Class GifImageHelper

java.lang.Object

com.itextpdf.io.image.GifImageHelper

public final class GifImageHelper
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	GifImageHelper.GifParameters

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final int	MAX_STACK_SIZE

Constructor Summary

Constructors

Constructor	Description
GifImageHelper()

Method Summary

Modifier and Type	Method	Description
private static boolean	decodeImageData(GifImageHelper.GifParameters gif)
private static int	newBpc(int bpc)
private static void	process(InputStream stream, GifImageHelper.GifParameters gif, int lastFrameNumber)
static void	processImage(GifImageData image)	Reads image source and fills GifImage object with parameters (frames, width, height)
static void	processImage(GifImageData image, int lastFrameNumber)	Reads image source and fills GifImage object with parameters (frames, width, height)
private static int	readBlock(GifImageHelper.GifParameters gif)	Reads next variable length block from input.
private static byte[]	readColorTable(int bpc, GifImageHelper.GifParameters gif)
private static void	readContents(GifImageHelper.GifParameters gif, int lastFrameNumber)
private static void	readFrame(GifImageHelper.GifParameters gif)	Reads next frame image
private static void	readGraphicControlExt(GifImageHelper.GifParameters gif)	Reads Graphics Control Extension values
private static void	readHeader(GifImageHelper.GifParameters gif)	Reads GIF file header information.
private static void	readLSD(GifImageHelper.GifParameters gif)	Reads Logical Screen Descriptor
private static int	readShort(GifImageHelper.GifParameters gif)	Reads next 16-bit value, LSB first
private static void	setPixel(int x, int y, int v, GifImageHelper.GifParameters gif)
private static void	skip(GifImageHelper.GifParameters gif)	Skips variable length blocks up to and including next zero length block.

Methods inherited from class Object

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

Field Details

MAX_STACK_SIZE

static final int MAX_STACK_SIZE

See Also:

• Constant Field Values

Constructor Details

GifImageHelper

public GifImageHelper()

Method Details

processImage

public static void processImage(GifImageData image)

Reads image source and fills GifImage object with parameters (frames, width, height)

Parameters:

image - GifImage

processImage

public static void processImage(GifImageData image,
 int lastFrameNumber)

Reads image source and fills GifImage object with parameters (frames, width, height)

Parameters:

image - GifImage

lastFrameNumber - the last frame of the gif image should be read

process

private static void process(InputStream stream,
 GifImageHelper.GifParameters gif,
 int lastFrameNumber)
                     throws IOException

Throws:

IOException

readHeader

private static void readHeader(GifImageHelper.GifParameters gif)
                        throws IOException

Reads GIF file header information.

Throws:

IOException

readLSD

private static void readLSD(GifImageHelper.GifParameters gif)
                     throws IOException

Reads Logical Screen Descriptor

Throws:

IOException

readShort

private static int readShort(GifImageHelper.GifParameters gif)
                      throws IOException

Reads next 16-bit value, LSB first

Throws:

IOException

readBlock

private static int readBlock(GifImageHelper.GifParameters gif)
                      throws IOException

Reads next variable length block from input.

Returns:

number of bytes stored in "buffer"

Throws:

IOException

readColorTable

private static byte[] readColorTable(int bpc,
 GifImageHelper.GifParameters gif)
                              throws IOException

Throws:

IOException

newBpc

private static int newBpc(int bpc)

readContents

private static void readContents(GifImageHelper.GifParameters gif,
 int lastFrameNumber)
                          throws IOException

Throws:

IOException

readFrame

private static void readFrame(GifImageHelper.GifParameters gif)
                       throws IOException

Reads next frame image

Throws:

IOException

decodeImageData

private static boolean decodeImageData(GifImageHelper.GifParameters gif)
                                throws IOException

Throws:

IOException

setPixel

private static void setPixel(int x,
 int y,
 int v,
 GifImageHelper.GifParameters gif)

readGraphicControlExt

private static void readGraphicControlExt(GifImageHelper.GifParameters gif)
                                   throws IOException

Reads Graphics Control Extension values

Throws:

IOException

skip

private static void skip(GifImageHelper.GifParameters gif)
                  throws IOException

Skips variable length blocks up to and including next zero length block.

Throws:

IOException