1use std::str::FromStr;
2use std::{env, str};
3
4use super::*;
5use crate::dpi::validate_scale_factor;
6use crate::platform_impl::platform::x11::{monitor, VideoModeHandle};
7
8use tracing::warn;
9use x11rb::protocol::randr::{self, ConnectionExt as _};
10
11/// Represents values of `WINIT_HIDPI_FACTOR`.
12pub enum EnvVarDPI {
13 Randr,
14 Scale(f64),
15 NotSet,
16}
17
18pub fn calc_dpi_factor(
19 (width_px: u32, height_px: u32): (u32, u32),
20 (width_mm: u64, height_mm: u64): (u64, u64),
21) -> f64 {
22 // See http://xpra.org/trac/ticket/728 for more information.
23 if width_mm == 0 || height_mm == 0 {
24 warn!("XRandR reported that the display's 0mm in size, which is certifiably insane");
25 return 1.0;
26 }
27
28 let ppmm: f64 = ((width_px as f64 * height_px as f64) / (width_mm as f64 * height_mm as f64)).sqrt();
29 // Quantize 1/12 step size
30 let dpi_factor: f64 = ((ppmm * (12.0 * 25.4 / 96.0)).round() / 12.0).max(1.0);
31 assert!(validate_scale_factor(dpi_factor));
32 if dpi_factor <= 20. {
33 dpi_factor
34 } else {
35 1.
36 }
37}
38
39impl XConnection {
40 // Retrieve DPI from Xft.dpi property
41 pub fn get_xft_dpi(&self) -> Option<f64> {
42 // Try to get it from XSETTINGS first.
43 if let Some(xsettings_screen) = self.xsettings_screen() {
44 match self.xsettings_dpi(xsettings_screen) {
45 Ok(Some(dpi)) => return Some(dpi),
46 Ok(None) => {},
47 Err(err) => {
48 tracing::warn!("failed to fetch XSettings: {err}");
49 },
50 }
51 }
52
53 self.database().get_string("Xft.dpi", "").and_then(|s| f64::from_str(s).ok())
54 }
55
56 pub fn get_output_info(
57 &self,
58 resources: &monitor::ScreenResources,
59 crtc: &randr::GetCrtcInfoReply,
60 ) -> Option<(String, f64, Vec<VideoModeHandle>)> {
61 let output_info = match self
62 .xcb_connection()
63 .randr_get_output_info(crtc.outputs[0], x11rb::CURRENT_TIME)
64 .map_err(X11Error::from)
65 .and_then(|r| r.reply().map_err(X11Error::from))
66 {
67 Ok(output_info) => output_info,
68 Err(err) => {
69 warn!("Failed to get output info: {:?}", err);
70 return None;
71 },
72 };
73
74 let bit_depth = self.default_root().root_depth;
75 let output_modes = &output_info.modes;
76 let resource_modes = resources.modes();
77
78 let modes = resource_modes
79 .iter()
80 // XRROutputInfo contains an array of mode ids that correspond to
81 // modes in the array in XRRScreenResources
82 .filter(|x| output_modes.iter().any(|id| x.id == *id))
83 .map(|mode| {
84 VideoModeHandle {
85 size: (mode.width.into(), mode.height.into()),
86 refresh_rate_millihertz: monitor::mode_refresh_rate_millihertz(mode)
87 .unwrap_or(0),
88 bit_depth: bit_depth as u16,
89 native_mode: mode.id,
90 // This is populated in `MonitorHandle::video_modes` as the
91 // video mode is returned to the user
92 monitor: None,
93 }
94 })
95 .collect();
96
97 let name = match str::from_utf8(&output_info.name) {
98 Ok(name) => name.to_owned(),
99 Err(err) => {
100 warn!("Failed to get output name: {:?}", err);
101 return None;
102 },
103 };
104 // Override DPI if `WINIT_X11_SCALE_FACTOR` variable is set
105 let deprecated_dpi_override = env::var("WINIT_HIDPI_FACTOR").ok();
106 if deprecated_dpi_override.is_some() {
107 warn!(
108 "The WINIT_HIDPI_FACTOR environment variable is deprecated; use \
109 WINIT_X11_SCALE_FACTOR"
110 )
111 }
112 let dpi_env = env::var("WINIT_X11_SCALE_FACTOR").ok().map_or_else(
113 || EnvVarDPI::NotSet,
114 |var| {
115 if var.to_lowercase() == "randr" {
116 EnvVarDPI::Randr
117 } else if let Ok(dpi) = f64::from_str(&var) {
118 EnvVarDPI::Scale(dpi)
119 } else if var.is_empty() {
120 EnvVarDPI::NotSet
121 } else {
122 panic!(
123 "`WINIT_X11_SCALE_FACTOR` invalid; DPI factors must be either normal \
124 floats greater than 0, or `randr`. Got `{var}`"
125 );
126 }
127 },
128 );
129
130 let scale_factor = match dpi_env {
131 EnvVarDPI::Randr => calc_dpi_factor(
132 (crtc.width.into(), crtc.height.into()),
133 (output_info.mm_width as _, output_info.mm_height as _),
134 ),
135 EnvVarDPI::Scale(dpi_override) => {
136 if !validate_scale_factor(dpi_override) {
137 panic!(
138 "`WINIT_X11_SCALE_FACTOR` invalid; DPI factors must be either normal \
139 floats greater than 0, or `randr`. Got `{dpi_override}`",
140 );
141 }
142 dpi_override
143 },
144 EnvVarDPI::NotSet => {
145 if let Some(dpi) = self.get_xft_dpi() {
146 dpi / 96.
147 } else {
148 calc_dpi_factor(
149 (crtc.width.into(), crtc.height.into()),
150 (output_info.mm_width as _, output_info.mm_height as _),
151 )
152 }
153 },
154 };
155
156 Some((name, scale_factor, modes))
157 }
158
159 pub fn set_crtc_config(
160 &self,
161 crtc_id: randr::Crtc,
162 mode_id: randr::Mode,
163 ) -> Result<(), X11Error> {
164 let crtc =
165 self.xcb_connection().randr_get_crtc_info(crtc_id, x11rb::CURRENT_TIME)?.reply()?;
166
167 self.xcb_connection()
168 .randr_set_crtc_config(
169 crtc_id,
170 crtc.timestamp,
171 x11rb::CURRENT_TIME,
172 crtc.x,
173 crtc.y,
174 mode_id,
175 crtc.rotation,
176 &crtc.outputs,
177 )?
178 .reply()
179 .map(|_| ())
180 .map_err(Into::into)
181 }
182
183 pub fn get_crtc_mode(&self, crtc_id: randr::Crtc) -> Result<randr::Mode, X11Error> {
184 Ok(self.xcb_connection().randr_get_crtc_info(crtc_id, x11rb::CURRENT_TIME)?.reply()?.mode)
185 }
186}
187