# Class ImageFilter

java.lang.Object
java.awt.image.ImageFilter

All Implemented Interfaces:
  `ImageConsumer, Cloneable`

Direct Known Subclasses:
  `BufferedImageFilter, CropImageFilter, ReplicateScaleFilter, RGBImageFilter`

public class ImageFilter extends Object implements ImageConsumer, Cloneable
This class implements a filter for the set of interface methods that are used to deliver data from an ImageProducer to an ImageConsumer. It is meant to be used in conjunction with a FilteredImageSource object to produce filtered versions of existing images. It is a base class that provides the calls needed to implement a "Null filter" which has no effect on the data being passed through. Filters should subclass this class and override the methods which deal with the data that needs to be filtered and modify it as necessary.

See Also:
  - `FilteredImageSource`
  - `ImageConsumer`

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected ImageConsumer`
  `consumer`
  The consumer of the particular image data stream for which this instance of the ImageFilter is filtering data.

  ### Fields declared in interface ImageConsumer

  `COMPLETESCANLINES, IMAGEABORTED, IMAGEERROR, RANDOMPIXELORDER, SINGLEFRAME, SINGLEFRAMEDONE, SINGLEPASS, STATICIMAGEDONE, TOPDOWNLEFTRIGHT`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `ImageFilter()`
  Constructs an `ImageFilter`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Object`
  `clone()`
  Clones this object.
  `ImageFilter`
  `getFilterInstance(ImageConsumer ic)`
  Returns a unique instance of an ImageFilter object which will actually perform the filtering for the specified ImageConsumer.
  `void`
  `imageComplete(int status)`
  Filters the information provided in the imageComplete method of the ImageConsumer interface.
  `void`
  `resendTopDownLeftRight(ImageProducer ip)`
  Responds to a request for a TopDownLeftRight (TDLR) ordered resend of the pixel data from an `ImageConsumer`.
  `void`
  `setColorModel(ColorModel model)`
  Filter the information provided in the setColorModel method of the ImageConsumer interface.
  `void`
  `setDimensions(int width, int height)`
  Filters the information provided in the setDimensions method of the ImageConsumer interface.
  `void`
  `setHints(int hints)`
  Filters the information provided in the setHints method of the ImageConsumer interface.
  `void`
  `setPixels(int x, int y, int w, int h, ColorModel model, byte[] pixels, int off, int scansize)`
  Filters the information provided in the setPixels method of the ImageConsumer interface which takes an array of bytes.
  `void`
  `setPixels(int x, int y, int w, int h, ColorModel model, int[] pixels, int off, int scansize)`
  Filters the information provided in the setPixels method of the ImageConsumer interface which takes an array of integers.
  `void`
  `setProperties(Hashtable<?,?> props)`
  Passes the properties from the source object along after adding a property indicating the stream of filters it has been run through.

  ### Methods declared in class Object

  `equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### consumer

    protected ImageConsumer consumer
    The consumer of the particular image data stream for which this instance of the ImageFilter is filtering data. It is not initialized during the constructor, but rather during the getFilterInstance() method call when the FilteredImageSource is creating a unique instance of this object for a particular image data stream.
    See Also:
      - `getFilterInstance(ImageConsumer)`
      - `ImageConsumer`

- ## Constructor Details

  - ### ImageFilter

    public ImageFilter()
    Constructs an `ImageFilter`.

- ## Method Details

  - ### getFilterInstance

    public ImageFilter getFilterInstance(ImageConsumer ic)
    Returns a unique instance of an ImageFilter object which will actually perform the filtering for the specified ImageConsumer. The default implementation just clones this object.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Parameters:
      `ic` - the specified `ImageConsumer`
    Returns:
      an `ImageFilter` used to perform the filtering for the specified `ImageConsumer`.

  - ### setDimensions

    public void setDimensions(int width, int height)
    Filters the information provided in the setDimensions method of the ImageConsumer interface.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setDimensions` in interface `ImageConsumer`
    Parameters:
      `width` - the width of the source image
      `height` - the height of the source image
    See Also:
      - `ImageConsumer.setDimensions(int, int)`

  - ### setProperties

    public void setProperties(Hashtable<?,?> props)
    Passes the properties from the source object along after adding a property indicating the stream of filters it has been run through.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setProperties` in interface `ImageConsumer`
    Parameters:
      `props` - the properties from the source object
    Throws:
      `NullPointerException` - if `props` is null

  - ### setColorModel

    public void setColorModel(ColorModel model)
    Filter the information provided in the setColorModel method of the ImageConsumer interface.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setColorModel` in interface `ImageConsumer`
    Parameters:
      `model` - the specified `ColorModel`
    See Also:
      - `ImageConsumer.setColorModel(ColorModel)`

  - ### setHints

    public void setHints(int hints)
    Filters the information provided in the setHints method of the ImageConsumer interface.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setHints` in interface `ImageConsumer`
    Parameters:
      `hints` - a set of hints that the ImageConsumer uses to process the pixels
    See Also:
      - `ImageConsumer.setHints(int)`

  - ### setPixels

    public void setPixels(int x, int y, int w, int h, ColorModel model, byte[] pixels, int off, int scansize)
    Filters the information provided in the setPixels method of the ImageConsumer interface which takes an array of bytes.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setPixels` in interface `ImageConsumer`
    Parameters:
      `x` - the X coordinate of the upper-left corner of the area of pixels to be set
      `y` - the Y coordinate of the upper-left corner of the area of pixels to be set
      `w` - the width of the area of pixels
      `h` - the height of the area of pixels
      `model` - the specified `ColorModel`
      `pixels` - the array of pixels
      `off` - the offset into the `pixels` array
      `scansize` - the distance from one row of pixels to the next in the `pixels` array
    See Also:
      - `ImageConsumer.setPixels(int, int, int, int, ColorModel, byte[], int, int)`

  - ### setPixels

    public void setPixels(int x, int y, int w, int h, ColorModel model, int[] pixels, int off, int scansize)
    Filters the information provided in the setPixels method of the ImageConsumer interface which takes an array of integers.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `setPixels` in interface `ImageConsumer`
    Parameters:
      `x` - the X coordinate of the upper-left corner of the area of pixels to be set
      `y` - the Y coordinate of the upper-left corner of the area of pixels to be set
      `w` - the width of the area of pixels
      `h` - the height of the area of pixels
      `model` - the specified `ColorModel`
      `pixels` - the array of pixels
      `off` - the offset into the `pixels` array
      `scansize` - the distance from one row of pixels to the next in the `pixels` array
    See Also:
      - `ImageConsumer.setPixels(int, int, int, int, ColorModel, byte[], int, int)`

  - ### imageComplete

    public void imageComplete(int status)
    Filters the information provided in the imageComplete method of the ImageConsumer interface.

    Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being filtered. Developers using this class to filter pixels from an image should avoid calling this method directly since that operation could interfere with the filtering operation.

    Specified by:
      `imageComplete` in interface `ImageConsumer`
    Parameters:
      `status` - the status of image loading
    See Also:
      - `ImageConsumer.imageComplete(int)`

  - ### resendTopDownLeftRight

    public void resendTopDownLeftRight(ImageProducer ip)
    Responds to a request for a TopDownLeftRight (TDLR) ordered resend of the pixel data from an `ImageConsumer`. When an `ImageConsumer` being fed by an instance of this `ImageFilter` requests a resend of the data in TDLR order, the `FilteredImageSource` invokes this method of the `ImageFilter`.

    An `ImageFilter` subclass might override this method or not, depending on if and how it can send data in TDLR order. Three possibilities exist:

    - Do not override this method. This makes the subclass use the default implementation, which is to forward the request to the indicated `ImageProducer` using this filter as the requesting `ImageConsumer`. This behavior is appropriate if the filter can determine that it will forward the pixels in TDLR order if its upstream producer object sends them in TDLR order.
    - Override the method to simply send the data. This is appropriate if the filter can handle the request itself — for example, if the generated pixels have been saved in some sort of buffer.
    - Override the method to do nothing. This is appropriate if the filter cannot produce filtered data in TDLR order.
    Parameters:
      `ip` - the ImageProducer that is feeding this instance of the filter - also the ImageProducer that the request should be forwarded to if necessary
    Throws:
      `NullPointerException` - if `ip` is null
    See Also:
      - `ImageProducer.requestTopDownLeftRightResend(ImageConsumer)`

  - ### clone

    public Object clone()
    Clones this object.
    Overrides:
      `clone` in class `Object`
    Returns:
      a clone of this instance.
    See Also:
      - `Cloneable`