Added FreeTypeFont has_characters()

Author: radarhere

Tests/test_imagefont.py

@@ -891,6 +891,15 @@ def test_anchor_invalid(font: ImageFont.FreeTypeFont) -> None:
             d.multiline_textbbox((0, 0), "foo\nbar", anchor=anchor)
 
 
+def test_has_characters(font: ImageFont.FreeTypeFont) -> None:
+    assert font.has_characters("")
+
+    assert font.has_characters("Test text")
+    assert font.has_characters(b"Test text")
+
+    assert not font.has_characters("Test \u0001")
+
+
 @pytest.mark.parametrize("bpp", (1, 2, 4, 8))
 def test_bitmap_font(layout_engine: ImageFont.Layout, bpp: int) -> None:
     text = "Bitmap Font"

src/PIL/ImageFont.py

@@ -636,6 +636,16 @@ def fill(width: int, height: int) -> Image.core.ImagingCore:
             start,
         )
 
+    def has_characters(self, text: str | bytes) -> bool:
+        """
+        Check if the font has all of the characters in the text.
+
+        :param text: Text to render.
+
+        :return: Boolean.
+        """
+        return self.font.hascharacters(text)
+
     def font_variant(
         self,
         font: StrOrBytesPath | BinaryIO | None = None,

src/PIL/_imagingft.pyi

@@ -54,6 +54,7 @@ class Font:
         lang: str | None,
         /,
     ) -> float: ...
+    def hascharacters(self, string: str | bytes) -> bool: ...
     def getvarnames(self) -> list[bytes]: ...
     def getvaraxes(self) -> list[ImageFont.Axis]: ...
     def setvarname(self, instance_index: int, /) -> None: ...

src/_imagingft.c

@@ -517,6 +517,44 @@ text_layout(
     return count;
 }
 
+static PyObject *
+font_hascharacters(FontObject *self, PyObject *args) {
+    int i;
+    char *buffer = NULL;
+    FT_ULong ch;
+    Py_ssize_t count;
+    FT_GlyphSlot glyph;
+    PyObject *string;
+
+    if (!PyArg_ParseTuple(args, "O", &string)) {
+        return NULL;
+    }
+
+    if (PyUnicode_Check(string)) {
+        count = PyUnicode_GET_LENGTH(string);
+    } else if (PyBytes_Check(string)) {
+        PyBytes_AsStringAndSize(string, &buffer, &count);
+    } else {
+        PyErr_SetString(PyExc_TypeError, "expected string or bytes");
+        return 0;
+    }
+    if (count == 0) {
+        return Py_True;
+    }
+
+    for (i = 0; i < count; i++) {
+        if (buffer) {
+            ch = buffer[i];
+        } else {
+            ch = PyUnicode_READ_CHAR(string, i);
+        }
+        if (FT_Get_Char_Index(self->face, ch) == 0) {
+            return Py_False;
+        }
+    }
+    return Py_True;
+}
+
 static PyObject *
 font_getlength(FontObject *self, PyObject *args) {
     int length;                   /* length along primary axis, in 26.6 precision */
@@ -1451,6 +1489,7 @@ static PyMethodDef font_methods[] = {
     {"render", (PyCFunction)font_render, METH_VARARGS},
     {"getsize", (PyCFunction)font_getsize, METH_VARARGS},
     {"getlength", (PyCFunction)font_getlength, METH_VARARGS},
+    {"hascharacters", (PyCFunction)font_hascharacters, METH_VARARGS},
 #if FREETYPE_MAJOR > 2 || (FREETYPE_MAJOR == 2 && FREETYPE_MINOR > 9) || \
     (FREETYPE_MAJOR == 2 && FREETYPE_MINOR == 9 && FREETYPE_PATCH == 1)
     {"getvarnames", (PyCFunction)font_getvarnames, METH_NOARGS},