn static method

Future<bool> printMultipleColumn({ required List<PrintColumn> columns, int canvasWidth = 832, double lineHeight = 1.5, Alignment alignment = Alignment.center, double padding = 10, })

Print multiple columns of text.

• columns: List of column objects specifying text, position, and style
• canvasWidth: Width of the print canvas in dots
• lineHeight: Line height multiplier
• alignment: Overall alignment
• padding: Padding around the content

Returns true if printing was successful.

Implementation

static Future<bool> printMultipleColumn({
  required List<PrintColumn> columns,
  int canvasWidth = 832,
  double lineHeight = 1.5,
  Alignment alignment = Alignment.center,
  double padding = 10,
}) async {
  try {
    final directory = await getTemporaryDirectory();
    final tempPath =
        '${directory.path}/multi_col_${DateTime.now().millisecondsSinceEpoch}.png';

    final recorder = PictureRecorder();
    final canvas = Canvas(recorder);
    final backgroundPaint = Paint()..color = Colors.white;

    final textPainters = columns.map((col) {
      final span = TextSpan(
        text: col.text,
        style: TextStyle(
          fontSize: col.fontSize,
          fontWeight: col.fontWeight,
          fontFamily: col.fontFamily,
          color: col.color,
        ),
      );
      final painter = TextPainter(
        text: span,
        textAlign: col.align,
        textDirection: TextDirection.ltr,
      );
      painter.layout();
      return painter;
    }).toList();

    // Estimate canvas height based on tallest text
    final maxHeight =
        textPainters.map((p) => p.height).reduce((a, b) => a > b ? a : b);
    final canvasHeight =
        (maxHeight * lineHeight).ceil() + (padding * 2).ceil();

    canvas.drawRect(
      Rect.fromLTWH(0, 0, canvasWidth.toDouble(), canvasHeight.toDouble()),
      backgroundPaint,
    );

    for (int i = 0; i < columns.length; i++) {
      final col = columns[i];
      final tp = textPainters[i];

      double dx = col.x;
      if (col.align == TextAlign.center) {
        dx = col.x - tp.width / 2;
      } else if (col.align == TextAlign.right) {
        dx = col.x - tp.width;
      }

      tp.paint(canvas, Offset(dx, padding));
    }

    final picture = recorder.endRecording();
    final img = await picture.toImage(canvasWidth, canvasHeight);
    final byteData = await img.toByteData(format: ImageByteFormat.png);
    final buffer = byteData!.buffer.asUint8List();

    await File(tempPath).writeAsBytes(buffer);
    return await PrinterCore.printImage(
      tempPath,
      width: canvasWidth,
      alignment: TextFormatter.convertAlignment(alignment),
    );
  } catch (e) {
    print('Error printing multiple columns: $e');
    return false;
  }
}