Allow changing margings/padding via remote control

Fixes #2546

docs/changelog.rst

@@ -8,7 +8,8 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 -----------------
 
 - Allow individually setting margins and padding for each edge (left, right,
-  top, bottom)
+  top, bottom). Margins can also be controlled per window via remote control
+  (:iss:`2546`)
 
 - Fix reverse video not being rendered correctly when using transparency or a
   background image (:iss:`2419`)

kitty/rc/set_spacing.py

@@ -0,0 +1,124 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPLv3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+from typing import TYPE_CHECKING, Dict, Optional, List
+
+from .base import (
+    MATCH_TAB_OPTION, MATCH_WINDOW_OPTION, ArgsType, Boss, PayloadGetType,
+    PayloadType, RCOptions, RemoteCommand, ResponseType, Window
+)
+
+if TYPE_CHECKING:
+    from kitty.cli_stub import SetSpacingRCOptions as CLIOptions
+    from kitty.options_stub import Options
+
+
+def patch_window_edges(w: Window, s: Dict[str, Optional[float]]) -> None:
+    for k, v in s.items():
+        which, edge = k.lower().split('-', 1)
+        if edge == 'left':
+            w.patch_edge_width(which, 'left', v)
+        elif edge == 'right':
+            w.patch_edge_width(which, 'right', v)
+        elif edge == 'top':
+            w.patch_edge_width(which, 'top', v)
+        elif edge == 'bottom':
+            w.patch_edge_width(which, 'bottom', v)
+
+
+def patch_configured_edges(opts: 'Options', s: Dict[str, Optional[float]]) -> None:
+    for k, val in s.items():
+        if val is None:
+            continue
+        which, edge = k.lower().split('-', 1)
+        q = f'window_{which}_width'
+        new_edges = getattr(opts, q)._replace(**{edge: val})
+        setattr(opts, q, new_edges)
+
+
+class SetSpacing(RemoteCommand):
+
+    '''
+    settings+: An object mapping margins/paddings using canonical form {'margin-top': 50, 'padding-left': null} etc
+    match_window: Window to change colors in
+    match_tab: Tab to change colors in
+    all: Boolean indicating change colors everywhere or not
+    configured: Boolean indicating whether to change the configured colors. Must be True if reset is True
+    '''
+
+    short_desc = 'Set window padding and margins'
+    desc = (
+        'Set the padding and margins for the specified windows (defaults to active window).'
+        ' For example: margin=20 or padding-left=10 or margin-h=30. The shorthand form sets'
+        ' all values, the *-h and *-v variants set horizontal and vertical values.'
+        ' The special value "default" resets to using the default value.'
+        ' If you specify a tab rather than a window, all windows in that tab are affected.'
+    )
+    options_spec = '''\
+--all -a
+type=bool-set
+By default, settings are only changed for the currently active window. This option will
+cause colors to be changed in all windows.
+
+
+--configured -c
+type=bool-set
+Also change the configured padding and margins (i.e. the settings kitty will use for new
+windows).
+''' + '\n\n' + MATCH_WINDOW_OPTION + '\n\n' + MATCH_TAB_OPTION.replace('--match -m', '--match-tab -t')
+    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
+        ans = {
+            'match_window': opts.match, 'match_tab': opts.match_tab,
+            'all': opts.all, 'configured': opts.configured,
+            'settings': settings
+        }
+        return ans
+
+    def response_from_kitty(self, boss: Boss, window: Optional[Window], payload_get: PayloadGetType) -> ResponseType:
+        windows = self.windows_for_payload(boss, window, payload_get)
+        settings: Dict[str, Optional[float]] = payload_get('settings')
+        dirtied_tabs = {}
+        if payload_get('configured'):
+            patch_configured_edges(boss.opts, settings)
+
+        for w in windows:
+            patch_window_edges(w, settings)
+            tab = w.tabref()
+            if tab is not None:
+                dirtied_tabs[tab.id] = tab
+
+        for tab in dirtied_tabs.values():
+            tab.relayout()
+
+
+set_spacing = SetSpacing()