大规模散点图性能优化

src/chart/scatter.js

@@ -164,16 +164,12 @@ define(function (require) {
                     ]);
                     
                 }
-                // todo
-                this._markMap(xAxis, yAxis, serie.data, pointList[seriesIndex]);
                 this.buildMark(
                     serie,
                     seriesIndex,
                     this.component,
                     {
-                        xMarkMap : this._needMarkMap(seriesIndex) 
-                                   ? this._markMap(xAxis, yAxis, serie.data, pointList[seriesIndex])
-                                   : {}
+                        xMarkMap : this._markMap(xAxis, yAxis, serie.data, pointList[seriesIndex])
                     }
                 );
             }
@@ -182,6 +178,7 @@ define(function (require) {
             this._buildPointList(pointList);
         },
         
+        /*
         _needMarkMap : function (seriesIndex) {
             var series = this.series;
             var serie = series[seriesIndex];
@@ -208,7 +205,8 @@ define(function (require) {
             }
             return false;
         },
-        
+        */
+       
         _markMap : function (xAxis, yAxis, data, pointList) {
             var xMarkMap = {
                 min0 : Number.POSITIVE_INFINITY,
@@ -342,7 +340,7 @@ define(function (require) {
                         singlePoint[2], // dataIndex
                         singlePoint[3], // name
                         singlePoint[0], // x
-                        singlePoint[1] // y
+                        singlePoint[1]  // y
                     );
                     shape && this.shapeList.push(shape);
                 }

src/util/shape/Symbol.js

@@ -33,7 +33,7 @@
  */
 define(function (require) {
     var Base = require('zrender/shape/Base');
-    var PolygonShape = require('zrender/shape/Polygon')
+    var PolygonShape = require('zrender/shape/Polygon');
     var polygonInstance = new PolygonShape({});
     var zrUtil = require('zrender/tool/util');
     
@@ -48,6 +48,29 @@ define(function (require) {
          * @param {Context2D} ctx Canvas 2D上下文
          * @param {Object} style 样式
          */
+        buildPath : function (ctx, style) {
+            var pointList = style.pointList;
+            var len = pointList.length;
+            var subSize = 10000;
+            var subSetLength = Math.ceil(len / subSize);
+            var sub;
+            var subLen;
+            for (var j = 0; j < subSetLength; j++) {
+                ctx.beginPath();
+                sub = j * subSize;
+                subLen = sub + subSize;
+                subLen = subLen > len ? len : subLen;
+                for (var i = sub; i < subLen; i++) {
+                    ctx.rect(pointList[i][0] - 1, pointList[i][1] - 1, 2, 2);
+                }
+                ctx.closePath();
+                j < (subSetLength - 1) && ctx.fill();
+            }
+            
+            return;
+        },
+        
+        /* 像素模式
         buildPath : function (ctx, style) {
             var pointList = style.pointList;
             var rect = this.getRect(style);
@@ -87,7 +110,8 @@ define(function (require) {
             // console.log(new Date() - ti);
             return;
         },
-
+        */
+       
         /**
          * 返回矩形区域，用于局部刷新和文字定位
          * @param {Object} style