使用ifstream获取图像的像素 [英] Getting pixel of the image using ifstream

问题描述

如何读取bmp图像格式的像素？我已经使用了fread功能，但我有无意义的信息。我应该正确阅读吗？

我应该跳过它的标题大小是什么？

我想要知道，当你用记事本++打开一个bmp图像时，输出是什么？为什么无法读取图像信息，通过这个程序（记事本++）？

How can i read pixels of bmp image format ? i have used fread function but i have got meaningless information.how should i read it correctly?
what is the header size that i should skip it ?
and i want to know , when you open a bmp image by notepad++ ,what is the output ? why can not read an image information, by this program (notepad++) ?

推荐答案

位图文件不兼容记事本，也不是只是一块简单的数据。



位图文件存储为二进制数据，而不是字符，并不是人类可读的。当您使用任何文本类型的编辑器应用程序打开它时，如果您很幸运，您将获得（非常无意义的）十六进制显示。如果你运气不好，你会得到一个充满异形斑点和问号的显示器。



您可以直接将位图文件读入您​​的程序，作为一个字节序列 - 但除非你正确处理这些字节，否则它仍然没有多大意义;那里有更多，而不仅仅是像素。 维基百科 [ ^ ]解释得非常好。



有一种更简单的方法：将BMP文件作为图像读取并让现有代码处理文件格式：然后它会向您显示数据和（通常，取决于系统）函数，以便在需要时以像素为基础访问和操作图像数据。



我不知道你正在使用什么语言，或者你正在构建的系统，所以我无法帮助你 - 但是开始寻找图像类或函数并从那里开始。

Bitmap files are not Notepad compatible, and aren't just a block of simple data either.

Bitmap files are stored as binary data, not characters and are not intended to be human readable. When you open it with any text-type editor application, if you are lucky you will get a (pretty meaningless) hexadecimal display. If you are unlucky, you will get a display full of odd shaped blobs and question marks for the most part.

You can read a bitmap file directly into your program, as a sequence of bytes - but unless you process those bytes correctly, it still isn't going to make much sense; there is more in there than just the pixels. Wikipedia[^] explains it pretty well.

There is an easier way: read the BMP file as an image and let existing code handle the file format: it will then present you with data and (normally, depending on the system) functions to access and manipulate the image data on a pixel basis if needs be.

I have no idea what language you are using, or system you are building for, so I can't help you any further - but start looking for an image class or function and start from there.

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