Implement fallback fonts in CoreText

kitty/core_text.m

@@ -105,16 +105,40 @@ coretext_all_fonts(PyObject UNUSED *_self) {
     return ans;
 }
 
-static PyObject*
-face_for_text(PyObject UNUSED *self, PyObject UNUSED *args) {
-    Py_RETURN_NONE;  // TODO: Implement this
-}
-
 static void
 free_font(void *f) {
     CFRelease((CTFontRef)f);
 }
 
+static inline PyObject*
+ft_face(CTFontRef font, float pt_sz, float xdpi, float ydpi) {
+    const char *psname = convert_cfstring(CTFontCopyPostScriptName(font), 1);
+    NSURL *url = (NSURL*)CTFontCopyAttribute(font, kCTFontURLAttribute);
+    PyObject *path = PyUnicode_FromString([[url path] UTF8String]);
+    [url release];
+    if (path == NULL) { CFRelease(font); return NULL; }
+    PyObject *ans =  ft_face_from_path_and_psname(path, psname, (void*)font, free_font, true, 3, pt_sz, xdpi, ydpi, CTFontGetLeading(font));
+    Py_DECREF(path);
+    if (ans == NULL) { CFRelease(font); }
+    return ans;
+}
+
+static PyObject*
+face_for_text(PyObject UNUSED *self, PyObject UNUSED *args) {
+    char *text;
+    PyObject *lp;
+    float pt_sz, xdpi, ydpi;
+    int bold, italic;
+    if (!PyArg_ParseTuple(args, "sO!fffpp", &text, &PyLong_Type, &lp, &pt_sz, &xdpi, &ydpi, &bold, &italic)) return NULL;
+    CTFontRef font = PyLong_AsVoidPtr(lp);
+    CFStringRef str = CFStringCreateWithCString(NULL, text, kCFStringEncodingUTF8);
+    if (str == NULL) return PyErr_NoMemory();
+    CFRange range = CFRangeMake(0, CFStringGetLength(str));
+    CTFontRef new_font = CTFontCreateForString(font, str, range);
+    if (new_font == NULL) { PyErr_SetString(PyExc_ValueError, "Failed to find fallback CTFont"); CFRelease(str); return NULL; }
+    return ft_face(new_font, pt_sz, xdpi, ydpi);
+}
+
 static PyObject*
 create_face(PyObject UNUSED *self, PyObject *args) {
     PyObject *descriptor;
@@ -127,15 +151,7 @@ create_face(PyObject UNUSED *self, PyObject *args) {
     CTFontRef font = CTFontCreateWithFontDescriptor(desc, scaled_point_sz, NULL);
     CFRelease(desc); desc = NULL;
     if (!font) { PyErr_SetString(PyExc_ValueError, "Failed to create CTFont object"); return NULL; }
-    const char *psname = convert_cfstring(CTFontCopyPostScriptName(font), 1);
-    NSURL *url = (NSURL*)CTFontCopyAttribute(font, kCTFontURLAttribute);
-    PyObject *path = PyUnicode_FromString([[url path] UTF8String]);
-    [url release];
-    if (path == NULL) { CFRelease(font); return NULL; }
-    PyObject *ans =  ft_face_from_path_and_psname(path, psname, (void*)font, free_font, true, 3, point_sz, xdpi, ydpi, CTFontGetLeading(font));
-    Py_DECREF(path);
-    if (ans == NULL) { CFRelease(font); }
-    return ans;
+    return ft_face(font, point_sz, xdpi, ydpi);
 }
 
 // Boilerplate {{{

kitty/fonts.c

@@ -224,6 +224,7 @@ update_cell_metrics(float pt_sz, float xdpi, float ydpi) {
     if (cell_height > 1000) { PyErr_SetString(PyExc_ValueError, "line height too large after adjustment"); return NULL; }
     underline_position = MIN(cell_height - 1, underline_position);
     sprite_tracker_set_layout(cell_width, cell_height);
+    global_state.cell_width = cell_width; global_state.cell_height = cell_height;
     free(canvas); canvas = malloc(CELLS_IN_CANVAS * cell_width * cell_height);
     if (canvas == NULL) return PyErr_NoMemory();
     return Py_BuildValue("IIIII", cell_width, cell_height, baseline, underline_position, underline_thickness);

kitty/fonts/core_text.py

@@ -117,7 +117,7 @@ def get_font_files(opts):
     return ans
 
 
-def face_from_font(font, pt_sz, xdpi, ydpi):
+def face_from_font(font, pt_sz=11.0, xdpi=72.0, ydpi=72.0):
     return get_face(font.resolved_family, pt_sz, xdpi, ydpi, bold=font.bold, italic=font.italic)
 
 
@@ -126,7 +126,7 @@ def save_medium_face(face):
 
 
 def font_for_text(text, current_font_family, pt_sz, xdpi, ydpi, bold=False, italic=False):
-    return face_for_text(text, pt_sz, xdpi, ydpi, bold, italic)
+    return face_for_text(text, save_medium_face.face.extra_data(), pt_sz, xdpi, ydpi, bold, italic)
 
 
 def font_for_family(family):
@@ -143,10 +143,9 @@ def test_font_matching(
 
 
 def test_family_matching(name='Menlo', dpi=72.0, font_size=11.0):
-    all_fonts = create_font_map(coretext_all_fonts())
     for bold in (False, True):
         for italic in (False, True):
             face = get_face(
-                all_fonts, name, 'Menlo', font_size, dpi, dpi, bold, italic
+                name, font_size, dpi, dpi, bold, italic
             )
             print(bold, italic, face)

kitty/fonts/fontconfig.py

@@ -102,4 +102,7 @@ def font_for_family(family):
 
 
 def font_for_text(text, current_font_family='monospace', pt_sz=11.0, xdpi=96.0, ydpi=96.0, bold=False, italic=False):
-    return fc_match('monospace', bold, italic, False, pt_sz, str(text), (xdpi + ydpi) / 2.0)
+    ans = fc_match('monospace', bold, italic, False, pt_sz, str(text), (xdpi + ydpi) / 2.0)
+    if ans is not None:
+        ans = face_from_font(ans, pt_sz, xdpi, ydpi)
+    return ans

kitty/fonts/render.py

@@ -10,7 +10,7 @@ from math import ceil, floor, pi, sin, sqrt
 from kitty.config import defaults
 from kitty.constants import isosx
 from kitty.fast_data_types import (
-    Screen, send_prerendered_sprites, set_font, set_font_size,
+    Screen, change_wcwidth, send_prerendered_sprites, set_font, set_font_size,
     set_send_sprite_to_gpu, sprite_map_set_limits, test_render_line
 )
 from kitty.fonts.box_drawing import render_box_char, render_missing_glyph
@@ -49,11 +49,10 @@ FontState = namedtuple(
 
 def get_fallback_font(text, bold, italic):
     state = set_font_family.state
-    font = font_for_text(
+    return font_for_text(
             text, state.family, state.pt_sz, state.xdpi, state.ydpi, bold,
             italic
         )
-    return None if font is None else create_face(font)
 
 
 def set_font_family(opts=None, override_font_size=None, override_dpi=None):
@@ -230,8 +229,20 @@ def test_render_string(text='Hello, world!', family='monospace', size=144.0, dpi
     print('\n')
 
 
+def test_fallback_font(qtext=None, bold=False, italic=False):
+    set_font_family(override_dpi=(96.0, 96.0))
+    for text in (qtext, '你好', 'He\u0347\u0305', '\U0001F929'):
+        if text:
+            f = get_fallback_font(text, bold, italic)
+            try:
+                print(text, f)
+            except UnicodeEncodeError:
+                sys.stdout.buffer.write((text + ' %s\n' % f).encode('utf-8'))
+
+
 def showcase():
+    change_wcwidth(True)
     test_render_string('He\u0347\u0305llo\u0341, w\u0302or\u0306l\u0354d!', family='Noto Sans Mono')
     test_render_string('你好,世界', family='Noto Sans Mono')
-    test_render_string('|\U0001F929|\U0001F921|\U0001F91f|', family='Noto Sans Mono')
+    test_render_string('|\U0001F601|\U0001F64f|\U0001F63a|', family='Noto Sans Mono')
     test_render_string('A=>>B!=C', family='Fira Code')