From 15daac26e7b6280dd02f7f2e3ca7171db297bac1 Mon Sep 17 00:00:00 2001
From: Jiri Drbalek <jiri.drbalek@firma.seznam.cz>
Date: Mon, 29 Aug 2016 15:24:49 +0000
Subject: [PATCH] cairo support for layer level comp-op and opacity

---
 src/cairo/cairo_renderer.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/cairo/cairo_renderer.cpp b/src/cairo/cairo_renderer.cpp
index 0fbb00972..43c3ffef4 100644
--- a/src/cairo/cairo_renderer.cpp
+++ b/src/cairo/cairo_renderer.cpp
@@ -188,12 +188,25 @@ void cairo_renderer<T>::start_layer_processing(layer const& lay, box2d<double> c
         common_.detector_->clear();
     }
     common_.query_extent_ = query_extent;
+
+    if (lay.comp_op() || lay.get_opacity() < 1.0)
+    {
+        context_.push_group();
+    }
 }
 
 template <typename T>
-void cairo_renderer<T>::end_layer_processing(layer const&)
+void cairo_renderer<T>::end_layer_processing(layer const& lay)
 {
     MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer: End layer processing";
+
+    if (lay.comp_op() || lay.get_opacity() < 1.0)
+    {
+        context_.pop_group();
+        composite_mode_e comp_op = lay.comp_op() ? *lay.comp_op() : src_over;
+        context_.set_operator(comp_op);
+        context_.paint(lay.get_opacity());
+    }
 }
 
 template <typename T>