disable variable gamma in agg renderer

disable-variable-gamma.diff

diff --git a/src/agg/agg_renderer.cpp b/src/agg/agg_renderer.cpp
index 32ea6d9..44bb3e7 100644
--- a/src/agg/agg_renderer.cpp
+++ b/src/agg/agg_renderer.cpp
@@ -297,7 +297,7 @@ void agg_renderer<T>::render_marker(pixel_position const& pos,
     typedef agg::pod_bvector<mapnik::svg::path_attributes> svg_attribute_type;
 
     ras_ptr->reset();
-    ras_ptr->gamma(agg::gamma_power());
+    //ras_ptr->gamma(agg::gamma_power());
     agg::scanline_u8 sl;
     agg::rendering_buffer buf(current_buffer_->raw_data(), width_, height_, width_ * 4);
     pixfmt_comp_type pixf(buf);
diff --git a/src/agg/process_building_symbolizer.cpp b/src/agg/process_building_symbolizer.cpp
index 5addaac..9b7becd 100644
--- a/src/agg/process_building_symbolizer.cpp
+++ b/src/agg/process_building_symbolizer.cpp
@@ -70,7 +70,7 @@ void agg_renderer<T>::process(building_symbolizer const& sym,
     agg::scanline_u8 sl;
 
     ras_ptr->reset();
-    ras_ptr->gamma(agg::gamma_power());
+    //ras_ptr->gamma(agg::gamma_power());
 
     double height = 0.0;
     expression_ptr height_expr = sym.height();
diff --git a/src/agg/process_line_symbolizer.cpp b/src/agg/process_line_symbolizer.cpp
index 8138ff0..6114bed 100644
--- a/src/agg/process_line_symbolizer.cpp
+++ b/src/agg/process_line_symbolizer.cpp
@@ -66,7 +66,7 @@ void agg_renderer<T>::process(line_symbolizer const& sym,
     unsigned a=col.alpha();
 
     ras_ptr->reset();
-    set_gamma_method(stroke_, ras_ptr);
+    //set_gamma_method(stroke_, ras_ptr);
 
     agg::rendering_buffer buf(current_buffer_->raw_data(),width_,height_, width_ * 4);
 
diff --git a/src/agg/process_markers_symbolizer.cpp b/src/agg/process_markers_symbolizer.cpp
index 9539985..eb00ce3 100644
--- a/src/agg/process_markers_symbolizer.cpp
+++ b/src/agg/process_markers_symbolizer.cpp
@@ -83,7 +83,7 @@ void agg_renderer<T>::process(markers_symbolizer const& sym,
         if (mark && *mark)
         {
             ras_ptr->reset();
-            ras_ptr->gamma(agg::gamma_power());
+            //ras_ptr->gamma(agg::gamma_power());
             agg::trans_affine geom_tr;
             evaluate_transform(geom_tr, feature, sym.get_transform());
             agg::trans_affine tr = agg::trans_affine_scaling(scale_factor_);
diff --git a/src/agg/process_polygon_pattern_symbolizer.cpp b/src/agg/process_polygon_pattern_symbolizer.cpp
index 5297ae3..6fc0d5b 100644
--- a/src/agg/process_polygon_pattern_symbolizer.cpp
+++ b/src/agg/process_polygon_pattern_symbolizer.cpp
@@ -61,7 +61,7 @@ void agg_renderer<T>::process(polygon_pattern_symbolizer const& sym,
 
     agg::rendering_buffer buf(current_buffer_->raw_data(), width_, height_, width_ * 4);
     ras_ptr->reset();
-    set_gamma_method(sym,ras_ptr);
+    //set_gamma_method(sym,ras_ptr);
 
     std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
     boost::optional<mapnik::marker_ptr> marker;
diff --git a/src/agg/process_polygon_symbolizer.cpp b/src/agg/process_polygon_symbolizer.cpp
index 107da80..3188240 100644
--- a/src/agg/process_polygon_symbolizer.cpp
+++ b/src/agg/process_polygon_symbolizer.cpp
@@ -48,7 +48,7 @@ void agg_renderer<T>::process(polygon_symbolizer const& sym,
 {
 
     ras_ptr->reset();
-    set_gamma_method(sym,ras_ptr);
+    //set_gamma_method(sym,ras_ptr);
 
     agg::trans_affine tr;
     evaluate_transform(tr, feature, sym.get_transform());