Rotate Barcode Images

Rotate Barcode Images

Aspose.BarCode for Java allows you to rotate the complete generated barcode image without changing the encoded data.

Rotation is applied to:

• barcode bars or modules;
• human-readable code text;
• captions;
• padding;
• borders.

The complete source code for the examples in this article is available on GitHub:

View RotationExample.java

set

Rotate a barcode by 90 degrees

Use setRotationAngle to rotate a generated image clockwise.

BarcodeGenerator generator = new BarcodeGenerator(
        EncodeTypes.CODE_128,
        "ROTATE-90"
);

generator.getParameters().setRotationAngle(90.0f);

generator.save(
        "code128_rotate_90.png",
        BarCodeImageFormat.PNG
);

Right-angle rotations such as 90, 180, and 270 degrees usually preserve crisp barcode geometry and are broadly compatible with scanners.

Rotate a barcode by 180 degrees

BarcodeGenerator generator = new BarcodeGenerator(
        EncodeTypes.CODE_128,
        "ROTATE-180"
);

generator.getParameters().setRotationAngle(180.0f);

generator.save(
        "code128_rotate_180.png",
        BarCodeImageFormat.PNG
);

Use a negative rotation angle

Negative values rotate the image counterclockwise.

BarcodeGenerator generator = new BarcodeGenerator(
        EncodeTypes.CODE_128,
        "ROTATE-NEGATIVE"
);

generator.getParameters().setRotationAngle(-90.0f);

generator.save(
        "code128_rotate_negative_90.png",
        BarCodeImageFormat.PNG
);

Rotate by an arbitrary angle

The API accepts arbitrary angle values.

BarcodeGenerator generator = new BarcodeGenerator(
        EncodeTypes.QR,
        "ARBITRARY-ANGLE"
);

generator.getParameters().setRotationAngle(25.0f);

generator.save(
        "qr_rotate_25.png",
        BarCodeImageFormat.PNG
);

Angles that are not multiples of 90 degrees can require a larger output canvas and may introduce interpolation around barcode edges. This can reduce recognition reliability for small or low-resolution images.

Recommendations

• Prefer 90, 180, and 270 degree rotations when possible.
• Use a sufficiently large module or bar width.
• Keep enough padding so that the rotated symbol is not clipped.
• Test arbitrary-angle images with the intended scanner.
• Verify the final image after printing or format conversion.