CODEWITHSUNDEEP
javaimageswingimage-processingtransparency
Ted
Ted

Reputation: 639

How to get rid of a color in an image

I want my image, a buffered Image, to have a transparent background, I first tries using a png, then a gif, then I tried using imageFilters but I could also not hit it off, so now I decided to use a simple jpeg, set the background to a color and then get rid of that color, again, I assume imageFilters would fit for that, but I don't know exactly how to use them, the color I want to get rid of is 0xff00d8 (Magenta).

Can anyone help with a way to do this, or an example?

Upvotes: 0

Views: 175

Answers (2)

Ted
Ted

Reputation: 639

I managed to fix it using JWindow, still, thank you Jason for all of your help

I have a translucentPane extending JPanel :

public TranslucentPane() {
    setOpaque(false);
}

@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g); 

    Graphics2D g2d = (Graphics2D) g.create();
    g2d.setComposite(AlphaComposite.SrcOver.derive(0.0f));
    g2d.setColor(getBackground());
    g2d.fillRect(0, 0, getWidth(), getHeight());

}

then I do this in my main UI :

robotUI roboUI = new robotUI();
    roboUI.setBackground(new Color(0,0,0,0));

and my content pane is :

TranslucentPane pane = new TranslucentPane();

I hope this is enough for anyone to understand

Upvotes: 1

Jason
Jason

Reputation: 13986

jpeg doesn't support transparency. Make sure your buffered image also supports transparency:

BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

The A in TYPE_INT_ARGB stands for alpha which is a measure of opacity.

You need to set the pixel value to 0x00000000 in order to make it transparent. 

//Load the image
BufferedImage in = ImageIO.read(img);
int width = in.getWidth(), height = in.getHeight();
BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = bi.createGraphics();
g.drawImage(in, 0, 0, null);
g.dispose();

//Change the color
int colorToChange = 0xff00d8;
for (int x=0;x<width;x++)
    for (int y=0;y<height;y++)
        if(bi.getRGB(x,y)==colorToChange)
            bi.setRGB(x,y,0x00FFFFFF&colorToChange);

bi.save(new File("out.png"));

Upvotes: 2

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