ImageSurface.create_for_data: support empty images

Author: Akuli

cairo/surface.c

@@ -857,12 +857,12 @@ image_surface_create_for_data (PyTypeObject *type, PyObject *args) {
 
   format = (cairo_format_t)format_arg;
 
-  if (width <= 0) {
-    PyErr_SetString(PyExc_ValueError, "width must be positive");
+  if (width < 0) {
+    PyErr_SetString(PyExc_ValueError, "width cannot be negative");
     return NULL;
   }
-  if (height <= 0) {
-    PyErr_SetString(PyExc_ValueError, "height must be positive");
+  if (height < 0) {
+    PyErr_SetString(PyExc_ValueError, "height cannot be negative");
     return NULL;
   }
   /* if stride is missing, calculate it from width */

tests/test_surface.py

@@ -726,9 +726,6 @@ def test_image_surface_create_for_data() -> None:
     with pytest.raises(ValueError):
         cairo.ImageSurface.create_for_data(buf, format_, -1, 3)
 
-    with pytest.raises(ValueError):
-        cairo.ImageSurface.create_for_data(buf, format_, 0, 0, -1)
-
     with pytest.raises(cairo.Error) as excinfo:
         cairo.ImageSurface.create_for_data(buf, format_, 3, 3, 3)
 
@@ -738,6 +735,16 @@ def test_image_surface_create_for_data() -> None:
         cairo.ImageSurface.create_for_data(buf, format_, 3, object())  # type: ignore
 
 
+@pytest.mark.parametrize("width, height", [(0, 0), (10, 0), (0, 10)])
+def test_image_surface_create_for_data_empty(width, height) -> None:
+    surface = cairo.ImageSurface.create_for_data(
+        bytearray(), cairo.FORMAT_ARGB32, width, height
+    )
+    assert surface.get_width() == width
+    assert surface.get_height() == height
+    assert surface.get_stride() == 4 * width
+
+
 def test_image_surface_get_data_finished() -> None:
     surface = cairo.ImageSurface(cairo.Format.ARGB32, 30, 30)
     surface.finish()