A codec to read and write Windows BMP image files.
Typical file extensions are .bmp and .rle (the latter is only used for compressed files).
Bounds
This codec supports the bounds concept for loading and saving.
Supported BMP types when loading
- Bilevel, 1 bit per pixel, uncompressed. BMP supports palettes for bilevel images, but the content of that palette is ignored and 0 is considered black and 1 white. Any class implementing {@link net.sourceforge.jiu.data.BilevelImage}can be given to the codec and it will load the image to that object (if the image's resolution is sufficient). If no image object is given to the codec, a new {@link net.sourceforge.jiu.data.MemoryBilevelImage} will be created.
- Paletted, 4 bits per pixel, uncompressed or RLE4 compression. Both types are loaded to a {@link net.sourceforge.jiu.data.Paletted8Image} object.This requires 50 % more space than is necessary, but there is no dedicated 4 bit image data class in JIU.
- Paletted, 8 bits per pixel, uncompressed or RLE8 compression. Both types are loaded to a {@link net.sourceforge.jiu.data.Paletted8Image} object.
- RGB truecolor, 24 bits per pixel, uncompressed. This is loaded to a {@link net.sourceforge.jiu.data.RGB24Image} object.
There is no support for 16 bpp images or BI_BITFIELDS compression (for lack of test files).
Supported JIU image data classes when saving to BMP
- {@link net.sourceforge.jiu.data.BilevelImage} objects are stored as 1 bit per pixel BMP files.
- {@link net.sourceforge.jiu.data.Gray8Image} and {@link net.sourceforge.jiu.data.Paletted8Image} objects are stored as paletted 8 bits per pixel files. It doesn't really matter how many entries the palette has, the BMP file's palette will always have 256 entries, filled up with zero entries if necessary.
- {@link net.sourceforge.jiu.data.RGB24Image} objects are stored as 24 bpp BMP files.
There is no support for compressed BMP files when saving.
I/O classes
BMPCodec works with all input and output classes supported by ImageCodec ( {@link java.io.InputStream}, {@link java.io.OutputStream}, {@link java.io.DataInput}, {@link java.io.DataOutput}, {@link java.io.RandomAccessFile}).
Problems
The RLE-compressed BMP files that I could test this codec on seem to have an end-of-line code at the end of every line instead of relying on the decoder to know when it has unpacked enough bytes for a line. Whenever this codec encounters an EOL symbol and has a current column value of 0, the EOL is ignored.
Usage examples
Write an image to a BMP file.
BMPCodec codec = new BMPCodec(); codec.setImage(image); codec.setFile("out.bmp", CodecMode.SAVE); codec.process(); codec.close(); Read an image from a BMP file.
BMPCodec codec = new BMPCodec(); codec.setFile("image.bmp", CodecMode.LOAD); codec.process(); codec.close(); PixelImage image = codec.getImage();
@author Marco Schmidt
@since 0.7.0