ImageDecoder

ALLOCATOR_DEFAULT

static val ALLOCATOR_DEFAULT: Int

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).

Value: 0

ALLOCATOR_HARDWARE

static val ALLOCATOR_HARDWARE: Int

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 java.lang.IllegalStateException.

Value: 3

ALLOCATOR_SHARED_MEMORY

static val ALLOCATOR_SHARED_MEMORY: Int

Use shared memory for the pixel memory.

Useful for sharing across processes.

Value: 2

ALLOCATOR_SOFTWARE

static val ALLOCATOR_SOFTWARE: Int

Use a software allocation for the pixel memory.

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

Value: 1

MEMORY_POLICY_DEFAULT

static val MEMORY_POLICY_DEFAULT: Int

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.

Value: 1

MEMORY_POLICY_LOW_RAM

static val MEMORY_POLICY_LOW_RAM: Int

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.

Value: 0

close

fun close(): Unit

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

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

Create a new Source from a android.net.Uri.

Accepts the following URI schemes:

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

createSource

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

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

createSource

static fun createSource(
    res: Resources, 
    resId: Int
): ImageDecoder.Source

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

createSource

static fun createSource(data: ByteArray): ImageDecoder.Source

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

static fun createSource(
    data: ByteArray, 
    offset: Int, 
    length: Int
): ImageDecoder.Source

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

static fun createSource(file: File): ImageDecoder.Source

Create a new Source from a java.io.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

static fun createSource(buffer: ByteBuffer): ImageDecoder.Source

Create a new Source from a java.nio.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

static fun createSource(callable: Callable<AssetFileDescriptor!>): ImageDecoder.Source

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 android.content.ContentResolver#openTypedAssetFileDescriptor, or enabling use of a android.os.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.

decodeBitmap

static fun decodeBitmap(src: ImageDecoder.Source): Bitmap

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.

decodeBitmap

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

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

decodeDrawable

static fun decodeDrawable(src: ImageDecoder.Source): Drawable

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

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

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

fun getAllocator(): Int

Return the allocator for the pixel memory.

getCrop

fun getCrop(): Rect?

Return the cropping rectangle, if set.

getMemorySizePolicy

fun getMemorySizePolicy(): Int

Retrieve the memory policy for the decoded Bitmap.

getOnPartialImageListener

fun getOnPartialImageListener(): ImageDecoder.OnPartialImageListener?

Return the OnPartialImageListener currently set.

getPostProcessor

fun getPostProcessor(): PostProcessor?

Return the PostProcessor currently set.

isDecodeAsAlphaMaskEnabled

fun isDecodeAsAlphaMaskEnabled(): Boolean

Return whether to treat single channel input as alpha.

This returns whether setDecodeAsAlphaMaskEnabled 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

static fun isMimeTypeSupported(mimeType: String): Boolean

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

fun isMutableRequired(): Boolean

Return whether the decoded Bitmap will be mutable.

isUnpremultipliedRequired

fun isUnpremultipliedRequired(): Boolean

Return whether the Bitmap will have unpremultiplied pixels.

setAllocator

fun setAllocator(allocator: Int): Unit

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

fun setCrop(subset: Rect?): Unit

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

subset must be contained within the size set by setTargetSize 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

fun setDecodeAsAlphaMaskEnabled(enabled: Boolean): Unit

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 java.lang.IllegalStateException.

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

setMemorySizePolicy

fun setMemorySizePolicy(policy: Int): Unit

Specify the memory policy for the decoded Bitmap.

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

setMutableRequired

fun setMutableRequired(mutable: Boolean): Unit

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 java.lang.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 java.lang.IllegalStateException.

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

setOnPartialImageListener

fun setOnPartialImageListener(listener: ImageDecoder.OnPartialImageListener?): Unit

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

fun setPostProcessor(postProcessor: PostProcessor?): Unit

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 and/or setCrop, 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

fun setTargetColorSpace(colorSpace: ColorSpace!): Unit

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 android.os.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 android.os.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

fun setTargetSampleSize(sampleSize: Int): Unit

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 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 is respected.

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

setTargetSize

fun setTargetSize(
    width: Int, 
    height: Int
): Unit

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 is respected.

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

setUnpremultipliedRequired

fun setUnpremultipliedRequired(unpremultipliedRequired: Boolean): Unit

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 android.view.View system (i.e. to a Canvas). Calling this method with a value of true will result in #decodeBitmap returning a Bitmap with unpremultiplied pixels. See Bitmap.isPremultiplied(). This is incompatible with #decodeDrawable; attempting to decode an unpremultiplied Drawable will throw an java.lang.IllegalStateException.

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

finalize

protected fun finalize(): Unit