Package net.sourceforge.jiu.data
Interface BilevelImage
- All Superinterfaces:
GrayImage
,GrayIntegerImage
,IntegerImage
,PixelImage
- All Known Implementing Classes:
MemoryBilevelImage
An interface for bilevel pixel image data classes.
Each pixel in a bilevel image can have two possible values,
BLACK
and WHITE
.
Those two constants are guaranteed to be 0
and 1
, although
you should not make any assumptions about what value any of the two constants has.
This is the type of image used for faxes.
Black and white photos are usually stored as grayscale images.
Apart from implementing PixelImage
- like all image data classes in JIU -
this interface is also an IntegerImage
(each sample is either 0 or 1) and
a GrayImage
(black and white are both grayscale values).
The combination of IntegerImage
and GrayImage
is GrayIntegerImage
,
which is the direct superinterface of this interface.
Packed bytes
There are methods to get and put packed bytes in this interface. A packed byte is abyte
value that stores eight horizontally neighbored bilevel
pixels in it (pixel and sample can be used interchangeably in the context of bilevel images
because there is only one sample per pixel).
The most significant bit of such a packed bit is defined to be the leftmost of the
eight pixels, the second-most significant bit is the pixel to the right of that leftmost pixel,
and so on. The least significant bit is the rightmost pixel.
If a bit is set, the corresponing pixel value is supposed to be white, otherwise black.
Usage examples
Here are some code examples that demonstrate how to access image data with this class.BilevelImage image = new MemoryBilevelImage(2000, 500); // now set all pixels in the first row to white for (int x = 0; x < image.getWidth(); x++) { image.putWhite(x, 0); } // put vertical stripes on the rest for (int y = 1; y < image.getHeight(); y++) { for (int x = 0; x < image.getWidth(); x++) { int sample; if ((x % 2) == 0) { sample = BilevelImage.BLACK; } else { sample = BilevelImage.WHITE; } image.putSample(x, y, sample); } }
- Author:
- Marco Schmidt
-
Field Summary
Fields -
Method Summary
Modifier and TypeMethodDescriptionvoid
getPackedBytes
(int x, int y, int numSamples, byte[] dest, int destOffset, int destBitOffset) Sets a number of samples in the argument array from this image.void
putPackedBytes
(int x, int y, int numSamples, byte[] src, int srcOffset, int srcBitOffset) Sets a number of samples in the image from the argument array data.Methods inherited from interface net.sourceforge.jiu.data.GrayImage
isBlack, isWhite, putBlack, putWhite
Methods inherited from interface net.sourceforge.jiu.data.IntegerImage
clear, clear, getMaxSample, getSample, getSample, getSamples, putSample, putSample, putSamples
Methods inherited from interface net.sourceforge.jiu.data.PixelImage
createCompatibleImage, createCopy, getAllocatedMemory, getBitsPerPixel, getHeight, getImageType, getNumChannels, getWidth
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Field Details
-
BLACK
static final int BLACKThe value for a black pixel. To be used with all methods that requireint
arguments for sample values. You can rely on this value being either 0 or 1 (that way you can safely store it in a byte or short).- See Also:
-
WHITE
static final int WHITEThe value for a white pixel. To be used with all methods that requireint
arguments for sample values. You can rely on this value being either 0 or 1 (that way you can safely store it in a byte or short).- See Also:
-
-
Method Details
-
getPackedBytes
void getPackedBytes(int x, int y, int numSamples, byte[] dest, int destOffset, int destBitOffset) Sets a number of samples in the argument array from this image.- Parameters:
x
- horizontal position of first sample of this image to ready
- vertical position of samples to be read from this imagenumSamples
- number of samples to be setdest
- array with packed pixels to which samples are copieddestOffset
- index into dest array of the first byte value to write sample values todestBitOffset
- index of first bit ofdest[destOffset]
to write a sample to (0 is leftmost, 1 is second-leftmost up to 7, which is the rightmost)
-
putPackedBytes
void putPackedBytes(int x, int y, int numSamples, byte[] src, int srcOffset, int srcBitOffset) Sets a number of samples in the image from the argument array data.- Parameters:
x
- horizontal position of first sample to be sety
- vertical position of samples to be setnumSamples
- number of samples to be setsrc
- array with packed pixels to be setsrcOffset
- index into src array of the first byte value to read sample values fromsrcBitOffset
- index of first bit ofsrc[srcOffset]
to read a sample from (0 is leftmost, 1 is second-leftmost up to 7, which is the rightmost)
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