diff --git a/src/_backend_agg.h b/src/_backend_agg.h
index 0265647cb463..53b73f179baa 100644
--- a/src/_backend_agg.h
+++ b/src/_backend_agg.h
@@ -182,8 +182,8 @@ class RendererAgg
     template <class CoordinateArray, class OffsetArray, class ColorArray>
     void draw_quad_mesh(GCAgg &gc,
                         agg::trans_affine &master_transform,
-                        size_t mesh_width,
-                        size_t mesh_height,
+                        unsigned int mesh_width,
+                        unsigned int mesh_height,
                         CoordinateArray &coordinates,
                         OffsetArray &offsets,
                         agg::trans_affine &offset_trans,
@@ -1148,8 +1148,8 @@ class QuadMeshGenerator
 template <class CoordinateArray, class OffsetArray, class ColorArray>
 inline void RendererAgg::draw_quad_mesh(GCAgg &gc,
                                         agg::trans_affine &master_transform,
-                                        size_t mesh_width,
-                                        size_t mesh_height,
+                                        unsigned int mesh_width,
+                                        unsigned int mesh_height,
                                         CoordinateArray &coordinates,
                                         OffsetArray &offsets,
                                         agg::trans_affine &offset_trans,
diff --git a/src/_backend_agg_wrapper.cpp b/src/_backend_agg_wrapper.cpp
index f6ed42bcd277..4806feda0282 100644
--- a/src/_backend_agg_wrapper.cpp
+++ b/src/_backend_agg_wrapper.cpp
@@ -390,8 +390,8 @@ static PyObject *PyRendererAgg_draw_quad_mesh(PyRendererAgg *self, PyObject *arg
 {
     GCAgg gc;
     agg::trans_affine master_transform;
-    size_t mesh_width;
-    size_t mesh_height;
+    unsigned int mesh_width;
+    unsigned int mesh_height;
     numpy::array_view<const double, 3> coordinates;
     numpy::array_view<const double, 2> offsets;
     agg::trans_affine offset_trans;