VectorLayer support options.roundPoint config close #1264 (#1265)

Author: deyihu

src/layer/VectorLayer.js

@@ -21,6 +21,7 @@ const TEMP_EXTENT = new PointExtent();
  * @property {Boolean} [options.altitudeProperty=altitude] - geometry's altitude property name, if enableAltitude is true, "altitude" by default
  * @property {Boolean} [options.drawAltitude=false]  - whether to draw altitude: a vertical line for marker, a vertical polygon for line
  * @property {Boolean} [options.sortByDistanceToCamera=false]  - markers Sort by camera distance
+ * @property {Boolean} [options.roundPoint=false]  - round point before painting to improve performance, but will cause geometry shaking in animation
  * @property {Number} [options.altitude=0]           - layer altitude
  * @property {Boolean} [options.debug=false]         - whether the geometries on the layer is in debug mode.
  * @memberOf VectorLayer
@@ -37,6 +38,7 @@ const options = {
     'altitudeProperty': 'altitude',
     'drawAltitude': false,
     'sortByDistanceToCamera': false,
+    'roundPoint': false,
     'altitude': 0
 };
 

src/renderer/geometry/Painter.js

@@ -214,6 +214,7 @@ class Painter extends Class {
             glZoom = map.getGLZoom();
         }
         let cPoints;
+        const roundPoint = this.getLayer().options['roundPoint'];
         function pointsContainerPoints(viewPoints = [], alts = []) {
             const pts = map._pointsToContainerPoints(viewPoints, glZoom, alts);
             for (let i = 0, len = pts.length; i < len; i++) {
@@ -222,6 +223,11 @@ class Painter extends Class {
                 if (dx || dy) {
                     p._add(dx || 0, dy || 0);
                 }
+                if (roundPoint) {
+                    //使用 round 会导致左右波动，用floor,ceil 要好点
+                    p.x = Math.ceil(p.x);
+                    p.y = Math.ceil(p.y);
+                }
             }
             return pts;
         }