Added in API level 28

Summary: Nested Classes | Constants | Methods | Protected Methods | Inherited Methods

ImageDecoder

Kotlin |Java

public final class ImageDecoder
extends Object implements AutoCloseable

java.lang.Object
↳	android.graphics.ImageDecoder

A class for converting encoded images (like PNG, JPEG, WEBP, GIF, or HEIF) into Drawable or Bitmap objects.

To use it, first create a Source using one of the createSource overloads. For example, to decode from a Uri, call createSource(android.content.ContentResolver, android.net.Uri) and pass the result to decodeDrawable(android.graphics.ImageDecoder.Source) or decodeBitmap(android.graphics.ImageDecoder.Source):

  File file = new File(...);
  ImageDecoder.Source source = ImageDecoder.createSource(file);
  Drawable drawable = ImageDecoder.decodeDrawable(source);

To change the default settings, pass the Source and an OnHeaderDecodedListener to decodeDrawable(android.graphics.ImageDecoder.Source, android.graphics.ImageDecoder.OnHeaderDecodedListener) or decodeBitmap(android.graphics.ImageDecoder.Source, android.graphics.ImageDecoder.OnHeaderDecodedListener). For example, to create a sampled image with half the width and height of the original image, call setTargetSampleSize(2) inside onHeaderDecoded:

  OnHeaderDecodedListener listener = new OnHeaderDecodedListener() {
      public void onHeaderDecoded(ImageDecoder decoder, ImageInfo info, Source source) {
          decoder.setTargetSampleSize(2);
      }
  };
  Drawable drawable = ImageDecoder.decodeDrawable(source, listener);

The ImageInfo contains information about the encoded image, like its width and height, and the Source can be used to match to a particular Source if a single OnHeaderDecodedListener is used with multiple Source objects.

The OnHeaderDecodedListener can also be implemented as a lambda:

  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
      decoder.setTargetSampleSize(2);
  });

If the encoded image is an animated GIF or WEBP, decodeDrawable will return an AnimatedImageDrawable. To start its animation, call AnimatedImageDrawable.start():

  Drawable drawable = ImageDecoder.decodeDrawable(source);
  if (drawable instanceof AnimatedImageDrawable) {
      ((AnimatedImageDrawable) drawable).start();
  }

By default, a Bitmap created by ImageDecoder (including one that is inside a Drawable) will be immutable (i.e. Bitmap.isMutable() returns false), and it will typically have Config Bitmap.Config.HARDWARE. Although these properties can be changed with setMutableRequired(true) (which is only compatible with decodeBitmap(android.graphics.ImageDecoder.Source) and decodeBitmap(android.graphics.ImageDecoder.Source, android.graphics.ImageDecoder.OnHeaderDecodedListener)) and setAllocator(int), it is also possible to apply custom effects regardless of the mutability of the final returned object by passing a PostProcessor to setPostProcessor. A PostProcessor can also be a lambda:

  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
      decoder.setPostProcessor((canvas) -> {
              // This will create rounded corners.
              Path path = new Path();
              path.setFillType(Path.FillType.INVERSE_EVEN_ODD);
              int width = canvas.getWidth();
              int height = canvas.getHeight();
              path.addRoundRect(0, 0, width, height, 20, 20, Path.Direction.CW);
              Paint paint = new Paint();
              paint.setAntiAlias(true);
              paint.setColor(Color.TRANSPARENT);
              paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
              canvas.drawPath(path, paint);
              return PixelFormat.TRANSLUCENT;
      });
  });

If the encoded image is incomplete or contains an error, or if an Exception occurs during decoding, a DecodeException will be thrown. In some cases, the ImageDecoder may have decoded part of the image. In order to display the partial image, an OnPartialImageListener must be passed to setOnPartialImageListener. For example:

  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
      decoder.setOnPartialImageListener((DecodeException e) -> {
              // Returning true indicates to create a Drawable or Bitmap even
              // if the whole image could not be decoded. Any remaining lines
              // will be blank.
              return true;
      });
  });

Summary

Nested classes
`class`	`ImageDecoder.DecodeException` Information about an interrupted decode.
`class`	`ImageDecoder.ImageInfo` Information about an encoded image.
`interface`	`ImageDecoder.OnHeaderDecodedListener` Interface for changing the default settings of a decode.
`interface`	`ImageDecoder.OnPartialImageListener` Interface for inspecting a `DecodeException` and potentially preventing it from being thrown.
`class`	`ImageDecoder.Source` Source of encoded image data.

Constants
`int`	`ALLOCATOR_DEFAULT` Use the default allocation for the pixel memory.
`int`	`ALLOCATOR_HARDWARE` Require a `Bitmap.Config.HARDWARE` `Bitmap`.
`int`	`ALLOCATOR_SHARED_MEMORY` Use shared memory for the pixel memory.
`int`	`ALLOCATOR_SOFTWARE` Use a software allocation for the pixel memory.
`int`	`MEMORY_POLICY_DEFAULT` Use the most natural `Bitmap.Config` for the internal `Bitmap`.
`int`	`MEMORY_POLICY_LOW_RAM` Save memory if possible by using a denser `Bitmap.Config` at the cost of some image quality.

Public methods
`void`	`close()` Closes this resource, relinquishing any underlying resources.
`static ImageDecoder.Source`	`createSource(byte[] data)` Create a new `Source` from a byte array.
`static ImageDecoder.Source`	`createSource(AssetManager assets, String fileName)` Create a new `Source` from a file in the "assets" directory.
`static ImageDecoder.Source`	`createSource(Callable<AssetFileDescriptor> callable)` Create a new `Source` from a `Callable` that returns a new `AssetFileDescriptor` for each request.
`static ImageDecoder.Source`	`createSource(ByteBuffer buffer)` Create a new `Source` from a `ByteBuffer`.
`static ImageDecoder.Source`	`createSource(File file)` Create a new `Source` from a `File`.
`static ImageDecoder.Source`	`createSource(Resources res, int resId)` Create a new `Source` from a resource.
`static ImageDecoder.Source`	`createSource(ContentResolver cr, Uri uri)` Create a new `Source` from a `Uri`.
`static ImageDecoder.Source`	`createSource(byte[] data, int offset, int length)` Create a new `Source` from a byte array.
`static Bitmap`	`decodeBitmap(ImageDecoder.Source src, ImageDecoder.OnHeaderDecodedListener listener)` Create a `Bitmap` from a `Source`.
`static Bitmap`	`decodeBitmap(ImageDecoder.Source src)` Create a `Bitmap` from a `Source`.
`static Drawable`	`decodeDrawable(ImageDecoder.Source src)` Create a `Drawable` from a `Source`.
`static Drawable`	`decodeDrawable(ImageDecoder.Source src, ImageDecoder.OnHeaderDecodedListener listener)` Create a `Drawable` from a `Source`.
`int`	`getAllocator()` Return the allocator for the pixel memory.
`Rect`	`getCrop()` Return the cropping rectangle, if set.
`int`	`getMemorySizePolicy()` Retrieve the memory policy for the decoded `Bitmap`.
`ImageDecoder.OnPartialImageListener`	`getOnPartialImageListener()` Return the `OnPartialImageListener` currently set.
`PostProcessor`	`getPostProcessor()` Return the `PostProcessor` currently set.
`boolean`	`isDecodeAsAlphaMaskEnabled()` Return whether to treat single channel input as alpha.
`static boolean`	`isMimeTypeSupported(String mimeType)` Return if the given MIME type is a supported file format that can be decoded by this class.
`boolean`	`isMutableRequired()` Return whether the decoded `Bitmap` will be mutable.
`boolean`	`isUnpremultipliedRequired()` Return whether the `Bitmap` will have unpremultiplied pixels.
`void`	`setAllocator(int allocator)` Choose the backing for the pixel memory.
`void`	`setCrop(Rect subset)` Crop the output to `subset` of the (possibly) scaled image.
`void`	`setDecodeAsAlphaMaskEnabled(boolean enabled)` Specify whether to potentially treat the output as an alpha mask.
`void`	`setMemorySizePolicy(int policy)` Specify the memory policy for the decoded `Bitmap`.
`void`	`setMutableRequired(boolean mutable)` Specify whether the `Bitmap` should be mutable.
`void`	`setOnPartialImageListener(ImageDecoder.OnPartialImageListener listener)` Set (replace) the `OnPartialImageListener` on this object.
`void`	`setPostProcessor(PostProcessor postProcessor)` Modify the image after decoding and scaling.
`void`	`setTargetColorSpace(ColorSpace colorSpace)` Specify the desired `ColorSpace` for the output.
`void`	`setTargetSampleSize(int sampleSize)` Set the target size with a sampleSize.
`void`	`setTargetSize(int width, int height)` Specify the size of the output `Drawable` or `Bitmap`.
`void`	`setUnpremultipliedRequired(boolean unpremultipliedRequired)` Specify whether the `Bitmap` should have unpremultiplied pixels.

Protected methods
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.lang.AutoCloseable


      close()

Closes this resource, relinquishing any underlying resources.

Constants

ALLOCATOR_DEFAULT

Added in API level 28

public static final int ALLOCATOR_DEFAULT

Use the default allocation for the pixel memory. Will typically result in a Bitmap.Config.HARDWARE allocation, but may be software for small images. In addition, this will switch to software when HARDWARE is incompatible, e.g. setMutableRequired(true) or setDecodeAsAlphaMaskEnabled(true).

Constant Value: 0 (0x00000000)

ALLOCATOR_HARDWARE

Added in API level 28

public static final int ALLOCATOR_HARDWARE

Require a Bitmap.Config.HARDWARE Bitmap.

When this is combined with incompatible options, like setMutableRequired(true) or setDecodeAsAlphaMaskEnabled(true), decodeDrawable or decodeBitmap will throw an IllegalStateException.

Constant Value: 3 (0x00000003)

ALLOCATOR_SHARED_MEMORY

Added in API level 28

public static final int ALLOCATOR_SHARED_MEMORY

Use shared memory for the pixel memory.

Useful for sharing across processes.

Constant Value: 2 (0x00000002)

ALLOCATOR_SOFTWARE

Added in API level 28

public static final int ALLOCATOR_SOFTWARE

Use a software allocation for the pixel memory.

Useful for drawing to a software Canvas or for accessing the pixels on the final output.

Constant Value: 1 (0x00000001)

MEMORY_POLICY_DEFAULT

Added in API level 28

public static final int MEMORY_POLICY_DEFAULT

Use the most natural Bitmap.Config for the internal Bitmap.

This is the recommended default for most applications and usages. This will use the closest Bitmap.Config for the encoded source. If the encoded source does not exactly match any Bitmap.Config, the next highest quality Bitmap.Config will be used avoiding any loss in image quality.

Constant Value: 1 (0x00000001)

MEMORY_POLICY_LOW_RAM

Added in API level 28

public static final int MEMORY_POLICY_LOW_RAM

Save memory if possible by using a denser Bitmap.Config at the cost of some image quality.

For example an opaque 8-bit image may be compressed into an Bitmap.Config.RGB_565 configuration, sacrificing image quality to save memory.

Constant Value: 0 (0x00000000)

Public methods

close

Added in API level 28

public void close ()

Closes this resource, relinquishing any underlying resources. This method is invoked automatically on objects managed by the try-with-resources statement.

This is an implementation detail of ImageDecoder, and should never be called manually.

createSource

Added in API level 31

public static ImageDecoder.Source createSource (byte[] data)

Create a new Source from a byte array.

Note: If this Source is passed to decodeDrawable, and the encoded image is animated, the returned AnimatedImageDrawable will continue reading from data, so its contents must not be modified, even after the AnimatedImageDrawable is returned. data's contents should never be modified during decode.

This method is safe to call from any thread.

Parameters
`data`	`byte`: byte array of compressed image data. This value cannot be `null`.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

Throws
`NullPointerException`	if data is null.

createSource

Added in API level 28

public static ImageDecoder.Source createSource (AssetManager assets, 
                String fileName)

Create a new Source from a file in the "assets" directory.
This method is safe to call from any thread.

Parameters
`assets`	`AssetManager`: This value cannot be `null`.
`fileName`	`String`: This value cannot be `null`.

Returns
`ImageDecoder.Source`	This value cannot be `null`.

createSource

Added in API level 29

public static ImageDecoder.Source createSource (Callable<AssetFileDescriptor> callable)

Create a new Source from a Callable that returns a new AssetFileDescriptor for each request. This provides control over how the AssetFileDescriptor is created, such as passing options into ContentResolver.openTypedAssetFileDescriptor, or enabling use of a CancellationSignal.

It's important for the given Callable to return a new, unique AssetFileDescriptor for each invocation, to support reuse of the returned Source.
This method is safe to call from any thread.

Parameters
`callable`	`Callable`: This value cannot be `null`.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

createSource

Added in API level 28

public static ImageDecoder.Source createSource (ByteBuffer buffer)

Create a new Source from a ByteBuffer.

Decoding will start from buffer.position(). The position of buffer will not be affected.

Note: If this Source is passed to decodeDrawable, and the encoded image is animated, the returned AnimatedImageDrawable will continue reading from the buffer, so its contents must not be modified, even after the AnimatedImageDrawable is returned. buffer's contents should never be modified during decode.

This method is safe to call from any thread.

Parameters
`buffer`	`ByteBuffer`: This value cannot be `null`.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

createSource

Added in API level 28

public static ImageDecoder.Source createSource (File file)

Create a new Source from a File.

This method should only be used for files that you have direct access to; if you'd like to work with files hosted outside your app, use an API like createSource(java.util.concurrent.Callable) or createSource(android.content.ContentResolver, android.net.Uri).
This method is safe to call from any thread.

Parameters
`file`	`File`: This value cannot be `null`.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

createSource

Added in API level 28

public static ImageDecoder.Source createSource (Resources res, 
                int resId)

Create a new Source from a resource.
This method is safe to call from any thread.

Parameters
`res`	`Resources`: the `Resources` object containing the image data. This value cannot be `null`.
`resId`	`int`: resource ID of the image data.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

createSource

Added in API level 28

public static ImageDecoder.Source createSource (ContentResolver cr, 
                Uri uri)

Create a new Source from a Uri.

Accepts the following URI schemes:

content (ContentResolver.SCHEME_CONTENT)
android.resource (ContentResolver.SCHEME_ANDROID_RESOURCE)
file (ContentResolver.SCHEME_FILE)

This method is safe to call from any thread.

Parameters
`cr`	`ContentResolver`: to retrieve from. This value cannot be `null`.
`uri`	`Uri`: of the image file. This value cannot be `null`.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

createSource

Added in API level 31

public static ImageDecoder.Source createSource (byte[] data, 
                int offset, 
                int length)

Create a new Source from a byte array.

This method is safe to call from any thread.

Parameters
`data`	`byte`: byte array of compressed image data. This value cannot be `null`.
`offset`	`int`: offset into data for where the decoder should begin parsing.
`length`	`int`: number of bytes, beginning at offset, to parse.

Returns
`ImageDecoder.Source`	a new Source object, which can be passed to `decodeDrawable` or `decodeBitmap`. This value cannot be `null`.

Throws
`NullPointerException`	if data is null.
`ArrayIndexOutOfBoundsException`	if offset and length are not within data.

decodeBitmap

Added in API level 28

public static Bitmap decodeBitmap (ImageDecoder.Source src, 
                ImageDecoder.OnHeaderDecodedListener listener)

Create a Bitmap from a Source.
This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
`src`	`ImageDecoder.Source`: representing the encoded image. This value cannot be `null`.
`listener`	`ImageDecoder.OnHeaderDecodedListener`: for learning the `ImageInfo` and changing any default settings on the `ImageDecoder`. This will be called on the same thread as `decodeBitmap` before that method returns. This is required in order to change any of the default settings. This value cannot be `null`.

Returns
`Bitmap`	Bitmap containing the image. This value cannot be `null`.

Throws
`IOException`	if `src` is not found, is an unsupported format, or cannot be decoded for any reason.

decodeBitmap

Added in API level 28

public static Bitmap decodeBitmap (ImageDecoder.Source src)

Create a Bitmap from a Source.

Since there is no OnHeaderDecodedListener, the default settings will be used. In order to change any settings, call decodeBitmap(android.graphics.ImageDecoder.Source, android.graphics.ImageDecoder.OnHeaderDecodedListener) instead.

This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
`src`	`ImageDecoder.Source`: representing the encoded image. This value cannot be `null`.

Returns
`Bitmap`	Bitmap containing the image. This value cannot be `null`.

Throws
`IOException`	if `src` is not found, is an unsupported format, or cannot be decoded for any reason.

decodeDrawable

Added in API level 28

public static Drawable decodeDrawable (ImageDecoder.Source src)

Create a Drawable from a Source.

Since there is no OnHeaderDecodedListener, the default settings will be used. In order to change any settings, call decodeDrawable(android.graphics.ImageDecoder.Source, android.graphics.ImageDecoder.OnHeaderDecodedListener) instead.

This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
`src`	`ImageDecoder.Source`: representing the encoded image. This value cannot be `null`.

Returns
`Drawable`	Drawable for displaying the image. This value cannot be `null`.

Throws
`IOException`	if `src` is not found, is an unsupported format, or cannot be decoded for any reason.

decodeDrawable

Added in API level 28

public static Drawable decodeDrawable (ImageDecoder.Source src, 
                ImageDecoder.OnHeaderDecodedListener listener)

Create a Drawable from a Source.
This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
`src`	`ImageDecoder.Source`: representing the encoded image. This value cannot be `null`.
`listener`	`ImageDecoder.OnHeaderDecodedListener`: for learning the `ImageInfo` and changing any default settings on the `ImageDecoder`. This will be called on the same thread as `decodeDrawable` before that method returns. This is required in order to change any of the default settings. This value cannot be `null`.

Returns
`Drawable`	Drawable for displaying the image. This value cannot be `null`.

Throws
`IOException`	if `src` is not found, is an unsupported format, or cannot be decoded for any reason.

getAllocator

Added in API level 28

public int getAllocator ()

Return the allocator for the pixel memory.

Returns
`int`	Value is `ALLOCATOR_DEFAULT`, `ALLOCATOR_SOFTWARE`, `ALLOCATOR_SHARED_MEMORY`, or `ALLOCATOR_HARDWARE`

getCrop

Added in API level 28

public Rect getCrop ()

Return the cropping rectangle, if set.

Returns
`Rect`	This value may be `null`.

getMemorySizePolicy

Added in API level 28

public int getMemorySizePolicy ()

Retrieve the memory policy for the decoded Bitmap.

Returns
`int`	Value is `MEMORY_POLICY_DEFAULT`, or `MEMORY_POLICY_LOW_RAM`

getOnPartialImageListener

Added in API level 28

public ImageDecoder.OnPartialImageListener getOnPartialImageListener ()

Return the OnPartialImageListener currently set.

Returns
`ImageDecoder.OnPartialImageListener`	This value may be `null`.

getPostProcessor

Added in API level 28

public PostProcessor getPostProcessor ()

Return the PostProcessor currently set.

Returns
`PostProcessor`	This value may be `null`.

isDecodeAsAlphaMaskEnabled

Added in API level 28

public boolean isDecodeAsAlphaMaskEnabled ()

Return whether to treat single channel input as alpha.

This returns whether setDecodeAsAlphaMaskEnabled(boolean) was set to true. It may still return true even if the image has more than one channel and therefore will not be treated as an alpha mask.

Returns
`boolean`

isMimeTypeSupported

Added in API level 29

public static boolean isMimeTypeSupported (String mimeType)

Return if the given MIME type is a supported file format that can be decoded by this class. This can be useful to determine if a file can be decoded directly, or if it needs to be converted into a more general format using an API like ContentResolver.openTypedAssetFile.

Parameters
`mimeType`	`String`: This value cannot be `null`.

Returns
`boolean`

isMutableRequired

Added in API level 28

public boolean isMutableRequired ()

Return whether the decoded Bitmap will be mutable.

Returns
`boolean`

isUnpremultipliedRequired

Added in API level 28

public boolean isUnpremultipliedRequired ()

Return whether the Bitmap will have unpremultiplied pixels.

Returns
`boolean`

setAllocator

Added in API level 28

public void setAllocator (int allocator)

Choose the backing for the pixel memory.

This is ignored for animated drawables.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`allocator`	`int`: Type of allocator to use. Value is `ALLOCATOR_DEFAULT`, `ALLOCATOR_SOFTWARE`, `ALLOCATOR_SHARED_MEMORY`, or `ALLOCATOR_HARDWARE`

setCrop

Added in API level 28

public void setCrop (Rect subset)

Crop the output to subset of the (possibly) scaled image.

subset must be contained within the size set by setTargetSize(int, int) or the bounds of the image if setTargetSize was not called. Otherwise an IllegalStateException will be thrown by decodeDrawable/decodeBitmap.

NOT intended as a replacement for BitmapRegionDecoder.decodeRegion(). This supports all formats, but merely crops the output.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`subset`	`Rect`: This value may be `null`.

setDecodeAsAlphaMaskEnabled

Added in API level 28

public void setDecodeAsAlphaMaskEnabled (boolean enabled)

Specify whether to potentially treat the output as an alpha mask.

If this is set to true and the image is encoded in a format with only one channel, treat that channel as alpha. Otherwise this call has no effect.

This is incompatible with ALLOCATOR_HARDWARE. Trying to combine them will result in decodeDrawable/ decodeBitmap throwing an IllegalStateException.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`enabled`	`boolean`

setMemorySizePolicy

Added in API level 28

public void setMemorySizePolicy (int policy)

Specify the memory policy for the decoded Bitmap.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`policy`	`int`: Value is `MEMORY_POLICY_DEFAULT`, or `MEMORY_POLICY_LOW_RAM`

setMutableRequired

Added in API level 28

public void setMutableRequired (boolean mutable)

Specify whether the Bitmap should be mutable.

By default, a Bitmap created by decodeBitmap will be immutable i.e. Bitmap.isMutable() returns false. This can be changed with setMutableRequired(true).

Mutable Bitmaps are incompatible with ALLOCATOR_HARDWARE, because Bitmap.Config.HARDWARE Bitmaps cannot be mutable. Attempting to combine them will throw an IllegalStateException.

Mutable Bitmaps are also incompatible with decodeDrawable, which would require retrieving the Bitmap from the returned Drawable in order to modify. Attempting to decode a mutable Drawable will throw an IllegalStateException.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`mutable`	`boolean`

setOnPartialImageListener

Added in API level 28

public void setOnPartialImageListener (ImageDecoder.OnPartialImageListener listener)

Set (replace) the OnPartialImageListener on this object.

Will be called if there is an error in the input. Without one, an error will result in an Exception being thrown.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`listener`	`ImageDecoder.OnPartialImageListener`: This value may be `null`.

setPostProcessor

Added in API level 28

public void setPostProcessor (PostProcessor postProcessor)

Modify the image after decoding and scaling.

This allows adding effects prior to returning a Drawable or Bitmap. For a Drawable or an immutable Bitmap, this is the only way to process the image after decoding.

If combined with setTargetSize(int, int) and/or setCrop(Rect), PostProcessor.onPostProcess occurs last.

If set on a nine-patch image, the nine-patch data is ignored.

For an animated image, the drawing commands drawn on the Canvas will be recorded immediately and then applied to each frame.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`postProcessor`	`PostProcessor`: This value may be `null`.

setTargetColorSpace

Added in API level 28

public void setTargetColorSpace (ColorSpace colorSpace)

Specify the desired ColorSpace for the output.

If non-null, the decoder will try to decode into colorSpace. If it is null, which is the default, or the request cannot be met, the decoder will pick either the color space embedded in the image or the ColorSpace best suited for the requested image configuration (for instance sRGB for the Bitmap.Config.ARGB_8888 configuration and EXTENDED_SRGB for Bitmap.Config.RGBA_F16).

Only ColorSpace.Model.RGB color spaces are currently supported. An IllegalArgumentException will be thrown by decodeDrawable/ decodeBitmap when setting a non-RGB color space such as Lab.

Prior to Build.VERSION_CODES.UPSIDE_DOWN_CAKE, the specified color space's transfer function must be an ICC parametric curve. An IllegalArgumentException will be thrown by the decode methods if calling ColorSpace.Rgb.getTransferParameters() on the specified color space returns null. Starting from Build.VERSION_CODES.UPSIDE_DOWN_CAKE, the color spaces with non ICC parametric curve transfer function are allowed. E.g., BT2020_HLG.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`colorSpace`	`ColorSpace`

setTargetSampleSize

Added in API level 28

public void setTargetSampleSize (int sampleSize)

Set the target size with a sampleSize.

By default, the output size will match the size of the encoded image, which can be retrieved from the ImageInfo in onHeaderDecoded.

Requests the decoder to subsample the original image, returning a smaller image to save memory. The sampleSize is the number of pixels in either dimension that correspond to a single pixel in the output. For example, sampleSize == 4 returns an image that is 1/4 the width/height of the original, and 1/16 the number of pixels.

Must be greater than or equal to 1.

This has the same effect as calling setTargetSize(int, int) with dimensions based on the sampleSize. Unlike dividing the original width and height by the sampleSize manually, calling this method allows ImageDecoder to round in the direction that it can do most efficiently.

Only the last call to this or setTargetSize(int, int) is respected.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`sampleSize`	`int`: sampling rate of the encoded image. Value is 1 or greater

setTargetSize

Added in API level 28

public void setTargetSize (int width, 
                int height)

Specify the size of the output Drawable or Bitmap.

By default, the output size will match the size of the encoded image, which can be retrieved from the ImageInfo in onHeaderDecoded.

This will sample or scale the output to an arbitrary size that may be smaller or larger than the encoded size.

Only the last call to this or setTargetSampleSize(int) is respected.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`width`	`int`: width in pixels of the output, must be greater than 0 The units of this value are pixels. Value is 1 or greater
`height`	`int`: height in pixels of the output, must be greater than 0 The units of this value are pixels. Value is 1 or greater

setUnpremultipliedRequired

Added in API level 28

public void setUnpremultipliedRequired (boolean unpremultipliedRequired)

Specify whether the Bitmap should have unpremultiplied pixels.

By default, ImageDecoder will create a Bitmap with premultiplied pixels, which is required for drawing with the View system (i.e. to a Canvas). Calling this method with a value of true will result in decodeBitmap(Source) returning a Bitmap with unpremultiplied pixels. See Bitmap.isPremultiplied(). This is incompatible with decodeDrawable; attempting to decode an unpremultiplied Drawable will throw an IllegalStateException.

Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.

Parameters
`unpremultipliedRequired`	`boolean`

Protected methods

finalize

Added in API level 28

protected void finalize ()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

Throws
`Throwable`

ImageDecoder

Summary

Nested classes

Constants

Public methods

Protected methods

Inherited methods

Constants

ALLOCATOR_DEFAULT

ALLOCATOR_HARDWARE

ALLOCATOR_SHARED_MEMORY

ALLOCATOR_SOFTWARE

MEMORY_POLICY_DEFAULT

MEMORY_POLICY_LOW_RAM

Public methods

close

createSource

createSource

createSource

createSource

createSource

createSource

createSource

Accepts the following URI schemes:

createSource

decodeBitmap

decodeBitmap

decodeDrawable

decodeDrawable

getAllocator

getCrop

getMemorySizePolicy

getOnPartialImageListener

getPostProcessor

isDecodeAsAlphaMaskEnabled

isMimeTypeSupported

isMutableRequired

isUnpremultipliedRequired

setAllocator

setCrop

setDecodeAsAlphaMaskEnabled

setMemorySizePolicy

setMutableRequired

setOnPartialImageListener

setPostProcessor

setTargetColorSpace

setTargetSampleSize

setTargetSize

setUnpremultipliedRequired

Protected methods

finalize