androidでgifアニメ 2014.08.06 kyoto.lt

Android !GIF

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!Shota Moriwaki!!

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GIFWhat is GIF?

GIF!Graphics Interchange Format

CompuServe

GIF87a GIF89a 2 GIF GIF89a 256 LZW

GIF GIF Header GIF !

Image Block

Graphic Control Extension

Application Extension GIF

Comment Extension

Plain Text Extension

Trailer

GIF87a GIF Header Image Block

Trailer

GIF89a GIF Header

Graphic Control Extension Image Block

Trailer

GIF GIF Header

Application Extension Graphic Control Extension

Image Block Graphic Control Extension

Image Block

Graphic Control Extension Image Block

Trailer

・  ・  ・

Android !How to show animated gif on android device?

!Try to decode animated gif like other file

Bitmap !!BitmapFactory.decodeByteArray(byte[]data, int offset, int length) BitmapFactory.decodeFile(String pathName)!BitmapFactory.decodeResource(Resources res, int id) BitmapFactory.decodeStream(InputStream is) !

PNG JPG GIF!!

“A bitmap image. Android supports bitmap files in a three formats: .png (preferred), .jpg (acceptable), .gif (discouraged).’’ http://developer.android.com/guide/topics/resources/drawable-resource.html#Bitmap

GIF !

WebViewTry to use android.webkit.WebView

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MovieTry to use android.graphics.Movie

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GIFTry to decode animated gif file

android-gifview!https://code.google.com/p/android-gifview/ GifDecoder.java!GIF Bitmap

GifView!Bitmap !

!GifDecoder.java Google+ !

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GIF

GifDecoder.java !Try to fix GifDecoder.java

1.  GIF 2.  GifHeader 3.  Application Extension 4.  Graphic Control Extension !

5.  ImageBlock !

Bitmap !

6.  4 5

GifDecoder.java

1.  GIF 2.  GifHeader 3.  Application Extension 4.  Graphic Control Extension !

5.  ImageBlock !

Bitmap !

6.  4 5

GifDecoder.java

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1.  GIF 2.  GifHeader 3.  Application Extension 4.  Graphic Control Extension !

5.  ImageBlock !

Bitmap !

6.  4 5

GifDecoder.java

Bitmap

GIF !GIF

GIF89a GIF Header

Graphic Control Extension Image Block

Trailer

GIF GIF Header

Application Extension Graphic Control Extension

Image Block Graphic Control Extension

Image Block Trailer

GIF Header Graphic Control Extension

Image Block Trailer

Bitmap

1.  GIF 2.  GifHeader 3.  Graphic Control Extension !

4.  ImageBlock GifHeader Graphic Control Extension!

5.  4 BitmapFactory Bitmap 6.  3 4 5

GifImageDecoder.java

Android OS 4.1 JellyBean !GIF Bitmap

BitmapFactory … GIF !

!GIF

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Android OS 4.4 KitKat !GIF !BitmapFactory https://code.google.com/p/android/issues/detail?id=62016

GIF…

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https://github.com/yysk/GifImageDecoderSample