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).