update webp defaults to use WebPConfigInit

src/image_util.cpp

@@ -620,19 +620,12 @@ void save_to_stream(T const& image,
         {
 #if defined(HAVE_WEBP)
             WebPConfig config;
-            if (!WebPConfigPreset(&config, WEBP_PRESET_DEFAULT, 90))
+            // Default values set here will be lossless=0 and quality=75 (as least as of webp v0.3.1)
+            if (!WebPConfigInit(&config))
             {
                 throw std::runtime_error("version mismatch");
             }
-            /*
-              WEBP_HINT_DEFAULT = 0,  // default preset.
-              WEBP_HINT_PICTURE,      // digital picture, like portrait, inner shot
-              WEBP_HINT_PHOTO,        // outdoor photograph, with natural lighting
-              WEBP_HINT_GRAPH,        // Discrete tone image (graph, map-tile etc).
-              WEBP_HINT_LAST
-            */
-            config.image_hint = WEBP_HINT_GRAPH;
-            config.method = 3;
+            // see for more details: https://github.com/mapnik/mapnik/wiki/Image-IO#webp-output-options
             bool alpha = true;
             handle_webp_options(t,config,alpha);
             save_as_webp(stream,image,config,alpha);

tests/python_tests/webp_encoding_test.py

@@ -19,6 +19,8 @@ if mapnik.has_webp():
 
     opts = [
         'webp',
+        'webp:method=0',
+        'webp:method=6',
         'webp:quality=64',
         'webp:alpha=false',
         'webp:partitions=3',
@@ -113,6 +115,7 @@ if mapnik.has_webp():
                 continue
             if mapnik.Image.open(actual).tostring() != expected_bytes:
                 fails.append('%s (actual) not == to %s (expected)' % (actual,expected))
+        # disabled to avoid failures on ubuntu when using old webp packages
         #eq_(fails,[],'\n'+'\n'.join(fails))
 
     def test_transparency_levels():
@@ -128,7 +131,7 @@ if mapnik.has_webp():
             for x in range(im.width()/2,im.width()):
                 im.set_pixel(x,y,c3)
 
-        t0 = tmp_dir + 'white0.webp'
+        t0 = tmp_dir + 'white0-actual.webp'
 
         # octree
         format = 'webp'
@@ -144,6 +147,7 @@ if mapnik.has_webp():
             # this will happen if libweb is old, since it cannot open images created by more recent webp
             print 'warning, cannot open webp expected image (your libwebp is likely too old)'
             return
+        # disabled to avoid failures on ubuntu when using old webp packages
         #eq_(t0_len,len(expected_bytes))