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Question

I am having a bit of trouble making this grid be drawn 10 pixels from the top and 10 pixels from the left of the Frame.

I can make it do it by increasing this.getY() + 10 to a higher number, just wondering why if is remove the + 10 it getting drawn off screen.

Ignore the variable names and any formatting I just threw this together

package griddrawing;

import java.awt.*;
import javax.swing.*;

public class Grid extends JFrame
{

    private int TILEWIDTH;
    private int TILEHEIGHT;
    private int COLS;
    private int ROWS;
    private int defaultX;
    private int defaultY;
    private int currentX;
    private int currentY;

    public Grid()
    {
        setSize(800,400);
        TILEWIDTH = 30;
        TILEHEIGHT = 30;
        COLS = 10;
        ROWS = 10;
        defaultX = this.getX() + 10;
        defaultY = this.getY() + 10;
        currentX = 0;
        currentY = 0;
    }

    @Override
    public void paint(Graphics g)
    {
        super.paint(g);

        currentX = defaultX;
        currentY = defaultY;

        g.setColor(Color.black);

        for(int i = 0; i < COLS; i++)
        {
            for(int k = 0 ; k < ROWS; k++)
            {
                g.drawRect(currentX - (TILEWIDTH / 2), currentY - (TILEHEIGHT / 2), TILEWIDTH, TILEHEIGHT);
                g.drawString("" + k, currentX, currentY);
                currentY += TILEWIDTH;
                System.out.println("COL: " + i + " ROW: " + k + " Current X: " + currentX + " Current Y: " + currentY);
            }
            currentY = defaultY;
            currentX += TILEHEIGHT;
        }
    }
}

Answer 1

1. Don't set the size of the frame.
2. Don't paint directly to the frame either.

Instead of both:

1. Override the paintComponent(Graphics) method of a JComponent or JPanel .
2. Either call theComponent.setPreferredSize(Dimension) or override that same method.
3. Add the custom component to the frame and call pack() .

That lot should mean you no longer need to account for any offset (which might change by platform or PLAF).