如何将ASCII数组（图像）转换为单个字符串 [英] How to convert ASCII array (image) to a single string

问题描述

我的元数据存储在HDF5文件中的8位无符号数据集中。导入到DM后，它将成为1 *长度尺寸的2D图像。每个像素将相应值的ASCII值存储到字符中。
为了进一步处理，我必须将ASCII数组转换为单个字符串，然后转换为TagGroup。这是我目前做的愚蠢的方法（逐个像素）：

My metadata is stored in a 8 bit unsigned dataset in a HDF5 file. After importing to DM, it become a 2D image of 1*length dimension. Each "pixel" stores the ASCII value of the corresponding value to the character. For further processing, I have to convert the ASCII array to a single string, and further to TagGroup. Here is the stupid method (pixel by pixel) I currently do:

String Img2Str (image img){
    Number dim1, dim2
    img.getsize(dim1,dim2)
    string out = ""
    for (number i=0; i<dim1*dim2; i++)
        out += img.getpixel(0,i).chr()
    Return out
}

这种像素操作非常慢！有没有其他更快的方法来完成这项工作？

This pixel-wise operation is really quite slow! Is there any other faster method to do this work?

推荐答案

是的，还有更好的方法。你真的想看一下原始数据流的章节：

Yes, there is a better way. You really want to look into the chapter of raw-data streaming:

如果您在stream对象中保存原始数据，则可以以任何您喜欢的形式进行读取和写入。所以你的问题的解决方案是

If you hold raw data in a "stream" object, you can read and write it in any form you like. So the solution to your problem is to

• 创建一个流


• 添加图像到流（写入二进制数据）


• 将蒸汽位置重置为开始


• 读取二进制数据字符串

• Create a stream
• Add the "image" to the stream (writing binary data)
• Reset the steam position to the start
• Read out the binary data a string

这是代码：

{
    number sx = 10
    number sy = 10
    image textImg := IntegerImage( "Text", 1, 0 , sx, sy )
    textImg = 97 + random()*26 
    textImg.showimage()

    object stream = NewStreamFromBuffer( 0 )
    ImageWriteImageDataToStream( textImg, stream, 0 )
    stream.StreamSetPos(0,0)
    string asString = StreamReadAsText( stream, 0, sx*sy )
    Result("\n as string:\n\t"+asString)
}

请注意，您可以创建链接到光盘上文件的流，如果您知道起始位置（以字节为单位），也可以直接从文件中读取。

Note that you could create a stream linked to file on disc and, provided you know the starting position in bytes, read from the file directly as well.

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