Add an option single_window_margin_width to allow different margins when only a single window is visible in the layout

Fixes #688

docs/changelog.rst

@@ -19,6 +19,9 @@ Changelog
 
 - Fix pasting large amounts of text very slow (:iss:`682`)
 
+- Add an option :opt:`single_window_margin_width` to allow different margins
+  when only a single window is visible in the layout (:iss:`688`)
+
 - Add a :option:`kitty --hold` command line option to stay open after the child process exits (:iss:`667`)
 
 - diff kitten: When triggering a search scroll to the first match automatically

kitty/config_data.py

@@ -452,6 +452,10 @@ Note that borders are displayed only when more than one window is visible. They
 o('window_margin_width', 0.0, option_type=positive_float, long_text=_('''
 The window margin (in pts) (blank area outside the border)'''))
 
+o('single_window_margin_width', -1000.0, option_type=float, long_text=_('''
+The window margin (in pts) to use when only a single window is visible.
+Negative values will cause the value of :opt:`window_margin_width` to be used instead.'''))
+
 o('window_padding_width', 0.0, option_type=positive_float, long_text=_('''
 The window padding (in pts) (blank area between the text and the window border)'''))
 

kitty/layout.py

@@ -158,13 +158,14 @@ class Layout:  # {{{
     needs_window_borders = True
     only_active_window_visible = False
 
-    def __init__(self, os_window_id, tab_id, margin_width, padding_width, border_width, layout_opts=''):
+    def __init__(self, os_window_id, tab_id, margin_width, single_window_margin_width, padding_width, border_width, layout_opts=''):
         self.os_window_id = os_window_id
         self.tab_id = tab_id
         self.set_active_window_in_os_window = partial(set_active_window, os_window_id, tab_id)
         self.swap_windows_in_os_window = partial(swap_windows, os_window_id, tab_id)
         self.border_width = border_width
         self.margin_width = margin_width
+        self.single_window_margin_width = single_window_margin_width
         self.padding_width = padding_width
         # A set of rectangles corresponding to the blank spaces at the edges of
         # this layout, i.e. spaces that are not covered by any window
@@ -336,7 +337,8 @@ class Layout:  # {{{
 
     # Utils {{{
     def layout_single_window(self, w):
-        wg = layout_single_window(self.margin_width, self.padding_width)
+        mw = self.margin_width if self.single_window_margin_width < 0 else self.single_window_margin_width
+        wg = layout_single_window(mw, self.padding_width)
         w.set_geometry(0, wg)
         self.blank_rects = blank_rects_for_window(w)
 
@@ -373,7 +375,8 @@ class Stack(Layout):  # {{{
     only_active_window_visible = True
 
     def do_layout(self, windows, active_window_idx):
-        wg = layout_single_window(self.margin_width, self.padding_width)
+        mw = self.margin_width if self.single_window_margin_width < 0 else self.single_window_margin_width
+        wg = layout_single_window(mw, self.padding_width)
         for i, w in enumerate(windows):
             w.set_geometry(i, wg)
             if w.is_visible_in_layout:
@@ -671,12 +674,13 @@ class Horizontal(Vertical):
 all_layouts = {o.name: o for o in globals().values() if isinstance(o, type) and issubclass(o, Layout) and o is not Layout}
 
 
-def create_layout_object_for(name, os_window_id, tab_id, margin_width, padding_width, border_width, layout_opts=''):
-    key = name, os_window_id, tab_id, margin_width, padding_width, border_width, layout_opts
+def create_layout_object_for(name, os_window_id, tab_id, margin_width, single_window_margin_width, padding_width, border_width, layout_opts=''):
+    key = name, os_window_id, tab_id, margin_width, single_window_margin_width, padding_width, border_width, layout_opts
     ans = create_layout_object_for.cache.get(key)
     if ans is None:
         name, layout_opts = name.partition(':')[::2]
-        ans = create_layout_object_for.cache[key] = all_layouts[name](os_window_id, tab_id, margin_width, padding_width, border_width, layout_opts)
+        ans = create_layout_object_for.cache[key] = all_layouts[name](
+            os_window_id, tab_id, margin_width, single_window_margin_width, padding_width, border_width, layout_opts)
     return ans
 
 

kitty/tabs.py

@@ -37,8 +37,9 @@ class Tab:  # {{{
         if not self.id:
             raise Exception('No OS window with id {} found, or tab counter has wrapped'.format(self.os_window_id))
         self.opts, self.args = tab_manager.opts, tab_manager.args
-        self.margin_width, self.padding_width = pt_to_px(
-                self.opts.window_margin_width, self.os_window_id), pt_to_px(self.opts.window_padding_width, self.os_window_id)
+        self.margin_width, self.padding_width, self.single_window_margin_width = map(
+            lambda x: pt_to_px(getattr(self.opts, x), self.os_window_id), (
+                'window_margin_width', 'window_padding_width', 'single_window_margin_width'))
         self.name = getattr(session_tab, 'name', '')
         self.enabled_layouts = [x.lower() for x in getattr(session_tab, 'enabled_layouts', None) or self.opts.enabled_layouts]
         self.borders = Borders(self.os_window_id, self.id, self.opts, pt_to_px(self.opts.window_border_width, self.os_window_id), self.padding_width)
@@ -139,7 +140,10 @@ class Tab:  # {{{
                 w.change_titlebar_color()
 
     def create_layout_object(self, name):
-        return create_layout_object_for(name, self.os_window_id, self.id, self.margin_width, self.padding_width, self.borders.border_width)
+        return create_layout_object_for(
+            name, self.os_window_id, self.id, self.margin_width,
+            self.single_window_margin_width, self.padding_width,
+            self.borders.border_width)
 
     def next_layout(self):
         if len(self.enabled_layouts) > 1:

kitty_tests/layout.py

@@ -27,7 +27,7 @@ def create_layout(cls, opts=None, border_width=2):
     if opts is None:
         opts = defaults
     mw, pw = map(pt_to_px, (opts.window_margin_width, opts.window_padding_width))
-    ans = cls(1, 1, mw, pw, border_width)
+    ans = cls(1, 1, mw, mw, pw, border_width)
     ans.set_active_window_in_os_window = lambda idx: None
     ans.swap_windows_in_os_window = lambda a, b: None
     return ans