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# CIImageAccumulator

An object that manages feedback-based image processing for tasks such as painting or fluid simulation.

```
class CIImageAccumulator
```

## Overview

The `CIImageAccumulator` class enables feedback-based image processing for such things as iterative painting operations or fluid dynamics simulations. You use `CIImageAccumulator` objects in conjunction with other Core Image classes, such as  [`CIFilter`](/documentation/CoreImage/CIFilter-swift.class), [`CIImage`](/documentation/CoreImage/CIImage), [`CIVector`](/documentation/CoreImage/CIVector), and [`CIContext`](/documentation/CoreImage/CIContext), to take advantage of the built-in Core Image filters when processing images.

## Topics

### Creating an Image Accumulator

[`imageAccumulatorWithExtent:format:`](/documentation/CoreImage/CIImageAccumulator/imageAccumulatorWithExtent:format:)

Creates an image accumulator with the specified extent and pixel format.

[`imageAccumulatorWithExtent:format:colorSpace:`](/documentation/CoreImage/CIImageAccumulator/imageAccumulatorWithExtent:format:colorSpace:)

Creates an image accumulator with the specified extent, pixel format, and color space.

### Initializing an Image Accumulator

[`init(extent:format:)`](/documentation/CoreImage/CIImageAccumulator/init(extent:format:))

Initializes an image accumulator with the specified extent and pixel format.

[`init(extent:format:colorSpace:)`](/documentation/CoreImage/CIImageAccumulator/init(extent:format:colorSpace:))

Initializes an image accumulator with the specified extent, pixel format, and color space.

### Setting an Image

[`setImage(_:)`](/documentation/CoreImage/CIImageAccumulator/setImage(_:))

Sets the contents of the image accumulator to the contents of the specified image object.

[`setImage(_:dirtyRect:)`](/documentation/CoreImage/CIImageAccumulator/setImage(_:dirtyRect:))

Updates an image accumulator with a subregion of an image object.

### Obtaining Data From an Image Accumulator

[`extent`](/documentation/CoreImage/CIImageAccumulator/extent)

The extent of the image associated with the image accumulator.

[`format`](/documentation/CoreImage/CIImageAccumulator/format)

The pixel format of the image accumulator.

[`image()`](/documentation/CoreImage/CIImageAccumulator/image())

Returns the current contents of the image accumulator.

### Resetting an Accumulator

[`clear()`](/documentation/CoreImage/CIImageAccumulator/clear())

Resets the accumulator, discarding any pending updates and the current content.


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