tidy: addressing clang-tidy warnings and errors.

Author: mfisher31

.clang-tidy

@@ -40,6 +40,7 @@ Checks: >
   -fuchsia-overloaded-operator,
   -fuchsia-statically-constructed-objects,
   -google-readability-casting,
+  -google-readability-todo,
   -google-runtime-references,
   -hicpp-avoid-c-arrays,
   -hicpp-deprecated-headers,
@@ -81,6 +82,7 @@ Checks: >
   -readability-convert-member-functions-to-static,
   -readability-identifier-length,
   -readability-implicit-bool-conversion,
+  -readability-isolate-declaration,
   -readability-qualified-auto,
   -readability-redundant-member-init,
 

src/cairo.cpp

@@ -52,7 +52,7 @@ class Context : public DrawingContext {
         double x_scale = 1.0, y_scale = 1.0;
         if (auto s = cairo_get_target (cr))
             cairo_surface_get_device_scale (s, &x_scale, &y_scale);
-        return static_cast<double> (y_scale);
+        return y_scale;
     }
 
     void save() override {