来自 4 位数据缓冲区的 BufferedImage

Question

你好，我在将我的 4 位数据缓冲区转换为 WritableRaster 时遇到了问题。图片分辨率：1024x768 (786432)

这是我正在做的描述。

1) 创建 4 位 BufferedImage

bit4Image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY, MY_BIT_4_COLOR_MODEL);
Graphics graphics = bit4Image.getGraphics();
graphics.drawImage(originalImage, 0, 0, null);
graphics.dispose();
//4-bit BufferedImage created. 4-bit BufferedImage is properly made cause it can be saved to hdd and looks good

2) 从DataBuffer中获取byte array from 4-bit

byte[] pixelData = ((DataBufferByte)  bit4Image.getRaster().getDataBuffer()).getData();
// pixelData length is 393216

3) 现在我想从这个字节数组 pixelData

创建 BufferedImage

BufferedImage dest = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY, MY_BIT_4_COLOR_MODEL);
DataBufferByte buffer = new DataBufferByte(pixelData, pixelData.length);
WritableRaster raster = Raster.createInterleavedRaster(buffer, width, height, width, 1, new int[]{0}, new Point(0, 0));
dest.setData(raster);

问题出在我调用 Raster.createInterleavedRaster 时。例外： java.awt.image.RasterFormatException: Data array too small (should be > 786431 )

我也试过类似的东西

BufferedImage dest = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY, MY_BIT_4_COLOR_MODEL);
dest.getRaster().setDataElements(0, 0, width, height, pixelData);

但是这个给了我类似的失败：
java.lang.ArrayIndexOutOfBoundsException: 393216

有人可以给我提示或展示将此 4 位像素数据设置为 WritableRaster 的正确方法吗？

Answer 1

已解决。我只需要通过给它 SampleModel:
创建 WritableRaster SampleModel sm = MY_BIT_4_COLOR_MODEL.createCompatibleSampleModel(width, height); WritableRaster wr = Raster.createWritableRaster(sm, buffer, new Point(0,0));

Answer 2

您几乎可以使用初始代码，唯一的问题是您试图创建一个 "interleaved" 光栅。对于调色板图像 (IndexColorModel)，通常每个像素只有一个样本（调色板索引），因此没有要交错的样本。

相反，您的像素数据是 4 bit/pixel，存储为每字节两个像素。每个存储单元存储更多样本，通常称为 "packed"。这意味着您需要使用 Raster.createPackedRaster 方法之一创建 "packed" 光栅。

这是一个完整的、可运行的示例：

public static void main(String[] args) {
        int width = 100;
        int height = 100;

        // Create initial 4 bit image
        IndexColorModel icm = new IndexColorModel(4, 16, new int[16], 0, false, -1, DataBuffer.TYPE_BYTE);
        BufferedImage bit4Image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY, icm);

        // ...you probably do something in between here

        // Get the pixel data
        byte[] pixelData = ((DataBufferByte) bit4Image.getRaster().getDataBuffer()).getData();

        // ...you probably do something in between here

        // Create a data buffer around the array, wrap in raster
        DataBufferByte buffer = new DataBufferByte(pixelData, pixelData.length);
        WritableRaster raster = Raster.createPackedRaster(buffer, width, height, 4, null);

        // Finally create a copy of the image, sharing pixel data
        BufferedImage copy = new BufferedImage(icm, raster, icm.isAlphaPremultiplied(), null);
        System.out.println("copy: " + copy);
    }

来自 4 位数据缓冲区的 BufferedImage

BufferedImage from 4-bit data buffer

java

bufferedimage

awt

raster

image-processing