saving bufferedimage to gif

Question

I have an application that plots images on a JPanel. I want to dispose of the GUI altogether, so that the application is called from code only, with no user interface, and so that the images are saved to a gif file only.

I have experimented with code from this question, and it seems to work fine when I call the save gif code from within the old GUI. However, the save gif code is not seeming to work when I remove the GUI, and I am wondering if that might be because the JPanel it is trying to print has not actually made it to a GUI container like a JFrame, etc.

The reason I am not posting code is that it is too verbose, an I am just asking for a simple, boilerplate answer.

I have experimented with writeablerasters for other applications. But that would require a major recoding project for this application, which paints by using the graphics.drawLine() method. Can anyone suggest a code-efficient way to take contents of a "phantom" JPanel, get it into a BufferedImage, and then save it as a gif without ever putting the JPanel in a GUI?

Whu doesn't your application draws on a `Graphics` obtained from the `BufferedImage` that you are going to save on the file? Isn't that working? — c.s., Aug 01 '13 at 19:21

score 1 · Accepted Answer · answered Aug 01 '13 at 19:29

Since your application draws on a JPanel then it just needs a Graphics object. You can use one from a BufferedImage which then you will save to file. Example code:

BufferedImage image = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB);

Graphics g = image.getGraphics();

// Pass this graphics object to your application to perform the drawing         
g.setColor(Color.red);
g.drawRoundRect(10, 10, 20, 20, 5, 5);

// save it to disk
ImageIO.write(image, "png", new File("test.png"));

score 0 · Answer 2 · answered Aug 01 '13 at 19:59

0

This is difficult to answer without any example code, however.

If the component you are trying to render is not displayed on the screen, it is likely that it has not being laid out.

Before painting, you should make sure you size the component.

componentToBePainted.setSize(componentToBePainted.getPreferredSize());

You should also be using print or printAll over paint. When not attached to a native peer, paint can cause issue

answered Aug 01 '13 at 19:59

MadProgrammer

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saving bufferedimage to gif

2 Answers2