feat(sankey): support disabling node sorting. close #21561

src/chart/sankey/SankeySeries.ts

@@ -136,6 +136,11 @@ export interface SankeySeriesOption
      * The number of iterations to change the position of the node
      */
     layoutIterations?: number
+    /**
+     * Sorting method used when resolving node collisions within each depth column.
+     * Set to null to preserve the original node order.
+     */
+    sort?: 'desc' | null
 
     nodeAlign?: 'justify' | 'left' | 'right'    // TODO justify should be auto
 
@@ -318,6 +323,7 @@ class SankeySeriesModel extends SeriesModel<SankeySeriesOption> {
         draggable: true,
 
         layoutIterations: 32,
+        sort: 'desc',
 
         // true | false | 'move' | 'scale', see module:component/helper/RoamController.
         roam: false,

src/chart/sankey/sankeyLayout.ts

@@ -57,8 +57,9 @@ export default function sankeyLayout(ecModel: GlobalModel, api: ExtensionAPI) {
         const orient = seriesModel.get('orient');
 
         const nodeAlign = seriesModel.get('nodeAlign');
+        const sort = seriesModel.get('sort');
 
-        layoutSankey(nodes, edges, nodeWidth, nodeGap, width, height, iterations, orient, nodeAlign);
+        layoutSankey(nodes, edges, nodeWidth, nodeGap, width, height, iterations, orient, nodeAlign, sort);
     });
 }
 
@@ -71,10 +72,11 @@ function layoutSankey(
     height: number,
     iterations: number,
     orient: LayoutOrient,
-    nodeAlign: SankeySeriesOption['nodeAlign']
+    nodeAlign: SankeySeriesOption['nodeAlign'],
+    sort: SankeySeriesOption['sort']
 ) {
     computeNodeBreadths(nodes, edges, nodeWidth, width, height, orient, nodeAlign);
-    computeNodeDepths(nodes, edges, height, width, nodeGap, iterations, orient);
+    computeNodeDepths(nodes, edges, height, width, nodeGap, iterations, orient, sort);
     computeEdgeDepths(nodes, orient);
 }
 
@@ -257,6 +259,7 @@ function scaleNodeBreadths(nodes: GraphNode[], kx: number, orient: LayoutOrient)
  * @param nodeGap  the vertical distance between two nodes
  *     in the same column.
  * @param iterations  the number of iterations for the algorithm
+ * @param sort  sorting method used when resolving collisions within each column
  */
 function computeNodeDepths(
     nodes: GraphNode[],
@@ -265,21 +268,22 @@ function computeNodeDepths(
     width: number,
     nodeGap: number,
     iterations: number,
-    orient: LayoutOrient
+    orient: LayoutOrient,
+    sort: SankeySeriesOption['sort']
 ) {
     const nodesByBreadth = prepareNodesByBreadth(nodes, orient);
 
     initializeNodeDepth(nodesByBreadth, edges, height, width, nodeGap, orient);
-    resolveCollisions(nodesByBreadth, nodeGap, height, width, orient);
+    resolveCollisions(nodesByBreadth, nodeGap, height, width, orient, sort);
 
     for (let alpha = 1; iterations > 0; iterations--) {
         // 0.99 is a experience parameter, ensure that each iterations of
         // changes as small as possible.
         alpha *= 0.99;
         relaxRightToLeft(nodesByBreadth, alpha, orient);
-        resolveCollisions(nodesByBreadth, nodeGap, height, width, orient);
+        resolveCollisions(nodesByBreadth, nodeGap, height, width, orient, sort);
         relaxLeftToRight(nodesByBreadth, alpha, orient);
-        resolveCollisions(nodesByBreadth, nodeGap, height, width, orient);
+        resolveCollisions(nodesByBreadth, nodeGap, height, width, orient, sort);
     }
 }
 
@@ -355,13 +359,16 @@ function resolveCollisions(
     nodeGap: number,
     height: number,
     width: number,
-    orient: LayoutOrient
+    orient: LayoutOrient,
+    sort: SankeySeriesOption['sort']
 ) {
     const keyAttr = orient === 'vertical' ? 'x' : 'y';
     zrUtil.each(nodesByBreadth, function (nodes) {
-        nodes.sort(function (a, b) {
-            return a.getLayout()[keyAttr] - b.getLayout()[keyAttr];
-        });
+        if (sort !== null) {
+            nodes.sort(function (a, b) {
+                return a.getLayout()[keyAttr] - b.getLayout()[keyAttr];
+            });
+        }
         let nodeX;
         let node;
         let dy;
@@ -528,4 +535,4 @@ function computeEdgeDepths(nodes: GraphNode[], orient: LayoutOrient) {
             ty += edge.getLayout().dy;
         });
     });
-}
+}