launch: Allow setting the margin and padding for the newly created window

Fixes #5463

docs/changelog.rst

@@ -42,6 +42,8 @@ Detailed list of changes
 
 - Fix regression in 0.26.0 that caused launching kitty without working STDIO handles to result in high CPU usage and prewarming failing (:iss:`5444`)
 
+- :doc:`/launch`: Allow setting the margin and padding for the newly created window (:iss:`5463`)
+
 - macOS: Fix regression in 0.26.0 that caused asking the user for a line of input such as for :ac:`set_tab_title` to not work (:iss:`5447`)
 
 - hints kitten: hyperlink matching: Fix hints occasionally matching text on subsequent line as part of hyperlink (:pull:`5450`)

kitty/launch.py

@@ -278,6 +278,14 @@ from, or specify them individually, for example::
     --color background=white --color foreground=red
 
 
+--spacing
+type=list
+Set the margin and padding for the newly created window.
+For example: :code:`margin=20` or :code:`padding-left=10` or :code:`margin-h=30`. The shorthand form sets
+all values, the :code:`*-h` and :code:`*-v` variants set horizontal and vertical values.
+Can be specified multiple times.
+
+
 --watcher -w
 type=list
 completion=type:file ext:py relative:conf group:"Python scripts"
@@ -457,6 +465,10 @@ def launch(
         'overlay_for': None,
         'stdin': None
     }
+    spacing = {}
+    if opts.spacing:
+        from .rc.set_spacing import parse_spacing_settings, patch_window_edges
+        spacing = parse_spacing_settings(opts.spacing)
     if opts.cwd:
         if opts.cwd == 'current':
             if active:
@@ -552,6 +564,9 @@ def launch(
         if tab is not None:
             watchers = load_watch_modules(opts.watcher)
             new_window: Window = tab.new_window(env=env or None, watchers=watchers or None, is_clone_launch=is_clone_launch, **kw)
+            if spacing:
+                patch_window_edges(new_window, spacing)
+                tab.relayout()
             if opts.color:
                 apply_colors(new_window, opts.color)
             if opts.keep_focus and active:

kitty/rc/launch.py

@@ -41,6 +41,7 @@ class Launch(RemoteCommand):
         @first_cmd_output_on_screen.@last_cmd_output.@last_visited_cmd_output: Where to get stdin for the process from
     stdin_add_formatting/bool: Boolean indicating whether to add formatting codes to stdin
     stdin_add_line_wrap_markers/bool: Boolean indicating whether to add line wrap markers to stdin
+    spacing/list.str: A list of spacing specifications, see the docs for the set-spacing command
     no_response/bool: Boolean indicating whether to send back the window id
     marker/str: Specification for marker for new window, for example: "text 1 ERROR"
     logo/str: Path to window logo

kitty/rc/set_spacing.py

@@ -2,7 +2,7 @@
 # License: GPLv3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from typing import TYPE_CHECKING, Dict, Optional, List
+from typing import TYPE_CHECKING, Dict, Iterable, List, Optional
 
 from .base import (
     MATCH_TAB_OPTION, MATCH_WINDOW_OPTION, ArgsType, Boss, PayloadGetType,
@@ -37,6 +37,34 @@ def patch_configured_edges(opts: 'Options', s: Dict[str, Optional[float]]) -> No
         setattr(opts, q, new_edges)
 
 
+def parse_spacing_settings(args: Iterable[str]) -> Dict[str, Optional[float]]:
+    mapper: Dict[str, List[str]] = {}
+    for q in ('margin', 'padding'):
+        mapper[q] = f'{q}-left {q}-top {q}-right {q}-bottom'.split()
+        mapper[f'{q}-h'] = mapper[f'{q}-horizontal'] = f'{q}-left {q}-right'.split()
+        mapper[f'{q}-v'] = mapper[f'{q}-vertical'] = f'{q}-top {q}-bottom'.split()
+        for edge in ('left', 'top', 'right', 'bottom'):
+            mapper[f'{q}-{edge}'] = [f'{q}-{edge}']
+    settings: Dict[str, Optional[float]] = {}
+    for spec in args:
+        parts = spec.split('=', 1)
+        if len(parts) != 2:
+            raise ValueError(f'{spec} is not a valid setting')
+        which = mapper.get(parts[0].lower())
+        if not which:
+            raise ValueError(f'{parts[0]} is not a valid edge specification')
+        if parts[1].lower() == 'default':
+            val = None
+        else:
+            try:
+                val = float(parts[1])
+            except Exception:
+                raise ValueError(f'{parts[1]} is not a number')
+        for q in which:
+            settings[q] = val
+    return settings
+
+
 class SetSpacing(RemoteCommand):
 
     '''
@@ -70,32 +98,12 @@ windows).
     argspec = 'MARGIN_OR_PADDING ...'
 
     def message_to_kitty(self, global_opts: RCOptions, opts: 'CLIOptions', args: ArgsType) -> PayloadType:
-        settings: Dict[str, Optional[float]] = {}
-        mapper: Dict[str, List[str]] = {}
-        for q in ('margin', 'padding'):
-            mapper[q] = f'{q}-left {q}-top {q}-right {q}-bottom'.split()
-            mapper[f'{q}-h'] = mapper[f'{q}-horizontal'] = f'{q}-left {q}-right'.split()
-            mapper[f'{q}-v'] = mapper[f'{q}-vertical'] = f'{q}-top {q}-bottom'.split()
-            for edge in ('left', 'top', 'right', 'bottom'):
-                mapper[f'{q}-{edge}'] = [f'{q}-{edge}']
         if not args:
             self.fatal('At least one setting must be specified')
-        for spec in args:
-            parts = spec.split('=', 1)
-            if len(parts) != 2:
-                self.fatal(f'{spec} is not a valid setting')
-            which = mapper.get(parts[0].lower())
-            if not which:
-                self.fatal(f'{parts[0]} is not a valid edge specification')
-            if parts[1].lower() == 'default':
-                val = None
-            else:
-                try:
-                    val = float(parts[1])
-                except Exception:
-                    self.fatal(f'{parts[1]} is not a number')
-            for q in which:
-                settings[q] = val
+        try:
+            settings = parse_spacing_settings(args)
+        except Exception as e:
+            self.fatal(str(e))
         ans = {
             'match_window': opts.match, 'match_tab': opts.match_tab,
             'all': opts.all, 'configured': opts.configured,