1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
use std::os::raw::*;

use parking_lot::Mutex;

use {PhysicalPosition, PhysicalSize};
use super::{util, XConnection, XError};
use super::ffi::{
    RRCrtcChangeNotifyMask,
    RROutputPropertyNotifyMask,
    RRScreenChangeNotifyMask,
    True,
    Window,
    XRRScreenResources,
};

// Used to test XRandR < 1.5 code path. This should always be committed as false.
const FORCE_RANDR_COMPAT: bool = false;
// Also used for testing. This should always be committed as false.
const DISABLE_MONITOR_LIST_CACHING: bool = false;

lazy_static! {
    static ref XRANDR_VERSION: Mutex<Option<(c_int, c_int)>> = Mutex::default();
    static ref MONITORS: Mutex<Option<Vec<MonitorId>>> = Mutex::default();
}

fn version_is_at_least(major: c_int, minor: c_int) -> bool {
    if let Some((avail_major, avail_minor)) = *XRANDR_VERSION.lock() {
        if avail_major == major {
            avail_minor >= minor
        } else {
            avail_major > major
        }
    } else {
        unreachable!();
    }
}

pub fn invalidate_cached_monitor_list() -> Option<Vec<MonitorId>> {
    // We update this lazily.
    (*MONITORS.lock()).take()
}

#[derive(Debug, Clone)]
pub struct MonitorId {
    /// The actual id
    id: u32,
    /// The name of the monitor
    pub(crate) name: String,
    /// The size of the monitor
    dimensions: (u32, u32),
    /// The position of the monitor in the X screen
    position: (i32, i32),
    /// If the monitor is the primary one
    primary: bool,
    /// The DPI scale factor
    pub(crate) hidpi_factor: f64,
    /// Used to determine which windows are on this monitor
    pub(crate) rect: util::AaRect,
}

impl MonitorId {
    fn from_repr(
        xconn: &XConnection,
        resources: *mut XRRScreenResources,
        id: u32,
        repr: util::MonitorRepr,
        primary: bool,
    ) -> Option<Self> {
        let (name, hidpi_factor) = unsafe { xconn.get_output_info(resources, &repr)? };
        let (dimensions, position) = unsafe { (repr.get_dimensions(), repr.get_position()) };
        let rect = util::AaRect::new(position, dimensions);
        Some(MonitorId {
            id,
            name,
            hidpi_factor,
            dimensions,
            position,
            primary,
            rect,
        })
    }

    pub fn get_name(&self) -> Option<String> {
        Some(self.name.clone())
    }

    #[inline]
    pub fn get_native_identifier(&self) -> u32 {
        self.id as u32
    }

    pub fn get_dimensions(&self) -> PhysicalSize {
        self.dimensions.into()
    }

    pub fn get_position(&self) -> PhysicalPosition {
        self.position.into()
    }

    #[inline]
    pub fn get_hidpi_factor(&self) -> f64 {
        self.hidpi_factor
    }
}

impl XConnection {
    pub fn get_monitor_for_window(&self, window_rect: Option<util::AaRect>) -> MonitorId {
        let monitors = self.get_available_monitors();
        let default = monitors
            .get(0)
            .expect("[winit] Failed to find any monitors using XRandR.");

        let window_rect = match window_rect {
            Some(rect) => rect,
            None => return default.to_owned(),
        };

        let mut largest_overlap = 0;
        let mut matched_monitor = default;
        for monitor in &monitors {
            let overlapping_area = window_rect.get_overlapping_area(&monitor.rect);
            if overlapping_area > largest_overlap {
                largest_overlap = overlapping_area;
                matched_monitor = &monitor;
            }
        }

        matched_monitor.to_owned()
    }

    fn query_monitor_list(&self) -> Vec<MonitorId> {
        unsafe {
            let root = (self.xlib.XDefaultRootWindow)(self.display);
            let resources = if version_is_at_least(1, 3) {
                (self.xrandr.XRRGetScreenResourcesCurrent)(self.display, root)
            } else {
                // WARNING: this function is supposedly very slow, on the order of hundreds of ms.
                // Upon failure, `resources` will be null.
                (self.xrandr.XRRGetScreenResources)(self.display, root)
            };

            if resources.is_null() {
                panic!("[winit] `XRRGetScreenResources` returned NULL. That should only happen if the root window doesn't exist.");
            }

            let mut available;
            let mut has_primary = false;

            if self.xrandr_1_5.is_some() && version_is_at_least(1, 5) && !FORCE_RANDR_COMPAT {
                // We're in XRandR >= 1.5, enumerate monitors. This supports things like MST and
                // videowalls.
                let xrandr_1_5 = self.xrandr_1_5.as_ref().unwrap();
                let mut monitor_count = 0;
                let monitors = (xrandr_1_5.XRRGetMonitors)(self.display, root, 1, &mut monitor_count);
                assert!(monitor_count >= 0);
                available = Vec::with_capacity(monitor_count as usize);
                for monitor_index in 0..monitor_count {
                    let monitor = monitors.offset(monitor_index as isize);
                    let is_primary = (*monitor).primary != 0;
                    has_primary |= is_primary;
                    MonitorId::from_repr(
                        self,
                        resources,
                        monitor_index as u32,
                        monitor.into(),
                        is_primary,
                    ).map(|monitor_id| available.push(monitor_id));
                }
                (xrandr_1_5.XRRFreeMonitors)(monitors);
            } else {
                // We're in XRandR < 1.5, enumerate CRTCs. Everything will work except MST and
                // videowall setups will also show monitors that aren't in the logical groups the user
                // cares about.
                let primary = (self.xrandr.XRRGetOutputPrimary)(self.display, root);
                available = Vec::with_capacity((*resources).ncrtc as usize);
                for crtc_index in 0..(*resources).ncrtc {
                    let crtc_id = *((*resources).crtcs.offset(crtc_index as isize));
                    let crtc = (self.xrandr.XRRGetCrtcInfo)(self.display, resources, crtc_id);
                    let is_active = (*crtc).width > 0 && (*crtc).height > 0 && (*crtc).noutput > 0;
                    if is_active {
                        let crtc = util::MonitorRepr::from(crtc);
                        let is_primary = crtc.get_output() == primary;
                        has_primary |= is_primary;
                        MonitorId::from_repr(
                            self,
                            resources,
                            crtc_id as u32,
                            crtc,
                            is_primary,
                        ).map(|monitor_id| available.push(monitor_id));
                    }
                    (self.xrandr.XRRFreeCrtcInfo)(crtc);
                }
            }

            // If no monitors were detected as being primary, we just pick one ourselves!
            if !has_primary {
                if let Some(ref mut fallback) = available.first_mut() {
                    // Setting this here will come in handy if we ever add an `is_primary` method.
                    fallback.primary = true;
                }
            }

            (self.xrandr.XRRFreeScreenResources)(resources);
            available
        }
    }

    pub fn get_available_monitors(&self) -> Vec<MonitorId> {
        let mut monitors_lock = MONITORS.lock();
        (*monitors_lock)
            .as_ref()
            .cloned()
            .or_else(|| {
                let monitors = Some(self.query_monitor_list());
                if !DISABLE_MONITOR_LIST_CACHING {
                    (*monitors_lock) = monitors.clone();
                }
                monitors
            })
            .unwrap()
    }

    #[inline]
    pub fn get_primary_monitor(&self) -> MonitorId {
        self.get_available_monitors()
            .into_iter()
            .find(|monitor| monitor.primary)
            .expect("[winit] Failed to find any monitors using XRandR.")
    }

    pub fn select_xrandr_input(&self, root: Window) -> Result<c_int, XError> {
        {
            let mut version_lock = XRANDR_VERSION.lock();
            if version_lock.is_none() {
                let mut major = 0;
                let mut minor = 0;
                let has_extension = unsafe {
                    (self.xrandr.XRRQueryVersion)(
                        self.display,
                        &mut major,
                        &mut minor,
                    )
                };
                if has_extension != True {
                    panic!("[winit] XRandR extension not available.");
                }
                *version_lock = Some((major, minor));
            }
        }

        let mut event_offset = 0;
        let mut error_offset = 0;
        let status = unsafe {
            (self.xrandr.XRRQueryExtension)(
                self.display,
                &mut event_offset,
                &mut error_offset,
            )
        };

        if status != True {
            self.check_errors()?;
            unreachable!("[winit] `XRRQueryExtension` failed but no error was received.");
        }

        let mask = RRCrtcChangeNotifyMask
            | RROutputPropertyNotifyMask
            | RRScreenChangeNotifyMask;
        unsafe { (self.xrandr.XRRSelectInput)(self.display, root, mask) };

        Ok(event_offset)
    }
}