Java: Saving Graphics to background BufferedImage

Asked Jan 14 '18 at 03:36

Active Jan 14 '18 at 04:17

Viewed 111 times

So right now my paint() repeatedly paints a BufferImage over and over again. Is there any way of adding new Graphics to this BufferedImage variable?

img is a variable that stores a .png file that we will draw over.

img = ImageIO.read(new File(fileName));

My paint() functions draws this .png image over and over again.

public void paint(Graphics g){
    g.drawImage(img, 0, 0, null);

    g.setColor(Color.RED);
    g.drawLine(startX, startY, endX, endY);
}

How would I add Graphics changes (i.e. lines) to the img variable?

edited Jan 14 '18 at 03:57

vinS

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asked Jan 14 '18 at 03:36

TheTerrible

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Please clarify: Are you trying to draw lines over an image that remain or that are dynamically changing? – Hovercraft Full Of Eels Jan 14 '18 at 03:41
If so, an example of how to do this [here](https://stackoverflow.com/a/40439601/522444) – Hovercraft Full Of Eels Jan 14 '18 at 03:45
1

Having obtained a `BufferedImage` via `ImageIO.read()`, you can use `BufferedImage.getGraphics()` to get a `Graphics` by which to draw on it. See https://stackoverflow.com/questions/3914265/drawing-multiple-lines-in-a-bufferedimage, for example. – John Bollinger Jan 14 '18 at 03:47
Sorry for the confusion. Yes, I am drawing lines over an image that is dynamically changing. – TheTerrible Jan 14 '18 at 03:50
Then again as per my answer in my [link](https://stackoverflow.com/a/40439601/522444) in my second comment, get the BufferedImage's Graphics object and draw on it, but be sure to dispose of it when done. – Hovercraft Full Of Eels Jan 14 '18 at 04:17
Ok thank you guys for the help! – TheTerrible Jan 14 '18 at 05:46

Java: Saving Graphics to background BufferedImage

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