Language Java Nosugar Custom Tabs Code Tabbar.java

// 
//	TabBar class
//	part of the set of documents known as Java no sugar.
//	Copyright (c) 1996,1997 Sunil Gupta, sunil@magnetic.demon.co.uk
//	placed into the public domain by the author
//
import java.awt.*;
import java.util.Vector;
import TabEntry;

public class TabBar extends Canvas
{
	//##################################################################
	//
	//##################################################################
	public static final int SQUARE = 0;
	public static final int TOP_BEVELLED = 1;
	public static final int BOTTOM_BEVELLED = 3;
	public static final int CASCADED = 2;

	public static final int HORIZONTAL = 0;
	public static final int VERTICAL = 1;
	
	
	//##################################################################
	//
	//##################################################################
	public int vspace = 5;				//pixels
	public int hspace = 10;				//pixels
	public int font_height = -1;
	public int fixed_width = -1;
	public int stagger = 2;
	
	private Vector items = new Vector();
	private int style = TOP_BEVELLED;
	private int orientation = HORIZONTAL;
	private boolean width_is_fixed = true;
	private boolean tab_pressed = false;
	private int active_index = 0;
	private long button_down_time=-1;
	
	private Color active_tab_colour = Color.yellow;
	private Color active_text_colour = Color.black;

	private Color inactive_tab_colour = Color.lightGray;
	private Color inactive_text_colour = Color.gray;
	
	
	//##################################################################
	//
	//##################################################################
	public TabBar( String string, char delim)
	{
		Vector tokens;
		String token;
		int index;
		
		tokens = tokenise_string(string, delim);
		for (index=0; index < tokens.size(); index++)
		{
			token = (String) tokens.elementAt(index);
			items.addElement( new TabEntry(token, index) );
		}
	}

	public TabBar( TabEntry entries[])
	{
		int index;
		
		for (index=0; index < entries.length; index++)
			items.addElement( entries[index]);
	}
	
	
	//##################################################################
	//
	//##################################################################
	//******************************************************************
	// anything to do with graphics initialisation gets done in the addNotify
	public void addNotify()
	{
		super.addNotify();
		set_item_widths();
		resize(this.preferredSize());

	}
	
	//******************************************************************
	public Dimension minimumSize()
	{
		int w,h,i;
		TabEntry entry;

		w = 0;
		h = 0;		
		
		if (orientation == HORIZONTAL)
		{
			h = font_height + 2*vspace;
			if (width_is_fixed)
				w = items.size() * (fixed_width + 2*hspace);
			else
				for (i =0; i < items.size(); i++)
				{
					entry = (TabEntry) items.elementAt(i);
					w += (2*hspace) +entry.width;
				}
		}
		else
		{
			w = font_height + (2*hspace);
			for (i =0; i < items.size(); i++)
			{
				entry = (TabEntry) items.elementAt(i);
				h += (2*vspace) + font_height* entry.caption.length();
			}
		}
		
		return ( new Dimension (w,h));
	}
	
	//******************************************************************
	public Dimension preferredSize()
	{
		return minimumSize();
	}
	
	//******************************************************************
	public void paint (Graphics g)
	{
		Dimension size = size();
		
		switch (style)
		{
			case SQUARE:
				draw_square_tabs(g);
				break;
			
			case TOP_BEVELLED:
				draw_bevelled_tabs(g,true);
				break;

			case BOTTOM_BEVELLED:
				draw_bevelled_tabs(g,false);
				break;
			
			case CASCADED:
				draw_cascaded_tabs(g);
				break;
			
			default:
				g.drawLine(1,1,size.width, size.height);
				break;
		}
	}
	
	//******************************************************************
	public boolean handleEvent(Event e)
	{
		long time_diff;
		
		switch (e.id)
		{
			case Event.MOUSE_DOWN:
				set_active_tab(e.x, e.y);
				tab_pressed = true;
				repaint();
				return true;
				
			case Event.MOUSE_UP:
				postEvent(new Event(this,Event.ACTION_EVENT,this));
				tab_pressed = false;
				repaint();
				return true;			
				
			default:								
				return super.handleEvent(e);
		}
	}
	
	//##################################################################
	//
	//##################################################################
	public void set_fixed_size( boolean flag)
	{
		if (flag != width_is_fixed)
		{
			width_is_fixed = flag;
			repaint();
		}
	}

	//******************************************************************
	public int getActiveTabID()
	{
		return active_index;
	}

	//******************************************************************
	public String getActiveTabName()
	{
		TabEntry entry;
		int i;
		
		for (i =0; i < items.size(); i++)
		{
			entry = (TabEntry) items.elementAt(i);
			if (entry.ID == active_index)
				return entry.caption;
		}
		
		return null;
	}

	//******************************************************************
	public void set_style( int style)
	{
		if (style != this.style) 
		{
			this.style = style;
			repaint();
		}
	}
	
	//##################################################################
	//
	//##################################################################
	private void draw_square_tabs(Graphics g)
	{
		int i, dx= 0;
		TabEntry entry;
		Color bg_colour, fg_colour;
		Dimension size=size();
		boolean raised = true;
		int item_width;
		
		for ( i=0; i <items.size(); i++)
		{
			raised = true;
			entry = (TabEntry) items.elementAt(i);
			if (active_index == entry.ID)
			{
				bg_colour = active_tab_colour; 
				fg_colour = active_text_colour;
				if (tab_pressed)	raised = false;
			}
			else
			{
				bg_colour = inactive_tab_colour; 
				fg_colour = inactive_text_colour;
			}
			
			if (width_is_fixed)
				item_width = fixed_width;
			else
				item_width = entry.width;
			
			g.setColor(bg_colour);
			g.fill3DRect(dx,0, item_width +(2*hspace), size.height, raised);
			g.setColor(fg_colour);
			g.drawString( entry.caption, dx+hspace, font_height + vspace);		
			
			dx += (2*hspace) + item_width;
		}
	}

	//******************************************************************
	// draw these backwards as they overlp from left to right
	private void draw_bevelled_tabs(Graphics g, boolean on_top)
	{
		int i,x;
		TabEntry entry;
		Color bg_colour, fg_colour;
		Dimension size=size();
		int item_width, total_width;
		int y1,y2;
		Polygon poly;
		
		//-----------find total width--------------------------------
		total_width= 0;
		if (width_is_fixed)
			total_width = items.size() *(fixed_width + 2*hspace);
		else
			for ( i=items.size(); i>0; i--)
			{
				entry = (TabEntry) items.elementAt(i-1);
				total_width += entry.width + (2*hspace);
			}
		
		if (on_top)
		{
			y1=size.height-1;
			y2=0;
		}
		else
		{
			y2=size.height-1;
			y1=0;
		}
		
		//-----------draw backwards-----------------------------------
		x= total_width;
		for ( i=items.size(); i>0; i--)
		{
			entry = (TabEntry) items.elementAt(i-1);
			if (width_is_fixed)
				item_width = fixed_width;
			else
				item_width = entry.width;
				
			x -= (2*hspace) + item_width;

			//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
			if (active_index == entry.ID)
			{
				bg_colour = active_tab_colour; 
				fg_colour = active_text_colour;
			}
			else
			{
				bg_colour = inactive_tab_colour; 
				fg_colour = inactive_text_colour;
			}
			
			
			//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
			g.setColor(bg_colour);
			poly = new Polygon();
			poly.addPoint( x-hspace, y1);
			poly.addPoint( x, y2);
			poly.addPoint( x+item_width+hspace,y2);
			poly.addPoint( x+(2*hspace)+item_width, y1);
			g.fillPolygon(poly);
			g.setColor(Color.black);
			g.drawPolygon(poly);
			
			g.setColor(fg_colour);
			g.drawString( entry.caption, x+hspace, font_height + vspace);		
			
		}
	}

	//******************************************************************
	private void draw_cascaded_tabs(Graphics g)
	{
	}
				
	//##################################################################
	//
	//##################################################################
	private Vector tokenise_string(String string, char delim)
	{
		int start,end;
		Vector tokens = new Vector();
		String substring;
		
		start = 0;
		end = string.indexOf(delim, start);
		while (end != -1)
		{
			if (end > start)
			{
				tokens.addElement( string.substring(start, end));
			}
			start = end+1;
			end = string.indexOf(delim, start);
		}
		
		tokens.addElement( string.substring(start, string.length()));
		
		return tokens;
	}
	
	//******************************************************************
	private void set_item_widths()
	{
		TabEntry entry;
		Graphics g;
		FontMetrics metrics; 
		int i, item_width, max_width=-1;
		
		g = getGraphics();
		metrics = g.getFontMetrics();

		//-------get individual string widths----------------
		for ( i=0 ; i<items.size() ; i++)
		{
			entry = (TabEntry) items.elementAt(i);
			item_width = metrics.stringWidth( entry.caption);
			entry.width = item_width;
			if (item_width > max_width)
				max_width = item_width;
		}
		
		//-------get overall font height--------------------
		font_height = metrics.getHeight();
		fixed_width = max_width;
	}
	
	//******************************************************************
	private void set_active_tab(int x, int y)
	{
		int i, dx=0, end_x = x, width;
		TabEntry entry;
		
		for ( i=0 ; i<items.size() ; i++)
		{
			entry = (TabEntry) items.elementAt(i);
			if (width_is_fixed)
				width = fixed_width;
			else
				width = entry.width;
			
			end_x = dx+(2*hspace)+width;
			if (  (x > dx) && (x < end_x)  )
			{
				active_index = entry.ID;
				break;
			}
			
			dx = end_x;
		}
		
	}
}

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