如何将.gif转换为字节[] []？ [英] How do you turn a .gif into a byte[][]?

问题描述

我正在使用具有方法的API

I am using an API that has a method

public void setImage(byte[][] newImage)

API参考中给出的唯一信息是

The only information given to be in the API Reference is

此图像的格式是一个简单的原始 2D数组个字节。每个字节代表从黑色（0）到 white（255）。索引 2D数组时， Y轴首先， X轴其次，例如image [y] [x]。
参数值未在内部克隆。不必要的共享，请在调用此方法之前克隆图像数据。

"The format of this image is a simple raw 2D array of bytes. Every byte represents shade of gray from black (0) to white (255). When indexing the 2D array, Y axis goes first, X axis goes second, e.g. image[y][x]. Parameter value is not cloned internally. To avoid unwanted sharing, clone the image data before calling this method."

我应该将.gif图像传递给此方法，但无法确定我如何将.gif转换为 byte [] []数组。

I am supposed to be passing a .gif image to this method but can not figure out for the life of me how to turn a .gif into a byte[][] array.

任何帮助都会很棒！谢谢。

Any help would be great! Thanks.

推荐答案

有多种方法可以将颜色转换为灰度，但是最简单的方法是对红色，灰色和蓝色值进行平均： / p>

There's various ways to convert color to grayscale but the simplest is to average the red, grean and blue values like this:

BufferedImage image = ImageIO.read(new File([your gif]));

int[][] imageBytes = new int[image.getHeight()][image.getWidth()];

for (int y = 0; y < image.getHeight(); y++) 
{
  for (int x = 0; x < image.getWidth(); x++) 
  {
    Color color = new Color(image.getRGB(x, y));
    imageBytes[y][x] = (color.getRed() + color.getGreen() + color.getBlue()) / 3;
  }
}

注意，我使用了 int 数组是因为（如我之前评论的）API声明了 setImage 方法存在一个基本问题。 Java中的 byte 是带符号的，因此代表最小值-128，最大值127，因此不能使用0-255的值。

Note, I have used an int array because (as I previously commented) there's a fundimental problem with the API that declared the setImage method. A byte in Java is signed and therefore represents a minimum of -128 and a maximum value of 127, so cannot be used to values 0 - 255.

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