PboeLedMatrix

PboeLedMatrix.java

///usr/bin/env jbang "$0" "$@" ; exit $?

//DEPS com.fazecast:jSerialComm:2.10.2
//SOURCES helper/PixelBlazeOutputExpanderHelper.java

import helper.PixelBlazeOutputExpanderHelper;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;

public class PboeLedMatrix {

	private static final int CHANNEL_MATRIX = 1;
	private static final int BYTES_PER_PIXEL = 3;
	private static final int NUMBER_OF_LEDS_MATRIX = 8 * 8;

	public static void main(String[] args) throws Exception {

		PixelBlazeOutputExpanderHelper helper = new PixelBlazeOutputExpanderHelper("/dev/ttyS0");
		helper.sendAllOff(CHANNEL_MATRIX, NUMBER_OF_LEDS_MATRIX);

		BufferedImage bImage = ImageIO.read(new File("heart_8x8.png"));
		if (bImage.getWidth() != 8 && bImage.getHeight() != 8)
			throw new IllegalStateException("Image is not 8x8!");

		bImage = rotateImage(bImage, 90);

		byte[] pixelsRgb = new byte[NUMBER_OF_LEDS_MATRIX * BYTES_PER_PIXEL];
		int i = 0;
		for (int x = 0; x < bImage.getWidth(); x++) {
			for (int y = 0; y < bImage.getHeight(); y++) {
				int rgb = bImage.getRGB(x, y);

				Color color = new Color(rgb, false);
				color = color.darker().darker().darker().darker().darker().darker().darker().darker().darker().darker();
				int blue = color.getBlue();
				int green = color.getGreen();
				int red = color.getRed();
				pixelsRgb[(i * BYTES_PER_PIXEL)] = (byte) red;
				pixelsRgb[(i * BYTES_PER_PIXEL) + 1] = (byte) green;
				pixelsRgb[(i * BYTES_PER_PIXEL) + 2] = (byte) blue;

				i++;
			}
		}

		helper.sendColors(CHANNEL_MATRIX, pixelsRgb, false);
		Thread.sleep(5000);

		helper.sendAllOff(CHANNEL_MATRIX, NUMBER_OF_LEDS_MATRIX);
		//Thread.sleep(100);

		helper.closePort();
	}

	private static BufferedImage rotateImage(BufferedImage buffImage, double angle) {
		double radian = Math.toRadians(angle);
		double sin = Math.abs(Math.sin(radian));
		double cos = Math.abs(Math.cos(radian));

		int width = buffImage.getWidth();
		int height = buffImage.getHeight();

		int nWidth = (int) Math.floor((double) width * cos + (double) height * sin);
		int nHeight = (int) Math.floor((double) height * cos + (double) width * sin);

		BufferedImage rotatedImage = new BufferedImage(nWidth, nHeight, BufferedImage.TYPE_INT_ARGB);

		Graphics2D graphics = rotatedImage.createGraphics();

		graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);

		graphics.translate((nWidth - width) / 2, (nHeight - height) / 2);
		// rotation around the center point
		graphics.rotate(radian, (double) (width / 2), (double) (height / 2));
		graphics.drawImage(buffImage, 0, 0, null);
		graphics.dispose();

		return rotatedImage;
	}
}

The input must be a 8x8 image. Using Color.darker() we can handle reduce the brightness, and with the rotateImage() we can handle the LED matrix lying on its side.