Extract pad destination texture dispatch helper

src/canvas.cpp

@@ -847,17 +847,16 @@ void Canvas::stroke_draw()
         },
     };
     const auto make_pad_destination_texture_dispatch = [&](int face_index) {
-        return pp::panopainter::LegacyCanvasStrokeTextureInputDispatch {
-            .activate_texture_unit = [&](int texture_slot) {
+        return pp::panopainter::make_legacy_canvas_stroke_pad_destination_texture_dispatch(
+            [&](int texture_slot) {
                 set_active_texture_unit(texture_slot);
             },
-            .bind_stroke_destination = [&] {
+            [&] {
                 m_tex[face_index].bind();
             },
-            .unbind_stroke_destination = [&] {
+            [&] {
                 m_tex[face_index].unbind();
-            },
-        };
+            });
     };
     [[maybe_unused]] const auto pad_result = pp::panopainter::execute_legacy_canvas_stroke_pad_faces(
         pp::panopainter::LegacyCanvasStrokePadExecutionRequest {