From 2d1c487410ca9420738276692db2af8083be49ea Mon Sep 17 00:00:00 2001
From: Pavel Sountsov <siege@google.com>
Date: Mon, 6 Nov 2023 21:37:39 -0800
Subject: [PATCH] Implement window borders on Windows and treat window position
 as referring to the client area.

It seems unlike GTK, the menu is counted as part of the border.
---
 include/allegro5/platform/aintwin.h |  1 +
 src/win/d3d_disp.cpp                |  1 +
 src/win/wgl_disp.c                  |  1 +
 src/win/wwindow.c                   | 40 ++++++++++++++++++++++++++---
 4 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/include/allegro5/platform/aintwin.h b/include/allegro5/platform/aintwin.h
index 944b9d6a8..a2b6a93fe 100644
--- a/include/allegro5/platform/aintwin.h
+++ b/include/allegro5/platform/aintwin.h
@@ -195,6 +195,7 @@ void _al_win_destroy_display_icons(ALLEGRO_DISPLAY *display);
 /* window decorations */
 void _al_win_set_window_position(HWND window, int x, int y);
 void _al_win_get_window_position(HWND window, int *x, int *y);
+bool _al_win_get_window_borders(ALLEGRO_DISPLAY *display, int *left, int *top, int *right, int *bottom);
 bool _al_win_set_window_constraints(ALLEGRO_DISPLAY *display, int min_w, int min_h, int max_w, int max_h);
 bool _al_win_get_window_constraints(ALLEGRO_DISPLAY *display, int *min_w, int *min_h, int *max_w, int *max_h);
 void _al_win_apply_window_constraints(ALLEGRO_DISPLAY *display, bool onoff);
diff --git a/src/win/d3d_disp.cpp b/src/win/d3d_disp.cpp
index ba236e0c0..8b07330e5 100644
--- a/src/win/d3d_disp.cpp
+++ b/src/win/d3d_disp.cpp
@@ -2919,6 +2919,7 @@ ALLEGRO_DISPLAY_INTERFACE *_al_display_d3d_driver(void)
    vt->set_icons = _al_win_set_display_icons;
    vt->set_window_position = d3d_set_window_position;
    vt->get_window_position = d3d_get_window_position;
+   vt->get_window_borders = _al_win_get_window_borders;
    vt->set_window_constraints = _al_win_set_window_constraints;
    vt->get_window_constraints = _al_win_get_window_constraints;
    vt->apply_window_constraints = _al_win_apply_window_constraints;
diff --git a/src/win/wgl_disp.c b/src/win/wgl_disp.c
index 98255a6b4..92fd3a54a 100644
--- a/src/win/wgl_disp.c
+++ b/src/win/wgl_disp.c
@@ -1563,6 +1563,7 @@ ALLEGRO_DISPLAY_INTERFACE *_al_display_wgl_driver(void)
    vt.set_icons = _al_win_set_display_icons;
    vt.set_window_position = wgl_set_window_position;
    vt.get_window_position = wgl_get_window_position;
+   vt.get_window_borders = _al_win_get_window_borders;
    vt.set_window_constraints = _al_win_set_window_constraints;
    vt.get_window_constraints = _al_win_get_window_constraints;
    vt.apply_window_constraints = _al_win_apply_window_constraints;
diff --git a/src/win/wwindow.c b/src/win/wwindow.c
index 14dcfde8c..ee1634041 100644
--- a/src/win/wwindow.c
+++ b/src/win/wwindow.c
@@ -206,6 +206,10 @@ HWND _al_win_create_window(ALLEGRO_DISPLAY *display, int width, int height, int
       width+lsize+rsize,
       height+tsize+bsize,
       SWP_NOZORDER | SWP_NOMOVE);
+   SetWindowPos(my_window, 0, pos_x-lsize, pos_y-tsize,
+      0, 0,
+      SWP_NOZORDER | SWP_NOSIZE);
+
 
    if (flags & ALLEGRO_FRAMELESS) {
       SetWindowLong(my_window, GWL_STYLE, WS_VISIBLE);
@@ -1192,13 +1196,25 @@ void _al_win_destroy_display_icons(ALLEGRO_DISPLAY *display)
       DestroyIcon(old_icon);
 }
 
+static void get_top_left_border(HWND window, int *left, int *top)
+{
+   WINDOWINFO wi;
+   wi.cbSize = sizeof(WINDOWINFO);
+   GetWindowInfo(window, &wi);
+
+   *left = (wi.rcClient.left - wi.rcWindow.left);
+   *top = (wi.rcClient.top - wi.rcWindow.top);
+}
+
 void _al_win_set_window_position(HWND window, int x, int y)
 {
+   int left, top;
+   get_top_left_border(window, &left, &top);
    SetWindowPos(
       window,
       HWND_TOP,
-      x,
-      y,
+      x - left,
+      y - top,
       0,
       0,
       SWP_NOSIZE | SWP_NOZORDER);
@@ -1207,13 +1223,15 @@ void _al_win_set_window_position(HWND window, int x, int y)
 void _al_win_get_window_position(HWND window, int *x, int *y)
 {
    RECT r;
+   int left, top;
+   get_top_left_border(window, &left, &top);
    GetWindowRect(window, &r);
 
    if (x) {
-      *x = r.left;
+      *x = r.left + left;
    }
    if (y) {
-      *y = r.top;
+      *y = r.top + top;
    }
 }
 
@@ -1465,6 +1483,20 @@ int _al_win_determine_adapter(void)
    return a;
 }
 
+bool _al_win_get_window_borders(ALLEGRO_DISPLAY *display, int *left, int *top, int *right, int *bottom)
+{
+   ALLEGRO_DISPLAY_WIN *win_display = (ALLEGRO_DISPLAY_WIN *)display;
+   WINDOWINFO wi;
+   wi.cbSize = sizeof(WINDOWINFO);
+   GetWindowInfo(win_display->window, &wi);
+
+   if (left) *left = (wi.rcClient.left - wi.rcWindow.left);
+   if (top) *top = (wi.rcClient.top - wi.rcWindow.top);
+   if (right) *right = (wi.rcWindow.right - wi.rcClient.right);
+   if (bottom) *bottom = (wi.rcWindow.bottom - wi.rcClient.bottom);
+   return true;
+}
+
 /* Function: al_win_add_window_callback
  */
 bool al_win_add_window_callback(ALLEGRO_DISPLAY *display,