wezterm.gui.screens: add optional effective_dpi field

This commit implements it for Windows. The other systems
report None for now.

lua-api-crates/window-funcs/src/lib.rs

@@ -21,6 +21,7 @@ pub struct ScreenInfo {
     pub height: isize,
     pub scale: f64,
     pub max_fps: Option<usize>,
+    pub effective_dpi: Option<f64>,
 }
 impl_lua_conversion_dynamic!(ScreenInfo);
 
@@ -46,6 +47,7 @@ impl From<window::screen::ScreenInfo> for ScreenInfo {
             height: info.rect.height(),
             scale: info.scale,
             max_fps: info.max_fps,
+            effective_dpi: info.effective_dpi,
         }
     }
 }

window/Cargo.toml

@@ -55,6 +55,7 @@ winapi = { version = "0.3", features = [
     "handleapi",
     "imm",
     "libloaderapi",
+    "shellscalingapi",
     "synchapi",
     "sysinfoapi",
     "winerror",

window/src/os/macos/connection.rs

@@ -229,6 +229,7 @@ pub fn nsscreen_to_screen_info(screen: *mut Object) -> ScreenInfo {
         rect,
         scale: 1.0,
         max_fps,
+        effective_dpi: None,
     }
 }
 

window/src/os/wayland/connection.rs

@@ -511,6 +511,7 @@ impl ConnectionOps for WaylandConnection {
                         rect,
                         scale,
                         max_fps: None,
+                        effective_dpi: None,
                     },
                 );
             });

window/src/os/wayland/output.rs

@@ -234,6 +234,7 @@ impl OutputHandler {
                     rect,
                     scale,
                     max_fps: None,
+                    effective_dpi: None,
                 },
             );
         }

window/src/os/windows/connection.rs

@@ -5,6 +5,7 @@ use crate::screen::{ScreenInfo, Screens};
 use crate::spawn::*;
 use crate::{Appearance, ScreenRect};
 use anyhow::Context;
+use config::ConfigHandle;
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::ffi::OsString;
@@ -14,6 +15,7 @@ use std::rc::Rc;
 use winapi::shared::minwindef::*;
 use winapi::shared::windef::*;
 use winapi::shared::winerror::{ERROR_INSUFFICIENT_BUFFER, ERROR_SUCCESS};
+use winapi::um::shellscalingapi::{GetDpiForMonitor, MDT_EFFECTIVE_DPI};
 use winapi::um::winbase::INFINITE;
 use winapi::um::wingdi::{
     DEVMODEW, DISPLAY_DEVICEW, DM_DISPLAYFREQUENCY, QDC_ONLY_ACTIVE_PATHS, QDC_VIRTUAL_MODE_AWARE,
@@ -177,6 +179,7 @@ pub(crate) struct ScreenInfoHelper {
     active_handle: HMONITOR,
     friendly_names: HashMap<String, String>,
     gdi_to_adapater: HashMap<String, String>,
+    config: ConfigHandle,
 }
 
 impl ScreenInfoHelper {
@@ -189,6 +192,7 @@ impl ScreenInfoHelper {
             active_handle: unsafe { MonitorFromWindow(GetFocus(), MONITOR_DEFAULTTONEAREST) },
             friendly_names: gdi_display_name_to_friendly_monitor_names()?,
             gdi_to_adapater: gdi_display_name_to_adapter_names(),
+            config: config::configuration(),
         })
     }
 
@@ -218,6 +222,22 @@ impl ScreenInfoHelper {
                 };
 
             let monitor_name = info.monitor_name(&mi);
+
+            let mut effective_dpi = None;
+
+            if let Some(dpi) = info.config.dpi_by_screen.get(&monitor_name).copied() {
+                effective_dpi.replace(dpi);
+            } else if let Some(dpi) = info.config.dpi {
+                effective_dpi.replace(dpi);
+            } else {
+                let mut dpi_x = 0;
+                let mut dpi_y = 0;
+                GetDpiForMonitor(mon, MDT_EFFECTIVE_DPI, &mut dpi_x, &mut dpi_y);
+                if dpi_x != 0 {
+                    effective_dpi.replace(dpi_x as f64);
+                }
+            }
+
             let screen_info = ScreenInfo {
                 name: monitor_name.clone(),
                 rect: euclid::rect(
@@ -228,6 +248,7 @@ impl ScreenInfoHelper {
                 ),
                 scale: 1.0,
                 max_fps,
+                effective_dpi,
             };
 
             info.virtual_rect = info.virtual_rect.union(&screen_info.rect);

window/src/os/x11/connection.rs

@@ -276,6 +276,7 @@ impl ConnectionOps for XConnection {
                     rect: bounds,
                     scale: 1.0,
                     max_fps,
+                    effective_dpi: None,
                 };
                 by_name.insert(name, info);
             }

window/src/screen.rs

@@ -15,4 +15,5 @@ pub struct ScreenInfo {
     pub rect: ScreenRect,
     pub scale: f64,
     pub max_fps: Option<usize>,
+    pub effective_dpi: Option<f64>,
 }