用Java提取光标图像

Question

我想知道是否有一种方法可以从Java中的Cursor对象中提取Image对象。

为此，例如：

Image img = extractCursorImage(Cursor.getDefaultCursor());

然后可以在工具栏按钮上进行绘制（这就是我想要的目的）。

Answer 1

将光标类是相当抽象的-
所有重要的东西委托给本机代码，所以你不能只画上一个在图形上下文。尚无立即显而易见的方法来绕过预定义图标或在本机代码中进行操作的需要。

您能帮我使用您提到的功能吗？

以下是一些使用JNA库绘制内置Windows光标的代码。如果可以使用JNA，则可以避免使用C
++编译器。

我可能打了太多本地电话，但是对于一次生成图标来说，花费并不大。

用Java
http://f.imagehost.org/0709/hand.png绘制的手形光标

将光标显示为Java图像的代码：

public class LoadCursor {

  public static void draw(BufferedImage image, int cursor,
      int diFlags) {
    int width = image.getWidth();
    int height = image.getHeight();

    User32 user32 = User32.INSTANCE;
    Gdi32 gdi32 = Gdi32.INSTANCE;

    Pointer hIcon = user32
        .LoadCursorW(Pointer.NULL, cursor);
    Pointer hdc = gdi32.CreateCompatibleDC(Pointer.NULL);
    Pointer bitmap = gdi32.CreateCompatibleBitmap(hdc,
        width, height);

    gdi32.SelectObject(hdc, bitmap);
    user32.DrawIconEx(hdc, 0, 0, hIcon, width, height, 0,
        Pointer.NULL, diFlags);

    for (int x = 0; x < width; x++) {
      for (int y = 0; y < width; y++) {
        int rgb = gdi32.GetPixel(hdc, x, y);
        image.setRGB(x, y, rgb);
      }
    }

    gdi32.DeleteObject(bitmap);
    gdi32.DeleteDC(hdc);
  }

  public static void main(String[] args) {
    final int width = 128;
    final int height = 128;

    BufferedImage image = new BufferedImage(width, height,
        BufferedImage.TYPE_INT_ARGB);
    draw(image, User32.IDC_HAND, User32.DI_NORMAL);
    BufferedImage mask = new BufferedImage(width, height,
        BufferedImage.TYPE_INT_RGB);
    draw(mask, User32.IDC_HAND, User32.DI_MASK);
    applyMask(image, mask);

    JLabel icon = new JLabel();
    icon.setIcon(new ImageIcon(image));

    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setContentPane(icon);
    frame.pack();
    frame.setVisible(true);
  }

  private static void applyMask(BufferedImage image,
      BufferedImage mask) {
    int width = image.getWidth();
    int height = image.getHeight();
    for (int x = 0; x < width; x++) {
      for (int y = 0; y < height; y++) {
        int masked = mask.getRGB(x, y);
        if ((masked & 0x00FFFFFF) == 0) {
          int rgb = image.getRGB(x, y);
          rgb = 0xFF000000 | rgb;
          image.setRGB(x, y, rgb);
        }
      }
    }
  }

}

User32.dll接口：

public interface User32 extends Library {

  public static User32 INSTANCE = (User32) Native
      .loadLibrary("User32", User32.class);

  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_ARROW = 32512;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_IBEAM = 32513;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_WAIT = 32514;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_CROSS = 32515;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_UPARROW = 32516;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZENWSE = 32642;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZENESW = 32643;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZEWE = 32644;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZENS = 32645;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZEALL = 32646;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_NO = 32648;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_HAND = 32649;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_APPSTARTING = 32650;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_HELP = 32651;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_ICON = 32641;
  /** @see #LoadCursorW(Pointer, int) */
  public static final int IDC_SIZE = 32640;

  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_COMPAT = 4;
  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_DEFAULTSIZE = 8;
  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_IMAGE = 2;
  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_MASK = 1;
  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_NORMAL = 3;
  /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
  public static final int DI_APPBANDING = 1;

  /** http://msdn.microsoft.com/en-us/library/ms648391(VS.85).aspx */
  public Pointer LoadCursorW(Pointer hInstance,
      int lpCursorName);

  /** http://msdn.microsoft.com/en-us/library/ms648065(VS.85).aspx */
  public boolean DrawIconEx(Pointer hdc, int xLeft,
      int yTop, Pointer hIcon, int cxWidth, int cyWidth,
      int istepIfAniCur, Pointer hbrFlickerFreeDraw,
      int diFlags);

}

Gdi32.dll接口：

public interface Gdi32 extends Library {

  public static Gdi32 INSTANCE = (Gdi32) Native
      .loadLibrary("Gdi32", Gdi32.class);

  /** http://msdn.microsoft.com/en-us/library/dd183489(VS.85).aspx */
  public Pointer CreateCompatibleDC(Pointer hdc);

  /** http://msdn.microsoft.com/en-us/library/dd183488(VS.85).aspx */
  public Pointer CreateCompatibleBitmap(Pointer hdc,
      int nWidth, int nHeight);

  /** http://msdn.microsoft.com/en-us/library/dd162957(VS.85).aspx */
  public Pointer SelectObject(Pointer hdc, Pointer hgdiobj);

  /** http://msdn.microsoft.com/en-us/library/dd145078(VS.85).aspx */
  public int SetPixel(Pointer hdc, int X, int Y, int crColor);

  /** http://msdn.microsoft.com/en-us/library/dd144909(VS.85).aspx */
  public int GetPixel(Pointer hdc, int nXPos, int nYPos);

  /** http://msdn.microsoft.com/en-us/library/dd183539(VS.85).aspx */
  public boolean DeleteObject(Pointer hObject);

  /** http://msdn.microsoft.com/en-us/library/dd183533(VS.85).aspx */
  public boolean DeleteDC(Pointer hdc);

}