1 use std::{env, slice};
2 use std::str::FromStr;
3
4 use validate_hidpi_factor;
5 use super::*;
6
calc_dpi_factor( (width_px, height_px): (u32, u32), (width_mm, height_mm): (u64, u64), ) -> f647 pub fn calc_dpi_factor(
8 (width_px, height_px): (u32, u32),
9 (width_mm, height_mm): (u64, u64),
10 ) -> f64 {
11 // Override DPI if `WINIT_HIDPI_FACTOR` variable is set
12 let dpi_override = env::var("WINIT_HIDPI_FACTOR")
13 .ok()
14 .and_then(|var| f64::from_str(&var).ok());
15 if let Some(dpi_override) = dpi_override {
16 if !validate_hidpi_factor(dpi_override) {
17 panic!(
18 "`WINIT_HIDPI_FACTOR` invalid; DPI factors must be normal floats greater than 0. Got `{}`",
19 dpi_override,
20 );
21 }
22 return dpi_override;
23 }
24
25 // See http://xpra.org/trac/ticket/728 for more information.
26 if width_mm == 0 || height_mm == 0 {
27 warn!("XRandR reported that the display's 0mm in size, which is certifiably insane");
28 return 1.0;
29 }
30
31 let ppmm = (
32 (width_px as f64 * height_px as f64) / (width_mm as f64 * height_mm as f64)
33 ).sqrt();
34 // Quantize 1/12 step size
35 let dpi_factor = ((ppmm * (12.0 * 25.4 / 96.0)).round() / 12.0).max(1.0);
36 assert!(validate_hidpi_factor(dpi_factor));
37 dpi_factor
38 }
39
40 pub enum MonitorRepr {
41 Monitor(*mut ffi::XRRMonitorInfo),
42 Crtc(*mut ffi::XRRCrtcInfo),
43 }
44
45 impl MonitorRepr {
get_output(&self) -> ffi::RROutput46 pub unsafe fn get_output(&self) -> ffi::RROutput {
47 match *self {
48 // Same member names, but different locations within the struct...
49 MonitorRepr::Monitor(monitor) => *((*monitor).outputs.offset(0)),
50 MonitorRepr::Crtc(crtc) => *((*crtc).outputs.offset(0)),
51 }
52 }
53
get_dimensions(&self) -> (u32, u32)54 pub unsafe fn get_dimensions(&self) -> (u32, u32) {
55 match *self {
56 MonitorRepr::Monitor(monitor) => ((*monitor).width as u32, (*monitor).height as u32),
57 MonitorRepr::Crtc(crtc) => ((*crtc).width as u32, (*crtc).height as u32),
58 }
59 }
60
get_position(&self) -> (i32, i32)61 pub unsafe fn get_position(&self) -> (i32, i32) {
62 match *self {
63 MonitorRepr::Monitor(monitor) => ((*monitor).x as i32, (*monitor).y as i32),
64 MonitorRepr::Crtc(crtc) => ((*crtc).x as i32, (*crtc).y as i32),
65 }
66 }
67 }
68
69 impl From<*mut ffi::XRRMonitorInfo> for MonitorRepr {
from(monitor: *mut ffi::XRRMonitorInfo) -> Self70 fn from(monitor: *mut ffi::XRRMonitorInfo) -> Self {
71 MonitorRepr::Monitor(monitor)
72 }
73 }
74
75 impl From<*mut ffi::XRRCrtcInfo> for MonitorRepr {
from(crtc: *mut ffi::XRRCrtcInfo) -> Self76 fn from(crtc: *mut ffi::XRRCrtcInfo) -> Self {
77 MonitorRepr::Crtc(crtc)
78 }
79 }
80
81 impl XConnection {
82 // Retrieve DPI from Xft.dpi property
get_xft_dpi(&self) -> Option<f64>83 pub unsafe fn get_xft_dpi(&self) -> Option<f64> {
84 (self.xlib.XrmInitialize)();
85 let resource_manager_str = (self.xlib.XResourceManagerString)(self.display);
86 if resource_manager_str == ptr::null_mut() {
87 return None;
88 }
89 if let Ok(res) = ::std::ffi::CStr::from_ptr(resource_manager_str).to_str() {
90 let name : &str = "Xft.dpi:\t";
91 for pair in res.split("\n") {
92 if pair.starts_with(&name) {
93 let res = &pair[name.len()..];
94 return f64::from_str(&res).ok();
95 }
96 }
97 }
98 None
99 }
get_output_info( &self, resources: *mut ffi::XRRScreenResources, repr: &MonitorRepr, ) -> Option<(String, f64)>100 pub unsafe fn get_output_info(
101 &self,
102 resources: *mut ffi::XRRScreenResources,
103 repr: &MonitorRepr,
104 ) -> Option<(String, f64)> {
105 let output_info = (self.xrandr.XRRGetOutputInfo)(
106 self.display,
107 resources,
108 repr.get_output(),
109 );
110 if output_info.is_null() {
111 // When calling `XRRGetOutputInfo` on a virtual monitor (versus a physical display)
112 // it's possible for it to return null.
113 // https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=816596
114 let _ = self.check_errors(); // discard `BadRROutput` error
115 return None;
116 }
117 let name_slice = slice::from_raw_parts(
118 (*output_info).name as *mut u8,
119 (*output_info).nameLen as usize,
120 );
121 let name = String::from_utf8_lossy(name_slice).into();
122 let hidpi_factor = if let Some(dpi) = self.get_xft_dpi() {
123 dpi / 96.
124 } else {
125 calc_dpi_factor(
126 repr.get_dimensions(),
127 ((*output_info).mm_width as u64, (*output_info).mm_height as u64),
128 )
129 };
130
131 (self.xrandr.XRRFreeOutputInfo)(output_info);
132 Some((name, hidpi_factor))
133 }
134 }
135