我有一个大小int[] shadesOfGray
n*n
数组,其中包含来自 [0,255] 的值。是否可以从此数组创建 8 位灰度位图?
例如,如果 int[] shadesOfGray = {255, 255, 255, 128, 128, 128, 0, 0, 0}
那么位图中相应像素的强度将为:
255 255 255
128 128 128
0 0 0
我试过这样的事情:
private static void generateBMPwithDistribution(int[] shadesOfGray, int sum, String path) throws IOException {
int dim = 100;
byte[] buffer = new byte[dim * dim];
for (int x = 0, i = 0; x < dim; x++)
for (int y = 0; y < dim; y++)
buffer[(x * dim) + y] = (byte) (shadesOfGray[i]); // problem
try {
ImageIO.write(getGrayscale(dim, buffer), "bmp", new File(path));
} catch (IOException e) {
...
}
}
public static BufferedImage getGrayscale(int width, byte[] buffer) {
int height = buffer.length / width;
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
int[] nBits = { 8 };
ColorModel cm = new ComponentColorModel(cs, nBits, false, true,
Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
SampleModel sm = cm.createCompatibleSampleModel(width, height);
DataBufferByte db = new DataBufferByte(buffer, buffer.length);
WritableRaster raster = Raster.createWritableRaster(sm, db, null);
BufferedImage result = new BufferedImage(cm, raster, false, null);
return result;
}
由于我想要 8 位.bmp,所以我在缓冲区中复制值,然后将缓冲区写入文件。问题在于值>= 128;字节被视为具有负值。Java中有没有办法解决这个问题?
您的过程可能如下所示:
private static void generateBMPwithDistribution(int[] shadesOfGray, int sum, String path) throws IOException {
int dim1 = (int)Math.sqrt(shadesOfGray.length), dim=100*dim1;
int[] buffer = new int[dim * dim];
int howManyTimes=dim/dim1;
for (int x = 0; x < dim; x++)
for (int y = 0; y < dim; y++) {
int valueToReplicate=shadesOfGray[(x + y*dim)/howManyTimes];
buffer[x + y*dim] = 0xff000000|(valueToReplicate<<16)|(valueToReplicate<<8)|valueToReplicate;
}
BufferedImage result=new BufferedImage(dim, dim, BufferedImage.TYPE_INT_RGB);
try {
ImageIO.write(result, "bmp", new File(path));
} catch (IOException e) {
...
}
}