IIOWriteProgressListener (Java SE 26 & JDK 26)
Description: declaration: module: java.desktop, package: javax.imageio.event, interface: IIOWriteProgressListener
Keywords: javax.imageio.event.IIOWriteProgressListener interface

# Interface IIOWriteProgressListener

All Superinterfaces:
  `EventListener`

public interface IIOWriteProgressListener extends EventListener
An interface used by `ImageWriter` implementations to notify callers of their image writing methods of progress.

See Also:
  - `ImageWriter.write(IIOMetadata, IIOImage, ImageWriteParam)`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `imageComplete(ImageWriter source)`
  Reports that the image write operation has completed.
  `void`
  `imageProgress(ImageWriter source, float percentageDone)`
  Reports the approximate degree of completion of the current `write` call within the associated `ImageWriter`.
  `void`
  `imageStarted(ImageWriter source, int imageIndex)`
  Reports that an image write operation is beginning.
  `void`
  `thumbnailComplete(ImageWriter source)`
  Reports that a thumbnail write operation has completed.
  `void`
  `thumbnailProgress(ImageWriter source, float percentageDone)`
  Reports the approximate degree of completion of the current thumbnail write within the associated `ImageWriter`.
  `void`
  `thumbnailStarted(ImageWriter source, int imageIndex, int thumbnailIndex)`
  Reports that a thumbnail write operation is beginning.
  `void`
  `writeAborted(ImageWriter source)`
  Reports that a write has been aborted via the writer's `abort` method.

- ## Method Details

  - ### imageStarted

    void imageStarted(ImageWriter source, int imageIndex)
    Reports that an image write operation is beginning. All `ImageWriter` implementations are required to call this method exactly once when beginning an image write operation.
    Parameters:
      `source` - the `ImageWriter` object calling this method.
      `imageIndex` - the index of the image being written within its containing input file or stream.

  - ### imageProgress

    void imageProgress(ImageWriter source, float percentageDone)
    Reports the approximate degree of completion of the current `write` call within the associated `ImageWriter`.

    The degree of completion is expressed as an index indicating which image is being written, and a percentage varying from `0.0F` to `100.0F` indicating how much of the current image has been output. The percentage should ideally be calculated in terms of the remaining time to completion, but it is usually more practical to use a more well-defined metric such as pixels decoded or portion of input stream consumed. In any case, a sequence of calls to this method during a given read operation should supply a monotonically increasing sequence of percentage values. It is not necessary to supply the exact values `0` and `100`, as these may be inferred by the callee from other methods.

    Each particular `ImageWriter` implementation may call this method at whatever frequency it desires. A rule of thumb is to call it around each 5 percent mark.

    Parameters:
      `source` - the `ImageWriter` object calling this method.
      `percentageDone` - the approximate percentage of decoding that has been completed.

  - ### imageComplete

    void imageComplete(ImageWriter source)
    Reports that the image write operation has completed. All `ImageWriter` implementations are required to call this method exactly once upon completion of each image write operation.
    Parameters:
      `source` - the `ImageWriter` object calling this method.

  - ### thumbnailStarted

    void thumbnailStarted(ImageWriter source, int imageIndex, int thumbnailIndex)
    Reports that a thumbnail write operation is beginning. All `ImageWriter` implementations are required to call this method exactly once when beginning a thumbnail write operation.
    Parameters:
      `source` - the `ImageWrite` object calling this method.
      `imageIndex` - the index of the image being written within its containing input file or stream.
      `thumbnailIndex` - the index of the thumbnail being written.

  - ### thumbnailProgress

    void thumbnailProgress(ImageWriter source, float percentageDone)
    Reports the approximate degree of completion of the current thumbnail write within the associated `ImageWriter`. The semantics are identical to those of `imageProgress`.
    Parameters:
      `source` - the `ImageWriter` object calling this method.
      `percentageDone` - the approximate percentage of decoding that has been completed.

  - ### thumbnailComplete

    void thumbnailComplete(ImageWriter source)
    Reports that a thumbnail write operation has completed. All `ImageWriter` implementations are required to call this method exactly once upon completion of each thumbnail write operation.
    Parameters:
      `source` - the `ImageWriter` object calling this method.

  - ### writeAborted

    void writeAborted(ImageWriter source)
    Reports that a write has been aborted via the writer's `abort` method. No further notifications will be given.
    Parameters:
      `source` - the `ImageWriter` object calling this method.