From 7dc791f4d411fd32b28324f1ba3fac448dff59ca Mon Sep 17 00:00:00 2001
From: Martin Askestad <MartinAskestad@users.github.com>
Date: Thu, 9 May 2024 12:25:57 +0200
Subject: [PATCH] Use async windows pos functions

---
 src/win32/mod.rs     | 58 +++++++++++++++++++++++++-------------------
 src/windowmanager.rs |  9 +++++--
 2 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/src/win32/mod.rs b/src/win32/mod.rs
index 5e376f7..99476ea 100644
--- a/src/win32/mod.rs
+++ b/src/win32/mod.rs
@@ -4,7 +4,6 @@ use std::{
     path::PathBuf,
 };
 
-use log::debug;
 use windows::{
     core::PCWSTR,
     w,
@@ -27,14 +26,14 @@ use windows::{
             Accessibility::{SetWinEventHook, HWINEVENTHOOK, WINEVENTPROC},
             Shell::{FOLDERID_LocalAppData, SHGetKnownFolderPath, KF_FLAG_DEFAULT},
             WindowsAndMessaging::{
-                DefWindowProcW, EnumWindows, FindWindowW, GetClassNameW, GetCursorPos,
-                GetSystemMetrics, GetWindow, GetWindowLongPtrW, GetWindowTextLengthW,
-                GetWindowTextW, GetWindowThreadProcessId, IsIconic, IsWindowVisible, LoadIconW,
-                PostMessageW, PostQuitMessage, RegisterClassW, RegisterShellHookWindow,
-                RegisterWindowMessageW, SetWindowLongPtrW, SetWindowPos, ShowWindow,
-                SystemParametersInfoW, GET_WINDOW_CMD, GWL_EXSTYLE, GWL_STYLE, HICON, HWND_TOP,
-                SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN, SM_YVIRTUALSCREEN,
-                SPI_GETWORKAREA, SWP_NOACTIVATE, SW_SHOWMINNOACTIVE,
+                BeginDeferWindowPos, DefWindowProcW, DeferWindowPos, EndDeferWindowPos,
+                EnumWindows, FindWindowW, GetClassNameW, GetCursorPos, GetSystemMetrics, GetWindow,
+                GetWindowLongPtrW, GetWindowTextLengthW, GetWindowTextW, GetWindowThreadProcessId,
+                IsIconic, IsWindowVisible, LoadIconW, PostMessageW, PostQuitMessage,
+                RegisterClassW, RegisterShellHookWindow, RegisterWindowMessageW, SetWindowLongPtrW,
+                ShowWindow, SystemParametersInfoW, GET_WINDOW_CMD, GWL_EXSTYLE, GWL_STYLE, HDWP,
+                HICON, HWND_TOP, SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN,
+                SM_YVIRTUALSCREEN, SPI_GETWORKAREA, SWP_NOACTIVATE, SW_SHOWMINNOACTIVE,
                 SYSTEM_PARAMETERS_INFO_UPDATE_FLAGS, WINDOW_LONG_PTR_INDEX, WINEVENT_OUTOFCONTEXT,
                 WNDCLASSW, WNDENUMPROC,
             },
@@ -50,6 +49,31 @@ pub(crate) mod taskbar;
 pub(crate) mod theme;
 pub(crate) mod virtualdesktop;
 
+pub fn begin_defer_window_pos(num_windows: usize) -> Result<HDWP> {
+    Ok(unsafe { BeginDeferWindowPos(num_windows as i32)? })
+}
+
+pub fn defer_window_pos(hdwp: HDWP, hwnd: HWND, rect: RECT) -> Result<HDWP> {
+    let margin = dwm::get_window_extended_frame_bounds(hwnd); // Should be: (left: 7, top: 0, right: -7, bottom: -7)
+    let res = unsafe {
+        DeferWindowPos(
+            hdwp,
+            hwnd,
+            HWND_TOP,
+            rect.left - margin.left,
+            rect.top - margin.top,
+            (rect.right - rect.left) + margin.left * 2,
+            (rect.bottom - rect.top) - margin.bottom,
+            SWP_NOACTIVATE,
+        )?
+    };
+    Ok(res)
+}
+
+pub fn end_defer_window_pos(hdwp: HDWP) {
+    unsafe { EndDeferWindowPos(hdwp) };
+}
+
 pub fn is_iconic(hwnd: HWND) -> bool {
     unsafe { IsIconic(hwnd).into() }
 }
@@ -101,22 +125,6 @@ pub fn get_working_area() -> Result<RECT> {
     }
 }
 
-pub fn set_window_pos(hwnd: HWND, r: RECT) {
-    let margin = dwm::get_window_extended_frame_bounds(hwnd); // should be: { left: 7, top: 0, right:-7, bottom -7 }
-    debug!("{margin:?}");
-    unsafe {
-        SetWindowPos(
-            hwnd,
-            HWND_TOP,
-            r.left - margin.left,
-            r.top - margin.top,
-            (r.right - r.left) - margin.right * 2,
-            (r.bottom - r.top) - margin.bottom,
-            SWP_NOACTIVATE,
-        );
-    }
-}
-
 pub fn get_module_handle() -> windows::core::Result<HMODULE> {
     unsafe { GetModuleHandleA(None) }
 }
diff --git a/src/windowmanager.rs b/src/windowmanager.rs
index 5931172..f7f3bb8 100644
--- a/src/windowmanager.rs
+++ b/src/windowmanager.rs
@@ -142,8 +142,13 @@ impl WindowManager {
             .collect();
         let number_of_windows = windows_on_screen.len();
         let ds = self.layout.arrange(self.working_area, number_of_windows);
-        for (w, d) in windows_on_screen.iter().zip(ds.iter()) {
-            win32::set_window_pos(w.0, *d);
+        if let Ok(mut hdwp) = win32::begin_defer_window_pos(number_of_windows) {
+            for (w, d) in windows_on_screen.iter().zip(ds.iter()) {
+                if let Ok(res) = win32::defer_window_pos(hdwp, w.0, *d) {
+                    hdwp = res;
+                }
+            }
+            win32::end_defer_window_pos(hdwp);
         }
         let _ = win32::dwm::invalidate_iconic_bitmaps(self.hwnd);
     }