feat: display the time-to-type a character histogram

packages/keybr-chart/lib/TimeToTypeHistogram.tsx

@@ -0,0 +1,87 @@
+import { useFormatter } from "@keybr/lesson-ui";
+import { Range, Vector } from "@keybr/math";
+import { timeToSpeed } from "@keybr/result";
+import { Canvas, type Rect, type ShapeList, Shapes } from "@keybr/widget";
+import { type ReactNode } from "react";
+import { Chart, chartArea, type SizeProps } from "./Chart.tsx";
+import { withStyles } from "./decoration.ts";
+import { bucketize } from "./dist/util.ts";
+import { type TimeToType } from "./types.ts";
+import { type ChartStyles, useChartStyles } from "./use-chart-styles.ts";
+
+export function TimeToTypeHistogram({
+  steps,
+  width,
+  height,
+}: {
+  readonly steps: readonly TimeToType[];
+} & SizeProps): ReactNode {
+  const styles = useChartStyles();
+  const paint = usePaint(styles, steps);
+  return (
+    <Chart width={width} height={height}>
+      <Canvas paint={chartArea(styles, paint)} />
+    </Chart>
+  );
+}
+
+function usePaint(styles: ChartStyles, steps: readonly TimeToType[]) {
+  const { formatSpeed } = useFormatter();
+  const g = withStyles(styles);
+
+  const histogram = buildHistogram(steps);
+
+  const vIndex = new Vector();
+  const vValue = new Vector();
+  for (let index = 0; index < histogram.length; index++) {
+    vIndex.add(index);
+    vValue.add(histogram[index]);
+  }
+  const rIndex = Range.from(vIndex);
+  const rValue = Range.from(vValue);
+
+  return (box: Rect): ShapeList => {
+    return [
+      g.paintGrid(box, "vertical", { lines: 5 }),
+      g.paintGrid(box, "horizontal", { lines: 5 }),
+      paintHistogram(),
+      g.paintAxis(box, "bottom"),
+      g.paintAxis(box, "left"),
+      g.paintTicks(box, rIndex, "bottom", {
+        lines: 5,
+        fmt: formatSpeed,
+        style: styles.valueLabel,
+      }),
+    ];
+
+    function paintHistogram(): ShapeList {
+      return Shapes.fill(
+        styles.speed,
+        [...rIndex.steps()].map((index) => {
+          const w = Math.ceil(box.width / rIndex.span);
+          const x = Math.round(rIndex.normalize(index, 1) * box.width);
+          const y = Math.round(rValue.normalize(vValue.at(index)) * box.height);
+          return Shapes.rect({
+            x: box.x + x,
+            y: box.y + box.height - y,
+            width: w,
+            height: y,
+          });
+        }),
+      );
+    }
+  };
+}
+
+function buildHistogram(steps: readonly TimeToType[]) {
+  const histogram = new Array(1501).fill(0);
+  for (const { timeToType } of steps) {
+    if (timeToType > 0) {
+      const index = Math.round(timeToSpeed(timeToType));
+      if (index >= 0 && index < histogram.length) {
+        histogram[index] += 1;
+      }
+    }
+  }
+  return bucketize(histogram, 30);
+}

packages/keybr-chart/lib/index.ts

@@ -12,4 +12,5 @@ export * from "./Marker.tsx";
 export * from "./ProgressOverviewChart.tsx";
 export * from "./SpeedChart.tsx";
 export * from "./SpeedHistogram.tsx";
+export * from "./TimeToTypeHistogram.tsx";
 export * from "./types.ts";

packages/keybr-chart/lib/types.ts

@@ -2,3 +2,5 @@ export type Threshold = {
   readonly label: string;
   readonly value: number;
 };
+
+export type TimeToType = { readonly timeToType: number };

packages/page-typing-test/lib/components/Report.tsx

@@ -3,6 +3,7 @@ import {
   makeAccuracyDistribution,
   makeSpeedDistribution,
   SpeedHistogram,
+  TimeToTypeHistogram,
 } from "@keybr/chart";
 import { useIntlNumbers } from "@keybr/intl";
 import { useFormatter } from "@keybr/lesson-ui";
@@ -118,6 +119,16 @@ export const Report = memo(function Report({
         </Name>
       </Para>
 
+      <Box alignItems="center" justifyContent="center">
+        <TimeToTypeHistogram
+          steps={result.steps}
+          width="45rem"
+          height="15rem"
+        />
+      </Box>
+
+      <Para align="center">Time to type a character histogram.</Para>
+
       <Spacer size={3} />
 
       <Replay settings={settings} result={result} />