Deprecate passing floats to FT2Image

These were silently truncated to int anyway, so we should make the types
explicit.

Author: QuLogic

doc/api/next_api_changes/deprecations/288XX-ES.rst

@@ -3,3 +3,10 @@ Passing floating-point values to ``RendererAgg.draw_text_image``
 
 Any floating-point values passed to the *x* and *y* parameters were truncated to integers
 silently. This behaviour is now deprecated, and only `int` values should be used.
+
+Passing floating-point values to ``FT2Image``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Any floating-point values passed to the `.FT2Image` constructor, or the *x0*, *y0*, *x1*,
+and *y1* parameters of `.FT2Image.draw_rect_filled` were truncated to integers silently.
+This behaviour is now deprecated, and only `int` values should be used.

lib/matplotlib/_mathtext.py

@@ -153,7 +153,7 @@ def to_raster(self, *, antialiased: bool) -> RasterParse:
         w = xmax - xmin
         h = ymax - ymin - self.box.depth
         d = ymax - ymin - self.box.height
-        image = FT2Image(np.ceil(w), np.ceil(h + max(d, 0)))
+        image = FT2Image(int(np.ceil(w)), int(np.ceil(h + max(d, 0))))
 
         # Ideally, we could just use self.glyphs and self.rects here, shifting
         # their coordinates by (-xmin, -ymin), but this yields slightly
@@ -172,7 +172,7 @@ def to_raster(self, *, antialiased: bool) -> RasterParse:
                 y = int(center - (height + 1) / 2)
             else:
                 y = int(y1)
-            image.draw_rect_filled(int(x1), y, np.ceil(x2), y + height)
+            image.draw_rect_filled(int(x1), y, int(np.ceil(x2)), y + height)
         return RasterParse(0, 0, w, h + d, d, image)
 
 

lib/matplotlib/ft2font.pyi

@@ -281,8 +281,8 @@ class FT2Font(Buffer):
 
 @final
 class FT2Image(Buffer):
-    def __init__(self, width: float, height: float) -> None: ...
-    def draw_rect_filled(self, x0: float, y0: float, x1: float, y1: float) -> None: ...
+    def __init__(self, width: int, height: int) -> None: ...
+    def draw_rect_filled(self, x0: int, y0: int, x1: int, y1: int) -> None: ...
     if sys.version_info[:2] >= (3, 12):
         def __buffer__(self, flags: int) -> memoryview: ...
 

src/ft2font_wrapper.cpp

@@ -206,6 +206,8 @@ P11X_DECLARE_ENUM(
  * FT2Image
  * */
 
+using double_or_long = std::variant<double, long>;
+
 const char *PyFT2Image__doc__ = R"""(
     An image buffer for drawing glyphs.
 )""";
@@ -226,9 +228,32 @@ const char *PyFT2Image_draw_rect_filled__doc__ = R"""(
         The bounds of the rectangle from (x0, y0) to (x1, y1).
 )""";
 
+static long
+_double_to_long(const char *name, double_or_long &var)
+{
+    if (auto value = std::get_if<double>(&var)) {
+        auto api = py::module_::import("matplotlib._api");
+        auto warn = api.attr("warn_deprecated");
+        warn("since"_a="3.10", "name"_a=name, "obj_type"_a="parameter as float",
+             "alternative"_a="int({})"_s.format(name));
+        return static_cast<long>(*value);
+    } else if (auto value = std::get_if<long>(&var)) {
+        return *value;
+    } else {
+        throw std::runtime_error("Should not happen");
+    }
+}
+
 static void
-PyFT2Image_draw_rect_filled(FT2Image *self, double x0, double y0, double x1, double y1)
+PyFT2Image_draw_rect_filled(FT2Image *self,
+                            double_or_long vx0, double_or_long vy0,
+                            double_or_long vx1, double_or_long vy1)
 {
+    auto x0 = _double_to_long("x0", vx0);
+    auto y0 = _double_to_long("y0", vy0);
+    auto x1 = _double_to_long("x1", vx1);
+    auto y1 = _double_to_long("y1", vy1);
+
     self->draw_rect_filled(x0, y0, x1, y1);
 }
 
@@ -1625,7 +1650,14 @@ PYBIND11_MODULE(ft2font, m)
 
     py::class_<FT2Image>(m, "FT2Image", py::is_final(), py::buffer_protocol(),
                          PyFT2Image__doc__)
-        .def(py::init<double, double>(), "width"_a, "height"_a, PyFT2Image_init__doc__)
+        .def(py::init(
+                [](double_or_long width, double_or_long height) {
+                    return new FT2Image(
+                        _double_to_long("width", width),
+                        _double_to_long("height", height)
+                    );
+                }),
+             "width"_a, "height"_a, PyFT2Image_init__doc__)
         .def("draw_rect_filled", &PyFT2Image_draw_rect_filled,
              "x0"_a, "y0"_a, "x1"_a, "y1"_a,
              PyFT2Image_draw_rect_filled__doc__)