如何在java中显示像素值的数组图像？ [英] How can I display an image from an array of pixels' values in java?

问题描述

我打算在窗口内显示一个28x28像素的图像。像素的值为0，所以我希望它显示一个黑色方块为28x28的窗口。但是没有显示图像。也许数组的数据（我不确定像素值是否必须是0到255范围内的int）必须是其他数据才能显示图像。谢谢！

I intended to display a 28x28 pixels image inside the window. The pixels have "0" value, so I expected it to display a window with a black square of 28x28. But no image is displayed instead. Maybe array's data (I don't know for sure if pixel values must be an int in range from 0 to 255) must be other in order to display the image. Thanks!

公共类ASD {

public static Image getImageFromArray(int[] pixels, int width, int height) {
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    WritableRaster raster = (WritableRaster) image.getData();
    System.out.println(pixels.length + " " + width + " " + height);
    raster.setPixels(0,0,width,height,pixels);
    return image;
}

public static void main(String[] args) throws IOException {
    JFrame jf = new JFrame();
    JLabel jl = new JLabel();

    int[] arrayimage = new int[784];
    for (int i = 0; i < 28; i++)
    {   for (int j = 0; j < 28; j++)
            arrayimage[i*28+j] = 0;
    }
    ImageIcon ii = new ImageIcon(getImageFromArray(arrayimage,28,28));
    jl.setIcon(ii);
    jf.add(jl);
    jf.pack();
    jf.setVisible(true);
}

推荐答案

image.getData（）返回栅格的副本。
也许如果你在修改光栅后调用 image.setData（光栅），你会看到结果。

image.getData() returns a copy of the raster. Perhaps if you call image.setData(raster) after you modify the raster you will see results.

另外，setPixels应该有一个足够大的数组来填充栅格的所有波段（A，R，G，B）。我已经得到一个数组索引超出范围的异常，直到我将像素的大小增加到28 * 28 * 4.

Also, setPixels should be given an array large enough to fill all the bands (A, R, G, B) of the raster. I had gotten an array index out of bounds exception until I increased the size of pixels to be 28*28*4.

对于TYPE_INT_RGB，以下应生成白色图像：

For TYPE_INT_RGB, the following should produce a white image:

public class ASD
{
  public static Image getImageFromArray(int[] pixels, int width, int height)
  {
    BufferedImage image =
        new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    WritableRaster raster = (WritableRaster) image.getData();
    raster.setPixels(0, 0, width, height, pixels);
    image.setData(raster);
    return image;
  }

  public static void main(String[] args) throws IOException
  {
    JFrame jf = new JFrame();
    JLabel jl = new JLabel();

    //3 bands in TYPE_INT_RGB
    int NUM_BANDS = 3;
    int[] arrayimage = new int[28 * 28 * NUM_BANDS];

    for (int i = 0; i < 28; i++)
    {
      for (int j = 0; j < 28; j++) {
        for (int band = 0; band < NUM_BANDS; band++)
          arrayimage[((i * 28) + j)*NUM_BANDS + band] = 255;
      }
    }
    ImageIcon ii = new ImageIcon(getImageFromArray(arrayimage, 28, 28));
    jl.setIcon(ii);
    jf.add(jl);
    jf.pack();
    jf.setVisible(true);
  }
}

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