Add tests to validate feature-from-spec

kitty/core_text.m

@@ -953,6 +953,20 @@ static CTFontRef nerd_font(CGFloat sz) {
     return variation_to_python(src);
 }
 
+static PyObject*
+applied_features(CTFace *self, PyObject *a UNUSED) {
+    RAII_PyObject(ans, PyTuple_New(self->font_features.count));
+    if (!ans) return NULL;
+    char buf[256];
+    for (size_t i = 0; i < self->font_features.count; i++) {
+        hb_feature_to_string(&self->font_features.features[i], buf, arraysz(buf));
+        PyObject *t = PyUnicode_FromString(buf);
+        if (!t) return NULL;
+        PyTuple_SET_ITEM(ans, i, t);
+    }
+    Py_INCREF(ans); return ans;
+}
+
 static PyObject*
 get_features(CTFace *self, PyObject *a UNUSED) {
     if (!ensure_name_table(self)) return NULL;
@@ -1012,6 +1026,7 @@ static CTFontRef nerd_font(CGFloat sz) {
     METHODB(display_name, METH_NOARGS),
     METHODB(postscript_name, METH_NOARGS),
     METHODB(get_variable_data, METH_NOARGS),
+    METHODB(applied_features, METH_NOARGS),
     METHODB(get_features, METH_NOARGS),
     METHODB(get_variation, METH_NOARGS),
     METHODB(identify_for_debug, METH_NOARGS),

kitty/fast_data_types.pyi

@@ -442,6 +442,7 @@ class Face:
     def render_sample_text(self, text: str, width: int, height: int, fg_color: int = 0xffffff) -> bytes: ...
     def get_variation(self) -> Optional[Dict[str, float]]: ...
     def get_features(self) -> Dict[str, Optional[FeatureData]]: ...
+    def applied_features(self) -> Tuple[str, ...]: ...
 
 
 class CoreTextFont(TypedDict):
@@ -478,6 +479,7 @@ class CTFace:
     def render_sample_text(self, text: str, width: int, height: int, fg_color: int = 0xffffff) -> bytes: ...
     def get_variation(self) -> Optional[Dict[str, float]]: ...
     def get_features(self) -> Dict[str, Optional[FeatureData]]: ...
+    def applied_features(self) -> Tuple[str, ...]: ...
 
 
 def coretext_all_fonts(monospaced_only: bool) -> Tuple[CoreTextFont, ...]:

kitty/fonts.c

@@ -290,6 +290,17 @@ desc_to_face(PyObject *desc, FONTS_DATA_HANDLE fg) {
     return ans;
 }
 
+static void
+add_feature(FontFeatures *output, const hb_feature_t *feature) {
+    for (size_t i = 0; i < output->count; i++) {
+        if (output->features[i].tag == feature->tag) {
+            output->features[i] = *feature;
+            return;
+        }
+    }
+    output->features[output->count++] = *feature;
+}
+
 bool
 create_features_for_face(const char *psname, PyObject *features, FontFeatures *output) {
     size_t count_from_descriptor = features ? PyTuple_GET_SIZE(features): 0;
@@ -304,16 +315,16 @@ create_features_for_face(const char *psname, PyObject *features, FontFeatures *o
     output->features = calloc(MAX(2u, count_from_opts + count_from_descriptor), sizeof(output->features[0]));
     if (!output->features) { PyErr_NoMemory(); return false; }
     for (size_t i = 0; i < count_from_opts; i++) {
-        output->features[output->count++] = from_opts->features[i];
+        add_feature(output, &from_opts->features[i]);
     }
     for (size_t i = 0; i < count_from_descriptor; i++) {
         ParsedFontFeature *f = (ParsedFontFeature*)PyTuple_GET_ITEM(features, i);
-        output->features[output->count++] = f->feature;
+        add_feature(output, &f->feature);
     }
     if (!output->count) {
         if (strstr(psname, "NimbusMonoPS-") == psname) {
-            output->features[output->count++] = hb_features[LIGA_FEATURE];
-            output->features[output->count++] = hb_features[DLIG_FEATURE];
+            add_feature(output, &hb_features[LIGA_FEATURE]);
+            add_feature(output, &hb_features[DLIG_FEATURE]);
         }
     }
     return true;

kitty/fonts/common.py

@@ -315,8 +315,11 @@ def get_font_from_spec(
     resolved_medium_font: Optional[Descriptor] = None, match_is_more_specific_than_family: Event = Event()
 ) -> Descriptor:
     if not spec.is_system:
-        return get_fine_grained_font(spec, bold, italic, resolved_medium_font=resolved_medium_font, family_axis_values=family_axis_values,
+        ans = get_fine_grained_font(spec, bold, italic, resolved_medium_font=resolved_medium_font, family_axis_values=family_axis_values,
                                      match_is_more_specific_than_family=match_is_more_specific_than_family)
+        if spec.features:
+            ans['features'] = spec.features
+        return ans
     family = spec.system or ''
     if family == 'auto':
         if bold or italic:

kitty/freetype.c

@@ -847,6 +847,20 @@ get_variation(Face *self, PyObject *a UNUSED) {
     Py_INCREF(ans); return ans;
 }
 
+static PyObject*
+applied_features(Face *self, PyObject *a UNUSED) {
+    RAII_PyObject(ans, PyTuple_New(self->font_features.count));
+    if (!ans) return NULL;
+    char buf[256];
+    for (size_t i = 0; i < self->font_features.count; i++) {
+        hb_feature_to_string(&self->font_features.features[i], buf, arraysz(buf));
+        PyObject *t = PyUnicode_FromString(buf);
+        if (!t) return NULL;
+        PyTuple_SET_ITEM(ans, i, t);
+    }
+    Py_INCREF(ans); return ans;
+}
+
 static PyObject*
 get_features(Face *self, PyObject *a UNUSED) {
     FT_Error err;
@@ -1023,6 +1037,7 @@ static PyMethodDef methods[] = {
     METHODB(identify_for_debug, METH_NOARGS),
     METHODB(extra_data, METH_NOARGS),
     METHODB(get_variable_data, METH_NOARGS),
+    METHODB(applied_features, METH_NOARGS),
     METHODB(get_features, METH_NOARGS),
     METHODB(get_variation, METH_NOARGS),
     METHODB(get_best_name, METH_O),

kitty_tests/fonts.py

@@ -10,6 +10,7 @@
 from kitty.constants import is_macos, read_kitty_resource
 from kitty.fast_data_types import (
     DECAWM,
+    ParsedFontFeature,
     get_fallback_font,
     sprite_map_set_layout,
     sprite_map_set_limits,
@@ -33,6 +34,7 @@ def parse_font_spec(spec):
 class Selection(BaseTest):
 
     def test_font_selection(self):
+        self.set_options({'font_features': {'LiberationMono': (ParsedFontFeature('-dlig'),)}})
         opts = Options()
         fonts_map = all_fonts_map(True)
         names = set(fonts_map['family_map']) | set(fonts_map['variable_map'])
@@ -140,6 +142,17 @@ def t(x, **kw):
             t('bold', spec='variable_name=CascadiaCodeRoman wght=603')
             t('bi', spec='variable_name= wght=603')
 
+        # Test font features
+        if has('liberation mono'):
+            opts = Options()
+            opts.font_family = parse_font_spec('family="liberation mono"')
+            ff = get_font_files(opts)
+            self.ae(face_from_descriptor(ff['medium']).applied_features(), ('-dlig',))
+            self.ae(face_from_descriptor(ff['bold']).applied_features(), ())
+            opts.font_family = parse_font_spec('family="liberation mono" features="dlig test"')
+            ff = get_font_files(opts)
+            self.ae(face_from_descriptor(ff['medium']).applied_features(), ('dlig', 'test'))
+
 
 class Rendering(BaseTest):