ImageDecoder

ALLOCATOR_DEFAULT

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

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

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

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

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

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)

close

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

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.

createSource

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.

createSource

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.

createSource

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.

createSource

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.

createSource

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.

createSource

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)

createSource

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

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.

decodeBitmap

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.

decodeBitmap

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.

decodeDrawable

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.

decodeDrawable

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.

getAllocator

public int getAllocator ()

Return the allocator for the pixel memory.

getCrop

public Rect getCrop ()

Return the cropping rectangle, if set.

getMemorySizePolicy

public int getMemorySizePolicy ()

Retrieve the memory policy for the decoded Bitmap.

getOnPartialImageListener

public ImageDecoder.OnPartialImageListener getOnPartialImageListener ()

Return the OnPartialImageListener currently set.

getPostProcessor

public PostProcessor getPostProcessor ()

Return the PostProcessor currently set.

isDecodeAsAlphaMaskEnabled

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.

isMimeTypeSupported

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.

isMutableRequired

public boolean isMutableRequired ()

Return whether the decoded Bitmap will be mutable.

isUnpremultipliedRequired

public boolean isUnpremultipliedRequired ()

Return whether the Bitmap will have unpremultiplied pixels.

setAllocator

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.

setCrop

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.

setDecodeAsAlphaMaskEnabled

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.

setMemorySizePolicy

public void setMemorySizePolicy (int policy)

Specify the memory policy for the decoded Bitmap.

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

setMutableRequired

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.

setOnPartialImageListener

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.

setPostProcessor

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.

setTargetColorSpace

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.

setTargetSampleSize

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.

setTargetSize

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.

setUnpremultipliedRequired

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.

finalize

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.