Optimize Z9 rendering

Z9 was quite anomaly in terms of rendering time. It was taking much
longer than Z8 and Z10 during pre-computation.

Dominant layer was landuse_gen0. It was using subpixel rendering for
landuse, which is useful at very low zoom but seems to be safely
discardable at Z9.

See as well
gravitystorm/openstreetmap-carto#2874 and
gravitystorm/openstreetmap-carto#3458 (comment).

See #644.

base.mss

@@ -17,8 +17,8 @@
   polygon-gamma: 0.75;
 }
 
-#landuse_gen0[zoom>1][zoom<=9],
-#landuse_gen1[zoom>9][zoom<=12],
+#landuse_gen0[zoom>1][zoom<=8],
+#landuse_gen1[zoom>8][zoom<=12],
 #landuse[zoom>=13] {
   [type='amenity_grave_yard'],
   [type='landuse_cemetery'] {

project.mml

@@ -84,7 +84,7 @@ Layer:
             CASE WHEN "natural" IS NOT NULL THEN ('natural_' || "natural") ELSE NULL END,
             CASE WHEN leisure IS NOT NULL THEN ('leisure_' || leisure) ELSE NULL END,
             CASE WHEN amenity IS NOT NULL THEN ('amenity_' || amenity) ELSE NULL END,
-            CASE WHEN highway IN ('pedestrian') THEN ('highway_' || highway) ELSE NULL END
+            CASE WHEN highway IS NOT NULL THEN ('highway_' || highway) ELSE NULL END
           ) AS type,
           sport
           FROM planet_osm_polygon
@@ -102,7 +102,7 @@ Layer:
   geometry: polygon
   properties:
     minzoom: 2
-    maxzoom: 9
+    maxzoom: 8
 - id: landuse_gen1
   <<: *extents
   Datasource:
@@ -129,12 +129,13 @@ Layer:
           OR highway IN ('pedestrian')
         )
         AND way_area > 1*!pixel_width!::real*!pixel_height!::real
+        AND way && !bbox!
         ORDER BY way_area DESC
       ) AS data
   geometry: polygon
   properties:
     cache-features: true
-    minzoom: 10
+    minzoom: 9
     maxzoom: 12
 - id: landuse
   <<: *extents
@@ -182,6 +183,7 @@ Layer:
           ("natural" = 'wood' OR landuse = 'forest')
           AND building IS NULL
           AND way_area > 1*!pixel_width!::real*!pixel_height!::real
+          AND way && !bbox!
         ORDER BY way_area DESC
       ) AS data
   geometry: polygon
@@ -336,6 +338,7 @@ Layer:
             OR landuse in ('basin', 'reservoir')
           )
           AND way_area > 0.1*!pixel_width!::real*!pixel_height!::real
+          AND way && !bbox!
           AND (tunnel IS NULL OR tunnel NOT IN ('yes', 'culvert'))
       ) AS data
   geometry: polygon
@@ -363,6 +366,7 @@ Layer:
             OR landuse in ('basin', 'reservoir')
           )
           AND way_area > 1*!pixel_width!::real*!pixel_height!::real
+          AND way && !bbox!
           AND (tunnel IS NULL OR tunnel NOT IN ('yes', 'culvert'))
       ) AS data
   geometry: polygon
@@ -924,6 +928,7 @@ Layer:
                 OR (boundary = 'protected_area' AND tags->'protect_class' IN ('1','1a','1b','2','3','4','5','6','7','24','97','98','99')))
           AND building IS NULL
           AND way_area > 1*!pixel_width!::real*!pixel_height!::real
+          AND way && !bbox!
       ) AS protected_areas
   properties:
     cache-features: true
@@ -1920,6 +1925,7 @@ Layer:
           (landuse = 'military' OR military = 'danger_area')
           AND building IS NULL
           AND way_area > 1*!pixel_width!::real*!pixel_height!::real
+          AND way && !bbox!
         ORDER BY way_area DESC
       ) AS data
   geometry: polygon