用Java提取光标图像 [英] Extract cursor image in Java

问题描述

我想知道是否有办法从 Java 中的 Cursor 对象中提取 Image 对象.

I was wondering if there is a way to extract an Image object from a Cursor object in Java.

例如:

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

然后您可以在工具栏按钮上绘制(这就是我想要的目的).

Which you then can draw on a toolbar button (that's the purpose I want it for).

推荐答案

Cursor 类非常抽象——所有重要的东西都委托给本机代码，所以你不能只在 图形 上下文.没有一种立即明显的方法可以绕过预先定义图标或在本机代码中进行的需求.

The Cursor class is pretty abstract - all the important stuff is delegated to native code, so you can't just draw one onto at graphics context. There isn't an immediately obvious way of getting round the need to either predefine the icons or do it in native code.

你能帮我使用你提到的那个功能吗?

could you help me use that function you mentioned?

下面是一些使用 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.

Below is some code to draw built-in Windows cursors using the JNA library. If you can use JNA, you can avoid C++ compilers.

我可能进行了过多的原生调用，但一次性图标生成的成本并不高.

I'm probably making too many native calls, but the cost is not significant for one-shot icon generation.

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

将光标显示为 Java 图像的代码:

Code to display a cursor as a Java image:

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:

User32.dll interface:

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:

Gdi32.dll interface:

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);

}

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