I am trying to write a grey scale image to an TIFF file using Sanselan. Obviously would like the save the data to be 8 bit grey scale file but somehow I always end up with a 24 bit colour file.
I have searched for file formats in general and ExifTagConstants.EXIF_TAG_PIXEL_FORMAT
in particular but was unable to find anything helpful.
I also considered colour profiles but there seem to be none for grey scale images. But then they all have wacky names — I might just have overlooked the right one.
Or do I have to use a different library?
Here the code I use (without business logic and experimental stuff:
Test_Only_Sanselan:
try
{
final Map <String, Object> parameter = new HashMap <>();
parameter.put(org.apache.sanselan.SanselanConstants.PARAM_KEY_COMPRESSION,
org.apache.sanselan.formats.tiff.constants.TiffConstants.TIFF_COMPRESSION_UNCOMPRESSED);
final java.io.OutputStream output = new java.io.FileOutputStream("Test-1.tiff");
org.apache.sanselan.Sanselan.writeImage(image, output,
org.apache.sanselan.ImageFormat.IMAGE_FORMAT_TIFF, parameter);
output.close();
}
catch (final IOException exception)
{
LdfImage.log.info("! Could not create tiff image.", exception);
}
catch (final org.apache.sanselan.ImageWriteException exception)
{
LdfImage.log.info("! Could not create tiff image.", exception);
}
I wonder if I need to add a special parameter. But I have not found a useful parameter yet.
The following is a test of the Java 7 image writer which creates a correct grey scale image. But as PNG and not TIFF:
Test_Only_Java_7:
try
{
final java.util.Iterator imageWriters = javax.imageio.ImageIO.getImageWritersByMIMEType ("image/png开发者_JS百科");
final javax.imageio.ImageWriter imageWriter = (javax.imageio.ImageWriter) imageWriters.next();
final java.io.File file = new java.io.File("Test-2.png");
final javax.imageio.stream.ImageOutputStream output = javax.imageio.ImageIO.createImageOutputStream(file);
imageWriter.setOutput(output);
imageWriter.write(image);
}
catch (final IOException exception)
{
LdfImage.log.info("! Could not create tiff image.", exception);
}
Is there a TIFF pug-in for imageio?
I'm not familiar with Sanselan but I see there is a ImageInfo.COLOR_TYPE_GRAYSCALE
constant, I'm guessing it could be used in the params
parameter map given to writeImage
.
I didn't find the javadoc for Sanselan, their link is broken, would you have one more up-to-date?
If you want to use JAI you can get your inspiration here:
void get8bitImage(byte[] data, int width, int height) {
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
byte[] rasterData = ((DataBufferByte)image.getRaster().getDataBuffer()).getData();
System.arraycopy(pixels, 0, rasterData, 0, pixels.length); // A LOT faster than 'setData()'
}
void main(String[] argv) {
TIFFEncodeParam ep = new TIFFEncodeParam();
FileOutputStream out = new FileOutputStream("c:\\test.tiff");
BufferedImage img = get8bitImage(myData);
ImageEncoder encoder = ImageCodec.createImageEncoder("tiff", out, ep);
encoder.encode(img);
}
Be sure that the BufferedImage
has BufferedImage.TYPE_BYTE_GRAY
as imageType
.
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