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Basically, i've been told to initialise a grid into the "canvas" section of this program i've made, I need to make a fine grid that stretches across the whole canvas horizontally and vertically, 10 x 10 pixels apart example of the code i'm editing to do this below...

class Canvas extends JPanel
    {
        // Called every time there is a change in the canvas contents.
        public void paintComponent(Graphics g)
        {
            super.paintComponent(g);        
            draw(g);
            g.setColor(new Color(0.8F, 0.8F, 0.8F));
            g.drawLine(10, 800, 10, 10);
            g.drawLine(20,800, 20, 10);
            g.drawLine(30, 800, 30, 10);
            g.drawLine(40,800, 40, 10);
            g.drawLine(50, 800, 50, 10);
            g.drawLine(60,800, 60, 10);
            g.drawLine(70, 800, 70, 10);
            g.drawLine(80,800, 80, 10);
            g.drawLine(90, 800, 90, 10);
            g.drawLine(100,800, 100, 10);
            g.drawLine(110, 800, 110, 10);
            g.drawLine(120,800, 120, 10);
            g.drawLine(130, 800, 130, 10);
            g.drawLine(140,800, 140, 10);
        }
    } // end inner class Canvas

^This is what i've been doing it like, adding a line one by one, but is there any way i can set it to fill the entire canvas with horizontal and vertical lines that are spaced 10 pixels apart, without having to write the whole thing out line by line, i assumed you would have to write an array, but i've got no idea how i can use it to keep adding lines until it finds the total height and width and stops adding them.

Any help would be appreciated.

//All the code in this particular program is below so you can test for yourself what it does. The lines i have put in already is a crude part of the end result :P.

For easier figuring out, the canvas is 800 width by 640 height.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
import java.io.*;

public class DrawingApplication extends JFrame
{
    // GUI Component dimentsions.
    private final int CANVAS_INITIAL_WIDTH = 800;
    private final int CANVAS_INITIAL_HEIGHT = 640;
    private final int CONTROL_PANEL_WIDTH = 200;
    private final int MESSAGE_AREA_HEIGHT = 100;

    class CanvasMouseMotionListener implements MouseMotionListener
    {
        public void mouseMoved(MouseEvent event)
        {
            canvas.addMouseMotionListener(new CanvasMouseMotionListener()); 
            ;
        }

        public void mouseDragged(MouseEvent event)
        {
            canvas.addMouseMotionListener(new CanvasMouseMotionListener()); 
            ;
        }

    }

    // Drawing area class (inner class).
    class Canvas extends JPanel
    {
        // Called every time there is a change in the canvas contents.
        public void paintComponent(Graphics g)
        {
            super.paintComponent(g);        
            draw(g);
            g.setColor(new Color(0.8F, 0.8F, 0.8F));
            g.drawLine(10, 800, 10, 10);
            g.drawLine(20,800, 20, 10);
            g.drawLine(30, 800, 30, 10);
            g.drawLine(40,800, 40, 10);
            g.drawLine(50, 800, 50, 10);
            g.drawLine(60,800, 60, 10);
            g.drawLine(70, 800, 70, 10);
            g.drawLine(80,800, 80, 10);
            g.drawLine(90, 800, 90, 10);
            g.drawLine(100,800, 100, 10);
            g.drawLine(110, 800, 110, 10);
            g.drawLine(120,800, 120, 10);
            g.drawLine(130, 800, 130, 10);
            g.drawLine(140,800, 140, 10);
        }
    } // end inner class Canvas

    private Canvas canvas;
    private JPanel controlPanel;
    private JLabel coordinatesLabel;
    private JRadioButton lineRadioButton, ovalRadioButton, rectangleRadioButton, freehandRadioButton;
    private JSlider freehandSizeSlider;
    private JCheckBox fineCheckBox, coarseCheckBox;
    private JButton colourButton, clearButton, animateButton;

    private JTextArea messageArea;

    private JMenuBar menuBar;

    /*****************************************************************
     * 
     * Constructor method starts here
     *    ... and goes on for quite a few lines of code 
     */
    public DrawingApplication()
    {
        setTitle("Drawing Application (da1)");
        setLayout(new BorderLayout());  // Layout manager for the frame.

        // Canvas
        canvas = new Canvas();
        canvas.setBorder(new TitledBorder(new EtchedBorder(), "Canvas"));
        canvas.setPreferredSize(new Dimension(CANVAS_INITIAL_WIDTH, CANVAS_INITIAL_HEIGHT));
        // next line changes the cursor's rendering whenever the mouse drifts onto the canvas
        canvas.setCursor(new Cursor(Cursor.CROSSHAIR_CURSOR));
        add(canvas, BorderLayout.CENTER);

        // Menu bar
        menuBar = new JMenuBar();
        JMenu fileMenu = new JMenu("File");
        JMenuItem fileSaveMenuItem = new JMenuItem("Save");
        fileMenu.add(fileSaveMenuItem);
        JMenuItem fileLoadMenuItem = new JMenuItem("Load");
        fileMenu.add(fileLoadMenuItem);
        fileMenu.addSeparator();
        JMenuItem fileExitMenuItem = new JMenuItem("Exit");
        fileMenu.add(fileExitMenuItem);
        menuBar.add(fileMenu);
        JMenu helpMenu = new JMenu("Help");
        JMenuItem helpAboutMenuItem = new JMenuItem("About");
        helpMenu.add(helpAboutMenuItem);
        menuBar.add(helpMenu);
        add(menuBar, BorderLayout.PAGE_START);

        // Control Panel
        controlPanel = new JPanel();
        controlPanel.setBorder(new TitledBorder(new EtchedBorder(), "Control Panel"));
        controlPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH, CANVAS_INITIAL_HEIGHT));
        // the following two lines put the control panel in a scroll pane (nicer?).      
        JScrollPane controlPanelScrollPane = new JScrollPane(controlPanel);
        controlPanelScrollPane.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH + 30, CANVAS_INITIAL_HEIGHT));
        add(controlPanelScrollPane, BorderLayout.LINE_START);        

        // Control Panel contents are specified in the next section: 
        //    mouse coords panel; 
        //    shape tools panel; 
        //    trace-slider panel; 
        //    grid panel; 
        //    colour choice panel; 
        //    "clear" n "animate" buttons

        // Mouse Coordinates panel
        JPanel coordinatesPanel = new JPanel();
        coordinatesPanel.setBorder(new TitledBorder(new EtchedBorder(), "Drawing Position"));
        coordinatesPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 60));
        coordinatesLabel = new JLabel ();
        coordinatesPanel.add(coordinatesLabel);
        controlPanel.add(coordinatesPanel);
        coordinatesLabel.setText("Co-ordinates");

        // Drawing tools panel
        JPanel drawingToolsPanel = new JPanel();
        drawingToolsPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 140));
        drawingToolsPanel.setLayout(new GridLayout(0, 1));
        drawingToolsPanel.setBorder(new TitledBorder(new EtchedBorder(), "Drawing Tools"));
        controlPanel.add(drawingToolsPanel);

        // Freehand trace size slider
        JPanel freehandSliderPanel = new JPanel();
        freehandSliderPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 90));
        drawingToolsPanel.setLayout(new GridLayout(0, 1));
        freehandSliderPanel.setBorder(new TitledBorder(new EtchedBorder(), "Freehand Size"));
        controlPanel.add(freehandSliderPanel);

        // Grid Panel
        JPanel gridPanel = new JPanel();
        gridPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 80));
        gridPanel.setLayout(new GridLayout(0, 1));
        gridPanel.setBorder(new TitledBorder(new EtchedBorder(), "Grid"));
        controlPanel.add(gridPanel);

        // Colour Panel
        JPanel colourPanel = new JPanel();
        colourPanel.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 90));
        colourPanel.setBorder(new TitledBorder(new EtchedBorder(), "Colour"));
        colourButton = new JButton();
        colourButton.setPreferredSize(new Dimension(50, 50));
        colourPanel.add(colourButton);
        controlPanel.add(colourPanel);

        // Clear button
        clearButton = new JButton("Clear Canvas");
        clearButton.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 50));
        controlPanel.add(clearButton);

        // Animate button 
        animateButton = new JButton("Animate");
        animateButton.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH - 20, 50));
        controlPanel.add(animateButton);

        // that completes the control panel section

        // Message area
        messageArea = new JTextArea();
        messageArea.setEditable(false);
        messageArea.setBackground(canvas.getBackground());
        JScrollPane textAreaScrollPane = new JScrollPane(messageArea);
        textAreaScrollPane.setBorder(new TitledBorder(new EtchedBorder(), "Message Area"));
        textAreaScrollPane.setPreferredSize(new Dimension(CONTROL_PANEL_WIDTH + CANVAS_INITIAL_WIDTH, MESSAGE_AREA_HEIGHT));
        add(textAreaScrollPane, BorderLayout.PAGE_END);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);

    }  // end of the DrawingApplication constructor method

    // Called by the canvas' paintComponent method
    void draw(Graphics g)
    {
        ;
    } // end draw method   

    public static void main(String args[])
    {
        DrawingApplication drawingApplicationInstance = new DrawingApplication();
    } // end main method

} // end of DrawingApplication class
2
Contributors
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Discussion Span
Last Post by Ntropy
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Break it down to a simple loop that draws the vertical lines stepping across from x=0 to x=width, adding 10 each time. After that write a second loop that draws your horizontal lines, from y=0 adding 10 until y=height. You don't need an array for that.

Edited by Ezzaral: n/a

0
public class Canvas extends JPanel
    {
        // Called every time there is a change in the canvas contents.
        public void paintComponent(Graphics g)
        { 
            for (x=0;x<800;x++)
            {
                super.paintComponent(g);        
                draw(g);
                g.setColor(new Color(0.8F, 0.8F, 0.8F));
                g.drawLine(10, 640, 10, 10);
            }
        }
    } // end inner class Canvas

What on earth am i doing wrong here? Says it's not public but it is!

0

You don't show where you have declared x, but in your loop it doesn't need to be public anyway. Just declare int x=0; in your loop. It's only needed locally.

Other things to note:
-You also want to reconsider your increment x by one unless you really want to color the whole area black.
- The calls to super.paintComponent() and draw() shouldn't be in the loop.
- Loop variables don't do much for you when you hard-code the coordinates in drawLine().

Edited by Ezzaral: n/a

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