JAI:如何将4波段32位CMYK图像转换为PNG? [英] JAI: How to convert 4-band 32-bits CMYK image into PNG?
问题描述
我正在尝试将图像转换为PNG格式,我的数据是由LZW压缩的4波段32位TIFF图像。现在,通过使用Java2D和JAI,我可以解压缩数据以表示CMYK空间中的颜色,并且可以使用与4波段32位格式相同的设置以tiff格式存储和查看数据。
I'm trying to convert a image into PNG format, the data I have is a 4-band 32-bits TIFF-like image compressed by LZW. By using Java2D and JAI now I have data uncompressed to represent colors in CMYK space and it can be exported and viewed when stored in tiff with the same settings as 4 band 32-bit format.
问题是,当我尝试转换为其他格式(如PNG)时会生成零大小的数据,所以我想问一下是否有人有类似的转换经验图片?我的一些代码粘贴如下,如果您发现任何错误也请更正,谢谢!!
The problem is when I try converting to other formats like PNG it produce zero-sized data, so I'd like to ask is there anyone have similar experience on converting such image? I have some of my code pasted as below for your reference, please also correct if you found any mistake, thanks!!
int bands = 4;
int w = sizeParam.getHorizonPts();
int h = sizeParam.getVerticalPts();
ColorModel cm = new ComponentColorModel(new CMYKColorSpace(), new int[]{8,8,8,8},
false, false, Transparency.OPAQUE, DataBuffer.TYPE_FLOAT);
// Create WritableRaster with four bands
WritableRaster r = RasterFactory.createBandedRaster(
DataBuffer.TYPE_FLOAT, w, h, bands, null);
for (int i = 0; i < bandStreams.length; i++) {
int x, y;
x = y = 0;
byte[] uncomp = new byte[w * h];
decoder.decode(bandStreams[i], uncomp, h);
for (int pos = 0; pos < uncomp.length; pos++) {
r.setSample(x++, y, i, (float) (uncomp[pos] & 0xff) / 255);
if (x >= w) {
x = 0;
y++;
}
}
}
// Create TiledImage
TiledImage tiledImage = new TiledImage(0, 0, w, h, 0, 0,
RasterFactory.createBandedSampleModel(DataBuffer.TYPE_FLOAT, w,
h, bands), cm);
tiledImage.setData(r);
JAI.create("filestore", tiledImage, "test.tif", "TIFF");
推荐答案
我终于通过将CMYK转换为RGB来解决这个问题可以生成PNG图像,在课程中使用以下代码,
I finally solved this by converting CMYK to RGB so it can generate PNG image, the following code is used during the course,
// Create target image with RGB color.
BufferedImage result = new BufferedImage(w, h,
BufferedImage.TYPE_INT_RGB);
// Convert pixels from YMCK to RGB.
ColorConvertOp cmykToRgb = new ColorConvertOp(new CMYKColorSpace(),
result.getColorModel().getColorSpace(), null);
cmykToRgb.filter(r, result.getRaster());
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