src/java.desktop/share/classes/java/awt/image/ImageConsumer.java

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package java.awt.image;

import java.util.Hashtable;


/**
 * The interface for objects expressing interest in image data through
 * the ImageProducer interfaces.  When a consumer is added to an image
 * producer, the producer delivers all of the data about the image
 * using the method calls defined in this interface.
 *
 * @see ImageProducer
 *
 * @author      Jim Graham
 */
public interface ImageConsumer {
    /**
     * The dimensions of the source image are reported using the
     * setDimensions method call.
     * @param width the width of the source image
     * @param height the height of the source image
     */
    void setDimensions(int width, int height);

    /**
     * Sets the extensible list of properties associated with this image.
     * @param props the list of properties to be associated with this
     *        image
     */
    void setProperties(Hashtable<?,?> props);

    /**
     * Sets the ColorModel object used for the majority of
     * the pixels reported using the setPixels method
     * calls.  Note that each set of pixels delivered using setPixels
     * contains its own ColorModel object, so no assumption should
     * be made that this model will be the only one used in delivering
     * pixel values.  A notable case where multiple ColorModel objects
     * may be seen is a filtered image when for each set of pixels
     * that it filters, the filter
     * determines  whether the
     * pixels can be sent on untouched, using the original ColorModel,
     * or whether the pixels should be modified (filtered) and passed
     * on using a ColorModel more convenient for the filtering process.
     * @param model the specified {@code ColorModel}
     * @see ColorModel
     */
    void setColorModel(ColorModel model);

    /**
     * Sets the hints that the ImageConsumer uses to process the
     * pixels delivered by the ImageProducer.
     * The ImageProducer can deliver the pixels in any order, but
     * the ImageConsumer may be able to scale or convert the pixels
     * to the destination ColorModel more efficiently or with higher
     * quality if it knows some information about how the pixels will
     * be delivered up front.  The setHints method should be called
     * before any calls to any of the setPixels methods with a bit mask
     * of hints about the manner in which the pixels will be delivered.
     * If the ImageProducer does not follow the guidelines for the
     * indicated hint, the results are undefined.
     * @param hintflags a set of hints that the ImageConsumer uses to
     *        process the pixels
     */
    void setHints(int hintflags);

    /**
     * The pixels will be delivered in a random order.  This tells the
     * ImageConsumer not to use any optimizations that depend on the
     * order of pixel delivery, which should be the default assumption
     * in the absence of any call to the setHints method.
     * @see #setHints
     */
    int RANDOMPIXELORDER = 1;

    /**
     * The pixels will be delivered in top-down, left-to-right order.
     * @see #setHints
     */
    int TOPDOWNLEFTRIGHT = 2;

    /**
     * The pixels will be delivered in (multiples of) complete scanlines
     * at a time.
     * @see #setHints
     */
    int COMPLETESCANLINES = 4;

    /**
     * The pixels will be delivered in a single pass.  Each pixel will
     * appear in only one call to any of the setPixels methods.  An
     * example of an image format which does not meet this criterion
     * is a progressive JPEG image which defines pixels in multiple
     * passes, each more refined than the previous.
     * @see #setHints
     */
    int SINGLEPASS = 8;

    /**
     * The image contain a single static image.  The pixels will be defined
     * in calls to the setPixels methods and then the imageComplete method
     * will be called with the STATICIMAGEDONE flag after which no more
     * image data will be delivered.  An example of an image type which
     * would not meet these criteria would be the output of a video feed,
     * or the representation of a 3D rendering being manipulated
     * by the user.  The end of each frame in those types of images will
     * be indicated by calling imageComplete with the SINGLEFRAMEDONE flag.
     * @see #setHints
     * @see #imageComplete
     */
    int SINGLEFRAME = 16;

    /**
     * Delivers the pixels of the image with one or more calls
     * to this method.  Each call specifies the location and
     * size of the rectangle of source pixels that are contained in
     * the array of pixels.  The specified ColorModel object should
     * be used to convert the pixels into their corresponding color
     * and alpha components.  Pixel (m,n) is stored in the pixels array
     * at index (n * scansize + m + off).  The pixels delivered using
     * this method are all stored as bytes.
     * @param x the X coordinate of the upper-left corner of the
     *        area of pixels to be set
     * @param y the Y coordinate of the upper-left corner of the
     *        area of pixels to be set
     * @param w the width of the area of pixels
     * @param h the height of the area of pixels
     * @param model the specified {@code ColorModel}
     * @param pixels the array of pixels
     * @param off the offset into the {@code pixels} array
     * @param scansize the distance from one row of pixels to the next in
     * the {@code pixels} array
     * @see ColorModel
     */
    void setPixels(int x, int y, int w, int h,
                   ColorModel model, byte[] pixels, int off, int scansize);

    /**
     * The pixels of the image are delivered using one or more calls
     * to the setPixels method.  Each call specifies the location and
     * size of the rectangle of source pixels that are contained in
     * the array of pixels.  The specified ColorModel object should
     * be used to convert the pixels into their corresponding color
     * and alpha components.  Pixel (m,n) is stored in the pixels array
     * at index (n * scansize + m + off).  The pixels delivered using
     * this method are all stored as ints.
     * this method are all stored as ints.
     * @param x the X coordinate of the upper-left corner of the
     *        area of pixels to be set
     * @param y the Y coordinate of the upper-left corner of the
     *        area of pixels to be set
     * @param w the width of the area of pixels
     * @param h the height of the area of pixels
     * @param model the specified {@code ColorModel}
     * @param pixels the array of pixels
     * @param off the offset into the {@code pixels} array
     * @param scansize the distance from one row of pixels to the next in
     * the {@code pixels} array
     * @see ColorModel
     */
    void setPixels(int x, int y, int w, int h,
                   ColorModel model, int[] pixels, int off, int scansize);

    /**
     * The imageComplete method is called when the ImageProducer is
     * finished delivering all of the pixels that the source image
     * contains, or when a single frame of a multi-frame animation has
     * been completed, or when an error in loading or producing the
     * image has occurred.  The ImageConsumer should remove itself from the
     * list of consumers registered with the ImageProducer at this time,
     * unless it is interested in successive frames.
     * @param status the status of image loading
     * @see ImageProducer#removeConsumer
     */
    void imageComplete(int status);

    /**
     * An error was encountered while producing the image.
     * @see #imageComplete
     */
    int IMAGEERROR = 1;

    /**
     * One frame of the image is complete but there are more frames
     * to be delivered.
     * @see #imageComplete
     */
    int SINGLEFRAMEDONE = 2;

    /**
     * The image is complete and there are no more pixels or frames
     * to be delivered.
     * @see #imageComplete
     */
    int STATICIMAGEDONE = 3;

    /**
     * The image creation process was deliberately aborted.
     * @see #imageComplete
     */
    int IMAGEABORTED = 4;
}