Modified the name of image_data_null to image_null.

include/mapnik/image_any.hpp

@@ -28,7 +28,7 @@
 
 namespace mapnik {
 
-struct image_data_null
+struct image_null
 {   
     using pixel_type = uint8_t;
     unsigned char const* getBytes() const { return nullptr; }
@@ -51,7 +51,7 @@ struct image_data_null
     }
 };
 
-using image_data_base = util::variant<image_data_null, 
+using image_data_base = util::variant<image_null, 
                                       image_rgba8, 
                                       image_gray8, 
                                       image_gray16, 
@@ -214,7 +214,7 @@ inline image_any create_image_any(int width,
       case image_dtype_gray32f:
         return image_any(std::move(image_gray32f(width, height, initialize, premultiplied, painted)));
       case image_dtype_null:
-        return image_any(std::move(image_data_null()));
+        return image_any(std::move(image_null()));
       case image_dtype_rgba8:
       default:
         return image_any(std::move(image_rgba8(width, height, initialize, premultiplied, painted)));

include/mapnik/image_data.hpp

@@ -282,7 +282,7 @@ using image_gray8 = image_data<std::uint8_t> ;
 using image_gray16 = image_data<std::int16_t>;
 using image_gray32f = image_data<float>;
 
-enum image_dtype
+enum image_dtype : std::uint8_t
 {
     image_dtype_rgba8 = 0,
     image_dtype_gray8,

include/mapnik/renderer_common/process_raster_symbolizer.hpp

@@ -69,7 +69,7 @@ struct image_data_dispatcher
         composite_(composite),
         nodata_(nodata) {}
 
-    void operator() (image_data_null const& data_in) const {}  //no-op
+    void operator() (image_null const& data_in) const {}  //no-op
     void operator() (image_rgba8 const& data_in) const
     {
         image_rgba8 data_out(width_, height_, true, true);
@@ -135,7 +135,7 @@ struct image_data_warp_dispatcher
         composite_(composite),
         nodata_(nodata) {}
 
-    void operator() (image_data_null const& data_in) const {} //no-op
+    void operator() (image_null const& data_in) const {} //no-op
 
     void operator() (image_rgba8 const& data_in) const
     {

include/mapnik/tiff_io.hpp

@@ -257,7 +257,7 @@ struct tag_setter
 
         }
     }
-    inline void operator() (image_data_null const&) const
+    inline void operator() (image_null const&) const
     {
         // Assume this would be null type
         throw ImageWriterException("Could not write TIFF - Null image provided");

src/image_util.cpp

@@ -431,7 +431,7 @@ template bool is_solid_visitor::operator()<image_view_gray16> (image_view_gray16
 template bool is_solid_visitor::operator()<image_view_gray32f> (image_view_gray32f const& data);
 
 template<>
-bool is_solid_visitor::operator()<image_data_null> (image_data_null const&)
+bool is_solid_visitor::operator()<image_null> (image_null const&)
 {
     return true;
 }
@@ -921,7 +921,7 @@ void visitor_set_rectangle::operator()<image_rgba8> (image_rgba8 & dst)
 }
 
 template<>
-void visitor_set_rectangle::operator()<image_data_null> (image_data_null &)
+void visitor_set_rectangle::operator()<image_null> (image_null &)
 {
     throw std::runtime_error("Set rectangle not support for null images");
 }
@@ -1250,7 +1250,7 @@ struct visitor_create_view
 };
 
 template <>
-image_view_any visitor_create_view::operator()<image_data_null> (image_data_null const&)
+image_view_any visitor_create_view::operator()<image_null> (image_null const&)
 {
     throw std::runtime_error("Can not make a view from a null image");
 }

src/image_util_jpeg.cpp

@@ -77,7 +77,7 @@ void jpeg_saver::operator()<image_view_rgba8> (image_view_rgba8 const& image) co
 }
 
 template<>
-void jpeg_saver::operator()<image_data_null> (image_data_null const& image) const
+void jpeg_saver::operator()<image_null> (image_null const& image) const
 {
     throw ImageWriterException("Can not save a null image to jpeg");
 }

src/image_util_png.cpp

@@ -184,13 +184,13 @@ png_saver_pal::png_saver_pal(std::ostream & stream, std::string const& t, rgba_p
     stream_(stream), t_(t), pal_(pal) {}
 
 template<>
-void png_saver::operator()<image_data_null> (image_data_null const& image) const
+void png_saver::operator()<image_null> (image_null const& image) const
 {
     throw ImageWriterException("null images not supported for png");
 }
 
 template<>
-void png_saver_pal::operator()<image_data_null> (image_data_null const& image) const
+void png_saver_pal::operator()<image_null> (image_null const& image) const
 {
     throw ImageWriterException("null images not supported for png");
 }

src/image_util_tiff.cpp

@@ -164,7 +164,7 @@ void handle_tiff_options(std::string const& type,
 tiff_saver::tiff_saver(std::ostream & stream, std::string const& t):
     stream_(stream), t_(t) {}
 template<>
-void tiff_saver::operator()<image_data_null> (image_data_null const& image) const
+void tiff_saver::operator()<image_null> (image_null const& image) const
 {
     throw ImageWriterException("null images not supported");
 }

src/image_util_webp.cpp

@@ -335,7 +335,7 @@ webp_saver::webp_saver(std::ostream & stream, std::string const& t):
     stream_(stream), t_(t) {}
 
 template<>
-void webp_saver::operator()<image_data_null> (image_data_null const& image) const
+void webp_saver::operator()<image_null> (image_null const& image) const
 {
     throw ImageWriterException("null images not supported");
 }

src/marker_cache.cpp

@@ -143,7 +143,7 @@ marker_ptr visitor_create_marker::operator()<image_rgba8> (image_rgba8 & data)
 }
 
 template<>
-marker_ptr visitor_create_marker::operator()<image_data_null> (image_data_null & data)
+marker_ptr visitor_create_marker::operator()<image_null> (image_null & data)
 {
     throw std::runtime_error("Can not make marker from null image data type");
 }

src/renderer_common/process_group_symbolizer.cpp

@@ -154,7 +154,7 @@ struct visitor_push_thunk
 };
 
 template <>
-void visitor_push_thunk::operator()<image_data_null> (image_data_null &)
+void visitor_push_thunk::operator()<image_null> (image_null &)
 {
     throw std::runtime_error("Push thunk does not support null images");
 }

src/renderer_common/render_pattern.cpp

@@ -72,12 +72,12 @@ std::shared_ptr<image_rgba8> render_pattern<image_rgba8>(rasterizer & ras,
 }
 
 template <>
-std::shared_ptr<image_data_null> render_pattern<image_data_null>(rasterizer & ras,
+std::shared_ptr<image_null> render_pattern<image_null>(rasterizer & ras,
                                               marker const& marker,
                                               agg::trans_affine const& tr,
                                               double opacity)
 {
-    throw std::runtime_error("Can not return image_data_null type from render pattern");
+    throw std::runtime_error("Can not return image_null type from render pattern");
 }
 /*
 template <>

src/warp.cpp

@@ -172,7 +172,7 @@ struct warp_image_visitor
           scaling_method_(scaling_method),
         filter_factor_(filter_factor) {}
 
-    void operator() (image_data_null const&) {}
+    void operator() (image_null const&) {}
 
     template <typename T>
     void operator() (T const& source)