Java Community | Help. Code. Learn.•5w ago

Drawing a JPanel to a BufferedImage, unexpected results

I'm building a node-based editor. Effectively it's Swing components on a giant carpet, connected with lines to denote relationships and flow of data. To achieve this I have my VisibleFrame with my Donatello JPanel that does the custom rendering. Donatello gets the Swing component of items in the view area, and then draws it like this:

private void drawOneNode(Graphics2D g,JPanel panel) {
    frame.add(panel);
    frame.pack();

    if (panel.getWidth() > 0 && panel.getHeight() > 0) {
        // create a BufferedImage the same size as the panel.
        BufferedImage bi = new BufferedImage(panel.getWidth(), panel.getHeight(), BufferedImage.TYPE_INT_RGB);
        // JPanel requires a Graphics2D object to draw to.  Create one from the BufferedImage.
        Graphics2D g2d = bi.createGraphics();
        // draw it.
        panel.paint(g2d);
        // done with the Graphics2D object.
        g2d.dispose();

        // TODO draw the node at the correct position
        int x = 0;//(int)camera.x;
        int y = 0;//(int)camera.y;

        // draw bitmap scaled to the screen
        g.drawImage(bi,
                x, y, x + panel.getWidth(), y + panel.getHeight(),
                0, 0, panel.getWidth(), panel.getHeight(),
                null);
    }
    frame.remove(panel);
}

private void drawOneNode(Graphics2D g,JPanel panel) {
    frame.add(panel);
    frame.pack();

    if (panel.getWidth() > 0 && panel.getHeight() > 0) {
        // create a BufferedImage the same size as the panel.
        BufferedImage bi = new BufferedImage(panel.getWidth(), panel.getHeight(), BufferedImage.TYPE_INT_RGB);
        // JPanel requires a Graphics2D object to draw to.  Create one from the BufferedImage.
        Graphics2D g2d = bi.createGraphics();
        // draw it.
        panel.paint(g2d);
        // done with the Graphics2D object.
        g2d.dispose();

        // TODO draw the node at the correct position
        int x = 0;//(int)camera.x;
        int y = 0;//(int)camera.y;

        // draw bitmap scaled to the screen
        g.drawImage(bi,
                x, y, x + panel.getWidth(), y + panel.getHeight(),
                0, 0, panel.getWidth(), panel.getHeight(),
                null);
    }
    frame.remove(panel);
}

Somehow Donatello is showing panel twice - once at my desired position and once in the top left corner. But I'm never connecting panel to Donatello, or frame to Donatello, so I'm not sure how this is possible. If I comment out panel.paint(g2d) both disappear. Anyone have a hint for me?

3 Replies

JavaBot•4w ago

⌛ This post has been reserved for your question.

Hey @i-make-robots! Please use /close or the Close Post button above when your problem is solved. Please remember to follow the help guidelines. This post will be automatically marked as dormant after 300 minutes of inactivity.

TIP: Narrow down your issue to simple and precise questions to maximize the chance that others will reply in here. 💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

i-make-robotsOP•4w ago

what the heck

JavaBot•4w ago

💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

Gaming

Programming

Drawing a JPanel to a BufferedImage, unexpected results