source: winedb/src/gamegui/ScrollList.java

package gamegui;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.util.*;

public class ScrollList extends Member {
        private ArrayList<Listable> lstObjects;
        private Listable selectedItem;
        private Font font;
        private int fontHeight;
        private int textStart;
        private boolean change;
        
        public ScrollList(String newName, int newX, int newY, int newWidth, int newHeight, Font font, FontMetrics metrics) {
                super(newName, newX, newY, newWidth, newHeight);
                
                lstObjects = new ArrayList<Listable>();
                selectedItem = null;
                this.font = font;
                if(metrics == null)
                        fontHeight = 0;
                else
                        fontHeight = metrics.getHeight();
                textStart = 0;
                change = false;
        }
        
        public ArrayList<Listable> getList() {
                return lstObjects;
        }
        
        public Listable getSelected() {
                return selectedItem;
        }
        
        public boolean isChanged() {
                return change;
        }
        
        public void changeHandled() {
                change = false;
        }
        
        public void deselect() {
                selectedItem = null;
        }
        
        public void clear() {
                lstObjects.clear();
                selectedItem = null;
                textStart = 0;
                changeHandled();
        }
        
        public boolean handleEvent(MouseEvent e) {
                // no need for item selection right now
                /*if(getX() < e.getX() && e.getX() < getX()+getWidth()) {
                        if(getY() < e.getY() && getY()-textStart+2 < e.getY() && e.getY() < getY()+getHeight() && e.getY() < getY()+lstObjects.size()*15-textStart+2) {
                                selectedItem = lstObjects.get((e.getY()-getY()+textStart-2)/15);
                                change = true;
                                return true;
                        }
                }*/
                
                //rest of the code handles the scroll bar and is necessary
                if(!getScrollBar().handleEvent(e))
                        return false;
                
                if(e.getY() < getY()+getScrollBar().getWidth()) {
                        changeTextStart(-30);
                }else if(getY()+getHeight()-getScrollBar().getWidth() < e.getY()) {
                        changeTextStart(30);
                }
                
                return true;
        }
        
        private void changeTextStart(int increment) {
                textStart += increment;
                
                //figures out number of vertical pixels required to display everything properly
                int listHeight = 0;
                
                if(lstObjects.size() > 0) {
                        Listable e = lstObjects.get(0);
                        listHeight = e.getHeight()*(int)Math.ceil(((double)lstObjects.size())/((getWidth())/e.getWidth()))+e.getYOffset();
                }
                
                if(listHeight>getHeight() && textStart >= listHeight-getHeight()) {
                        textStart = listHeight-getHeight();
                        getScrollBar().setPosition(getScrollBar().getMaxSize()-getScrollBar().getSize());
                }else if(textStart < 0 || listHeight<=getHeight()) {
                        textStart = 0;
                        getScrollBar().setPosition(0);
                }else
                        getScrollBar().setPosition(textStart*getScrollBar().getMaxSize()/listHeight);
        }
        
        public int getTextStart() {
                return textStart;
        }
        
        public void draw(Graphics g) {
                GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice device = env.getDefaultScreenDevice();
        GraphicsConfiguration gc = device.getDefaultConfiguration();
        
        BufferedImage source = gc.createCompatibleImage(getWidth(), getHeight());
        Graphics2D srcGraphics = source.createGraphics();
        
        srcGraphics.setColor(Color.green);
        if(font != null)
                srcGraphics.setFont(font);
                
                int listHeight = 0;
                Listable e = null;
                
                if(lstObjects.size() > 0) {
                        e = lstObjects.get(0);
                        listHeight = e.getHeight()*(int)Math.ceil(((double)lstObjects.size())/((getWidth())/e.getWidth()))+e.getYOffset();
                }
                
                int numPerRow = 0;
                if(e != null)
                        numPerRow = getWidth()/e.getWidth();
                
        for(int x=0; x<lstObjects.size(); x++)
                lstObjects.get(x).draw(e.getHeight()*(x%numPerRow)+e.getXOffset(), fontHeight+(x/numPerRow)*e.getHeight()-textStart, srcGraphics);
                
                g.drawImage(source, getX(), getY(), null);
                
                g.setColor(Color.red);
                g.drawRect(getX(), getY(), getWidth(), getHeight());
                
                if(listHeight > getHeight())
                        getScrollBar().setSize(getScrollBar().getMaxSize()*getHeight()/listHeight);
                else
                        getScrollBar().setSize(getScrollBar().getMaxSize());
                
                getScrollBar().draw(g);
        }
}