winapi_easy/
media.rs

1//! Multimedia.
2
3use std::ffi::{
4    OsStr,
5    OsString,
6    c_void,
7};
8use std::io;
9use std::marker::PhantomData;
10use std::os::windows::ffi::OsStringExt;
11
12use windows::Win32::Devices::FunctionDiscovery::PKEY_Device_FriendlyName;
13use windows::Win32::Graphics::Gdi::{
14    GetDC,
15    HDC,
16    ReleaseDC,
17};
18use windows::Win32::Media::Audio::{
19    DEVICE_STATE_ACTIVE,
20    IMMDevice,
21    IMMDeviceEnumerator,
22    MMDeviceEnumerator,
23    eConsole,
24    eRender,
25};
26use windows::Win32::System::Com::STGM_READ;
27use windows::Win32::System::Com::StructuredStorage::PROPVARIANT;
28use windows::Win32::UI::ColorSystem::{
29    GetDeviceGammaRamp,
30    SetDeviceGammaRamp,
31};
32use windows::core::GUID;
33
34use crate::com::{
35    ComInterfaceExt,
36    ComTaskMemory,
37};
38use crate::internal::{
39    ResultExt,
40    ReturnValue,
41};
42use crate::string::ZeroTerminatedWideString;
43
44#[derive(Debug)]
45pub(crate) struct ScreenDeviceContext {
46    raw_context: HDC,
47    phantom: PhantomData<*mut ()>,
48}
49
50impl ScreenDeviceContext {
51    #[expect(dead_code)]
52    pub(crate) fn get() -> io::Result<Self> {
53        let result = unsafe { GetDC(None).if_null_to_error(|| io::ErrorKind::Other.into())? };
54        Ok(Self {
55            raw_context: result,
56            phantom: PhantomData,
57        })
58    }
59
60    #[expect(dead_code)]
61    pub(crate) fn get_raw_gamma_ramp(&self) -> io::Result<[[u16; 256]; 3]> {
62        let mut rgbs: [[u16; 256]; 3] = [[0; 256]; 3];
63        let _ = unsafe {
64            GetDeviceGammaRamp(self.raw_context, rgbs.as_mut_ptr().cast::<c_void>())
65                .if_null_to_error(|| io::ErrorKind::Other.into())?
66        };
67        Ok(rgbs)
68    }
69
70    #[expect(dead_code)]
71    pub(crate) fn set_raw_gamma_ramp(&self, values: &[[u16; 256]; 3]) -> io::Result<()> {
72        let _ = unsafe {
73            SetDeviceGammaRamp(self.raw_context, values.as_ptr().cast::<c_void>())
74                .if_null_to_error(|| io::ErrorKind::Other.into())?
75        };
76        Ok(())
77    }
78}
79
80impl Drop for ScreenDeviceContext {
81    fn drop(&mut self) {
82        unsafe { ReleaseDC(None, self.raw_context) }
83            .if_null_to_error_else_drop(|| io::ErrorKind::Other.into())
84            .unwrap_or_default_and_print_error();
85    }
86}
87
88impl ReturnValue for HDC {
89    const NULL_VALUE: Self = HDC(std::ptr::null_mut());
90}
91
92impl ComInterfaceExt for IMMDeviceEnumerator {
93    const CLASS_GUID: GUID = MMDeviceEnumerator;
94}
95
96/// A representation of a windows audio output device.
97#[derive(Clone, Eq, Debug)]
98pub struct AudioOutputDevice {
99    id: OsString,
100    friendly_name: String,
101}
102
103impl AudioOutputDevice {
104    /// Returns all devices that are active (currently plugged in)
105    pub fn get_active_devices() -> io::Result<Vec<Self>> {
106        let enumerator = IMMDeviceEnumerator::new_instance()?;
107        let endpoints = unsafe { enumerator.EnumAudioEndpoints(eRender, DEVICE_STATE_ACTIVE) }?;
108        let num_endpoints = unsafe { endpoints.GetCount() }?;
109        (0..num_endpoints)
110            .map(|idx| {
111                let item = unsafe { endpoints.Item(idx)? };
112                item.try_into()
113            })
114            .collect()
115    }
116
117    /// Returns the internal windows ID.
118    pub fn get_id(&self) -> &OsStr {
119        &self.id
120    }
121
122    /// Returns a friendly name usable for humans to identify the device.
123    pub fn get_friendly_name(&self) -> &str {
124        &self.friendly_name
125    }
126
127    /// Returns the current global default audio output device set in the audio settings.
128    pub fn get_global_default() -> io::Result<Self> {
129        let enumerator = IMMDeviceEnumerator::new_instance()?;
130        let raw_device = unsafe { enumerator.GetDefaultAudioEndpoint(eRender, eConsole) }?;
131        raw_device.try_into()
132    }
133
134    /// Sets the device as the new default global output device.
135    pub fn set_global_default(&self) -> io::Result<()> {
136        let policy_config = policy_config::IPolicyConfig::new_instance()?;
137        let result = unsafe {
138            policy_config.SetDefaultEndpoint(
139                ZeroTerminatedWideString::from_os_str(self.get_id()).as_raw_pcwstr(),
140                eConsole,
141            )
142        };
143        result.map_err(Into::into)
144    }
145}
146
147impl TryFrom<IMMDevice> for AudioOutputDevice {
148    type Error = io::Error;
149
150    fn try_from(item: IMMDevice) -> Result<Self, Self::Error> {
151        let raw_id = unsafe { item.GetId()? };
152        let _raw_id_memory = ComTaskMemory(raw_id.as_ptr());
153        let property_store = unsafe { item.OpenPropertyStore(STGM_READ) }?;
154        let friendly_name_prop: PROPVARIANT =
155            unsafe { property_store.GetValue(&PKEY_Device_FriendlyName)? };
156        let friendly_name = friendly_name_prop.to_string();
157        let copy = AudioOutputDevice {
158            id: OsString::from_wide(unsafe { raw_id.as_wide() }),
159            friendly_name,
160        };
161        Ok(copy)
162    }
163}
164
165impl PartialEq for AudioOutputDevice {
166    fn eq(&self, other: &Self) -> bool {
167        self.id == other.id
168    }
169}
170
171mod policy_config {
172    #![allow(non_upper_case_globals, non_snake_case)]
173
174    use std::ffi::c_void;
175
176    use windows::Win32::Media::Audio::ERole;
177    use windows::core::{
178        GUID,
179        Interface,
180        PCWSTR,
181    };
182
183    use crate::com::ComInterfaceExt;
184
185    #[repr(transparent)]
186    pub struct IPolicyConfig(windows::core::IUnknown);
187
188    impl IPolicyConfig {
189        pub unsafe fn SetDefaultEndpoint<P0, P1>(
190            &self,
191            deviceId: P0,
192            eRole: P1,
193        ) -> windows::core::Result<()>
194        where
195            P0: Into<PCWSTR>,
196            P1: Into<ERole>,
197        {
198            unsafe {
199                (Interface::vtable(self).SetDefaultEndpoint)(
200                    Interface::as_raw(self),
201                    deviceId.into(),
202                    eRole.into(),
203                )
204                .ok()
205            }
206        }
207    }
208
209    #[expect(clippy::transmute_ptr_to_ptr)]
210    mod interface_hierarchy {
211        use super::IPolicyConfig;
212
213        windows::core::imp::interface_hierarchy!(IPolicyConfig, windows::core::IUnknown);
214    }
215
216    impl Clone for IPolicyConfig {
217        fn clone(&self) -> Self {
218            Self(self.0.clone())
219        }
220    }
221    impl PartialEq for IPolicyConfig {
222        fn eq(&self, other: &Self) -> bool {
223            self.0 == other.0
224        }
225    }
226    impl Eq for IPolicyConfig {}
227    impl core::fmt::Debug for IPolicyConfig {
228        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
229            f.debug_tuple("IPolicyConfig").field(&self.0).finish()
230        }
231    }
232
233    unsafe impl Interface for IPolicyConfig {
234        type Vtable = IPolicyConfig_Vtbl;
235        const IID: GUID = GUID::from_u128(0xf8679f50_850a_41cf_9c72_430f290290c8);
236    }
237
238    #[repr(C)]
239    #[allow(non_camel_case_types)]
240    pub struct IPolicyConfig_Vtbl {
241        pub base__: windows::core::IUnknown_Vtbl,
242        padding: [*const c_void; 10], // Other fns may be added later
243        pub SetDefaultEndpoint: unsafe extern "system" fn(
244            this: *mut c_void,
245            wszDeviceId: PCWSTR,
246            eRole: ERole,
247        ) -> windows::core::HRESULT,
248        padding2: [*const c_void; 1], // Other fns may be added later
249    }
250
251    const CPolicyConfigClient: GUID = GUID::from_u128(0x870af99c_171d_4f9e_af0d_e63df40c2bc9);
252
253    impl ComInterfaceExt for IPolicyConfig {
254        const CLASS_GUID: GUID = CPolicyConfigClient;
255    }
256}
257
258#[cfg(test)]
259mod tests {
260    use super::*;
261
262    #[test]
263    fn check_audio_device_list() -> io::Result<()> {
264        let devices = AudioOutputDevice::get_active_devices()?;
265        if let Some(device) = devices.first() {
266            assert!(!device.id.is_empty());
267        }
268        Ok(())
269    }
270
271    #[test]
272    fn check_get_global_default() {
273        // Accept errors here since there may be no default
274        if let Ok(device) = AudioOutputDevice::get_global_default() {
275            std::hint::black_box(&device);
276        }
277    }
278}
winapi_easy/media.rs

winapi_easy/
media.rs
