lwtoolkit.java

Zaval Light-Weight Visual Components Library (LwVCL) is a pure Java alternative to humble AWT-based

/**
 *     Caption: Zaval Light-Weight Visual Components Library
 *     $Revision: 2.79 $
 *     $Date: 2003/08/22 11:24:16 $
 *
 *     @author:     Andrei Vishnevsky
 *     @version:    3.50
 *
 * Zaval Light-Weight Visual Components Library (LwVCL) is a pure Java
 * alternative to humble AWT-based and SWING-based GUI interfaces for
 * wide ranges of platforms, including J2SE, PersonalJava and J2ME.
 *
 * Designed as light-weight but, alternatively to Swing, built separately
 * from AWT (not on top of the java.awt library like Swing), the LwVCL is
 * the good alternative to highly performant, memory-efficient, flexible
 * GUI solution for embedded, stand-alone and applet applications.
 *
 * For more info on this product read Zaval Light-Weight Visual Components Library Tutorial
 * (It comes within this package).
 * The latest product version is always available from the product's homepage:
 * http://www.zaval.org/products/lwvcl/
 * and from the SourceForge:
 * http://sourceforge.net/projects/zaval0003/
 *
 * Contacts:
 *   Support : [e-mail]
 *   Change Requests : [e-mail]
 *   Feedback : [e-mail]
 *   Other : [e-mail]
 *
 * Copyright (C) 2001-2003  Zaval Creative Engineering Group (http://www.zaval.org)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * (version 2) as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */
package org.zaval.lw;

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

/**
 * This class provides set of useful static methods for the lightweight library.
 */
public class LwToolkit
{
 /**
  * The horizontal alignment constant.
  */
  public static final int HORIZONTAL = 1;

 /**
  * The vertical alignment constant.
  */
  public static final int VERTICAL = 2;

 /**
  * The none vertical and none horizontal alignment constant.
  */
  public static final int NONE = 0;

 /**
  * The dark blue color definition.
  */
  public static final Color darkBlue = new Color(0, 0, 140);

 /**
  * The default font definition.
  */
  public static final Font FONT = new Font("dialog", Font.PLAIN, 12);

 /**
  * The default small font definition.
  */
  public static final Font SFONT = new Font("dialog", Font.PLAIN, 10);

 /**
  * The default bold font definition.
  */
  public static final Font BFONT = new Font("dialog", Font.BOLD, 12);

 /**
  * The default font metrics definition.
  */
  public static final FontMetrics FONT_METRICS = Toolkit.getDefaultToolkit().getFontMetrics(FONT);

 /**
  * The default foreground color definition.
  */
  public static final Color FG_COLOR = Color.black;

 /**
  * The default background color definition.
  */
  public static final Color BACK_COLOR = new Color(204, 204, 204);

 /**
  * The default preferred size definition.
  */
  public static final Dimension PS_SIZE = new Dimension();

  private static final int MAX_CASH_SIZE = 500000;

  private static final Toolkit  tool = Toolkit.getDefaultToolkit();
  private static final String   resources = "rs/";
  private static Hashtable      images;
  private static int            currentCashSize;
  private static Component      observer = new Canvas();
  private static MediaTracker   media    = new MediaTracker(observer);

 /**
  * Creates a desktop instance.
  * @return a desktop instance.
  */
  public static final LwDesktop createDesktop() {
    return new LwRoot();
  }

 /**
  * Gets a desktop container for the specified component. Desktop container is top-level
  * container where the specified component is resided.
  * @param <code>c</code> the specified component.
  * @return a desktop.
  */
  public static LwDesktop getDesktop(LwComponent c) {
    for (;c != null && !(c instanceof LwDesktop);c = c.getLwParent());
    return c==null?null:(LwDesktop)c;
  }

 /**
  * Reads a properties file by the specified path and returns it as java.util.Properties instance.
  * The specified path points to the properties file relatively "org/zaval/lw" light weight
  * directory.
  * @param <code>name</code> the specified path.
  */
  public static Properties getProperties(String name)
  {
    InputStream is = LwToolkit.class.getResourceAsStream(name);
    if (is != null)
    {
      Properties p = new Properties();
      try {
        p.load(is);
        return p;
      }
      catch (IOException e) { e.printStackTrace (); }
    }
    return null;
  }

 /**
  * Reads an image using the specified path. The specified path points to the image relatively
  * "org/zaval/lw/rs" light weight resources directory. The method tries to find the image in
  * the internal cash and if the image is absent, reads the image. The method is supposed to
  * be used for fetching light weight library resource images.
  * @param <code>name</code> the specified path.
  */
  public static Image getRsImage(String name){
    return getImage(resources + name);
  }

 /**
  * Reads an image by the specified path. The path is relative to org/zaval/lw directory.
  * @param <code>name</code> the specified path.
  */
  public static Image getImage(String name)
  {
    if (images == null) images = new Hashtable();
    Image img = (Image)images.get(name);
    if (img != null) return img;
    InputStream is = LwToolkit.class.getResourceAsStream(name);
    if (is == null) return null;
    ByteArrayOutputStream bo = new ByteArrayOutputStream();
    byte[] buf   = new byte[512];
    int    count = 0;
    try {
      while ((count = is.read(buf, 0, buf.length))>=0)
        bo.write(buf, 0, count);
      img = tool.createImage(bo.toByteArray());

      media.addImage(img, 0);
      media.waitForID(0);
      if (media.isErrorID(0)) System.out.println ("Cannot load " + (resources + name));
    }
    catch (Exception e) {
      e.printStackTrace();
      return null;
    }
    finally {
      try {
        if (is != null) is.close();
      } catch(Exception ee) {}
    }

    if (bo.size() + currentCashSize < MAX_CASH_SIZE)
    {
      currentCashSize += bo.size();
      images.put(name, img);
    }
    return img;
  }

  //public static Image getImage(String image)
  //{
  //}

 /**
  * Gets the font metrics for the specified font.
  * @param <code>f</code> the specified font.
  * @return a font metrics for the specified font.
  */
  public static FontMetrics getFontMetrics(Font f) {
    return f == null?FONT_METRICS:tool.getFontMetrics(f);
  }

 /**
  * Draws the horizontal dotted line between the (x1,y1) and (x2,y1) coordinates.
  * @param <code>gr</code> the specified context to be used for drawing.
  * @param <code>x1</code> the x coordinate of the start of the line.
  * @param <code>x2</code> the x coordinate of the end of the line.
  * @param <code>y1</code> the y coordinate of the start and end of the line.
  */
  public static void drawDotHLine(Graphics gr, int x1, int x2, int y1) {
    for (;x1 <= x2; x1+=2)  gr.drawLine (x1, y1, x1, y1);
  }

 /**
  * Draws the vertical dotted line between the (x1,y1) and (x1,y2) coordinates.
  * @param <code>gr</code> the specified context to be used for drawing.
  * @param <code>y1</code> the y coordinate of the start of the line.
  * @param <code>y2</code> the y coordinate of the end of the line.
  * @param <code>x1</code> the x coordinate of the start and end of the line.
  */
  public static void drawDotVLine(Graphics gr, int y1, int y2, int x1) {
    for (;y1 <= y2; y1+=2)  gr.drawLine (x1, y1, x1, y1);
  }

 /**
  * Draws the dotted outline of the specified rectangle using the current color.
  * The resulting rectangle will cover an area (w + 1) pixels wide by (h + 1) pixels tall.
  * @param <code>gr</code> the specified context to be used for drawing.
  * @param <code>x</code> the x coordinate of the rectangle to be drawn (left top corner).
  * @param <code>y</code> the y coordinate of the rectangle to be drawn (left top corner).
  * @param <code>w</code> the width of the rectangle to be drawn.
  * @param <code>h</code> the height of the rectangle to be drawn.
  */
  public static void drawDotRect(Graphics gr, int x, int y, int w, int h)
  {
     int x2 = x + w - 1, y2 = y + h - 1;
     drawDotVLine(gr, y, y2, x);
     drawDotHLine(gr, x, x2, y);
     drawDotVLine(gr, y, y2, x2);
     drawDotHLine(gr, x, x2, y2);
  }


 /**
  * Returns the immediate child component for the parent and child.
  * @param <code>parent</code> the parent component.
  * @param <code>child</code>  the child component.
  * @return an immediate child component.
  */
  public static LwComponent getDirectChild(LwComponent parent, LwComponent child) {
    for (;child != null && child.getLwParent() != parent; child = child.getLwParent());
    return child;
  }

 /**
  * Returns the immediate child component at the specified location of the parent component.
  * @param <code>x</code> the x coordinate relatively the parent component.
  * @param <code>y</code> the y coordinate relatively the parent component.
  * @param <code>p</code> the parent component.
  * @return an immediate child component.
  */
  public static int getDirectCompAt(int x, int y, LwContainer p)
  {
    for (int i=0; i<p.count(); i++)
    {
      LwComponent c = (LwComponent)p.get(i);
      if (c.isVisible())
      {
        Rectangle b = c.getBounds();
        if (b.contains(x, y)) return i;
      }
    }
    return -1;
  }

 /**
  * Checks if the component is contained in the component hierarchy of this container.
  * @param <code>p</code> the specified parent component.
  * @param <code>c</code> the specified child component.
  * @return <code>true</code> if the component is contained in the parent component hierarchy;
  * otherwise <code>false</code>.
  */
  public static boolean isAncestorOf(LwComponent p, LwComponent c) {
    while (c != null && c != p) c = c.getLwParent();
    return c != null;
  }