Package org.lwjgl.input

Source Code of org.lwjgl.input.Cursor$CursorElement

/*
* Copyright (c) 2002-2008 LWJGL Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
*   notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
*   notice, this list of conditions and the following disclaimer in the
*   documentation and/or other materials provided with the distribution.
*
* * Neither the name of 'LWJGL' nor the names of
*   its contributors may be used to endorse or promote products derived
*   from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.lwjgl.input;

import java.nio.IntBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.NondirectBufferWrapper;
import org.lwjgl.Sys;

/**
*
* A class representing a native cursor. Instances of this
* class can be used with Mouse.setCursor(), if available.
*
* @author elias_naur <elias_naur@users.sourceforge.net>
* @version $Revision: 3418 $
* $Id: Cursor.java 3418 2010-09-28 21:11:35Z spasi $
*/

public class Cursor {
  /** 1 bit transparency for native cursor */
  public static final int    CURSOR_ONE_BIT_TRANSPARENCY  = 1;

  /** 8 bit alhpa native cursor */
  public static final int    CURSOR_8_BIT_ALPHA          = 2;

  /** animation native cursor */
  public static final int    CURSOR_ANIMATION            = 4;

  /** First element to display */
  private final CursorElement[] cursors;

  /** Index into list of cursors */
  private int index;

  private boolean destroyed;

  /**
   * Constructs a new Cursor, with the given parameters. Mouse must have been created before you can create
   * Cursor objects. Cursor images are in ARGB format, but only one bit transparancy is guaranteed to be supported.
   * So to maximize portability, lwjgl applications should only create cursor images with 0x00 or 0xff as alpha values.
   * The constructor will copy the images and delays, so there's no need to keep them around.
   *
   * @param width cursor image width
   * @param height cursor image height
   * @param xHotspot the x coordinate of the cursor hotspot
   * @param yHotspot the y coordinate of the cursor hotspot
   * @param numImages number of cursor images specified. Must be 1 if animations are not supported.
   * @param images A buffer containing the images. The origin is at the lower left corner, like OpenGL.
   * @param delays An int buffer of animation frame delays, if numImages is greater than 1, else null
   * @throws LWJGLException if the cursor could not be created for any reason
   */
  public Cursor(int width, int height, int xHotspot, int yHotspot, int numImages, IntBuffer images, IntBuffer delays) throws LWJGLException {
    synchronized (OpenGLPackageAccess.global_lock) {
      if ((getCapabilities() & CURSOR_ONE_BIT_TRANSPARENCY) == 0)
        throw new LWJGLException("Native cursors not supported");
      images = NondirectBufferWrapper.wrapBuffer(images, width*height*numImages);
      if (delays != null)
        delays = NondirectBufferWrapper.wrapBuffer(delays, numImages);
      if (!Mouse.isCreated())
        throw new IllegalStateException("Mouse must be created before creating cursor objects");
      if (width*height*numImages > images.remaining())
        throw new IllegalArgumentException("width*height*numImages > images.remaining()");
      if (xHotspot >= width || xHotspot < 0)
        throw new IllegalArgumentException("xHotspot > width || xHotspot < 0");
      if (yHotspot >= height || yHotspot < 0)
        throw new IllegalArgumentException("yHotspot > height || yHotspot < 0");

      Sys.initialize();

      // Hmm
      yHotspot = height - 1 - yHotspot;

      // create cursor (or cursors if multiple images supplied)
      cursors = createCursors(width, height, xHotspot, yHotspot, numImages, images, delays);
    }
  }

  /**
   * Gets the minimum size of a native cursor. Can only be called if
   * The Mouse is created and cursor caps includes at least
   * CURSOR_ONE_BIT_TRANSPARANCY.
   *
   * @return the maximum size of a native cursor
   */
  public static int getMinCursorSize() {
    synchronized (OpenGLPackageAccess.global_lock) {
      if (!Mouse.isCreated())
        throw new IllegalStateException("Mouse must be created.");
      return Mouse.getImplementation().getMinCursorSize();
    }
  }

  /**
   * Gets the maximum size of a native cursor. Can only be called if
   * The Mouse is created and cursor caps includes at least
   * CURSOR_ONE_BIT_TRANSPARANCY.
   *
   * @return the maximum size of a native cursor
   */
  public static int getMaxCursorSize() {
    synchronized (OpenGLPackageAccess.global_lock) {
      if (!Mouse.isCreated())
        throw new IllegalStateException("Mouse must be created.");
      return Mouse.getImplementation().getMaxCursorSize();
    }
  }

  /**
   * Get the capabilities of the native cursor. Return a bit mask of the native cursor capabilities.
   * The CURSOR_ONE_BIT_TRANSPARANCY indicates support for cursors with one bit transparancy,
   * the CURSOR_8_BIT_ALPHA indicates support for 8 bit alpha and CURSOR_ANIMATION indicates
   * support for cursor animations.
   *
   * @return A bit mask with native cursor capabilities.
   */
  public static int getCapabilities() {
    synchronized (OpenGLPackageAccess.global_lock) {
      if (Mouse.getImplementation() != null)
        return Mouse.getImplementation().getNativeCursorCapabilities();
      else
        return OpenGLPackageAccess.createImplementation().getNativeCursorCapabilities();
    }
  }

  /**
   * Creates the actual cursor, using a platform specific class
   */
  private static CursorElement[] createCursors(int width, int height, int xHotspot, int yHotspot, int numImages, IntBuffer images, IntBuffer delays) throws LWJGLException {
    // create copy and flip images to match ogl
    IntBuffer images_copy = BufferUtils.createIntBuffer(images.remaining());
    flipImages(width, height, numImages, images, images_copy);

    // Win32 doesn't (afaik) allow for animation based cursors, except when they're
    // in the .ani format, which we don't support.
    // The cursor animation was therefor developed using java side time tracking.
    // unfortunately X flickers when changing cursor. We therefore check for either
    // Win32 or X and do accordingly. This hasn't been implemented on Mac, but we
    // might want to split it into a X/Win/Mac cursor if it gets too cluttered

    CursorElement[] cursors;
    switch (LWJGLUtil.getPlatform()) {
      case LWJGLUtil.PLATFORM_MACOSX:
        /* Fall through */
      case LWJGLUtil.PLATFORM_WINDOWS:
        // create our cursor elements
        cursors = new CursorElement[numImages];
        for(int i=0; i<numImages; i++) {

          // iterate through the images, and make sure that the pixels are either 0xffxxxxxx or 0x00000000
          int size = width * height;
          for(int j=0; j<size; j++) {
            int index = j + (i*size);
            int alpha = images_copy.get(index) >> 24 & 0xff;
            if(alpha != 0xff) {
              images_copy.put(index, 0);
            }
          }

          Object handle = Mouse.getImplementation().createCursor(width, height, xHotspot, yHotspot, 1, images_copy, null);
          long delay = (delays != null) ? delays.get(i) : 0;
          long timeout = System.currentTimeMillis();
          cursors[i] = new CursorElement(handle, delay, timeout);

          // offset to next image
          images_copy.position(width*height*(i+1));
        }
        break;
      case LWJGLUtil.PLATFORM_LINUX:
        // create our cursor elements
        Object handle = Mouse.getImplementation().createCursor(width, height, xHotspot, yHotspot, numImages, images_copy, delays);
        CursorElement cursor_element = new CursorElement(handle, -1, -1);
        cursors = new CursorElement[]{cursor_element};
        break;
      default:
        throw new RuntimeException("Unknown OS");
    }
    return cursors;
  }

  /**
   * Flips the images so they're oriented according to opengl
   *
   * @param width Width of image
   * @param height Height of images
   * @param numImages How many images to flip
   * @param images Source images
   * @param images_copy Destination images
   */
  private static void flipImages(int width, int height, int numImages, IntBuffer images, IntBuffer images_copy) {
    for (int i = 0; i < numImages; i++) {
      int start_index = i*width*height;
      flipImage(width, height, start_index, images, images_copy);
    }
  }

  /**
   * @param width Width of image
   * @param height Height of images
   * @param start_index index into source buffer to copy to
   * @param images Source images
   * @param images_copy Destination images
   */
  private static void flipImage(int width, int height, int start_index, IntBuffer images, IntBuffer images_copy) {
    for (int y = 0; y < height>>1; y++) {
      int index_y_1 = y*width + start_index;
      int index_y_2 = (height - y - 1)*width + start_index;
      for (int x = 0; x < width; x++) {
        int index1 = index_y_1 + x;
        int index2 = index_y_2 + x;
        int temp_pixel = images.get(index1 + images.position());
        images_copy.put(index1, images.get(index2 + images.position()));
        images_copy.put(index2, temp_pixel);
      }
    }
  }

  /**
   * Gets the native handle associated with the cursor object.
   */
  Object getHandle() {
    checkValid();
    return cursors[index].cursorHandle;
  }

  private void checkValid() {
    if (destroyed)
      throw new IllegalStateException("The cursor is destroyed");
  }

  /**
   * Destroy the native cursor. If the cursor is current,
   * the current native cursor is set to null (the default
   * OS cursor)
   */
  public void destroy() {
    synchronized (OpenGLPackageAccess.global_lock) {
      if (destroyed)
        return;
      if (Mouse.getNativeCursor() == this) {
        try {
          Mouse.setNativeCursor(null);
        } catch (LWJGLException e) {
          // ignore
        }
      }
      for ( CursorElement cursor : cursors ) {
        Mouse.getImplementation().destroyCursor(cursor.cursorHandle);
      }
      destroyed = true;
    }
  }

  /**
   * Sets the timout property to the time it should be changed
   */
  protected void setTimeout() {
    checkValid();
    cursors[index].timeout = System.currentTimeMillis() + cursors[index].delay;
  }

  /**
   * Determines whether this cursor has timed out
   * @return true if the this cursor has timed out, false if not
   */
  protected boolean hasTimedOut() {
    checkValid();
    return cursors.length > 1 && cursors[index].timeout < System.currentTimeMillis();
  }

  /**
   * Changes to the next cursor
   */
  protected void nextCursor() {
    checkValid();
    index = ++index % cursors.length;
  }

  /**
   * A single cursor element, used when animating
   */
  private static class CursorElement {
    /** Handle to cursor */
    final Object cursorHandle;

    /** How long a delay this element should have */
    final long delay;

    /** Absolute time this element times out */
    long timeout;

    CursorElement(Object cursorHandle, long delay, long timeout) {
      this.cursorHandle = cursorHandle;
      this.delay = delay;
      this.timeout = timeout;
    }
  }
}
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