[Java 7 SE+MySQL+NetBeans 7.2.1+Graphics (2D)]paint and paintComponent problem

Dear Sirs and Madams!

In the following code, I have class, subclassed from JPanel, which acts as my "drawing board"-canvas. In this class I fetch records from database and I want to show them as JLabel elements in JPanel's GridLayout. In addition to I have implemented following functionalities in this class:

• drawing AutoCad like mouse cursor (cross cursor), which is drawn on mouseMove() event
• drawing Ruler

Now, I had to implement double buffering, because screen was flickering if I moved a mouse, but now I do not see neither ruler neither my JLabel items, fetched from mysql database. Since I do not understand Java Graphics yet, I've overriden methods paint() and paintComponents and I think, I've messed things up. Can someme give me a little guidance? Here is the code:

Code:

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/**
 *
 */
package ha.configurator.gui;

import ha.global.dbmanager.CDatabaseManager;
import ha.global.dbmanager.entities.CEntityMultimedia;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.Point;
import java.awt.Stroke;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.image.BufferedImage;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EtchedBorder;

/**
 * @author markof
 */
public class CPanelGraphics extends JPanel implements MouseListener,
        MouseMotionListener,MouseWheelListener
{
        private class CZoomHandler implements MouseWheelListener
        {
            @Override
            public void mouseWheelMoved(MouseWheelEvent e)
            {
                double distanceX=maxX-minX;
                double distanceY=maxY-minY;

                double cursorX=minX+distanceX/2.0;
                double cursorY=minY+distanceY/2.0;

                int rotation=e.getWheelRotation();
                if(rotation<0)
                {
                    distanceX/=COEFF_ZOOM;
                    distanceY/=COEFF_ZOOM;
                }
                else
                {
                    distanceX*=COEFF_ZOOM;
                    distanceY*=COEFF_ZOOM;
                }

                minX = cursorX - distanceX / 2.0;
                maxX = cursorX + distanceX / 2.0;
                minY = cursorY - distanceY / 2.0;
                maxY = cursorY + distanceY / 2.0;

                repaint();
            }
        }  // class CZoomHandler

    private static final long serialVersionUID=7300896943408520338L;

    public static final int GRID_NUMBER_OF_COLUMNS=4;
    public static final int GRID_NUMBER_OF_ROWS=4;
    public static final int GRID_GAP_HORIZONTAL=2;
    public static final int GRID_GAP_VERTICAL=2;
    private static final Color COLOR_BACKGROUND=Color.WHITE;
    private static final Color COLOR_MAJOR_GRID=Color.RED/*GRAY.brighter()*/;
    private static final Color COLOR_MINOR_GRID=Color.RED.brighter();/*new Color(220,
            220,
            220);*/
    private static final Color COLOR_AXIS=Color.BLACK;
    private static final float STROKE_AXIS=1.2f;
    private static final float STROKE_GRID=1.0f;
    private static final float COEFF_ZOOM=1.1f;
    private int m_iMouseXPos=0;
    private int m_iMouseYPos=0;
    private Image mImage;

    private GridLayout m_oLayouMain=new GridLayout(CPanelGraphics.GRID_NUMBER_OF_ROWS,
            CPanelGraphics.GRID_NUMBER_OF_COLUMNS,
            CPanelGraphics.GRID_GAP_HORIZONTAL,
            CPanelGraphics.GRID_GAP_VERTICAL);
    protected GridLayout layoutMain()
        { return this.m_oLayouMain; }
    protected void setLayoutMain(final GridLayout gl /* GridLayout */)
        { this.m_oLayouMain=gl; }

    private List<CEntityMultimedia> m_oListMultimediaEntities=new ArrayList<>();
    protected List<CEntityMultimedia> listMultimediaEntites()
        { return this.m_oListMultimediaEntities; }
    protected void setListMultimediaEntities(final ArrayList<CEntityMultimedia> lae /* ListAbstractEntity */)
        { this.m_oListMultimediaEntities=lae; }

    private List<JLabel> m_oListMultimediaEntitesButtons=new ArrayList<>();
    protected List<JLabel> listMultimediaEntitiesButtons()
        { return this.m_oListMultimediaEntitesButtons; }
    protected void setListMultimediaEntitiesButtons(final List<JLabel> lmmeb /* ListMultiMediaListButtons */)
        { this.m_oListMultimediaEntitesButtons=lmmeb; }

    protected double minX;
    protected double maxX;
    protected double minY;
    protected double maxY;

    private double originX;
    private double originY;

    private double majorX;
    private int minorX;
    private double majorY;
    private int minorY;

    private NumberFormat formatter;

    private CZoomHandler zoomHandler;

    /**
    *
    */
    public CPanelGraphics()
    {
        super();

        this.init();
    }  // default constructor

    @Override
    public void mouseClicked(final MouseEvent me)
    {
//        this.m_iMouseXPos=(int)me.getPoint().getX();
//        this.m_iMouseYPos=(int)me.getPoint().getY();
//
//        final Graphics g=this.getGraphics();
//        g.drawString("("+Integer.toString(this.m_iMouseXPos)+", "
//                +Integer.toString(this.m_iMouseYPos)+")", this.m_iMouseXPos-10,
//                this.m_iMouseYPos+10);
//        // g.dispose();
    }

    @Override
    public void mouseDragged(final MouseEvent me)
    {
    }

    @Override
    public void mouseEntered(final MouseEvent me)
    {
    }

    /*
    * (non-Javadoc)
    * @see java.awt.event.MouseListener#mouseExited(java.awt.event.MouseEvent)
    */
    @Override
    public void mouseExited(final MouseEvent me)
    {
    }

    @Override
    public void mouseMoved(final MouseEvent me)
    {
        final Graphics g=this.getGraphics();

        this.m_iMouseXPos=(int)me.getPoint().getX();
        this.m_iMouseYPos=(int)me.getPoint().getY();

        this.repaint();
    }  // mouseMoved

    /*
    * (non-Javadoc)
    * @see java.awt.event.MouseListener#mousePressed(java.awt.event.MouseEvent)
    */
    @Override
    public void mousePressed(final MouseEvent me)
    {
    }

    /*
    * (non-Javadoc)
    * @see
    * java.awt.event.MouseListener#mouseReleased(java.awt.event.MouseEvent)
    */
    @Override
    public void mouseReleased(final MouseEvent me)
    {
    }

    /*
    * (non-Javadoc)
    * @see java.awt.event.MouseWheelListener#mouseWheelMoved(java.awt.event.
    * MouseWheelEvent)
    */
    @Override
    public void mouseWheelMoved(final MouseWheelEvent e)
    {
    }

    @Override
    public void paint(Graphics g)
    {
        Graphics2D g2=(Graphics2D)g;
        Stroke stroke=g2.getStroke();
        Dimension d=getSize();

        this.checkOffScreenImage();
        Graphics offG=mImage.getGraphics();
        offG.setColor(getBackground());
        offG.fillRect(0,
                0,
                d.width,
                d.height);
        this.paintOffScreen(mImage.getGraphics());
        g.drawImage(mImage,
                0,
                0,
                null);
    }  // paint

    @Override
    protected void paintComponent(Graphics g)
    {
        Graphics2D g2=(Graphics2D)g;

        this.drawGrid(g2);
        this.drawAxis(g2);
    }  // paintComponent

    private void init()
    {
        final Cursor blankCursor=Toolkit.getDefaultToolkit()
                .createCustomCursor(
                        new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB),
                        new Point(0, 0), "blank cursor");

        this.formatter=NumberFormat.getInstance();
        this.zoomHandler=new CZoomHandler();
        this.addMouseWheelListener(this.zoomHandler);
        this.setCursor(blankCursor);
        this.addMouseListener(this);
        this.addMouseMotionListener(this);
        this.addMouseWheelListener(this);
        this.setDoubleBuffered(true);
        this.initLayout();
    }  // init

    private void initLayout()
    {
        this.setLayout(this.layoutMain());
    }  // initLayout

    /**
    *
    * @throws Exception
    */
    public void populatePanelWithItems() throws Exception
    {
        try
        {
            int iNumberOfColumns=GRID_NUMBER_OF_COLUMNS;
            int iNumberOfRows=0;
            int iNumberOfElementsLastRow=0;

            this.setListMultimediaEntities(CDatabaseManager.getMultimediaEntitiesArrayList());
            int iNumberOfElements=this.listMultimediaEntites().size();
            iNumberOfRows=iNumberOfElements/iNumberOfColumns;
            iNumberOfElementsLastRow=iNumberOfElements%iNumberOfColumns;

            for(int iIndexY=0; iIndexY<iNumberOfRows; iIndexY++)
            {
                if((iIndexY==(iNumberOfRows-1))&&(iNumberOfElementsLastRow>0))
                {
                    for(int iIndexX=0; iIndexX<iNumberOfElementsLastRow; iIndexX++)
                    {
                        JLabel item=new JLabel(this.listMultimediaEntites().
                                get(iIndexY*iNumberOfColumns+iIndexX).name());
                        item.setBorder(new EtchedBorder(EtchedBorder.RAISED));
                        //item.setBackground(Color.WHITE);
                        this.listMultimediaEntitiesButtons().add(item);
                    }
                }
                else
                {
                    for(int iIndexX=0; iIndexX<iNumberOfColumns; iIndexX++)
                    {
                        JLabel item=new JLabel(this.listMultimediaEntites().
                                get(iIndexY*iNumberOfColumns+iIndexX).name());
                        item.setBorder(new EtchedBorder(EtchedBorder.RAISED));
                        this.listMultimediaEntitiesButtons().add(item);
                    }  // x-coord loop
                }  // if
            }  // y-coord loop

            for(int iIndex=0; iIndex<this.listMultimediaEntitiesButtons().size(); iIndex++)
            {
                this.add(this.listMultimediaEntitiesButtons().get(iIndex));
                //this.listMultimediaEntitiesButtons().get(iIndex).setVisible(true);
            }  // for
        }
        catch(Exception ex)
        {
            throw(ex);
        }  // try-catch
    }  // populatePanelWithItems

    private void checkOffScreenImage()
    {
        Dimension d=getSize();
        if(mImage==null||
                mImage.getWidth(null)!=d.width||
                mImage.getHeight(null)!=d.height)
        {
            mImage = createImage(d.width,
                    d.height);
        }
    }  // checkOffScreenImage

    private void paintOffScreen(Graphics g)
    {
        g.drawLine(this.m_iMouseXPos,
                0,
                this.m_iMouseXPos,
                this.getHeight());
        g.drawLine(0,
                this.m_iMouseYPos,
                this.getWidth(),
                this.m_iMouseYPos);
/*
        g.drawString("("+Integer.toString(this.m_iMouseXPos)+", "
                +Integer.toString(this.m_iMouseYPos)+")", this.m_iMouseXPos+10,
                this.m_iMouseYPos-10);
*/
    }  // paintOffScreen

    private void drawHorizontalGrid(Graphics2D g2)
    {
        double minorSpacing=majorY/minorY;
        double axisV=xPositionToPixel(originX);

        Stroke gridStroke=new BasicStroke(STROKE_GRID);
        Stroke axisStroke=new BasicStroke(STROKE_AXIS);

        for(double y=originY+majorY; y<maxY+majorY; y+=majorY)
        {
            g2.setStroke(gridStroke);
            g2.setColor(COLOR_MINOR_GRID);
            for(int i=0; i<minorY; i++)
            {
                int position=(int)yPositionToPixel(y-i*minorSpacing);
                g2.drawLine(0,
                        position,
                        getWidth(),
                        position);
            }  // for

            int position=(int)yPositionToPixel(y);
            g2.setColor(COLOR_MAJOR_GRID);
            g2.drawLine(0,
                    position,
                    getWidth(),
                    position);

            g2.setStroke(axisStroke);
            g2.setColor(COLOR_AXIS);
            g2.drawLine((int)axisV-3,
                    position,
                    (int)axisV+3,
                    position);
        }
    }  // drawHorizontalGrid

    private void drawVerticalGrid(Graphics2D g2)
    {
        double minorSpacing=majorX/minorX;
        double axisH=yPositionToPixel(originY);

        Stroke gridStroke=new BasicStroke(STROKE_GRID);
        Stroke axisStroke=new BasicStroke(STROKE_AXIS);

        for(double x=originX+majorX; x<maxX+majorX; x+=majorX)
        {
            g2.setStroke(gridStroke);
            g2.setColor(COLOR_MINOR_GRID);
            for(int i=0; i<minorX; i++)
            {
                int position=(int)xPositionToPixel(x-i*minorSpacing);
                g2.drawLine(position,
                        0,
                        position,
                        getHeight());
            }

            int position=(int)xPositionToPixel(x);
            g2.setColor(COLOR_MAJOR_GRID);
            g2.drawLine(position,
                    0,
                    position,
                    getHeight());

            g2.setStroke(axisStroke);
            g2.setColor(COLOR_AXIS);
            g2.drawLine(position,
                    (int)axisH-3,
                    position,
                    (int)axisH+3);
        }  // for

        for(double x=originX-majorX; x>minX-majorX; x-=majorX)
        {
            g2.setStroke(gridStroke);
            g2.setColor(COLOR_MINOR_GRID);
            for (int i=0; i<minorX; i++)
            {
                int position=(int)xPositionToPixel(x+i*minorSpacing);
                g2.drawLine(position,
                        0,
                        position,
                        getHeight());
            }

            int position=(int)xPositionToPixel(x);
            g2.setColor(COLOR_MAJOR_GRID);
            g2.drawLine(position,
                    0,
                    position,
                    getHeight());

            g2.setStroke(axisStroke);
            g2.setColor(COLOR_AXIS);
            g2.drawLine(position,
                    (int)axisH-3,
                    position,
                    (int)axisH+3);
        }
    }  // drawVerticalGrid

    private void drawAxis(Graphics2D g2)
    {
        double axisH=yPositionToPixel(originY);
        double axisV=xPositionToPixel(originX);

        g2.setColor(COLOR_AXIS);
        Stroke stroke=g2.getStroke();
        g2.setStroke(new BasicStroke(STROKE_AXIS));

        g2.drawLine(0,
                (int)axisH,
                getWidth(),
                (int)axisH);
        g2.drawLine((int)axisV,
                0,
                (int)axisV,
                getHeight());

        FontMetrics metrics=g2.getFontMetrics();
        g2.drawString(formatter.format(0.0),
                (int)axisV+5,
                (int)axisH+metrics.getHeight());

        g2.setStroke(stroke);
    }

    private void drawGrid(Graphics2D g2)
    {
        Stroke stroke=g2.getStroke();

        this.drawVerticalGrid(g2);
        this.drawHorizontalGrid(g2);

//        if (drawText)
//        {
//            drawVerticalLabels(g2);
//            drawHorizontalLabels(g2);
//        }  // if

        g2.setStroke(stroke);
    }  // drawGrid

    protected double yPositionToPixel(double position)
    {
        double height=(double)getHeight();

        return height-((position-minY)*height/(maxY-minY));
    }

    protected double xPositionToPixel(double position)
    {
        return (position-minX)*(double)getWidth()/(maxX-minX);
    }

    protected double xPixelToPosition(double pixel)
    {
        double axisV=xPositionToPixel(originX);

        return (pixel-axisV)*(maxX-minX)/(double)getWidth();
    }

    protected double yPixelToPosition(double pixel)
    {
        double axisH=yPositionToPixel(originY);

        return (getHeight()-pixel-axisH)*(maxY-minY)/(double)getHeight();
    }
}

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Moved to the Swing forum.

Quote:

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Originally Posted by KernelPanic

I've overriden methods paint() and paintComponents and I think, I've messed things up.

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Yup. Neither one is the correct method to override.

Go through Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

db