[windows] Terminal background colour

[gvanem]

Hello folks, my first issue.

The function ColorPrintf() ass-u-mes that all users of this library have terminals with a black background colour.
I.e. using it in Microsoft's STL library and the benchmark-std_copy.exe program, the output like like this:

Not very nice IMHO.

With my blue terminal background I'd like it to look like:

which I fixed with:

--- a/src/colorprint.cc  2022-09-10 14:58:12
+++ b/src/colorprint.cc 2022-09-10 14:54:32
@@ -136,13 +136,16 @@
   CONSOLE_SCREEN_BUFFER_INFO buffer_info;
   GetConsoleScreenBufferInfo(stdout_handle, &buffer_info);
   const WORD old_color_attrs = buffer_info.wAttributes;
+  WORD  new_attr;

   // We need to flush the stream buffers into the console before each
   // SetConsoleTextAttribute call lest it affect the text that is already
   // printed but has not yet reached the console.
   fflush(stdout);
+  new_attr = (buffer_info.wAttributes & ~7);
+  new_attr &= ~8;    // Since 'wAttributes' could have been hi-intensity at startup.
   SetConsoleTextAttribute(stdout_handle,
-                          GetPlatformColorCode(color) | FOREGROUND_INTENSITY);
+                          new_attr | GetPlatformColorCode(color) | FOREGROUND_INTENSITY);
   vprintf(fmt, args);

   fflush(stdout);

PS. I use JPsoft's 4NT as the shell.

System

• Win-10
• Compiler and version: MSVC ver. 19.34.31721 for x64

[dmah42]

could you create a pull request for this?

[gvanem]

I'm not very familiar with git pull request. But my attempt: #1488

[imrichardcole]

Taking a look

[imrichardcole]

Confirmed issue is still present:

Will review the original PR and associated comments to work out a solution.

[imrichardcole]

To confirm why this is happening (PR incoming) the issue can be captured like so:

In a blue background console, the 5th bit is lost at the point the green message is written.

There are #defines (C:\Program Files (x86)\Windows Kits\10\Include\10.0.22621.0\um\consoleapi2.h) for all the colours supported, so can be done without any magic numbers.

[dmah42]

yeah i think we just assume the background colour is black and reset to that instead of reading the current bg colour.

[gvanem]

yeah i think we just assume the background colour is black and reset to that instead of reading the current bg colour.

That's just what I wrote 2 years ago. So much for being a Member of Google.

[dmah42]

yeah i think we just assume the background colour is black and reset to that instead of reading the current bg colour.

That's just what I wrote 2 years ago. So much for being a Member of Google.

i'm not sure i understand what point you're trying to make, but it's reflecting more poorly on you than on me. as you are still active on github, did you want to finish the PR you started but never finished two years ago?

[dmah42]

fixed by #1865