在C中创建位图-如何将/r/n写入1个字节? [英] Creating bitmap in C - How to write /r /n as 1 byte?

问题描述

我正在尝试在C中创建位图.首先，我要执行的操作是复制标头和其他位图文件中的所有像素数据.问题是数字"10"，当我读时它只是1个字节，但是当我写时是2个字节.我知道/r/n的内容，但是例如Paint如何将其保存为1个字符?

I'm trying to create bitmap in C. Firstly what i want to do is copy header and all pixels data from other bitmap file. The problem is with number '10', which when i'm reading it's just 1 byte, but when i write it's 2 bytes. I know about /r /n things, but how for example Paint can save it as 1 char?

我正在以这种方式读取标题:

I'm reading header in this way:

unsigned char* header = malloc(54);
fread(header, sizeof(unsigned char), 54, file);

并以此方式书写:

fwrite(img->fileHeader, sizeof(unsigned char), 54, file);

推荐答案

在处理非文本文件时，必须始终使用ios::binary标志:

You have to use ios::binary flag when dealing with non-text files, always:

ofstream myfile;
myfile.open ("example.bin", ios::out | ios::app | ios::binary);

如果您使用的是Windows，并且在此处打开流时未指定ios::binary标志，会发生什么情况:

If you're using Windows and not specifying the ios::binary flag when opening your streams here what happens:

13 10序列将转换为10:内存中的数据已损坏.如果数据首先是二进制的，那么您将很不幸无法获得这些序列，但它可能会发生

13 10 sequences are converted to 10 when reading: corrupt data in memory. If the data is binary in the first place you'd be unlucky to get those sequences but it can happen

10会转换为13 10(CR + LF).这更有可能发生，并且会损坏您的输出文件.

10 is converted to 13 10 (CR+LF) when writing. That is more likely to happen and corrupts your output file.

注意:即使已损坏，也可以以文本形式读取和以二进制形式写回来修复损坏(或将13 10替换为10)

Note: even if it's corrupt, reading as text and writing back as binary fixes the corruption (or replace 13 10 by 10)

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