Package com.luna.common.img.gif

Class GifDecoder

java.lang.Object
com.luna.common.img.gif.GifDecoder
public class GifDecoder extends Object
GIF文件解析 Class GifDecoder - Decodes a GIF file into one or more frames.

Example: 

 
 GifDecoder d = new GifDecoder();
 d.read("sample.gif");
 int n = d.getFrameCount();
 for (int i = 0; i < n; i++) {
     BufferedImage frame = d.getFrame(i); // frame i
     int t = d.getDelay(i); // display duration of frame in milliseconds
     // do something with frame
 }

来自：https://github.com/rtyley/animated-gif-lib-for-java

Author:
Kevin Weiner, FM Software; LZW decoder adapted from John Cristy's ImageMagick.

  • Field Details

    • STATUS_OK

      public static final int STATUS_OK
      File read status: No errors.
      See Also:

    • STATUS_FORMAT_ERROR

      public static final int STATUS_FORMAT_ERROR
      File read status: Error decoding file (may be partially decoded)
      See Also:

    • STATUS_OPEN_ERROR

      public static final int STATUS_OPEN_ERROR
      File read status: Unable to open source.
      See Also:

    • MAX_STACK_SIZE

      protected static final int MAX_STACK_SIZE
      See Also:

    • in

      protected BufferedInputStream in

    • status

      protected int status

    • width

      protected int width

    • height

      protected int height

    • gctFlag

      protected boolean gctFlag

    • gctSize

      protected int gctSize

    • loopCount

      protected int loopCount

    • gct

      protected int[] gct

    • lct

      protected int[] lct

    • act

      protected int[] act

    • bgIndex

      protected int bgIndex

    • bgColor

      protected int bgColor

    • lastBgColor

      protected int lastBgColor

    • pixelAspect

      protected int pixelAspect

    • lctFlag

      protected boolean lctFlag

    • interlace

      protected boolean interlace

    • lctSize

      protected int lctSize

    • ix

      protected int ix

    • iy

      protected int iy

    • iw

      protected int iw

    • ih

      protected int ih

    • lastRect

      protected Rectangle lastRect

    • image

      protected BufferedImage image

    • lastImage

      protected BufferedImage lastImage

    • block

      protected byte[] block

    • blockSize

      protected int blockSize

    • dispose

      protected int dispose

    • lastDispose

      protected int lastDispose

    • transparency

      protected boolean transparency

    • delay

      protected int delay

    • transIndex

      protected int transIndex

    • prefix

      protected short[] prefix

    • suffix

      protected byte[] suffix

    • pixelStack

      protected byte[] pixelStack

    • pixels

      protected byte[] pixels

    • frames

      protected ArrayList<com.luna.common.img.gif.GifDecoder.GifFrame> frames

    • frameCount

      protected int frameCount

  • Constructor Details

    • GifDecoder

      public GifDecoder()

  • Method Details

    • getDelay

      public int getDelay(int n)
      Gets display duration for specified frame.
      Parameters:
      n - int index of frame
      Returns:
      delay in milliseconds

    • getFrameCount

      public int getFrameCount()
      Gets the number of frames read from file.
      Returns:
      frame count

    • getImage

      public BufferedImage getImage()
      Gets the first (or only) image read.
      Returns:
      BufferedImage containing first frame, or null if none.

    • getLoopCount

      public int getLoopCount()
      Gets the "Netscape" iteration count, if any. A count of 0 means repeat indefinitiely.
      Returns:
      iteration count if one was specified, else 1.

    • setPixels

      protected void setPixels()
      Creates new frame image from current data (and previous frames as specified by their disposition codes).

    • getFrame

      public BufferedImage getFrame(int n)
      Gets the image contents of frame n.
      Parameters:
      n - frame
      Returns:
      BufferedImage

    • getFrameSize

      public Dimension getFrameSize()
      Gets image size.
      Returns:
      GIF image dimensions

    • read

      public int read(BufferedInputStream is)
      Reads GIF image from stream
      Parameters:
      is - BufferedInputStream containing GIF file.
      Returns:
      read status code (0 = no errors)

    • read

      public int read(InputStream is)
      Reads GIF image from stream
      Parameters:
      is - InputStream containing GIF file.
      Returns:
      read status code (0 = no errors)

    • read

      public int read(String name)
      Reads GIF file from specified file/URL source (URL assumed if name contains ":/" or "file:")
      Parameters:
      name - String containing source
      Returns:
      read status code (0 = no errors)

    • decodeImageData

      protected void decodeImageData()
      Decodes LZW image data into pixel array. Adapted from John Cristy's ImageMagick.

    • err

      protected boolean err()
      Returns true if an error was encountered during reading/decoding
      Returns:
      true if an error was encountered during reading/decoding

    • init

      protected void init()
      Initializes or re-initializes reader

    • read

      protected int read()
      Reads a single byte from the input stream.
      Returns:
      single byte

    • readBlock

      protected int readBlock()
      Reads next variable length block from input.
      Returns:
      number of bytes stored in "buffer"

    • readColorTable

      protected int[] readColorTable(int ncolors)
      Reads color table as 256 RGB integer values
      Parameters:
      ncolors - int number of colors to read
      Returns:
      int array containing 256 colors (packed ARGB with full alpha)

    • readContents

      protected void readContents()
      Main file parser. Reads GIF content blocks.

    • readGraphicControlExt

      protected void readGraphicControlExt()
      Reads Graphics Control Extension values

    • readHeader

      protected void readHeader()
      Reads GIF file header information.

    • readImage

      protected void readImage()
      Reads next frame image

    • readLSD

      protected void readLSD()
      Reads Logical Screen Descriptor

    • readNetscapeExt

      protected void readNetscapeExt()
      Reads Netscape extenstion to obtain iteration count

    • readShort

      protected int readShort()
      Reads next 16-bit value, LSB first
      Returns:
      next 16-bit value

    • resetFrame

      protected void resetFrame()
      Resets frame state for reading next image.

    • skip

      protected void skip()
      Skips variable length blocks up to and including next zero length block.