com.alee.graphics.image.gif.GifEncoder Maven / Gradle / Ivy
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/*
* This file is part of WebLookAndFeel library.
*
* WebLookAndFeel library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* WebLookAndFeel library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with WebLookAndFeel library. If not, see
*
* Example:
* GifEncoder e = new GifEncoder();
* e.start(outputFileName);
* e.setDelay(1000);
* e.addFrame(image1);
* e.addFrame(image2);
* e.finish();
*
*
* @author Kevin Weiner, FM Software
* @version 1.03 November 2003
*/
public class GifEncoder
{
protected int width; // image size
protected int height;
protected Color transparent = null; // transparent color if given
protected int transIndex; // transparent index in color table
protected int repeat = -1; // no repeat
public int delay = 0; // frame delay (hundredths)
protected boolean started = false; // ready to output frames
protected OutputStream out;
protected BufferedImage image; // current frame
protected byte[] pixels; // BGR byte array from frame
protected byte[] indexedPixels; // converted frame indexed to palette
protected int colorDepth; // number of bit planes
protected byte[] colorTab; // RGB palette
protected boolean[] usedEntry = new boolean[ 256 ]; // active palette entries
protected int palSize = 7; // color table size (bits-1)
protected int dispose = -1; // disposal code (-1 = use default)
protected boolean closeStream = false; // close stream when finished
protected boolean firstFrame = true;
protected boolean sizeSet = false; // if false, get size from first frame
protected int sample = 10; // default sample interval for quantizer
/**
* Sets the delay time between each frame, or changes it for subsequent frames (applies to last
* frame added).
*
* @param ms int delay time in milliseconds
*/
public void setDelay ( final int ms )
{
delay = Math.round ( ms / 10.0f );
}
/**
* Sets the GIF frame disposal code for the last added frame and any subsequent frames. Default
* is 0 if no transparent color has been set, otherwise 2.
*
* @param code int disposal code.
*/
public void setDispose ( final int code )
{
if ( code >= 0 )
{
dispose = code;
}
}
/**
* Sets the number of times the set of GIF frames should be played.
* Default is 1; 0 means play indefinitely. Must be invoked before the first image is added.
*
* @param iter int number of iterations.
*/
public void setRepeat ( final int iter )
{
if ( iter >= 0 )
{
repeat = iter;
}
}
/**
* Sets the transparent color for the last added frame and any subsequent frames. Since all
* colors are subject to modification in the quantization process, the color in the final
* palette for each frame closest to the given color becomes the transparent color for that
* frame. May be set to null to indicate no transparent color.
*
* @param c Color to be treated as transparent on display.
*/
public void setTransparent ( final Color c )
{
transparent = c;
}
/**
* Adds next GIF frame. The frame is not written immediately, but is actually deferred until the
* next frame is received so that timing data can be inserted. Invoking {@code finish()}
* flushes all frames. If {@code setSize} was not invoked, the size of the first image is
* used for all subsequent frames.
*
* @param im BufferedImage containing frame to write.
* @return true if successful.
*/
public boolean addFrame ( final BufferedImage im )
{
if ( ( im == null ) || !started )
{
return false;
}
boolean ok = true;
try
{
if ( !sizeSet )
{
// use first frame's size
setSize ( im.getWidth (), im.getHeight () );
}
image = im;
getImagePixels (); // convert to correct format if necessary
analyzePixels (); // build color table & map pixels
if ( firstFrame )
{
writeLSD (); // logical screen descriptior
writePalette (); // global color table
if ( repeat >= 0 )
{
// use NS app extension to indicate reps
writeNetscapeExt ();
}
}
writeGraphicCtrlExt (); // write graphic control extension
writeImageDesc (); // image descriptor
if ( !firstFrame )
{
writePalette (); // local color table
}
writePixels (); // encode and write pixel data
firstFrame = false;
}
catch ( final IOException e )
{
ok = false;
}
return ok;
}
/**
* Flushes any pending data and closes output file. If writing to an OutputStream, the stream is
* not closed.
*/
public boolean finish ()
{
if ( !started )
{
return false;
}
boolean ok = true;
started = false;
try
{
out.write ( 0x3b ); // gif trailer
out.flush ();
if ( closeStream )
{
out.close ();
}
}
catch ( final IOException e )
{
ok = false;
}
// reset for subsequent use
transIndex = 0;
out = null;
image = null;
pixels = null;
indexedPixels = null;
colorTab = null;
closeStream = false;
firstFrame = true;
return ok;
}
/**
* Sets frame rate in frames per second. Equivalent to setDelay(1000/fps).
*
* @param fps float frame rate (frames per second)
*/
public void setFrameRate ( final float fps )
{
if ( fps != 0f )
{
delay = Math.round ( 100f / fps );
}
}
/**
* Sets quality of color quantization (conversion of images to the maximum 256 colors allowed by
* the GIF specification). Lower values (minimum = 1) produce better colors, but slow processing
* significantly. 10 is the default, and produces good color mapping at reasonable speeds.
* Values greater than 20 do not yield significant improvements in speed.
*
* @param quality int greater than 0.
*/
public void setQuality ( int quality )
{
if ( quality < 1 )
{
quality = 1;
}
sample = quality;
}
/**
* Sets the GIF frame size. The default size is the size of the first frame added if this method
* is not invoked.
*
* @param w int frame width.
* @param h int frame width.
*/
public void setSize ( final int w, final int h )
{
if ( started && !firstFrame )
{
return;
}
width = w;
height = h;
if ( width < 1 )
{
width = 320;
}
if ( height < 1 )
{
height = 240;
}
sizeSet = true;
}
/**
* Initiates GIF file creation on the given stream. The stream is not closed automatically.
*
* @param os OutputStream on which GIF images are written.
* @return false if initial write failed.
*/
public boolean start ( final OutputStream os )
{
if ( os == null )
{
return false;
}
boolean ok = true;
closeStream = false;
out = os;
try
{
writeString ( "GIF89a" ); // header
}
catch ( final IOException e )
{
ok = false;
}
return started = ok;
}
/**
* Initiates writing of a GIF file with the specified name.
*
* @param file String containing output file name.
* @return false if open or initial write failed.
*/
public boolean start ( final String file )
{
boolean ok;
try
{
out = new BufferedOutputStream ( new FileOutputStream ( file ) );
ok = start ( out );
closeStream = true;
}
catch ( final IOException e )
{
ok = false;
}
return started = ok;
}
/**
* Analyzes image colors and creates color map.
*/
protected void analyzePixels ()
{
final int len = pixels.length;
final int nPix = len / 3;
indexedPixels = new byte[ nPix ];
final NeuQuant nq = new NeuQuant ( pixels, len, sample );
// initialize quantizer
colorTab = nq.process (); // create reduced palette
// convert map from BGR to RGB
for ( int i = 0; i < colorTab.length; i += 3 )
{
final byte temp = colorTab[ i ];
colorTab[ i ] = colorTab[ i + 2 ];
colorTab[ i + 2 ] = temp;
usedEntry[ i / 3 ] = false;
}
// map image pixels to new palette
int k = 0;
for ( int i = 0; i < nPix; i++ )
{
final int index = nq.map ( pixels[ k++ ] & 0xff, pixels[ k++ ] & 0xff, pixels[ k++ ] & 0xff );
usedEntry[ index ] = true;
indexedPixels[ i ] = ( byte ) index;
}
pixels = null;
colorDepth = 8;
palSize = 7;
// get closest match to transparent color if specified
if ( transparent != null )
{
transIndex = findClosest ( transparent );
}
}
/**
* Returns index of palette color closest to c
*/
protected int findClosest ( final Color c )
{
if ( colorTab == null )
{
return -1;
}
final int r = c.getRed ();
final int g = c.getGreen ();
final int b = c.getBlue ();
int minpos = 0;
int dmin = 256 * 256 * 256;
final int len = colorTab.length;
for ( int i = 0; i < len; )
{
final int dr = r - ( colorTab[ i++ ] & 0xff );
final int dg = g - ( colorTab[ i++ ] & 0xff );
final int db = b - ( colorTab[ i ] & 0xff );
final int d = dr * dr + dg * dg + db * db;
final int index = i / 3;
if ( usedEntry[ index ] && ( d < dmin ) )
{
dmin = d;
minpos = index;
}
i++;
}
return minpos;
}
/**
* Extracts image pixels into byte array "pixels"
*/
protected void getImagePixels ()
{
final int w = image.getWidth ();
final int h = image.getHeight ();
final int type = image.getType ();
if ( ( w != width ) || ( h != height ) || ( type != BufferedImage.TYPE_3BYTE_BGR ) )
{
// create new image with right size/format
final BufferedImage temp = new BufferedImage ( width, height, BufferedImage.TYPE_3BYTE_BGR );
final Graphics2D g = temp.createGraphics ();
g.drawImage ( image, 0, 0, null );
g.dispose ();
// // clear "transparent" pixels
// for ( int i = 0; i < image.getWidth (); i++ )
// {
// for ( int j = 0; j < image.getHeight (); j++ )
// {
// Color color = new Color ( image.getRGB ( i, j ), true );
// if ( color.getAlpha () == 0 )
// {
// temp.getRaster ().setDataElements ( i, j, new byte[]{ 0,0,0 } );
// }
// }
// }
image = temp;
}
pixels = ( ( DataBufferByte ) image.getRaster ().getDataBuffer () ).getData ();
}
/**
* Writes Graphic Control Extension
*/
protected void writeGraphicCtrlExt () throws IOException
{
out.write ( 0x21 ); // extension introducer
out.write ( 0xf9 ); // GCE label
out.write ( 4 ); // data block size
final int transp;
int disp;
if ( transparent == null )
{
transp = 0;
disp = 0; // dispose = no action
}
else
{
transp = 1;
disp = 2; // force clear if using transparent color
}
if ( dispose >= 0 )
{
disp = dispose & 7; // user override
}
disp <<= 2;
// packed fields
out.write ( disp | transp ); // 8 transparency flag
writeShort ( delay ); // delay x 1/100 sec
out.write ( transIndex ); // transparent color index
out.write ( 0 ); // block terminator
}
/**
* Writes Image Descriptor
*/
protected void writeImageDesc () throws IOException
{
out.write ( 0x2c ); // image separator
writeShort ( 0 ); // image position x,y = 0,0
writeShort ( 0 );
writeShort ( width ); // image size
writeShort ( height );
// packed fields
if ( firstFrame )
{
// no LCT - GCT is used for first (or only) frame
out.write ( 0 );
}
else
{
// specify normal LCT
out.write ( 0x80 | palSize ); // 6-8 size of color table
}
}
/**
* Writes Logical Screen Descriptor
*/
protected void writeLSD () throws IOException
{
// logical screen size
writeShort ( width );
writeShort ( height );
// packed fields
out.write ( 0x80 | 0x70 | palSize ); // 6-8 : gct size
out.write ( 0 ); // background color index
out.write ( 0 ); // pixel aspect ratio - assume 1:1
}
/**
* Writes Netscape application extension to define repeat count.
*/
protected void writeNetscapeExt () throws IOException
{
out.write ( 0x21 ); // extension introducer
out.write ( 0xff ); // app extension label
out.write ( 11 ); // block size
writeString ( "NETSCAPE" + "2.0" ); // app id + auth code
out.write ( 3 ); // sub-block size
out.write ( 1 ); // loop sub-block id
writeShort ( repeat ); // loop count (extra iterations, 0=repeat forever)
out.write ( 0 ); // block terminator
}
/**
* Writes color table
*/
protected void writePalette () throws IOException
{
out.write ( colorTab, 0, colorTab.length );
final int n = ( 3 * 256 ) - colorTab.length;
for ( int i = 0; i < n; i++ )
{
out.write ( 0 );
}
}
/**
* Encodes and writes pixel data
*/
protected void writePixels () throws IOException
{
final LZWEncoder encoder = new LZWEncoder ( width, height, indexedPixels, colorDepth );
encoder.encode ( out );
}
/**
* Write 16-bit value to output stream, LSB first
*/
protected void writeShort ( final int value ) throws IOException
{
out.write ( value & 0xff );
out.write ( ( value >> 8 ) & 0xff );
}
/**
* Writes string to output stream
*/
protected void writeString ( final String s ) throws IOException
{
for ( int i = 0; i < s.length (); i++ )
{
out.write ( ( byte ) s.charAt ( i ) );
}
}
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