1 /*

     2 * Copyright (c) 2002 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:

    15 *

    16 */

    17 

    18 

    19 package javax.microedition.lcdui.game;

    20 

    21 import javax.microedition.lcdui.Graphics;

    22 

    23 import java.util.Vector;

    24 

    25 public class LayerManager

    26 {

    27     private Vector iLayers;

    28     private int iViewX;

    29     private int iViewY;

    30     private int iViewWidth  = Integer.MAX_VALUE;

    31     private int iViewHeight = Integer.MAX_VALUE;

    32 

    33     public LayerManager()

    34     {

    35         iLayers = new Vector();

    36     }

    37 

    38     public void append(Layer aLayer)

    39     {

    40         remove(aLayer);

    41         iLayers.addElement(aLayer);

    42     }

    43 

    44     public void insert(Layer aLayer,int aIndex)

    45     {

    46         if (aLayer == null)

    47         {

    48             throw new NullPointerException();

    49         }

    50 

    51         int indexLimit = iLayers.size();

    52         if (aIndex<0 || aIndex>indexLimit)

    53         {

    54             throw new IndexOutOfBoundsException();

    55         }

    56 

    57         indexLimit--;

    58         if (aIndex>indexLimit && iLayers.contains(aLayer))

    59         {

    60             throw new IndexOutOfBoundsException();

    61         }

    62 

    63         remove(aLayer);

    64         iLayers.insertElementAt(aLayer,aIndex);

    65     }

    66 

    67     public void remove(Layer aLayer)

    68     {

    69         if (aLayer == null)

    70         {

    71             throw new NullPointerException();

    72         }

    73         iLayers.removeElement(aLayer);

    74     }

    75 

    76     public Layer getLayerAt(int aIndex)

    77     {

    78         return (Layer)iLayers.elementAt(aIndex);

    79     }

    80 

    81     public int getSize()

    82     {

    83         return iLayers.size();

    84     }

    85 

    86 

    87 

    88     public void setViewWindow(int aX,int aY,int aWidth,int aHeight)

    89     {

    90         if (aWidth<0 || aHeight<0)

    91         {

    92             throw new IllegalArgumentException("Width or height is less than 0");

    93         }

    94         iViewX=aX;

    95         iViewY=aY;

    96         iViewWidth=aWidth;

    97         iViewHeight=aHeight;

    98     }

    99 

   100     public void paint(Graphics aGraphics,int aX,int aY)

   101     {

   102         // save Graphics clip and translate

   103         final int clipX = aGraphics.getClipX();

   104         final int clipY = aGraphics.getClipY();

   105         final int clipWidth = aGraphics.getClipWidth();

   106         final int clipHeight = aGraphics.getClipHeight();

   107         final int transX = aGraphics.getTranslateX();

   108         final int transY = aGraphics.getTranslateY();

   109 

   110         // intersect Graphics clip region with View Window

   111         if ((iViewWidth<Integer.MAX_VALUE) && (iViewWidth<Integer.MAX_VALUE))

   112             aGraphics.clipRect(aX,aY,iViewWidth,iViewHeight);

   113 

   114         // translate the graphics object so the point (aX,aY) corresponds to

   115         // the location of the viewWindow in the coordinate system of the LayerManager.

   116         aGraphics.translate(-iViewX,-iViewY);

   117 

   118         // paint visible Layers

   119         final int size = iLayers.size();

   120         for (int i=size-1; i>=0; i--)

   121         {

   122             final Layer layer = getLayerAt(i);

   123             if (layerVisible(aGraphics,layer,aX,aY))

   124             {

   125                 aGraphics.translate(aX,aY);

   126                 layer.paint(aGraphics);

   127                 aGraphics.translate(-aX,-aY);

   128             }

   129         }

   130 

   131         // restore Graphics translation

   132         // because translation is concatenated, we need to translate back to 0,0 first

   133         aGraphics.translate(-aGraphics.getTranslateX(), -aGraphics.getTranslateY());

   134         // now back to original translation, per spec

   135         aGraphics.translate(transX,transY);

   136         // restore Graphics clip - must do after restore translation

   137         aGraphics.setClip(clipX,clipY,clipWidth,clipHeight);

   138     }

   139 

   140     /**

   141      * Check if Layer is visible in Graphics clip region.

   142      */

   143     private boolean layerVisible(Graphics aGraphics, Layer aLayer, int aX, int aY)

   144     {

   145         final int clipTlX = aGraphics.getClipX();

   146         final int clipTlY = aGraphics.getClipY();

   147         final int clipBrX = clipTlX + aGraphics.getClipWidth();

   148         final int clipBrY = clipTlY + aGraphics.getClipHeight();

   149 

   150         final int layerTlX = aLayer.getX() + aX;

   151         final int layerTlY = aLayer.getY() + aY;

   152         final int layerBrX = layerTlX + aLayer.getWidth();

   153         final int layerBrY = layerTlY + aLayer.getHeight();

   154 

   155         return(!(clipBrX<=layerTlX || clipBrY<=layerTlY || clipTlX>=layerBrX || clipTlY>=layerBrY));

   156     }

   157 

   158 }

   159 

   160