patch 8.2.1228: scrollbars not flush against the window edges when maximised

Problem:    Scrollbars not flush against the window edges when maximised.
Solution:   Add padding. (Ken Takata, closes #5602, closes #6466)
diff --git a/src/gui.c b/src/gui.c
index dc408bb..4981d73 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -1418,11 +1418,13 @@
     if (gui.which_scrollbars[SBAR_BOTTOM])
 	gui_mch_set_scrollbar_pos(&gui.bottom_sbar,
 				  text_area_x,
-				  text_area_y + text_area_height,
+				  text_area_y + text_area_height
+					+ gui_mch_get_scrollbar_ypadding(),
 				  text_area_width,
 				  gui.scrollbar_height);
     gui.left_sbar_x = 0;
-    gui.right_sbar_x = text_area_x + text_area_width;
+    gui.right_sbar_x = text_area_x + text_area_width
+					+ gui_mch_get_scrollbar_xpadding();
 
     --hold_gui_events;
 }
diff --git a/src/gui_athena.c b/src/gui_athena.c
index 6a64de5..4384740 100644
--- a/src/gui_athena.c
+++ b/src/gui_athena.c
@@ -1889,6 +1889,22 @@
     XtManageChild(sb->id);
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
     void
 gui_mch_enable_scrollbar(scrollbar_T *sb, int flag)
 {
diff --git a/src/gui_gtk.c b/src/gui_gtk.c
index fa63bf9..aaebf30 100644
--- a/src/gui_gtk.c
+++ b/src/gui_gtk.c
@@ -1008,6 +1008,22 @@
 	gtk_form_move_resize(GTK_FORM(gui.formwin), sb->id, x, y, w, h);
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
 /*
  * Take action upon scrollbar dragging.
  */
diff --git a/src/gui_haiku.cc b/src/gui_haiku.cc
index 78ca7b2..60926f9 100644
--- a/src/gui_haiku.cc
+++ b/src/gui_haiku.cc
@@ -3665,6 +3665,22 @@
     }
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
 void
 gui_mch_create_scrollbar(
 	scrollbar_T *sb,
diff --git a/src/gui_mac.c b/src/gui_mac.c
index 1ca2d56..b190617 100644
--- a/src/gui_mac.c
+++ b/src/gui_mac.c
@@ -4992,6 +4992,22 @@
 #endif
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
     void
 gui_mch_create_scrollbar(
 	scrollbar_T *sb,
diff --git a/src/gui_motif.c b/src/gui_motif.c
index 90c5df9..9d13b57 100644
--- a/src/gui_motif.c
+++ b/src/gui_motif.c
@@ -1743,6 +1743,22 @@
     }
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
     void
 gui_mch_enable_scrollbar(scrollbar_T *sb, int flag)
 {
diff --git a/src/gui_photon.c b/src/gui_photon.c
index 1a7288b..cdb5e15 100644
--- a/src/gui_photon.c
+++ b/src/gui_photon.c
@@ -1758,6 +1758,22 @@
     PtSetResource(sb->id, Pt_ARG_AREA, &area, 0);
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
     void
 gui_mch_create_scrollbar(scrollbar_T *sb, int orient)
 {
diff --git a/src/gui_w32.c b/src/gui_w32.c
index c46cb47..30ce3ea 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -1412,6 +1412,34 @@
 			      SWP_NOZORDER | SWP_NOACTIVATE | SWP_SHOWWINDOW);
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    RECT    rcTxt, rcWnd;
+    int	    xpad;
+
+    GetWindowRect(s_textArea, &rcTxt);
+    GetWindowRect(s_hwnd, &rcWnd);
+    xpad = rcWnd.right - rcTxt.right - gui.scrollbar_width
+	- GetSystemMetrics(SM_CXFRAME)
+	- GetSystemMetrics(SM_CXPADDEDBORDER);
+    return (xpad < 0) ? 0 : xpad;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    RECT    rcTxt, rcWnd;
+    int	    ypad;
+
+    GetWindowRect(s_textArea, &rcTxt);
+    GetWindowRect(s_hwnd, &rcWnd);
+    ypad = rcWnd.bottom - rcTxt.bottom - gui.scrollbar_height
+	- GetSystemMetrics(SM_CYFRAME)
+	- GetSystemMetrics(SM_CXPADDEDBORDER);
+    return (ypad < 0) ? 0 : ypad;
+}
+
     void
 gui_mch_create_scrollbar(
     scrollbar_T *sb,
diff --git a/src/proto/gui_athena.pro b/src/proto/gui_athena.pro
index a834dac..e74128b 100644
--- a/src/proto/gui_athena.pro
+++ b/src/proto/gui_athena.pro
@@ -21,6 +21,8 @@
 void gui_mch_def_colors(void);
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, long val, long size, long max);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_enable_scrollbar(scrollbar_T *sb, int flag);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
diff --git a/src/proto/gui_gtk.pro b/src/proto/gui_gtk.pro
index 319e27d..7b87ba0 100644
--- a/src/proto/gui_gtk.pro
+++ b/src/proto/gui_gtk.pro
@@ -9,6 +9,8 @@
 void gui_mch_destroy_menu(vimmenu_T *menu);
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, long val, long size, long max);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
 char_u *gui_mch_browse(int saving, char_u *title, char_u *dflt, char_u *ext, char_u *initdir, char_u *filter);
diff --git a/src/proto/gui_haiku.pro b/src/proto/gui_haiku.pro
index f392233..51ee93a 100644
--- a/src/proto/gui_haiku.pro
+++ b/src/proto/gui_haiku.pro
@@ -33,6 +33,8 @@
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, int val, int size, int max);
 
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
 
diff --git a/src/proto/gui_mac.pro b/src/proto/gui_mac.pro
index a36ad90..1fa3453 100644
--- a/src/proto/gui_mac.pro
+++ b/src/proto/gui_mac.pro
@@ -36,6 +36,8 @@
 void gui_mch_enable_scrollbar(scrollbar_T *sb, int flag);
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, long val, long size, long max);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
 int gui_mch_adjust_charheight(void);
diff --git a/src/proto/gui_motif.pro b/src/proto/gui_motif.pro
index 493f5e7..ccbdc0a 100644
--- a/src/proto/gui_motif.pro
+++ b/src/proto/gui_motif.pro
@@ -23,6 +23,8 @@
 void gui_mch_def_colors(void);
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, long val, long size, long max);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_enable_scrollbar(scrollbar_T *sb, int flag);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
diff --git a/src/proto/gui_photon.pro b/src/proto/gui_photon.pro
index 9fcc512..5fcc9ba 100644
--- a/src/proto/gui_photon.pro
+++ b/src/proto/gui_photon.pro
@@ -18,6 +18,8 @@
 void gui_mch_settitle(char_u *title, char_u *icon);
 void gui_mch_set_scrollbar_thumb(scrollbar_T *sb, int val, int size, int max);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 void gui_mch_enable_scrollbar(scrollbar_T *sb, int flag);
 void gui_mch_destroy_scrollbar(scrollbar_T *sb);
diff --git a/src/proto/gui_w32.pro b/src/proto/gui_w32.pro
index 4ead92e..68e45b3 100644
--- a/src/proto/gui_w32.pro
+++ b/src/proto/gui_w32.pro
@@ -14,6 +14,8 @@
 void gui_mch_set_text_area_pos(int x, int y, int w, int h);
 void gui_mch_enable_scrollbar(scrollbar_T *sb, int flag);
 void gui_mch_set_scrollbar_pos(scrollbar_T *sb, int x, int y, int w, int h);
+int gui_mch_get_scrollbar_xpadding(void);
+int gui_mch_get_scrollbar_ypadding(void);
 void gui_mch_create_scrollbar(scrollbar_T *sb, int orient);
 int gui_mch_adjust_charheight(void);
 GuiFont gui_mch_get_font(char_u *name, int giveErrorIfMissing);
diff --git a/src/version.c b/src/version.c
index d585377..388cd16 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1228,
+/**/
     1227,
 /**/
     1226,