如何在摇摆中设置光标的自定义大小？

Question

I am using the below code to set a custom cursor for JPanel, but when i run the code its enlarging the image which i set for cursor. Is there a way to set a userdefined cursor size ?

Toolkit toolkit = Toolkit.getDefaultToolkit();
BufferedImage erasor=new BufferedImage(10,10, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d=(Graphics2D) erasor.createGraphics();
g2d.setPaint(Color.red);
g2d.drawRect(e.getX(),e.getY() ,10, 10);
toolkit.getBestCursorSize(10, 10);
Cursor mcursor=toolkit.createCustomCursor(erasor, new Point(10,10), "Eraser");
setCursor(mcursor);

Answer 1

一个简单的解决方案是使用“标准”尺寸和透明背景的图像。

Answer 2

Windows seem to only allow cursors of size 32x32 pixels so if you want another size you have to work around it.

To get a smaller size use createCustomCursor() with a 32x32 image where the unwanted pixels are transparent. If you use BufferedImage.TYPE_INT_ARGB you can make pixels transparent.

To make a larger cursor I believe this will work:

• Create a custom cursor that is completely transparent.

• Use a mouseMotionListener to get the position of the cursor.

• Draw your cursor image at the position of the real (transparent) cursor.

Answer 3

Windows has a defult cursor, which is always 32x32 pixels. You can set a image aa cursor with a other size, but windows resize this image to 32x32 pixel, which can trigger other side effects especially when your image is not quadratic.

You can do a workaround with a transparent image like in this example.

    /**
     * Create a transparent cursor with a given frame. Note: The name of the
     * cursor is <code>Trans</code>.
     * <br>
     * <b>Note</b>: The maximal size for the cursor is 32x32 pixel under windows.
     * Technically it is possible to create a cursor bigger than 32x32 pixel, but this method must run under windows 
     * and so the size is limited to 32 pixel.
     * 
     * @param size the size of the frame (horizontal/vertical) 
     * <br>
     * <b>Note</b>: maximal size is 32 pixel.
     * @param frameThickness the thickness of the frame
     * @param frameColor the color of the frame
     * @return a cursor which is a frame with the given size and color.
     */

    public static synchronized Cursor createTransparentCursor( int size, int frameThickness, Color frameColor ) {

            final int cursourSize = size + (2 * frameThickness);
            System.out.println("cursourSize: "+cursourSize);

            final BufferedImage bufferedImage = new BufferedImage( 32 + 2, 32 + 2, BufferedImage.TYPE_INT_ARGB );
            final Graphics graphic = bufferedImage.getGraphics();
            final Color colTrans = new Color( 0, 0, 0, 0 );
            for( int i = 0 ; i < cursourSize ; i++ ){
                    for( int j = 0 ; j < cursourSize ; j++ ){
                            if( i <= frameThickness || i > cursourSize - frameThickness -1 || j <= frameThickness
                                            | j > cursourSize - frameThickness - 1 ){
                                    graphic.setColor( frameColor );
                            }
                            else{
                                    graphic.setColor( colTrans );
                            }
                            graphic.fillRect( i, j, 1, 1 );
                    }
            }
            System.out.println("Buffered size:" +bufferedImage.getHeight() +"/"+ bufferedImage.getWidth());
            final Point hotSpot = new Point( cursourSize / 2, cursourSize / 2 );
            return Toolkit.getDefaultToolkit().createCustomCursor( bufferedImage, hotSpot, "Trans" );
    }

Sorry, but I can't upload a image of this facts. I don't have enough reputations. ;/

Answer 4

You can determine the cursor size at runtime, it is controlled by the 'best-size'.

Dimension aBestSize = Toolkit.getDefaultToolkit().getBestCursorSize(0, 0);

(For windows this is 32x32)

Then blit the cursor image of the size you want onto a transparent buffered image of the best size, it will no longer be resized.