Java - convert image to black and white - with vibrant colors

Question

I am trying to convert an image only to black and white (not gray).

I used this:

BufferedImage blackAndWhiteImage = new BufferedImage(
        dWidth.intValue(),
        dHeight.intValue(),
        BufferedImage.TYPE_BYTE_BINARY);
Graphics2D graphics = blackAndWhiteImage.createGraphics();
graphics.drawImage(colourImage, 0, 0, null);

return blackAndWhiteImage;

Everything is fine until I decided to try bright colors, for example, the Google logo:

and it turned out:

Then I first tried going through the gray scale using:

BufferedImage blackAndWhiteImage2 = new BufferedImage(
        dWidth.intValue(),
        dHeight.intValue(),
        BufferedImage.TYPE_USHORT_GRAY);

And it seems that he retained the blue color, but not the brightest (in this case, yellow), and, as you can see, it decreased in quality:

Any suggestions are greatly appreciated; I believe that I am looking to convert every color to black except white (which will be the background color), this is already done by applying TYPE_BYTE_BINARY removing the alpha channel.

---

EDIT: Maybe I didn’t explain very clearly:

• the final image should have a white background ** 1

** 1 - , . (whiteOnBlackExample), , , "" .

, -, → - ;

Answer 1

JavaFX, ColorAdjust -1 (), ( ) :

public class Main extends Application {

    Image image = new Image("https://i.stack.imgur.com/UPmqE.png");

    @Override
    public void start(Stage primaryStage) {
        ImageView colorView = new ImageView(image);
        ImageView bhView = new ImageView(image);

        ColorAdjust colorAdjust = new ColorAdjust();
        colorAdjust.setBrightness(-1);
        bhView.setEffect(colorAdjust);

        primaryStage.setScene(new Scene(new VBox(colorView, bhView)));
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

Effect , , , , , .

Edit

,

• , , ,
• , , ,

, , . :

WritableImage writableImage = new WritableImage(image.getPixelReader(), (int) image.getWidth(), (int) image.getHeight());
PixelWriter pixelWriter = writableImage.getPixelWriter();
PixelReader pixelReader = writableImage.getPixelReader();
for (int i = 0; i < writableImage.getHeight(); i++) {
    for (int j = 0; j < writableImage.getWidth(); j++) {
        Color c = pixelReader.getColor(j, i);
        if (c.getOpacity() < 1) {
            pixelWriter.setColor(j, i, Color.WHITE);
        }
        if (c.getRed() > 0 || c.getGreen() > 0 || c.getBlue() > 0) {
            pixelWriter.setColor(j, i, Color.BLACK);
        }
    }
}
ImageView imageView = new ImageView(writableImage);

, , , . , 1, 2, 2, 1, . , WHITE BLACK . , , . .

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Answer 2

. .

BufferedImage myColorImage = ImageIO.read(fileInput);
BufferedImage myBWImage = new BufferedImage(myColorImage.getWidth(), myColorImage.getHeight(), BufferedImage.TYPE_BYTE_BINARY);

rgb :

for (int x = 0; x < myColorImage.getWidth(); x++)
    for (int y = 0; y < myColorImage.getHeight(); y++)
        if (rgbToGray(myColorImage.getRGB(x, y), MODE.AVERAGE) > threshold)
            myBWImage.setRGB(x, y, 0);
        else
            myBWImage.setRGB(x, y, 0xffffff); 

rgbToGray :

private static int rgbToGray(int rgb, MODE mode) {
    // split rgb integer into R, G and B components
    int r = (rgb >> 16) & 0xff;
    int g = (rgb >> 8) & 0xff;
    int b = rgb & 0xff;
    int gray;
    // Select mode
    switch (mode) {
        case LIGHTNESS:
            gray = Math.round((Math.max(r, Math.max(g, b)) + Math.min(r, Math.min(g, b))) / 2);
            break;
        case LUMINOSITY:
            gray = Math.round(0.21f * r + 0.72f * g + 0.07f * b);
            break;
        case AVERAGE:
        default:
            gray = Math.round((r + g + b) / 3);
            break;
    }
    return gray;
}

:

private enum MODE {
    LIGHTNESS, AVERAGE, LUMINOSITY
}

:

: Google threshold = 1 , [0..255]. , , 100-150. MODE .