From a7ea07ee0daa9e3ef50d83c45d3bb7eb2e590d48 Mon Sep 17 00:00:00 2001
From: Alberto Valverde <alberto@meteogrid.com>
Date: Fri, 12 Mar 2010 13:34:32 +0000
Subject: [PATCH] modified raster_colorizer so the color of the last band is
 used if the value matches its value exactly. This is to make declaring
 legends for rasters with discrete values easier (ie: no need to define a
 dummy band for N+1)

---
 include/mapnik/raster_colorizer.hpp         | 12 ++++++++----
 tests/python_tests/raster_colorizer_test.py |  7 ++++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/mapnik/raster_colorizer.hpp b/include/mapnik/raster_colorizer.hpp
index af6efcf14..dc76e5eba 100644
--- a/include/mapnik/raster_colorizer.hpp
+++ b/include/mapnik/raster_colorizer.hpp
@@ -153,9 +153,11 @@ namespace mapnik
          *   if cs[pos].value <= value < cs[pos+1].value: cs[pos].color
          *   otherwise: transparent
          *     where 0 <= pos < length(bands)-1
+         *   Last band is special, its value represents the upper bound and its
+         *   color will only be used if the value matches its value exactly.
          */
          color get_color(float value) const {
-            int pos=-1, lo=0, hi=colors_.size()-1;
+            int pos=-1, last=(int)colors_.size()-1, lo=0, hi=last;
             while (lo<=hi) {
                 pos = (lo+hi)/2;
                 if (colors_[pos].value_<value) {
@@ -168,9 +170,11 @@ namespace mapnik
                 }
             }
             lo--;
-            return (0 <= lo && lo < (int)colors_.size()-1)?
-                colors_[lo].color_:
-                color(0,0,0,0);
+            if ((0 <= lo && lo < last) ||
+                (lo==last && colors_[last].value_==value))
+                return colors_[lo].color_;
+            else
+                return color(0,0,0,0);
          }
 
          void colorize(mapnik::raster_ptr const& raster) const {
diff --git a/tests/python_tests/raster_colorizer_test.py b/tests/python_tests/raster_colorizer_test.py
index 8f0e63133..c0b3c474d 100644
--- a/tests/python_tests/raster_colorizer_test.py
+++ b/tests/python_tests/raster_colorizer_test.py
@@ -18,8 +18,7 @@ class test_raster_colorizer():
         ( 70, "#cc00cc"),
         ( 80, "#990099"),
         ( 90, "#660066"),
-        ( 200, "#00000"), # last band denotes upper limit, values above it will
-                          # not return the color
+        ( 200, "#ffffff"),
         ]]
     for value, color in bands:
         colorizer.append_band(value, color)
@@ -28,5 +27,7 @@ class test_raster_colorizer():
     eq_(colorizer.get_color(0), bands[0][1])
     eq_(colorizer.get_color(5), bands[0][1])
     eq_(colorizer.get_color(10), bands[1][1])
-    eq_(colorizer.get_color(200), mapnik2.Color("transparent"))
+    # last value is used if it matches exactly
+    eq_(colorizer.get_color(200), bands[-1][1])
+    #  values greater than the last value are mapped to "transparent"
     eq_(colorizer.get_color(201), mapnik2.Color("transparent"))