A fix to the jpeg driver making it operate with parameters like the other file formats.

include/mapnik/image.hpp

@@ -340,7 +340,8 @@ enum image_dtype : std::uint8_t
     image_dtype_gray64,
     image_dtype_gray64s,
     image_dtype_gray64f,
-    image_dtype_null
+    image_dtype_null,
+    IMAGE_DTYPE_MAX
 };
 
 } // end ns

include/mapnik/image_any.hpp

@@ -306,6 +306,7 @@ inline image_any create_image_any(int width,
       case image_dtype_null:
         return image_any(std::move(image_null()));
       case image_dtype_rgba8:
+      case IMAGE_DTYPE_MAX:
       default:
         return image_any(std::move(image_rgba8(width, height, initialize, premultiplied, painted)));
     }

src/image_copy.cpp

@@ -340,6 +340,10 @@ MAPNIK_DECL image_any image_copy(image_any const& data, image_dtype type, double
             return image_any(std::move(image_copy<image_gray64f>(data, offset, scaling)));
         case image_dtype_null:
             throw std::runtime_error("Can not cast a null image");
+        case IMAGE_DTYPE_MAX:
+        default:
+            throw std::runtime_error("Can not cast unknown type");
+
     }
     throw std::runtime_error("Unknown image type passed");
 }

src/image_util_jpeg.cpp

@@ -46,11 +46,24 @@ jpeg_saver::jpeg_saver(std::ostream & stream, std::string const& t):
     stream_(stream), t_(t) {}
 
 template <typename T>
-void process_rgba8_jpeg(T const& image, std::string const& t, std::ostream & stream)
+void process_rgba8_jpeg(T const& image, std::string const& type, std::ostream & stream)
 {
 #if defined(HAVE_JPEG)
     int quality = 85;
-    std::string val = t.substr(5);
+    //std::string val = type.substr(4);
+    if (type != "jpeg")
+    {
+        boost::char_separator<char> sep(":");
+        boost::tokenizer< boost::char_separator<char> > tokens(type, sep);
+        for (auto const& t : tokens)
+        {
+            if (t == "jpeg")
+            {
+                continue;
+            }
+            else if (boost::algorithm::starts_with(t, "quality="))
+            {
+                std::string val = t.substr(8);
                 if (!val.empty())
                 {
                     if (!mapnik::util::string2int(val,quality) || quality < 0 || quality > 100)
@@ -58,6 +71,9 @@ void process_rgba8_jpeg(T const& image, std::string const& t, std::ostream & str
                         throw ImageWriterException("invalid jpeg quality: '" + val + "'");
                     }
                 }
+            }
+        }
+    }
     save_as_jpeg(stream, quality, image);
 #else
     throw ImageWriterException("jpeg output is not enabled in your build of Mapnik");