ImageObserver

Name

Description

ImageObserver is an interface that provides constants and the callback mechanism to receive asynchronous information about the status of an image as it loads.

Interface Definition

public abstract interface java.awt.image.ImageObserver {
 // Constants public static final int ABORT;
public static final int ALLBITS;
public static final int ERROR;
public static final int FRAMEBITS;
public static final int HEIGHT;
public static final int PROPERTIES;
public static final int SOMEBITS;
public static final int WIDTH; // Interface Methods public abstract boolean imageUpdate (Image image, int infoflags, int x, int y, int width, int height);
}

Constants

ABORT

public static final int ABORT

The ABORT flag indicates that the image aborted during loading. An attempt to reload the image may succeed, unless ERROR is also set.

ALLBITS

public static final int ALLBITS

The ALLBITS flag indicates that the image has completely loaded successfully. The x, y, width, and height arguments to imageUpdate() should be ignored.

ERROR

public static final int ERROR

The ERROR flag indicates that an error happened during the image loading process. An attempt to reload the image will fail.

FRAMEBITS

public static final int FRAMEBITS

The FRAMEBITS flag indicates that a complete frame of a multi-frame image has loaded. The x, y, width, and height arguments to imageUpdate() should be ignored.

HEIGHT

public static final int HEIGHT

The HEIGHT flag indicates that the height information is available for an image; the image's height is in the height argument to imageUpdate().

PROPERTIES

public static final int PROPERTIES

The PROPERTIES flag indicates that the properties information is available for an image.

SOMEBITS

public static final int SOMEBITS

The SOMEBITS flag indicates that the image has started loading and some pixels are available. The bounding rectangle for the pixels that have been delivered so far is indicated by the x, y, width, and height arguments to imageUpdate().

WIDTH

public static final int WIDTH

The WIDTH flag indicates that the width information is available for an image; the image's width is in the width argument to imageUpdate().

Interface Methods

imageUpdate

public abstract boolean imageUpdate (Image image, int infoflags, int x, int y, int width, int height)

• Parameters
• • image
  • Image that is being loaded.
  • infoflags
  • The ImageObserver flags for the information that is currently available.
  • x
  • Meaning depends on infoflags that are set.
  • y
  • Meaning depends on infoflags that are set.
  • width
  • Meaning depends on infoflags that are set.
  • height
  • Meaning depends on infoflags that are set.
• Returns
• true if image has completed loading (successfully or unsuccessfully), false if additional information needs to be loaded.
• Description
• Provides the callback mechanism for the asynchronous loading of images.

See Also

Component, Image, Object