A new option narrow_symbols to turn off opportunistic wide rendering of private use codepoints

docs/changelog.rst

@@ -88,6 +88,8 @@ Detailed list of changes
 
 - Improve CWD detection when there are multiple foreground processes in the TTY process group
 
+- A new option :opt:`narrow_symbols` to turn off opportunistic wide rendering of private use codepoints
+
 - ssh kitten: Fix location of generated terminfo files on NetBSD (:iss:`4622`)
 
 - A new action to clear the screen up to the line containing the cursor, see

docs/faq.rst

@@ -6,21 +6,22 @@ Frequently Asked Questions
 Some special symbols are rendered small/truncated in kitty?
 -----------------------------------------------------------
 
-The number of cells a unicode character takes up are controlled by the unicode
-standard.  All characters are rendered in a single cell unless the unicode
+The number of cells a Unicode character takes up are controlled by the Unicode
+standard. All characters are rendered in a single cell unless the Unicode
 standard says they should be rendered in two cells. When a symbol does not fit,
 it will either be rescaled to be smaller or truncated (depending on how much
 extra space it needs). This is often different from other terminals which just
 let the character overflow into neighboring cells, which is fine if the
 neighboring cell is empty, but looks terrible if it is not.
 
-Some programs, like powerline, vim with fancy gutter symbols/status-bar, etc.
-misuse unicode characters from the private use area to represent symbols. Often
-these symbols are square and should be rendered in two cells.  However, since
-private use area symbols all have their width set to one in the unicode
+Some programs, like Powerline, vim with fancy gutter symbols/status-bar, etc.
+use Unicode characters from the private use area to represent symbols. Often
+these symbols are wide and should be rendered in two cells. However, since
+private use area symbols all have their width set to one in the Unicode
 standard, |kitty| renders them either smaller or truncated. The exception is if
 these characters are followed by a space or empty cell in which case kitty
-makes use of the extra cell to render them in two cells.
+makes use of the extra cell to render them in two cells. This behavior can be
+turned off for specific symbols using :opt:`narrow_symbols`.
 
 
 Using a color theme with a background color does not work well in vim?

kitty/fast_data_types.pyi

@@ -967,7 +967,8 @@ def set_font_data(
     descriptor_for_idx: Callable[[int], Tuple[FontObject, bool, bool]],
     bold: int, italic: int, bold_italic: int, num_symbol_fonts: int,
     symbol_maps: Tuple[Tuple[int, int, int], ...], font_sz_in_pts: float,
-    font_feature_settings: Dict[str, Tuple[FontFeature, ...]]
+    font_feature_settings: Dict[str, Tuple[FontFeature, ...]],
+    narrow_symbols: Tuple[Tuple[int, int, int], ...],
 ) -> None:
     pass
 

kitty/fonts.c

@@ -50,8 +50,8 @@ typedef struct {
     size_t font_idx;
 } SymbolMap;
 
-static SymbolMap *symbol_maps = NULL;
-static size_t num_symbol_maps = 0;
+static SymbolMap *symbol_maps = NULL, *narrow_symbols = NULL;
+static size_t num_symbol_maps = 0, num_narrow_symbols = 0;
 
 typedef enum { SPACER_STRATEGY_UNKNOWN, SPACERS_BEFORE, SPACERS_AFTER, SPACERS_IOSEVKA } SpacerStrategy;
 
@@ -1219,6 +1219,17 @@ is_non_emoji_dingbat(char_type ch) {
     return false;
 }
 
+static unsigned int
+cell_cap_for_codepoint(const char_type cp) {
+    unsigned int ans = UINT_MAX;
+    for (size_t i = 0; i < num_narrow_symbols; i++) {
+        SymbolMap *sm = narrow_symbols + i;
+        if (sm->left <= cp && cp <= sm->right) ans = sm->font_idx;
+    }
+    return ans;
+}
+
+
 void
 render_line(FONTS_DATA_HANDLE fg_, Line *line, index_type lnum, Cursor *cursor, DisableLigature disable_ligature_strategy) {
 #define RENDER if (run_font_idx != NO_FONT && i > first_cell_in_run) { \
@@ -1251,6 +1262,7 @@ render_line(FONTS_DATA_HANDLE fg_, Line *line, index_type lnum, Cursor *cursor,
                 int width = get_glyph_width(font->face, glyph_id);
                 desired_cells = (unsigned int)ceilf((float)width / fg->cell_width);
             }
+            desired_cells = MIN(desired_cells, cell_cap_for_codepoint(cpu_cell->ch));
 
             unsigned int num_spaces = 0;
             while (
@@ -1303,6 +1315,7 @@ render_simple_text(FONTS_DATA_HANDLE fg_, const char *text) {
 static void
 clear_symbol_maps(void) {
     if (symbol_maps) { free(symbol_maps); symbol_maps = NULL; num_symbol_maps = 0; }
+    if (narrow_symbols) { free(narrow_symbols); narrow_symbols = NULL; num_narrow_symbols = 0; }
 }
 
 typedef struct {
@@ -1311,26 +1324,33 @@ typedef struct {
 
 DescriptorIndices descriptor_indices = {0};
 
-static PyObject*
-set_font_data(PyObject UNUSED *m, PyObject *args) {
-    PyObject *sm;
-    Py_CLEAR(box_drawing_function); Py_CLEAR(prerender_function); Py_CLEAR(descriptor_for_idx); Py_CLEAR(font_feature_settings);
-    if (!PyArg_ParseTuple(args, "OOOIIIIO!dO",
-                &box_drawing_function, &prerender_function, &descriptor_for_idx,
-                &descriptor_indices.bold, &descriptor_indices.italic, &descriptor_indices.bi, &descriptor_indices.num_symbol_fonts,
-                &PyTuple_Type, &sm, &OPT(font_size), &font_feature_settings)) return NULL;
-    Py_INCREF(box_drawing_function); Py_INCREF(prerender_function); Py_INCREF(descriptor_for_idx); Py_INCREF(font_feature_settings);
-    free_font_groups();
-    clear_symbol_maps();
-    num_symbol_maps = PyTuple_GET_SIZE(sm);
-    symbol_maps = calloc(num_symbol_maps, sizeof(SymbolMap));
-    if (symbol_maps == NULL) return PyErr_NoMemory();
-    for (size_t s = 0; s < num_symbol_maps; s++) {
+static bool
+set_symbol_maps(SymbolMap **symbol_maps, size_t *num_symbol_maps, const PyObject *sm) {
+    *num_symbol_maps = PyTuple_GET_SIZE(sm);
+    *symbol_maps = calloc(*num_symbol_maps, sizeof(SymbolMap));
+    if (*symbol_maps == NULL) { PyErr_NoMemory(); return false; }
+    for (size_t s = 0; s < *num_symbol_maps; s++) {
         unsigned int left, right, font_idx;
-        SymbolMap *x = symbol_maps + s;
+        SymbolMap *x = *symbol_maps + s;
         if (!PyArg_ParseTuple(PyTuple_GET_ITEM(sm, s), "III", &left, &right, &font_idx)) return NULL;
         x->left = left; x->right = right; x->font_idx = font_idx;
     }
+    return true;
+}
+
+static PyObject*
+set_font_data(PyObject UNUSED *m, PyObject *args) {
+    PyObject *sm, *ns;
+    Py_CLEAR(box_drawing_function); Py_CLEAR(prerender_function); Py_CLEAR(descriptor_for_idx); Py_CLEAR(font_feature_settings);
+    if (!PyArg_ParseTuple(args, "OOOIIIIO!dOO!",
+                &box_drawing_function, &prerender_function, &descriptor_for_idx,
+                &descriptor_indices.bold, &descriptor_indices.italic, &descriptor_indices.bi, &descriptor_indices.num_symbol_fonts,
+                &PyTuple_Type, &sm, &OPT(font_size), &font_feature_settings, &PyTuple_Type, &ns)) return NULL;
+    Py_INCREF(box_drawing_function); Py_INCREF(prerender_function); Py_INCREF(descriptor_for_idx); Py_INCREF(font_feature_settings);
+    free_font_groups();
+    clear_symbol_maps();
+    set_symbol_maps(&symbol_maps, &num_symbol_maps, sm);
+    set_symbol_maps(&narrow_symbols, &num_narrow_symbols, ns);
     Py_RETURN_NONE;
 }
 

kitty/fonts/render.py

@@ -21,6 +21,7 @@ from kitty.fonts.box_drawing import (
 )
 from kitty.options.types import Options, defaults
 from kitty.typing import CoreTextFont, FontConfigPattern
+from kitty.types import _T
 from kitty.utils import log_error
 
 if is_macos:
@@ -50,10 +51,9 @@ def font_for_family(family: str) -> Tuple[FontObject, bool, bool]:
     return font_for_family_fontconfig(family)
 
 
-Range = Tuple[Tuple[int, int], str]
-
-
-def merge_ranges(a: Range, b: Range, priority_map: Dict[Tuple[int, int], int]) -> Generator[Range, None, None]:
+def merge_ranges(
+    a: Tuple[Tuple[int, int], _T], b: Tuple[Tuple[int, int], _T], priority_map: Dict[Tuple[int, int], int]
+) -> Generator[Tuple[Tuple[int, int], _T], None, None]:
     a_start, a_end = a[0]
     b_start, b_end = b[0]
     a_val, b_val = a[1], b[1]
@@ -95,7 +95,7 @@ def merge_ranges(a: Range, b: Range, priority_map: Dict[Tuple[int, int], int]) -
             after_range = ((b_end + 1, a_end), a_val)
             after_range_prio = a_prio
     # check if the before, mid and after ranges can be coalesced
-    ranges: List[Range] = []
+    ranges: List[Tuple[Tuple[int, int], _T]] = []
     priorities: List[int] = []
     for rq, prio in ((before_range, before_range_prio), (mid_range, mid_range_prio), (after_range, after_range_prio)):
         if rq is None:
@@ -117,7 +117,7 @@ def merge_ranges(a: Range, b: Range, priority_map: Dict[Tuple[int, int], int]) -
     yield from ranges
 
 
-def coalesce_symbol_maps(maps: Dict[Tuple[int, int], str]) -> Dict[Tuple[int, int], str]:
+def coalesce_symbol_maps(maps: Dict[Tuple[int, int], _T]) -> Dict[Tuple[int, int], _T]:
     if not maps:
         return maps
     priority_map = {r: i for i, r in enumerate(maps.keys())}
@@ -155,6 +155,10 @@ def create_symbol_map(opts: Options) -> Tuple[Tuple[int, int, int], ...]:
     return sm
 
 
+def create_narrow_symbols(opts: Options) -> Tuple[Tuple[int, int, int], ...]:
+    return tuple((a, b, v) for (a, b), v in coalesce_symbol_maps(opts.narrow_symbols).items())
+
+
 def descriptor_for_idx(idx: int) -> Tuple[FontObject, bool, bool]:
     return current_faces[idx]
 
@@ -193,6 +197,7 @@ def set_font_family(opts: Optional[Options] = None, override_font_size: Optional
             current_faces.append((font_map[k], 'b' in k, 'i' in k))
     before = len(current_faces)
     sm = create_symbol_map(opts)
+    ns = create_narrow_symbols(opts)
     num_symbol_fonts = len(current_faces) - before
     font_features = {}
     for face, _, _ in current_faces:
@@ -203,7 +208,7 @@ def set_font_family(opts: Optional[Options] = None, override_font_size: Optional
     set_font_data(
         render_box_drawing, prerender_function, descriptor_for_idx,
         indices['bold'], indices['italic'], indices['bi'], num_symbol_fonts,
-        sm, sz, font_features
+        sm, sz, font_features, ns
     )
 
 

kitty/options/definition.py

@@ -124,6 +124,22 @@ Syntax is::
 '''
     )
 
+opt('+narrow_symbols', 'U+E0A0-U+E0A3,U+E0C0-U+E0C7 1',
+    option_type='narrow_symbols',
+    add_to_default=False,
+    long_text='''
+Usually, for Private Use Unicode characters and some symbol/dingbat characters,
+if the character is followed by one or more spaces, kitty will use those extra cells
+to render the character larger, if the character in the font has a wide aspect ratio.
+Using this setting you can force kitty to restrict the specified code points to render in
+the specified number of cells (defaulting to one cell).
+Syntax is::
+
+    narrow_symbols codepoints Optionally the number of cells
+'''
+    )
+
+
 opt('disable_ligatures', 'never',
     option_type='disable_ligatures', ctype='int',
     long_text='''

kitty/options/parse.py

@@ -11,12 +11,12 @@ from kitty.options.utils import (
     clipboard_control, config_or_absolute_path, copy_on_select, cursor_text_color,
     deprecated_hide_window_decorations_aliases, deprecated_macos_show_window_title_in_menubar_alias,
     deprecated_send_text, disable_ligatures, edge_width, env, font_features, hide_window_decorations,
-    macos_option_as_alt, macos_titlebar_color, optional_edge_width, parse_map, parse_mouse_map,
-    resize_draw_strategy, scrollback_lines, scrollback_pager_history_size, shell_integration,
-    store_multiple, symbol_map, tab_activity_symbol, tab_bar_edge, tab_bar_margin_height,
-    tab_bar_min_tabs, tab_fade, tab_font_style, tab_separator, tab_title_template, titlebar_color,
-    to_cursor_shape, to_font_size, to_layout_names, to_modifiers, url_prefixes, url_style,
-    visual_window_select_characters, window_border_width, window_size
+    macos_option_as_alt, macos_titlebar_color, narrow_symbols, optional_edge_width, parse_map,
+    parse_mouse_map, resize_draw_strategy, scrollback_lines, scrollback_pager_history_size,
+    shell_integration, store_multiple, symbol_map, tab_activity_symbol, tab_bar_edge,
+    tab_bar_margin_height, tab_bar_min_tabs, tab_fade, tab_font_style, tab_separator,
+    tab_title_template, titlebar_color, to_cursor_shape, to_font_size, to_layout_names, to_modifiers,
+    url_prefixes, url_style, visual_window_select_characters, window_border_width, window_size
 )
 
 
@@ -1079,6 +1079,10 @@ class Parser:
     def mouse_hide_wait(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['mouse_hide_wait'] = float(val)
 
+    def narrow_symbols(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
+        for k, v in narrow_symbols(val):
+            ans["narrow_symbols"][k] = v
+
     def open_url_with(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['open_url_with'] = to_cmdline(val)
 
@@ -1331,6 +1335,7 @@ def create_result_dict() -> typing.Dict[str, typing.Any]:
         'exe_search_path': {},
         'font_features': {},
         'kitten_alias': {},
+        'narrow_symbols': {},
         'symbol_map': {},
         'watcher': {},
         'map': [],

kitty/options/types.py

@@ -387,6 +387,7 @@ option_names = (  # {{{
  'mark3_foreground',
  'mouse_hide_wait',
  'mouse_map',
+ 'narrow_symbols',
  'open_url_with',
  'placement_strategy',
  'pointer_shape_when_dragging',
@@ -594,6 +595,7 @@ class Options:
     exe_search_path: typing.Dict[str, str] = {}
     font_features: typing.Dict[str, typing.Tuple[kitty.fonts.FontFeature, ...]] = {}
     kitten_alias: typing.Dict[str, str] = {}
+    narrow_symbols: typing.Dict[typing.Tuple[int, int], int] = {}
     symbol_map: typing.Dict[typing.Tuple[int, int], str] = {}
     watcher: typing.Dict[str, str] = {}
     map: typing.List[kitty.options.utils.KeyDefinition] = []
@@ -712,6 +714,7 @@ defaults.env = {}
 defaults.exe_search_path = {}
 defaults.font_features = {}
 defaults.kitten_alias = {}
+defaults.narrow_symbols = {}
 defaults.symbol_map = {}
 defaults.watcher = {}
 defaults.map = [

kitty/options/utils.py

@@ -818,19 +818,19 @@ def action_alias(val: str) -> Iterable[Tuple[str, str]]:
 kitten_alias = action_alias
 
 
-def symbol_map(val: str) -> Iterable[Tuple[Tuple[int, int], str]]:
+def symbol_map(val: str, min_size: int = 2) -> Iterable[Tuple[Tuple[int, int], str]]:
     parts = val.split()
 
     def abort() -> None:
         log_error(f'Symbol map: {val} is invalid, ignoring')
 
-    if len(parts) < 2:
+    if len(parts) < min_size:
         return abort()
     family = ' '.join(parts[1:])
 
     def to_chr(x: str) -> int:
         if not x.startswith('U+'):
-            raise ValueError()
+            raise ValueError(f'{x} is not a unicode codepoint of the form U+number')
         return int(x[2:], 16)
 
     for x in parts[0].split(','):
@@ -845,6 +845,11 @@ def symbol_map(val: str) -> Iterable[Tuple[Tuple[int, int], str]]:
         yield (a, b), family
 
 
+def narrow_symbols(val: str) -> Iterable[Tuple[Tuple[int, int], int]]:
+    for x, y in symbol_map(val, min_size=1):
+        yield x, int(y or 1)
+
+
 def parse_key_action(action: str, action_type: str = 'map') -> KeyAction:
     parts = action.strip().split(maxsplit=1)
     func = parts[0]