/** Graphic instance for rendering Barcode position and content information in an overlay view. */
public class BarcodeGraphic extends Graphic {

  private static final int TEXT_COLOR = Color.WHITE;
  private static final float TEXT_SIZE = 54.0f;
  private static final float STROKE_WIDTH = 4.0f;

  private final Paint rectPaint;
  private final Paint barcodePaint;
  private final FirebaseVisionBarcode barcode;

  BarcodeGraphic(GraphicOverlay overlay, FirebaseVisionBarcode barcode) {
    super(overlay);

    this.barcode = barcode;

    rectPaint = new Paint();
    rectPaint.setColor(TEXT_COLOR);
    rectPaint.setStyle(Paint.Style.STROKE);
    rectPaint.setStrokeWidth(STROKE_WIDTH);

    barcodePaint = new Paint();
    barcodePaint.setColor(TEXT_COLOR);
    barcodePaint.setTextSize(TEXT_SIZE);
    // Redraw the overlay, as this graphic has been added.
    postInvalidate();
  }

  /**
   * Draws the barcode block annotations for position, size, and raw value on the supplied canvas.
   */
  @Override
  public void draw(Canvas canvas) {
    if (barcode == null) {
      throw new IllegalStateException("Attempting to draw a null barcode.");
    }

    // Draws the bounding box around the BarcodeBlock.
    RectF rect = new RectF(barcode.getBoundingBox());
    rect.left = translateX(rect.left);
    rect.top = translateY(rect.top);
    rect.right = translateX(rect.right);
    rect.bottom = translateY(rect.bottom);
    canvas.drawRect(rect, rectPaint);

    // Renders the barcode at the bottom of the box.
    canvas.drawText(barcode.getRawValue(), rect.left, rect.bottom, barcodePaint);
  }
}