Add hover-over highlighting to the scatterplot (#900)

* small perf improvement - do not recreate functions each time component is updated

* add hover-over highlighting to scatterplot

client/src/components/graph/graph.js

@@ -53,6 +53,12 @@ function createModelTF() {
 }
 
 function renderThrottle(callback) {
+  /*
+  This wraps a call to requestAnimationFrame(), enforcing a single
+  render callback at any given time (ie, you can call this any number
+  of times, and it will coallesce multiple inter-frame calls into a
+  single render).
+  */
   let rafCurrentlyInProgress = null;
   return function f() {
     if (rafCurrentlyInProgress) return;
@@ -326,62 +332,6 @@ class Graph extends React.Component {
       }
     }
 
-    const createToolSVG = () => {
-      /* clear out whatever was on the div, even if nothing, but usually the brushes etc */
-      d3.select("#graphAttachPoint")
-        .select("#tool")
-        .remove();
-
-      let handleStart;
-      let handleDrag;
-      let handleEnd;
-      let handleCancel;
-      if (selectionTool === "brush") {
-        handleStart = this.handleBrushStartAction.bind(this);
-        handleDrag = this.handleBrushDragAction.bind(this);
-        handleEnd = this.handleBrushEndAction.bind(this);
-      } else {
-        handleStart = this.handleLassoStart.bind(this);
-        handleEnd = this.handleLassoEnd.bind(this);
-        handleCancel = this.handleLassoCancel.bind(this);
-      }
-
-      const { svg: newToolSVG, tool, container } = setupSVGandBrushElements(
-        selectionTool,
-        handleStart,
-        handleDrag,
-        handleEnd,
-        handleCancel,
-        responsive,
-        this.graphPaddingRight,
-        graphInteractionMode
-      );
-
-      stateChanges = { ...stateChanges, toolSVG: newToolSVG, tool, container };
-    };
-
-    const createCentroidSVG = () => {
-      d3.select("#graphAttachPoint")
-        .select("#centroid-container")
-        .remove();
-
-      if (centroidLabel.metadataField === "" || !centroidLabel.centroidXY) {
-        return;
-      }
-
-      const centroidScreen = this.mapPointToScreen(centroidLabel.centroidXY);
-
-      const newCentroidSVG = setupCentroidSVG(
-        responsive,
-        this.graphPaddingRight,
-        centroidScreen,
-        centroidLabel.categoryField,
-        colorAccessor
-      );
-
-      stateChanges = { ...stateChanges, centroidSVG: newCentroidSVG };
-    };
-
     // Centroid SVG creation is disabled for now but should go into the
     // first and third cases if enabled
     if (
@@ -389,14 +339,14 @@ class Graph extends React.Component {
       prevProps.responsive.width !== responsive.width
     ) {
       // If the window size has changed we want to recreate all SVGs
-      createToolSVG();
+      stateChanges = { ...stateChanges, ...this.createToolSVG() };
     } else if (
       (responsive.height && responsive.width && !toolSVG) ||
       selectionTool !== prevProps.selectionTool ||
       prevProps.graphInteractionMode !== graphInteractionMode
     ) {
       // first time or change of selection tool6
-      createToolSVG();
+      stateChanges = { ...stateChanges, ...this.createToolSVG() };
     } else if (
       centroidLabel !== prevProps.centroidLabel ||
       (responsive.height && responsive.width && !centroidSVG)
@@ -433,6 +383,75 @@ class Graph extends React.Component {
     }
   };
 
+  createToolSVG() {
+    /*
+    Called from componentDidUpdate. Create the tool SVG, and return any
+    state changes that should be passed to setState().
+    */
+    const { responsive, selectionTool, graphInteractionMode } = this.props;
+
+    /* clear out whatever was on the div, even if nothing, but usually the brushes etc */
+    d3.select("#graphAttachPoint")
+      .select("#tool")
+      .remove();
+
+    let handleStart;
+    let handleDrag;
+    let handleEnd;
+    let handleCancel;
+    if (selectionTool === "brush") {
+      handleStart = this.handleBrushStartAction.bind(this);
+      handleDrag = this.handleBrushDragAction.bind(this);
+      handleEnd = this.handleBrushEndAction.bind(this);
+    } else {
+      handleStart = this.handleLassoStart.bind(this);
+      handleEnd = this.handleLassoEnd.bind(this);
+      handleCancel = this.handleLassoCancel.bind(this);
+    }
+
+    const { svg: newToolSVG, tool, container } = setupSVGandBrushElements(
+      selectionTool,
+      handleStart,
+      handleDrag,
+      handleEnd,
+      handleCancel,
+      responsive,
+      this.graphPaddingRight,
+      graphInteractionMode
+    );
+
+    return { toolSVG: newToolSVG, tool, container };
+  }
+
+  createCentroidSVG() {
+    /*
+    Called from componentDidUpdate. Create the centroid SVG, and return any
+    state changes that should be passed to setState().
+
+    CURRENTLY UNUSED
+    */
+    const { responsive, centroidLabel, colorAccessor } = this.props;
+    d3.select("#graphAttachPoint")
+      .select("#centroid-container")
+      .remove();
+
+    if (centroidLabel.metadataField === "" || !centroidLabel.centroidXY) {
+      return {};
+    }
+
+    const centroidScreen = this.mapPointToScreen(centroidLabel.centroidXY);
+
+    const newCentroidSVG = setupCentroidSVG(
+      responsive,
+      this.graphPaddingRight,
+      centroidScreen,
+      centroidLabel.categoryField,
+      colorAccessor
+    );
+
+    return { centroidSVG: newCentroidSVG };
+  }
+
   brushToolUpdate(tool, container) {
     /*
     this is called from componentDidUpdate(), so be very careful using

client/src/components/scatterplot/drawPointsRegl.js

@@ -26,8 +26,7 @@ export default function(regl) {
       bool isNaN, isSelected, isHighlight;
       getFlags(flag, isNaN, isSelected, isHighlight);
 
-      float size = isHighlight ? 8. : isSelected ? 4. : 1.;
-      gl_PointSize = size;
+      gl_PointSize = isHighlight ? 8. : isSelected ? 4. : 1.;
 
       float z = isNaN ? zBottom : (isHighlight ? zTop : zMiddle);
       vec3 xy = projection * vec3(position, 1.);

client/src/components/scatterplot/scatterplot.js

@@ -25,12 +25,12 @@ function createProjectionTF(viewportWidth, viewportHeight) {
 @connect(state => {
   const { world, crossfilter, universe } = state;
   const { scatterplotXXaccessor, scatterplotYYaccessor } = state.controls;
-  const expressionX =
-    scatterplotXXaccessor &&
-    world.varData.col(scatterplotXXaccessor)?.asArray();
-  const expressionY =
-    scatterplotYYaccessor &&
-    world.varData.col(scatterplotYYaccessor)?.asArray();
+  const expressionX = scatterplotXXaccessor
+    ? world.varData.col(scatterplotXXaccessor)?.asArray()
+    : null;
+  const expressionY = scatterplotYYaccessor
+    ? world.varData.col(scatterplotYYaccessor)?.asArray()
+    : null;
 
   return {
     world,
@@ -40,6 +40,8 @@ function createProjectionTF(viewportWidth, viewportHeight) {
     colorScale: state.colors.scale,
     colorAccessor: state.colors.colorAccessor,
 
+    centroidLabel: state.centroidLabel,
+
     // Accessors are var/gene names (strings)
     scatterplotXXaccessor,
     scatterplotYYaccessor,
@@ -85,32 +87,42 @@ class Scatterplot extends React.Component {
     }
   );
 
-  computePointFlags = memoize((world, crossfilter, colorAccessor) => {
-    const flagSelected = 1;
-    const flagNaN = 2;
-    // XXX - coming soon.
-    // const flagHighlight = 4;
+  computePointFlags = memoize(
+    (world, crossfilter, colorAccessor, centroidLabel) => {
+      const flagSelected = 1;
+      const flagNaN = 2;
+      const flagHighlight = 4;
 
-    const flags = this.computeSelectedFlags(
-      crossfilter,
-      flagSelected,
-      0
-    ).slice();
+      const flags = this.computeSelectedFlags(
+        crossfilter,
+        flagSelected,
+        0
+      ).slice();
 
-    const colorByColumn = colorAccessor
-      ? world.obsAnnotations.col(colorAccessor)?.asArray() ||
-        world.varData.col(colorAccessor)?.asArray()
-      : null;
-    const colorByData =
-      colorByColumn && isTypedArray(colorByColumn) ? colorByColumn : null;
+      const { metadataField, categoryField } = centroidLabel;
+      const highlightData = metadataField
+        ? world.obsAnnotations.col(metadataField)?.asArray()
+        : null;
+      const colorByColumn = colorAccessor
+        ? world.obsAnnotations.col(colorAccessor)?.asArray() ||
+          world.varData.col(colorAccessor)?.asArray()
+        : null;
+      const colorByData =
+        colorByColumn && isTypedArray(colorByColumn) ? colorByColumn : null;
 
-    if (colorByData) {
-      for (let i = 0, len = flags.length; i < len; i += 1) {
-        flags[i] += Number.isFinite(colorByData[i]) ? 0 : flagNaN;
+      if (colorByData || highlightData) {
+        for (let i = 0, len = flags.length; i < len; i += 1) {
+          if (highlightData) {
+            flags[i] += highlightData[i] === categoryField ? flagHighlight : 0;
+          }
+          if (colorByData) {
+            flags[i] += Number.isFinite(colorByData[i]) ? 0 : flagNaN;
+          }
+        }
       }
+      return flags;
     }
-    return flags;
-  });
+  );
 
   constructor(props) {
     super(props);
@@ -183,7 +195,8 @@ class Scatterplot extends React.Component {
       expressionX,
       expressionY,
       colorRGB,
-      colorAccessor
+      colorAccessor,
+      centroidLabel
     } = this.props;
     const {
       regl,
@@ -233,7 +246,8 @@ class Scatterplot extends React.Component {
       const newFlags = this.computePointFlags(
         world,
         crossfilter,
-        colorAccessor
+        colorAccessor,
+        centroidLabel
       );
       if (renderCache.flags !== newFlags) {
         renderCache.flags = newFlags;