disconnect zero value outputs from flow diagram

frontend/src/app/components/tx-bowtie-graph/tx-bowtie-graph.component.html

@@ -21,6 +21,15 @@
           markerWidth="1.5" markerHeight="1"
           orient="auto">
       </marker>
+      <radialGradient id="gradient0" x1="0%" y1="0%" x2="100%" y2="100%">
+        <stop [attr.stop-color]="gradient[0]" />
+      </radialGradient>
+      <radialGradient id="gradient1" x1="0%" y1="0%" x2="100%" y2="100%">
+        <stop [attr.stop-color]="gradient[1]" />
+      </radialGradient>
+      <radialGradient id="gradient2" x1="0%" y1="0%" x2="100%" y2="100%">
+        <stop [attr.stop-color]="gradient[2]" />
+      </radialGradient>
       <linearGradient id="input-gradient" x1="0%" y1="0%" x2="100%" y2="0%">
         <stop offset="0%" [attr.stop-color]="gradient[0]" />
         <stop offset="100%" [attr.stop-color]="gradient[1]" />
@@ -117,7 +126,7 @@
         (pointerout)="onBlur($event, 'output-connector', i);"
         (click)="onClick($event, 'output-connector', outputData[i].index);"
       />
-      <path
+      <path *ngIf="!output.zeroValue"
         [attr.d]="output.markerPath"
         class="output marker-target {{output.class}}"
         [class.highlight]="outputData[i].index === outputIndex"
@@ -125,7 +134,7 @@
         (pointerout)="onBlur($event, 'output', i);"
         (click)="onClick($event, 'output', outputData[i].index);"
       />
-      <path
+      <path *ngIf="!output.zeroValue"
         [attr.d]="output.path"
         class="line {{output.class}}"
         [class.highlight]="outputIndex != null && outputData[i].index === outputIndex"
@@ -135,6 +144,16 @@
         (pointerout)="onBlur($event, 'output', i);"
         (click)="onClick($event, 'output', outputData[i].index);"
       />
+      <path *ngIf="output.zeroValue"
+        [attr.d]="output.path"
+        class="line {{output.class}} zerovalue"
+        [class.highlight]="outputIndex != null && outputData[i].index === outputIndex"
+        [class.zerovalue]="output.zeroValue"
+        [style]="output.style"
+        (pointerover)="onHover($event, 'output', i);"
+        (pointerout)="onBlur($event, 'output', i);"
+        (click)="onClick($event, 'output', outputData[i].index);"
+      />
     </ng-container>
   </svg>
 

frontend/src/app/components/tx-bowtie-graph/tx-bowtie-graph.component.scss

@@ -11,6 +11,10 @@
     &.fee {
       stroke: url(#fee-gradient);
     }
+    &.zerovalue {
+      stroke: url(#gradient0);
+      stroke-linecap: round;
+    }
 
     &.highlight {
       z-index: 8;
@@ -21,6 +25,9 @@
       &.output {
         stroke: url(#output-highlight-gradient);
       }
+      &.zerovalue {
+        stroke: #1bd8f4;
+      }
     }
   }
 
@@ -36,6 +43,9 @@
     &.fee {
       stroke: url(#fee-hover-gradient);
     }
+    &.zerovalue {
+      stroke: white;
+    }
   }
 
   .connector {

frontend/src/app/components/tx-bowtie-graph/tx-bowtie-graph.component.ts

@@ -13,6 +13,7 @@ interface SvgLine {
   class?: string;
   connectorPath?: string;
   markerPath?: string;
+  zeroValue?: boolean;
 }
 
 interface Xput {
@@ -63,6 +64,8 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
   hoverConnector: boolean = false;
   tooltipPosition = { x: 0, y: 0 };
   outspends: Outspend[] = [];
+  zeroValueWidth = 60;
+  zeroValueThickness = 20;
 
   outspendsSubscription: Subscription;
   refreshOutspends$: ReplaySubject<string> = new ReplaySubject();
@@ -130,6 +133,7 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
     this.txWidth = this.connectors ? Math.max(this.width - 200, this.width * 0.8) : this.width - 20;
     this.combinedWeight = Math.min(this.maxCombinedWeight, Math.floor((this.txWidth - (2 * this.midWidth)) / 6));
     this.connectorWidth = (this.width - this.txWidth) / 2;
+    this.zeroValueWidth = Math.max(20, Math.min((this.txWidth / 2) - this.midWidth - 110, 60));
 
     const totalValue = this.calcTotalValue(this.tx);
     let voutWithFee = this.tx.vout.map((v, i) => {
@@ -236,10 +240,10 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
   }
 
   linesFromWeights(side: 'in' | 'out', xputs: Xput[], weights: number[], maxVisibleStrands: number): SvgLine[] {
-    const lineParams = weights.map((w) => {
+    const lineParams = weights.map((w, i) => {
       return {
         weight: w,
-        thickness: Math.max(this.minWeight - 1, w) + 1,
+        thickness: xputs[i].value === 0 ? this.zeroValueThickness : Math.max(this.minWeight - 1, w) + 1,
         offset: 0,
         innerY: 0,
         outerY: 0,
@@ -265,6 +269,12 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
     let lastWeight = 0;
     let pad = 0;
     lineParams.forEach((line, i) => {
+      if (xputs[i].value === 0) {
+        line.outerY = lastOuter + this.zeroValueThickness / 2;
+        lastOuter += this.zeroValueThickness + spacing;
+        return;
+      }
+
       // set the vertical position of the (center of the) outer side of the line
       line.outerY = lastOuter + (line.thickness / 2);
       line.innerY = Math.min(innerBottom + (line.thickness / 2), Math.max(innerTop + (line.thickness / 2), lastInner + (line.weight / 2)));
@@ -318,13 +328,22 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
     maxOffset -= minOffset;
 
     return lineParams.map((line, i) => {
-      return {
-        path: this.makePath(side, line.outerY, line.innerY, line.thickness, line.offset, pad + maxOffset),
-        style: this.makeStyle(line.thickness, xputs[i].type),
-        class: xputs[i].type,
-        connectorPath: this.connectors ? this.makeConnectorPath(side, line.outerY, line.innerY, line.thickness): null,
-        markerPath: this.makeMarkerPath(side, line.outerY, line.innerY, line.thickness),
-      };
+      if (xputs[i].value === 0) {
+        return {
+          path: this.makeZeroValuePath(side, line.outerY),
+          style: this.makeStyle(this.zeroValueThickness, xputs[i].type),
+          class: xputs[i].type,
+          zeroValue: true,
+        };
+      } else {
+        return {
+          path: this.makePath(side, line.outerY, line.innerY, line.thickness, line.offset, pad + maxOffset),
+          style: this.makeStyle(line.thickness, xputs[i].type),
+          class: xputs[i].type,
+          connectorPath: this.connectors ? this.makeConnectorPath(side, line.outerY, line.innerY, line.thickness): null,
+          markerPath: this.makeMarkerPath(side, line.outerY, line.innerY, line.thickness),
+        };
+      }
     });
   }
 
@@ -347,6 +366,16 @@ export class TxBowtieGraphComponent implements OnInit, OnChanges {
     }
   }
 
+  makeZeroValuePath(side: 'in' | 'out', y: number): string {
+    const offset = this.zeroValueThickness / 2;
+    const start = this.connectorWidth + 10;
+    if (side === 'in') {
+      return `M ${start + offset} ${y} L ${start + this.zeroValueWidth + offset} ${y + 1}`;
+    } else { // mirrored in y-axis for the right hand side
+      return `M ${this.width - start - offset} ${y} L ${this.width - start - this.zeroValueWidth - offset} ${y + 1}`;
+    }
+  }
+
   makeConnectorPath(side: 'in' | 'out', y: number, inner, weight: number): string {
     const halfWidth = weight * 0.5;
     const offset = 10; //Math.max(2, halfWidth * 0.2);