Package org.jzy3d.io.gif

Class GifDecoder

java.lang.Object
org.jzy3d.io.gif.GifDecoder
public class GifDecoder extends Object
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
    }
No copyright asserted on the source code of this class. May be used for any purpose, however, refer to the Unisys LZW patent for any additional restrictions. Please forward any corrections to questions at fmsware.com.
Version:
1.03 November 2003
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:

    • 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

    • MaxStackSize

      protected static final int MaxStackSize
      See Also:

    • prefix

      protected short[] prefix

    • suffix

      protected byte[] suffix

    • pixelStack

      protected byte[] pixelStack

    • pixels

      protected byte[] pixels

    • frames

      protected ArrayList 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.
      Returns:
      BufferedImage representation of frame, or null if n is invalid.

    • 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

    • init

      protected void init()
      Initializes or re-initializes reader

    • read

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

    • 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

    • 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.