GraphNG: Bars, Staircase, Smooth modes (#29359)

* initial impl of Bars, Staircase, Smooth modes

* fix fillTo for staircase and smooth paths

* fix pointSize

* [bars] adjust gap factor & reduce bar width to include stroke width. remove rounding to favor gap & width uniformity over edge crispness.

* remove line path fallback for too-dense data

* "Auto" points mode implies "Never" for Bars

* slightly reduce x axis tick density

* fix bars height calc, make bars crisp again.

* [bars] don't use hard-coded 'x' scale key

* refactor catmullRomFitting() to accept x & y coord arrays. restrict to processing only visible data range.

* move path building functions to own file

* export typed functions

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

packages/grafana-ui/src/components/GraphNG/GraphNG.tsx

@@ -104,7 +104,10 @@ export const GraphNG: React.FC<GraphNGProps> = ({
     for (let i = 0; i < alignedFrame.fields.length; i++) {
       const field = alignedFrame.fields[i];
       const config = field.config as FieldConfig<GraphFieldConfig>;
-      const customConfig = config.custom || defaultConfig;
+      const customConfig: GraphFieldConfig = {
+        ...defaultConfig,
+        ...config.custom,
+      };
 
       if (field === xField || field.type !== FieldType.number) {
         continue;
@@ -134,14 +137,14 @@ export const GraphNG: React.FC<GraphNGProps> = ({
 
       builder.addSeries({
         scaleKey: scale,
-        line: (customConfig.mode ?? GraphMode.Line) === GraphMode.Line,
+        mode: customConfig.mode!,
         lineColor: seriesColor,
         lineWidth: customConfig.lineWidth,
+        lineInterpolation: customConfig.lineInterpolation,
         points: pointsMode,
-        pointSize: customConfig.pointRadius,
+        pointSize: customConfig.pointSize,
         pointColor: seriesColor,
-        fill: customConfig.fillAlpha !== undefined,
-        fillOpacity: customConfig.fillAlpha,
+        fillOpacity: customConfig.fillOpacity,
         fillColor: seriesColor,
       });
 

packages/grafana-ui/src/components/uPlot/config.ts

@@ -11,13 +11,13 @@ export enum AxisPlacement {
 
 export enum PointMode {
   Auto = 'auto', // will show points when the density is low or line is hidden
-  Always = 'always',
   Never = 'never',
+  Always = 'always',
 }
 
 export enum GraphMode {
   Line = 'line', // default
-  Bar = 'bar', // will also have a gap percent
+  Bars = 'bars', // will also have a gap percent
   Points = 'points', // Only show points
 }
 
@@ -27,31 +27,43 @@ export enum LineInterpolation {
   Smooth = 'smooth', // https://leeoniya.github.io/uPlot/demos/line-smoothing.html
 }
 
-export interface GraphFieldConfig {
-  mode: GraphMode;
+export interface LineConfig {
+  lineColor?: string;
+  lineWidth?: number;
+  lineInterpolation?: LineInterpolation;
+}
 
-  lineMode?: LineInterpolation;
-  lineWidth?: number; // pixels
-  fillAlpha?: number; // 0-1
+export interface AreaConfig {
+  fillColor?: string;
+  fillOpacity?: number;
+}
 
+export interface PointsConfig {
   points?: PointMode;
-  pointRadius?: number; // pixels
-  symbol?: string; // eventually dot,star, etc
+  pointSize?: number;
+  pointColor?: string;
+  pointSymbol?: string; // eventually dot,star, etc
+}
 
-  // Axis is actually unique based on the unit... not each field!
+// Axis is actually unique based on the unit... not each field!
+export interface AxisConfig {
   axisPlacement?: AxisPlacement;
   axisLabel?: string;
   axisWidth?: number; // pixels ideally auto?
 }
 
+export interface GraphFieldConfig extends LineConfig, AreaConfig, PointsConfig, AxisConfig {
+  mode?: GraphMode;
+}
+
 export const graphFieldOptions = {
   mode: [
     { label: 'Lines', value: GraphMode.Line },
-    { label: 'Bars', value: GraphMode.Bar },
+    { label: 'Bars', value: GraphMode.Bars },
     { label: 'Points', value: GraphMode.Points },
   ] as Array<SelectableValue<GraphMode>>,
 
-  lineMode: [
+  lineInterpolation: [
     { label: 'Linear', value: LineInterpolation.Linear },
     { label: 'Staircase', value: LineInterpolation.Staircase },
     { label: 'Smooth', value: LineInterpolation.Smooth },

packages/grafana-ui/src/components/uPlot/config/UPlotAxisBuilder.ts

@@ -83,7 +83,7 @@ function calculateSpace(self: uPlot, axisIdx: number, scaleMin: number, scaleMax
 
   // For x-axis (bottom) we need bigger spacing between labels
   if (axis.side === 2) {
-    return 50;
+    return 55;
   }
 
   return 30;

packages/grafana-ui/src/components/uPlot/config/UPlotConfigBuilder.test.ts

@@ -3,7 +3,7 @@
 import { UPlotConfigBuilder } from './UPlotConfigBuilder';
 import { GrafanaTheme } from '@grafana/data';
 import { expect } from '../../../../../../public/test/lib/common';
-import { AxisPlacement, PointMode } from '../config';
+import { AxisPlacement, GraphMode, PointMode } from '../config';
 
 describe('UPlotConfigBuilder', () => {
   describe('scales config', () => {
@@ -122,14 +122,13 @@ describe('UPlotConfigBuilder', () => {
   it('allows series configuration', () => {
     const builder = new UPlotConfigBuilder();
     builder.addSeries({
+      mode: GraphMode.Line,
       scaleKey: 'scale-x',
-      fill: true,
       fillColor: '#ff0000',
       fillOpacity: 0.5,
       points: PointMode.Auto,
       pointSize: 5,
       pointColor: '#00ff00',
-      line: true,
       lineColor: '#0000ff',
       lineWidth: 1,
     });
@@ -142,6 +141,7 @@ describe('UPlotConfigBuilder', () => {
           Object {},
           Object {
             "fill": "rgba(255, 0, 0, 0.5)",
+            "paths": [Function],
             "points": Object {
               "fill": "#00ff00",
               "size": 5,

packages/grafana-ui/src/components/uPlot/config/UPlotSeriesBuilder.ts

@@ -1,31 +1,52 @@
 import tinycolor from 'tinycolor2';
-import { Series } from 'uplot';
-import { PointMode } from '../config';
+import uPlot, { Series } from 'uplot';
+import { GraphMode, LineConfig, AreaConfig, PointsConfig, PointMode, LineInterpolation } from '../config';
+import { barsBuilder, smoothBuilder, staircaseBuilder } from '../paths';
 import { PlotConfigBuilder } from '../types';
 
-export interface SeriesProps {
+export interface SeriesProps extends LineConfig, AreaConfig, PointsConfig {
+  mode: GraphMode;
   scaleKey: string;
-  line?: boolean;
-  lineColor?: string;
-  lineWidth?: number;
-  points?: PointMode;
-  pointSize?: number;
-  pointColor?: string;
-  fill?: boolean;
-  fillOpacity?: number;
-  fillColor?: string;
 }
 
 export class UPlotSeriesBuilder extends PlotConfigBuilder<SeriesProps, Series> {
   getConfig() {
-    const { line, lineColor, lineWidth, points, pointColor, pointSize, fillColor, fillOpacity, scaleKey } = this.props;
+    const {
+      mode,
+      lineInterpolation,
+      lineColor,
+      lineWidth,
+      points,
+      pointColor,
+      pointSize,
+      fillColor,
+      fillOpacity,
+      scaleKey,
+    } = this.props;
 
-    const lineConfig = line
-      ? {
-          stroke: lineColor,
-          width: lineWidth,
+    let lineConfig: Partial<Series> = {};
+
+    if (mode === GraphMode.Points) {
+      lineConfig.paths = () => null;
+    } else {
+      lineConfig.stroke = lineColor;
+      lineConfig.width = lineWidth;
+      lineConfig.paths = (self: uPlot, seriesIdx: number, idx0: number, idx1: number) => {
+        let pathsBuilder = self.paths;
+
+        if (mode === GraphMode.Bars) {
+          pathsBuilder = barsBuilder;
+        } else if (mode === GraphMode.Line) {
+          if (lineInterpolation === LineInterpolation.Staircase) {
+            pathsBuilder = staircaseBuilder;
+          } else if (lineInterpolation === LineInterpolation.Smooth) {
+            pathsBuilder = smoothBuilder;
+          }
         }
-      : {};
+
+        return pathsBuilder(self, seriesIdx, idx0, idx1);
+      };
+    }
 
     const pointsConfig: Partial<Series> = {
       points: {
@@ -36,7 +57,11 @@ export class UPlotSeriesBuilder extends PlotConfigBuilder<SeriesProps, Series> {
     };
 
     // we cannot set points.show property above (even to undefined) as that will clear uPlot's default auto behavior
-    if (points === PointMode.Never) {
+    if (points === PointMode.Auto) {
+      if (mode === GraphMode.Bars) {
+        pointsConfig.points!.show = false;
+      }
+    } else if (points === PointMode.Never) {
       pointsConfig.points!.show = false;
     } else if (points === PointMode.Always) {
       pointsConfig.points!.show = true;

packages/grafana-ui/src/components/uPlot/paths.ts

@@ -0,0 +1,257 @@
+import uPlot, { Series } from 'uplot';
+
+export const barsBuilder: Series.PathBuilder = (u: uPlot, seriesIdx: number, idx0: number, idx1: number) => {
+  const series = u.series[seriesIdx];
+  const xdata = u.data[0];
+  const ydata = u.data[seriesIdx];
+  const scaleX = u.series[0].scale as string;
+  const scaleY = series.scale as string;
+
+  const gapFactor = 0.25;
+
+  let gap = (u.width * gapFactor) / (idx1 - idx0);
+  let maxWidth = Infinity;
+
+  //@ts-ignore
+  let fillTo = series.fillTo(u, seriesIdx, series.min, series.max);
+
+  let y0Pos = u.valToPos(fillTo, scaleY, true);
+  let colWid = u.bbox.width / (idx1 - idx0);
+
+  let strokeWidth = Math.round(series.width! * devicePixelRatio);
+
+  let barWid = Math.round(Math.min(maxWidth, colWid - gap) - strokeWidth);
+
+  let stroke = new Path2D();
+
+  for (let i = idx0; i <= idx1; i++) {
+    let yVal = ydata[i];
+
+    if (yVal == null) {
+      continue;
+    }
+
+    let xVal = u.scales.x.distr === 2 ? i : xdata[i];
+
+    // TODO: all xPos can be pre-computed once for all series in aligned set
+    let xPos = u.valToPos(xVal, scaleX, true);
+    let yPos = u.valToPos(yVal, scaleY, true);
+
+    let lft = Math.round(xPos - barWid / 2);
+    let btm = Math.round(Math.max(yPos, y0Pos));
+    let top = Math.round(Math.min(yPos, y0Pos));
+    let barHgt = btm - top;
+
+    stroke.rect(lft, top, barWid, barHgt);
+  }
+
+  let fill = series.fill != null ? new Path2D(stroke) : undefined;
+
+  return {
+    stroke,
+    fill,
+  };
+};
+
+export const staircaseBuilder: Series.PathBuilder = (u: uPlot, seriesIdx: number, idx0: number, idx1: number) => {
+  const series = u.series[seriesIdx];
+  const xdata = u.data[0];
+  const ydata = u.data[seriesIdx];
+  const scaleX = u.series[0].scale as string;
+  const scaleY = series.scale as string;
+
+  const stroke = new Path2D();
+  stroke.moveTo(Math.round(u.valToPos(xdata[0], scaleX, true)), Math.round(u.valToPos(ydata[0]!, scaleY, true)));
+
+  for (let i = idx0; i <= idx1 - 1; i++) {
+    let x0 = Math.round(u.valToPos(xdata[i], scaleX, true));
+    let y0 = Math.round(u.valToPos(ydata[i]!, scaleY, true));
+    let x1 = Math.round(u.valToPos(xdata[i + 1], scaleX, true));
+    let y1 = Math.round(u.valToPos(ydata[i + 1]!, scaleY, true));
+
+    stroke.lineTo(x0, y0);
+    stroke.lineTo(x1, y0);
+
+    if (i === idx1 - 1) {
+      stroke.lineTo(x1, y1);
+    }
+  }
+
+  const fill = new Path2D(stroke);
+
+  //@ts-ignore
+  let fillTo = series.fillTo(u, seriesIdx, series.min, series.max);
+
+  let minY = Math.round(u.valToPos(fillTo, scaleY, true));
+  let minX = Math.round(u.valToPos(u.scales[scaleX].min!, scaleX, true));
+  let maxX = Math.round(u.valToPos(u.scales[scaleX].max!, scaleX, true));
+
+  fill.lineTo(maxX, minY);
+  fill.lineTo(minX, minY);
+
+  return {
+    stroke,
+    fill,
+  };
+};
+
+// adapted from https://gist.github.com/nicholaswmin/c2661eb11cad5671d816 (MIT)
+/**
+ * Interpolates a Catmull-Rom Spline through a series of x/y points
+ * Converts the CR Spline to Cubic Beziers for use with SVG items
+ *
+ * If 'alpha' is 0.5 then the 'Centripetal' variant is used
+ * If 'alpha' is 1 then the 'Chordal' variant is used
+ *
+ *
+ * @param  {Array} data - Array of points, each point in object literal holding x/y values
+ * @return {String} d - SVG string with cubic bezier curves representing the Catmull-Rom Spline
+ */
+function catmullRomFitting(xCoords: number[], yCoords: number[], alpha: number) {
+  const path = new Path2D();
+
+  const dataLen = xCoords.length;
+
+  let p0x,
+    p0y,
+    p1x,
+    p1y,
+    p2x,
+    p2y,
+    p3x,
+    p3y,
+    bp1x,
+    bp1y,
+    bp2x,
+    bp2y,
+    d1,
+    d2,
+    d3,
+    A,
+    B,
+    N,
+    M,
+    d3powA,
+    d2powA,
+    d3pow2A,
+    d2pow2A,
+    d1pow2A,
+    d1powA;
+
+  path.moveTo(Math.round(xCoords[0]), Math.round(yCoords[0]));
+
+  for (let i = 0; i < dataLen - 1; i++) {
+    let p0i = i === 0 ? 0 : i - 1;
+
+    p0x = xCoords[p0i];
+    p0y = yCoords[p0i];
+
+    p1x = xCoords[i];
+    p1y = yCoords[i];
+
+    p2x = xCoords[i + 1];
+    p2y = yCoords[i + 1];
+
+    if (i + 2 < dataLen) {
+      p3x = xCoords[i + 2];
+      p3y = yCoords[i + 2];
+    } else {
+      p3x = p2x;
+      p3y = p2y;
+    }
+
+    d1 = Math.sqrt(Math.pow(p0x - p1x, 2) + Math.pow(p0y - p1y, 2));
+    d2 = Math.sqrt(Math.pow(p1x - p2x, 2) + Math.pow(p1y - p2y, 2));
+    d3 = Math.sqrt(Math.pow(p2x - p3x, 2) + Math.pow(p2y - p3y, 2));
+
+    // Catmull-Rom to Cubic Bezier conversion matrix
+
+    // A = 2d1^2a + 3d1^a * d2^a + d3^2a
+    // B = 2d3^2a + 3d3^a * d2^a + d2^2a
+
+    // [   0             1            0          0          ]
+    // [   -d2^2a /N     A/N          d1^2a /N   0          ]
+    // [   0             d3^2a /M     B/M        -d2^2a /M  ]
+    // [   0             0            1          0          ]
+
+    d3powA = Math.pow(d3, alpha);
+    d3pow2A = Math.pow(d3, 2 * alpha);
+    d2powA = Math.pow(d2, alpha);
+    d2pow2A = Math.pow(d2, 2 * alpha);
+    d1powA = Math.pow(d1, alpha);
+    d1pow2A = Math.pow(d1, 2 * alpha);
+
+    A = 2 * d1pow2A + 3 * d1powA * d2powA + d2pow2A;
+    B = 2 * d3pow2A + 3 * d3powA * d2powA + d2pow2A;
+    N = 3 * d1powA * (d1powA + d2powA);
+
+    if (N > 0) {
+      N = 1 / N;
+    }
+
+    M = 3 * d3powA * (d3powA + d2powA);
+
+    if (M > 0) {
+      M = 1 / M;
+    }
+
+    bp1x = (-d2pow2A * p0x + A * p1x + d1pow2A * p2x) * N;
+    bp1y = (-d2pow2A * p0y + A * p1y + d1pow2A * p2y) * N;
+
+    bp2x = (d3pow2A * p1x + B * p2x - d2pow2A * p3x) * M;
+    bp2y = (d3pow2A * p1y + B * p2y - d2pow2A * p3y) * M;
+
+    if (bp1x === 0 && bp1y === 0) {
+      bp1x = p1x;
+      bp1y = p1y;
+    }
+
+    if (bp2x === 0 && bp2y === 0) {
+      bp2x = p2x;
+      bp2y = p2y;
+    }
+
+    path.bezierCurveTo(bp1x, bp1y, bp2x, bp2y, p2x, p2y);
+  }
+
+  return path;
+}
+
+export const smoothBuilder: Series.PathBuilder = (u: uPlot, seriesIdx: number, idx0: number, idx1: number) => {
+  const series = u.series[seriesIdx];
+  const xdata = u.data[0];
+  const ydata = u.data[seriesIdx];
+  const scaleX = u.series[0].scale as string;
+  const scaleY = series.scale as string;
+
+  const alpha = 0.5;
+
+  let xCoords = [];
+  let yCoords = [];
+
+  for (let i = idx0; i <= idx1; i++) {
+    if (ydata[i] != null) {
+      xCoords.push(u.valToPos(xdata[i], scaleX, true));
+      yCoords.push(u.valToPos(ydata[i]!, scaleY, true));
+    }
+  }
+
+  const stroke = catmullRomFitting(xCoords, yCoords, alpha);
+
+  const fill = new Path2D(stroke);
+
+  //@ts-ignore
+  let fillTo = series.fillTo(u, seriesIdx, series.min, series.max);
+
+  let minY = Math.round(u.valToPos(fillTo, scaleY, true));
+  let minX = Math.round(u.valToPos(u.scales[scaleX].min!, scaleX, true));
+  let maxX = Math.round(u.valToPos(u.scales[scaleX].max!, scaleX, true));
+
+  fill.lineTo(maxX, minY);
+  fill.lineTo(minX, minY);
+
+  return {
+    stroke,
+    fill,
+  };
+};

public/app/plugins/panel/graph3/module.tsx

@@ -33,28 +33,27 @@ export const plugin = new PanelPlugin<Options, GraphFieldConfig>(GraphPanel)
           },
         })
         .addRadio({
-          path: 'lineMode',
+          path: 'lineInterpolation',
           name: 'Line interpolation',
-          description: 'NOTE: not implemented yet',
-          defaultValue: graphFieldOptions.lineMode[0].value,
+          defaultValue: graphFieldOptions.lineInterpolation[0].value,
           settings: {
-            options: graphFieldOptions.lineMode,
+            options: graphFieldOptions.lineInterpolation,
           },
-          showIf: c => !(c.mode === GraphMode.Bar || c.mode === GraphMode.Points),
+          showIf: c => c.mode === GraphMode.Line,
         })
         .addSliderInput({
           path: 'lineWidth',
           name: 'Line width',
           defaultValue: 1,
           settings: {
-            min: 1,
+            min: 0,
             max: 10,
             step: 1,
           },
-          showIf: c => !(c.mode === GraphMode.Bar || c.mode === GraphMode.Points),
+          showIf: c => c.mode !== GraphMode.Points,
         })
         .addSliderInput({
-          path: 'fillAlpha',
+          path: 'fillOpacity',
           name: 'Fill area opacity',
           defaultValue: 0.1,
           settings: {
@@ -62,7 +61,7 @@ export const plugin = new PanelPlugin<Options, GraphFieldConfig>(GraphPanel)
             max: 1,
             step: 0.1,
           },
-          showIf: c => !(c.mode === GraphMode.Bar || c.mode === GraphMode.Points),
+          showIf: c => c.mode !== GraphMode.Points,
         })
         .addRadio({
           path: 'points',
@@ -73,9 +72,9 @@ export const plugin = new PanelPlugin<Options, GraphFieldConfig>(GraphPanel)
           },
         })
         .addSliderInput({
-          path: 'pointRadius',
-          name: 'Point radius',
-          defaultValue: 4,
+          path: 'pointSize',
+          name: 'Point size',
+          defaultValue: 5,
           settings: {
             min: 1,
             max: 10,