Justify text with leading whitespace

Question

To justify text on vim I use :set textwidth=77 and space+v to select and finally gq to justify the text.

This is the result

original:

   Most of the command-line options that you can use with GCC are useful for C programs; when an option is only useful with another language (usually C++), the explanation says so
   explicitly.  If the description for a particular option does not mention a source language, you can use that option with all supported languages.

"justified"

       Most of the command-line options that you can use with GCC are useful
for C programs; when an option is only useful with another language (usually
C++), the explanation says so explicitly.  If the description for a
particular option does not mention a source language, you can use that option
with all supported languages.

I want a text like this

Most of the command-line options that you can use with GCC are useful
for C programs; when an option is only useful with another language (
usually C++), the explanation says so explicitly.  If the description
for a particular option does not mention a source language, you can u
se that option with all supported languages.

Is possible with vim without using external tools like fmt?

Answer 1

I would do:

:set tw=77

ggShift vG to select the text,

:left to kill the leading spaces,

gv to restore the selection,

gq to wrap the text.