CODEWITHSUNDEEP
javagraphphysics
Ted
Ted

Reputation: 570

How do I draw an interactive Graph/Lines in Java?

Solved.

I had a question before but it was very badly posted so here it goes again, according to better rules.

I want to create some style of a graph such as this image:

enter image description here.

It's based on a physics law, Snell's Law. As of now I've managed to paint the graph it self with a basic Line2D.Double which you can see here (Line.java). Then all I need to do is, in the interface class, add the lines to the array in that class as so:

LinesArray.addLine(150 , 25 , 150 , 275);

And every time it adds a new one, it repaints as you can see in the code sample.

But the problem is that I have no idea how to make this interactive. I wanted to make it interactive, as in that you could actually move those lines and at the same time you move the first line, the second would move accordingly to the Snell's Law formula, which is:

n1 * sin( a1 ) = n2 * sin ( a2 )

Considering that a1 is the first (left) angle, and a2 the second (right) angle in the first image posted.

A perfect example of what I'd hope to achieve is this one. And if interactive movement is too hard (I'm on a 2 days schedule), this example is also a possibility.

Correct me if I'm wrong but for the second one, all that I'd need to do is calculate the mouse's coordinates and draw and calculate everything from there.

Here (menu_ui.java) is my interface class, in which the method I'm currently working with the lines is "menuSnell()" and here (Snell.java is my Snell class which contains the logic. Apologies for portuguese comments but it's fairly simple code which you don't really need comments to understand, plus I've separated it into readable methods.

So basically, my question is how do I make those lines interactive in the way I've described above.

Thanks!

Upvotes: 0

Views: 1579

Answers (1)

crog
crog

Reputation: 98

I am not a graphic expert, but I had similar work a long time ago. I had an object that I need to repaint. I created my own JPanel, which holds my objects that should be paint. Whenever something changed, I call repaint method on JPanel. It looked like this http://sourceforge.net/p/scribbler-cvut/code/132/tree/Tuzka/src/cz/cvut/scribbler/panel/RewritableGlassPane.java.

private LinkedList<ColoredArea> background = new LinkedList<ColoredArea>();
/**
 * Vykreslí všechny položky v senamu vykreslených obrazců
 * @param g2d grafika k vykreslení
 */
public void paintShape(Graphics2D g2d) {
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
    for (ColoredArea area : background) {
        area.fill(g2d);
    }
    if (mouse != null && !block) {
        g2d.setColor(mouse_color);
        g2d.draw(mouse);
    }
    if (point!=null){
        SetPointsDialog.paintPoints(point, maxPoint, parent.getChildsSize(), g2d);
    }
}

@Override
public void paint(Graphics g) {
    paintShape((Graphics2D) g);
}

@Override
protected void paintComponent(Graphics g) {
    paintShape((Graphics2D) g);
}

Everything I need to paint was stored in background variable. When something I LinkedList changed, I invoke repaint () method on the window.

I have a full source code store here: http://sourceforge.net/projects/scribbler-cvut/ but it was my long term project, so it is a little bit big.

Upvotes: 1

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