Package com.bumptech.glide.gifdecoder

Class StandardGifDecoder

java.lang.Object

com.bumptech.glide.gifdecoder.StandardGifDecoder

All Implemented Interfaces:

GifDecoder

public class StandardGifDecoder
extends Object
implements GifDecoder

Reads frame data from a GIF image source and decodes it into individual frames for animation purposes. Image data can be read from either and InputStream source or a byte[].

This class is optimized for running animations with the frames, there are no methods to get individual frame images, only to decode the next frame in the animation sequence. Instead, it lowers its memory footprint by only housing the minimum data necessary to decode the next frame in the animation sequence.

The animation must be manually moved forward using advance() before requesting the next frame. This method must also be called before you request the first frame or an error will occur.

Implementation adapted from sample code published in Lyons. (2004). Java for Programmers, republished under the MIT Open Source License

See Also:

• GIF 89a Specification

Nested Class Summary

Nested classes/interfaces inherited from interface com.bumptech.glide.gifdecoder.GifDecoder

GifDecoder.BitmapProvider, GifDecoder.GifDecodeStatus

Field Summary

Fields inherited from interface com.bumptech.glide.gifdecoder.GifDecoder

STATUS_FORMAT_ERROR, STATUS_OK, STATUS_OPEN_ERROR, STATUS_PARTIAL_DECODE, TOTAL_ITERATION_COUNT_FOREVER

Constructor Summary

Constructors

Constructor	Description
StandardGifDecoder(GifDecoder.BitmapProvider provider)
StandardGifDecoder(GifDecoder.BitmapProvider provider, GifHeader gifHeader, ByteBuffer rawData)
StandardGifDecoder(GifDecoder.BitmapProvider provider, GifHeader gifHeader, ByteBuffer rawData, int sampleSize)

Method Summary

Modifier and Type	Method	Description
void	advance()	Move the animation frame counter forward.
void	clear()
int	getByteSize()	Returns an estimated byte size for this decoder based on the data provided to GifDecoder.setData(GifHeader, byte[]), as well as internal buffers.
int	getCurrentFrameIndex()	Gets the current index of the animation frame, or -1 if animation hasn't not yet started.
ByteBuffer	getData()
int	getDelay(int n)	Gets display duration for specified frame.
int	getFrameCount()	Gets the number of frames read from file.
int	getHeight()
int	getLoopCount()	Deprecated.
int	getNetscapeLoopCount()	Gets the "Netscape" loop count, if any.
int	getNextDelay()	Gets display duration for the upcoming frame in ms.
Bitmap	getNextFrame()	Get the next frame in the animation sequence.
int	getStatus()	Returns the current status of the decoder.
int	getTotalIterationCount()	Gets the total count which represents how many times the animation sequence should be displayed.
int	getWidth()
int	read(byte[] data)	Reads GIF image from byte array.
int	read(InputStream is, int contentLength)	Reads GIF image from stream.
void	resetFrameIndex()	Resets the frame pointer to before the 0th frame, as if we'd never used this decoder to decode any frames.
void	setData(GifHeader header, byte[] data)
void	setData(GifHeader header, ByteBuffer buffer)
void	setData(GifHeader header, ByteBuffer buffer, int sampleSize)
void	setDefaultBitmapConfig(Bitmap.Config config)	Sets the default Bitmap.Config to use when decoding frames of a GIF.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

StandardGifDecoder

public StandardGifDecoder(@NonNull
 GifDecoder.BitmapProvider provider,
 GifHeader gifHeader,
 ByteBuffer rawData)

StandardGifDecoder

public StandardGifDecoder(@NonNull
 GifDecoder.BitmapProvider provider,
 GifHeader gifHeader,
 ByteBuffer rawData,
 int sampleSize)

StandardGifDecoder

public StandardGifDecoder(@NonNull
 GifDecoder.BitmapProvider provider)

Method Details

getWidth

public int getWidth()

Specified by:

getWidth in interface GifDecoder

getHeight

public int getHeight()

Specified by:

getHeight in interface GifDecoder

getData

@NonNull
public ByteBuffer getData()

Specified by:

getData in interface GifDecoder

getStatus

public int getStatus()

Description copied from interface: GifDecoder

Returns the current status of the decoder.

Status will update per frame to allow the caller to tell whether or not the current frame was decoded successfully and/or completely. Format and open failures persist across frames.

Specified by:

getStatus in interface GifDecoder

advance

public void advance()

Description copied from interface: GifDecoder

Move the animation frame counter forward.

Specified by:

advance in interface GifDecoder

getDelay

public int getDelay(int n)

Description copied from interface: GifDecoder

Gets display duration for specified frame.

Specified by:

getDelay in interface GifDecoder

Parameters:

n - int index of frame.

Returns:

delay in milliseconds.

getNextDelay

public int getNextDelay()

Description copied from interface: GifDecoder

Gets display duration for the upcoming frame in ms.

Specified by:

getNextDelay in interface GifDecoder

getFrameCount

public int getFrameCount()

Description copied from interface: GifDecoder

Gets the number of frames read from file.

Specified by:

getFrameCount in interface GifDecoder

Returns:

frame count.

getCurrentFrameIndex

public int getCurrentFrameIndex()

Description copied from interface: GifDecoder

Gets the current index of the animation frame, or -1 if animation hasn't not yet started.

Specified by:

getCurrentFrameIndex in interface GifDecoder

Returns:

frame index.

resetFrameIndex

public void resetFrameIndex()

Description copied from interface: GifDecoder

Resets the frame pointer to before the 0th frame, as if we'd never used this decoder to decode any frames.

Specified by:

resetFrameIndex in interface GifDecoder

getLoopCount

@Deprecated
public int getLoopCount()

Deprecated.

Description copied from interface: GifDecoder

Gets the "Netscape" loop count, if any. A count of 0 means repeat indefinitely.

Specified by:

getLoopCount in interface GifDecoder

Returns:

loop count if one was specified, else 1.

getNetscapeLoopCount

public int getNetscapeLoopCount()

Description copied from interface: GifDecoder

Gets the "Netscape" loop count, if any. A count of 0 (GifHeader.NETSCAPE_LOOP_COUNT_FOREVER) means repeat indefinitely. It must not be a negative value.
Use GifDecoder.getTotalIterationCount() to know how many times the animation sequence should be displayed.

Specified by:

getNetscapeLoopCount in interface GifDecoder

Returns:

loop count if one was specified, else -1 (GifHeader.NETSCAPE_LOOP_COUNT_DOES_NOT_EXIST).

getTotalIterationCount

public int getTotalIterationCount()

Description copied from interface: GifDecoder

Gets the total count which represents how many times the animation sequence should be displayed. A count of 0 (GifDecoder.TOTAL_ITERATION_COUNT_FOREVER) means repeat indefinitely. It must not be a negative value.

The total count is calculated as follows by using GifDecoder.getNetscapeLoopCount(). This behavior is the same as most web browsers.

getNetscapeLoopCount()	The total count
GifHeader.NETSCAPE_LOOP_COUNT_FOREVER	GifDecoder.TOTAL_ITERATION_COUNT_FOREVER
GifHeader.NETSCAPE_LOOP_COUNT_DOES_NOT_EXIST	1
n (n > 0)	n + 1

Specified by:

getTotalIterationCount in interface GifDecoder

Returns:

total iteration count calculated from "Netscape" loop count.

See Also:

• Discussion about the iteration count of animated GIFs (Chromium Issue 592735)

getByteSize

public int getByteSize()

Description copied from interface: GifDecoder

Returns an estimated byte size for this decoder based on the data provided to GifDecoder.setData(GifHeader, byte[]), as well as internal buffers.

Specified by:

getByteSize in interface GifDecoder

getNextFrame

@Nullable
public Bitmap getNextFrame()

Description copied from interface: GifDecoder

Get the next frame in the animation sequence.

Specified by:

getNextFrame in interface GifDecoder

Returns:

Bitmap representation of frame.

read

public int read(@Nullable
 InputStream is,
 int contentLength)

Description copied from interface: GifDecoder

Reads GIF image from stream.

Specified by:

read in interface GifDecoder

Parameters:

is - containing GIF file.

Returns:

read status code (0 = no errors).

clear

public void clear()

Specified by:

clear in interface GifDecoder

setData

public void setData(@NonNull
 GifHeader header,
 @NonNull
 byte[] data)

Specified by:

setData in interface GifDecoder

setData

public void setData(@NonNull
 GifHeader header,
 @NonNull
 ByteBuffer buffer)

Specified by:

setData in interface GifDecoder

setData

public void setData(@NonNull
 GifHeader header,
 @NonNull
 ByteBuffer buffer,
 int sampleSize)

Specified by:

setData in interface GifDecoder

read

public int read(@Nullable
 byte[] data)

Description copied from interface: GifDecoder

Reads GIF image from byte array.

Specified by:

read in interface GifDecoder

Parameters:

data - containing GIF file.

Returns:

read status code (0 = no errors).

setDefaultBitmapConfig

public void setDefaultBitmapConfig(@NonNull
 Bitmap.Config config)

Description copied from interface: GifDecoder

Sets the default Bitmap.Config to use when decoding frames of a GIF.

Valid options are Bitmap.Config.ARGB_8888 and Bitmap.Config.RGB_565. Bitmap.Config.ARGB_8888 will produce higher quality frames, but will also use 2x the memory of Bitmap.Config.RGB_565.

Defaults to Bitmap.Config.ARGB_8888

This value is not a guarantee. For example if set to Bitmap.Config.RGB_565 and the GIF contains transparent pixels, Bitmap.Config.ARGB_8888 will be used anyway to support the transparency.

Specified by:

setDefaultBitmapConfig in interface GifDecoder