如何快速将未签名的char数组保存到图像文件？

Question

I have an array of unsigned char array which is actually a RGBA raw image. How to export it into the image file? Any image file format is OK.

Answer 1

You can write it straight out as RGBA in binary. Then use ImageMagick, which is installed on most Linux distros, and available for OSX and Windows to convert it to PNG or something more common:

convert -size 300x400 -depth 8 binary.rgba result.png

You will need to tell ImageMagick the dimensions of the image as above because they are obviously not embedded within a raw file like they would be in a JPEG or PNG with a header.

If the filename you choose does not end in .rgba , you will need to prefix it with RGBA: like this

convert -size ... RGBA:something.bin result.png

If you are using OSX, I personally think homebrew is the easiest way to install ImageMagick...

brew install imagemagick

Answer 2

I think your best bet is just saving it to a .bmp file, because basically bitmap is a (upside down) array of rgba values. So you can just write a simple header and then write it line by line to the file.

For a header you'd have to write the file header first, and after that there is the DIB header. There are multiple options for this, but i'd suggest the simple one .

The bitmap format has support for a lot of fancy stuff, but most of it is optional and for your propose not necessary.