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Allow volume control of system audio device on MS-Windows

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* src/sound.c (Fw32_sound_volume): New function.

* etc/NEWS: Announce it.
This commit is contained in:
Eli Zaretskii 2025-12-07 11:31:40 +02:00
parent 2d459d8377
commit 300c6dc2f9
2 changed files with 72 additions and 0 deletions
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5
etc/NEWS
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@ -3719,6 +3719,11 @@ means of the GDI+ library.
In addition to ':file FILE' for playing a sound from a file, ':data
DATA' can now be used to play a sound from memory.
---
** New primitive 'w32-sound-volume'.
This primitive allows to get and set the volume of the system's default
audio device (or the "optimal device", if there are several devices).
---
** The MS-DOS port of Emacs now supports more recent releases of GCC and Binutils.
Accordingly, we have revised our recommendations for a suitable DJGPP

67
src/sound.c
View file

@ -1357,6 +1357,70 @@ do_play_sound (const char *psz_file_or_data, unsigned long ui_volume, bool in_me
return i_result;
}
DEFUN ("w32-sound-volume", Fw32_sound_volume, Sw32_sound_volume, 0, 1, 0,
doc: /* Get or set the MS-Windows audio volume setting.
If VOLUME is specified, it should be the volume to set, either an integer
in the range [0, 100], or a float in the range [0, 1.0]. Value of zero
means mute the audio, value of 100 or 1.0 means maximum volume.
When called with the VOLUME argument nil or omitted, just return the
current volume setting.
The return value is the integer volume setting before the change, if any. */)
(Lisp_Object volume)
{
DWORD ui_volume, ui_volume_orig;
MMRESULT mm_result = MMSYSERR_NOERROR;
if (FIXNUMP (volume))
ui_volume = XFIXNUM (volume);
else if (FLOATP (volume))
ui_volume = XFLOAT_DATA (volume) * 100;
else if (BIGNUMP (volume))
{
double dvolume = bignum_to_double (volume);
if (dvolume < 0)
ui_volume = 0;
else if (dvolume > 100.0)
ui_volume = 100;
else
ui_volume = dvolume + 0.5;
}
else if (!NILP (volume))
wrong_type_argument (Qnumberp, volume);
mm_result = waveOutGetVolume ((HWAVEOUT) WAVE_MAPPER, &ui_volume_orig);
if (mm_result == MMSYSERR_NOERROR)
{
/* Look only at the low 16 bits, assuming left and right channels
have identical volume settings. */
ui_volume_orig &= 0xFFFF;
/* The value is between 0 and 0xFFFF, convert to our scale. */
ui_volume_orig = ui_volume_orig * 100.0 / 65535.0 + 0.5;
}
else
{
SOUND_WARNING (waveOutGetErrorText, mm_result,
"waveOutGetVolume: failed to obtain the original"
" volume level of the WAVE_MAPPER device.");
ui_volume_orig = 100;
}
if (!NILP (volume))
{
if (ui_volume > 100)
ui_volume = 100;
/* Set the same volume for left and right channels. */
ui_volume = ui_volume * 0xFFFF / 100;
ui_volume = (ui_volume << 16) + ui_volume;
mm_result = waveOutSetVolume ((HWAVEOUT) WAVE_MAPPER, ui_volume);
if (mm_result != MMSYSERR_NOERROR)
{
SOUND_WARNING (waveOutGetErrorText, mm_result,
"waveOutSetVolume: failed to set the volume level"
" of the WAVE_MAPPER device.");
}
}
return make_fixnum (ui_volume_orig);
}
/* END: Windows specific functions */
#endif /* WINDOWSNT */
@ -1482,6 +1546,9 @@ syms_of_sound (void)
DEFSYM (Qplay_sound_functions, "play-sound-functions");
defsubr (&Splay_sound_internal);
#ifdef WINDOWSNT
defsubr (&Sw32_sound_volume);
#endif
}
#endif /* HAVE_SOUND */