From 55d011ba7b17d24bc084f4752fe4fce3b114ece8 Mon Sep 17 00:00:00 2001
From: stefan schippers <stefan.schippers@gmail.com>
Date: Sun, 4 Jun 2023 22:54:39 +0200
Subject: [PATCH] added necessary comments in swap_windows() / swap_tabs()
 functions

---
 src/scheduler.c |  2 +-
 src/xinit.c     | 21 ++++++++++++++-------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/scheduler.c b/src/scheduler.c
index f9c3d1d5..32c6a754 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -702,7 +702,7 @@ int xschem(ClientData clientdata, Tcl_Interp *interp, int argc, const char * arg
               }
               if(!xctx->modified || !strcmp(tclresult(), "ok")) {
                 swap_windows();
-                set_modify(0);
+                set_modify(0); /* set modified status to 0 to avoid another confirm in following line */
                 new_schematic("destroy", xctx->current_win_path, NULL);
               }
             } else {
diff --git a/src/xinit.c b/src/xinit.c
index 4b35390d..972c901d 100644
--- a/src/xinit.c
+++ b/src/xinit.c
@@ -1182,7 +1182,8 @@ void preview_window(const char *what, const char *win_path, const char *fname)
   semaphore--;
 }
 
-/* swap primary view (.drw) with first valid tab (x1.drw, x2.drw, ...)  */
+/* swap primary view (.drw) with first valid tab (x1.drw, x2.drw, ...)
+ * used for window close ('xschem exit' command) */
 void swap_tabs(void)
 {
   int wc = window_count;
@@ -1224,11 +1225,13 @@ void swap_tabs(void)
     set_modify(-1);
     xctx = ctx;
     set_modify(-1);
+    /* set context to tab that is about to be deleted */
     new_schematic("switch_tab", save_xctx[j]->current_win_path, NULL);
   }
 }
 
-/* swap primary view (.drw) with first valid tab (x1.drw, x2.drw, ...)  */
+/* swap primary view (.drw) with first valid tab (x1.drw, x2.drw, ...)
+ * used for window close ('xschem exit' command) */
 void swap_windows(void)
 {
   int wc = window_count;
@@ -1258,12 +1261,15 @@ void swap_windows(void)
     }
     dbg(1, "swap_windows(): i=%d, j=%d\n", i, j);
 
-    my_snprintf(wp_i, S(wp_i), "%s", save_xctx[i]->current_win_path);
-    my_snprintf(wp_j, S(wp_j), "%s", save_xctx[j]->current_win_path);
+    my_snprintf(wp_i, S(wp_i), "%s", save_xctx[i]->current_win_path); /* primary (.drw) window */
+    my_snprintf(wp_j, S(wp_j), "%s", save_xctx[j]->current_win_path); /* sub (.x?.drw) window */
 
     mainwindow = Tk_MainWindow(interp);
+    /* get parent of wp_j window, since window manager reparents application windows to a
+     * parent window with title bar and borders. This gives accurate geometry data */
     tkwin = Tk_Parent(Tk_NameToWindow(interp, wp_j, mainwindow));
 
+    /* get sub-window geometry and position. primary window wp_i will be sized and moved there. */
     dbg(1, "swap_windows(): %s: %dx%d+%d+%d\n",
             wp_j, Tk_Width(tkwin), Tk_Height(tkwin), Tk_X(tkwin), Tk_Y(tkwin));
     my_snprintf(geometry, S(geometry), "%dx%d+%d+%d",
@@ -1301,16 +1307,17 @@ void swap_windows(void)
     tclvareval("housekeeping_ctx", NULL);
     tclvareval("xschem build_colors", NULL);
     resetwin(1, 1, 1, 0, 0);
+    /* move primary window to location of deleted window */
+    tclvareval("wm geometry . ", geometry, NULL);
     draw();
     
+    /* set context to window that is about to be deleted */
     tclvareval("restore_ctx ", wp_j, NULL);
     new_schematic("switch_win", wp_j, "");
     tclvareval("housekeeping_ctx", NULL);
     tclvareval("xschem build_colors", NULL);
     resetwin(1, 1, 1, 0, 0);
-    draw();
-    /* move primary window to location of deleted window */
-    tclvareval("wm geometry . ", geometry, NULL);
+    /* draw(); */ /* avoid drawing, since usually this will be destroyed soon after */
   }
 }