Thread: Help about Graphics

Hello everyone

I have a problem as I built a drag-drop gui appilcation using netbeans, and I wand to add some drawings (using filloval or so) but I have no Idea about how to do so with the generated code of the netbeans.

also I know how to do it in normal hand build gui, but I am asking about the drag-drop gui of netbeans.

Thanks in advance

Originally Posted by Varial

I guess you should just:

import java.awt.Graphics;

After you've imported the graphics, you can make an method which draws your Oval.
Like this:

public void DrawtheOval(Graphics g) {
g.fillOval(x,y,width,height);
}

Well sometimes you might have to use the method in another class/method, to make the Oval to actually get drawn.

Hope this helped a bit

PS: what is cross posting? ;x

It lets the forums know that the same person has asked the question at multiple forums.

I tried what you have said, as follows:

class draw{
public void DrawtheOval(Graphics g) {
g.setColor(Color.BLACK);
g.fillOval(30,30,30,30);
}
}

then at the beginning of netbeans generated code:
draw d = new draw();


The question now is about the next to step. to call the method I have to get it from object "d" but I have to pass some Graphics object to it. What will be the next step?

also I want to add this Oval in a panel (panel generated by netbeans gui designer, not by hand code). How about this?

I have tried something but it has not worked (although it seems logic):
jPanel.getGraphics().drawOval(30, 30, 30, 30);


Thanks for your help

Override the paintComponent method for the panel and put your drawing code there.

another way would depend on what you're drawing too. If it's a JPanel I would do something like this:
JPanel myPanel = new DrawMyPanel();

and below I would have a the DrawMyPanel class

public class DrawMyPanel extends JPanel {
@Override
paintComponent(Graphics g) {
Graphics2d 2dg;

if (g instanceOf Graphics2D) {
2dg = (Graphics2D)g;
}

// now you can draw your graphics
g.setColor(Color.blue);

g.drawOval(x, y, width, height);
}

look at this approach for drawing forms. first of all you need a frame that holds the canvas for your paintings. here is the code of the DrawableFrame.java

public class DrawableFrame extends java.awt.Frame {
 
	public DrawableFrame(String title) {
		// set the title of the frame
		super(title);
		// create a drawable canvas for the frame
		DrawableCanvas drawableCanvas = new DrawableCanvas();
		// add the canvas to the frame
		add(drawableCanvas);
		// set the desired size
		setSize(400, 400);
		// set the desired position
		setLocation(300, 200);
		// set the frame visible
		setVisible(true);
 
		// for closing the window
		addWindowListener(new java.awt.event.WindowAdapter() {
			public void windowClosing(java.awt.event.WindowEvent we) {
				System.exit(0);
			}
		});
	}
}

look at the comments in the code. next, you will need the canvas where you instantiate your forms. here is the code of DrawableCanvas.java

import java.awt.Color;
 
public class DrawableCanvas extends java.awt.Canvas {
 
	public void paint(java.awt.Graphics g) {
 
		// create instances of class DrawableClasses and send message draw()
 
			ColoredRectangle rec1 = new ColoredRectangle(22, 22, 150, 150, Color.blue); 
			// Note, each class share the same Graphics g
			rec1.draw(g);
			ColoredOval oval1 = new ColoredOval(44, 44, 150, 150, Color.blue);
			oval1.draw(g);
 
	}
}

inside the canvas the two forms Rectangle and Oval are instantiate and with the call of draw(g) also painted on the canvas. if you need further forms copy/paste the code an adapt it to the form you need. here's is the code of the ColoredRectangle.java

import java.awt.Color;
 
public class ColoredRectangle {
 
	private int x;
	private int y;
	private int width;
	private int height;
	private java.awt.Color color;
	private java.awt.Color line_color = Color.WHITE;
 
	public ColoredRectangle(int x, int y, int width, int height, java.awt.Color c ) {
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
		this.color = c;
	}
	public void draw(java.awt.Graphics g) {
		g.setColor(line_color);
		g.drawRect(x, y, width, height);
		g.setColor(color);
		g.fillRect(x + 1, y + 1, width - 1, height - 1);
	}	
}

and here the code for the ColoredOval.java

import java.awt.Color;
 
public class ColoredOval {
	private int x;
	private int y;
	private int width;
	private int height;
	private java.awt.Color color;
	private java.awt.Color line_color = Color.WHITE;
 
	public ColoredOval(int x, int y, int width, int height, java.awt.Color c ) {
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
		this.color = c;
	}
	public void draw(java.awt.Graphics g) {
		g.setColor(line_color);
		g.drawOval(x, y, width, height);
		g.setColor(color);
		g.fillOval(x + 1, y + 1, width - 1, height - 1);
	}
}

note that two calls are made inside the draw()-method. one for drawing the form and the other for drawing the borders of the form, which is helpful when the forms are overlapping.

and last but not least the class with the main method(). inside the main() only the DrawableFrame is instantiated.

public class DrawableExercise {
 
    /* methods */
    public static void main(String[] args) {
        new DrawableFrame("Some drawables...");
    }
}

hope you got some ideas with this code. you can copy/paste and then compile and run the code.

Thank you very much for your help.

The Problem is that I want to do this by Gui builder of Netbeans, so the question now is: How can I override the paint() method in Canvas or in Panel?

Or Is there another methods that I can add drawings to Canvas or Panel in runtime?

How can I override the paint() method in Canvas or in Panel?

Do you know how to use an anonymous class? That's one of the easiest ways to override an method.

Panel pnl = new Panel() {
  @Override
  public void paint(Graphics g) {
    // do your painting here
  }
};

Yes, But In Gui builder I do not create neither panel nor canvas with something like : Panel pnl = new Panel()
but it is a matter of drag and drop.

Your solution works only if I made the code by hand form the beginning

I thought that netbeans is a famous IDE and I thought that I can get help concerning dealing with some helpful tools in it as Gui builder

Perhaps you should have named this thread: Need help using Netbeans.
Your title says you want help using Grahpics.