Packages This Package Prev Next Index
§2.11 Interface ImageObserver
public interface java.awt.image.ImageObserver
{
// flags for the infoflags argument to imageUpdate
public final static int ABORT; §2.11.1
public final static int ALLBITS; §2.11.2
public final static int ERROR; §2.11.3
public final static int FRAMEBITS; §2.11.4
public final static int HEIGHT; §2.11.5
public final static int PROPERTIES; §2.11.6
public final static int SOMEBITS; §2.11.7
public final static int WIDTH; §2.11.8
// Methods
public abstract boolean §2.11.9
imageUpdate(Image img, int infoflags,
int x, int y, int width, int height);
}
The image observer interface specifies the methods that all image observers must implement.
An image observer is interested in receiving asynchronous notifications about the image as
the image is being constructed.
ABORT
public final static int ABORT = 128
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
the image was aborted before production was complete.
- No more information will become available without further action to trigger another image production sequence.
- If the ERROR flag was not also set in this image update, then accessing any
of the data in the image restarts the production again, possibly from the
beginning.
ALLBITS
public final static int ALLBITS = 32
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
a static image is now complete and can be drawn in its final form.
- The x, y, width, and height arguments to the imageUpdate method should be
ignored when this flag is set in the status.
- See Also:
- drawImage in class Graphics (II-§1.20.12).
ERROR
public final static int ERROR = 64
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
an image which was being tracked asynchronously has encountered an
error. No further information will become available, and drawing the
image will fail.
- Whenever this flag is set, the ABORT flag must also be set.
FRAMEBITS
public final static int FRAMEBITS = 16
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
another complete frame of a multi-frame image can now be drawn.
- The x, y, width, and height arguments to the imageUpdate method should be
ignored when this flag is set in the status.
- See Also:
- drawImage in class Graphics (II-§1.20.12).
HEIGHT
public final static int HEIGHT = 2
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
the height of the base image is now available and can be taken from the
height argument to the imageUpdate method.
- See Also:
- getHeight in class Image (II-§1.24.5).
PROPERTIES
public final static int PROPERTIES = 4
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
the properties of the image are now available.
- See Also:
- getProperty in class Image (II-§1.24.6).
SOMEBITS
public final static int SOMEBITS = 8
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
the pixels needed for drawing a scaled variation of the image are now
available.
- The bounding box of the new pixels can be taken from the x, y, width, and
height arguments to the imageUpdate method.
- See Also:
- drawImage in class Graphics (II-§1.20.12).
WIDTH
public final static int WIDTH
- This flag in the infoflags argument to imageUpdate (II-§2.11.9) indicates that
the width of the base image is now available and can be taken from the
width argument to the imageUpdate method.
- See Also:
- getWidth in class Image (II-§1.24.8).
imageUpdate
public abstract boolean
imageUpdate(Image img, int infoflags, int x, int y,
int width, int height)
- This image observer method is called when previously requested information about an image becomes available.
- Asynchronous interfaces are method calls such as getWidth (II-§1.24.8),
getHeight (II-§1.24.5),and drawImage (II-§1.20.12) which take an image
observer as an argument. These methods register the caller as being interested either in information about the image or about an output version of
the image.
- This method should return true if further calls to imageUpdate are needed by
this image observer; false if it needs no more information.
- The infoflags argument should be the OR of the following flags:
WIDTH (II-§2.11.8) HEIGHT (II-§2.11.5)
PROPERTIES (II-§2.11.6) SOMEBITS (II-§2.11.7)
FRAMEBITS (II-§2.11.4) ALLBITS (II-§2.11.2)
ERROR (II-§2.11.3) ABORT (II-§2.11.1)
- The interpretation of the x, y, width, and height arguments depends on the
infoflags argument.
- Parameters:
img
-
The image being observed
infoflags
-
the OR of the above flags
x
-
an x coordinate
y
-
a y coordinate
width
-
the width
height
-
the height
- Returns:
- true if further calls to imageUpdate are needed by this image observer;
false otherwise.
Packages This Package Prev Next Index
Java API Document (HTML generated by dkramer on April 22, 1996)
Copyright © 1996 Sun Microsystems, Inc.
All rights reserved
Please send any comments or corrections to doug.kramer@sun.com