Add inner chart sample

docs/.vuepress/config.js

@@ -126,6 +126,7 @@ module.exports = {
             'label/callout',
             'label/canvas',
             'label/image',
+            'label/innerChart',
             'label/lowerUpper',
           ]
         },

docs/samples/label/innerChart.md

@@ -0,0 +1,158 @@
+# Inner chart
+
+```js chart-editor
+// <block:setup:5>
+const DATA_COUNT = 12;
+const MIN = 0;
+const MAX = 100;
+
+const innerChart = Utils.getChart();
+const innerDataset = innerChart.data.datasets[0];
+
+const numberCfg = {count: DATA_COUNT, min: MIN, max: MAX};
+
+const data = {
+  labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
+  datasets: [{
+    data: Utils.numbers(numberCfg),
+    borderColor: innerDataset.backgroundColor[0],
+    backgroundColor: 'transparent'
+  }, {
+    data: Utils.numbers(numberCfg),
+    borderColor: innerDataset.backgroundColor[1],
+    backgroundColor: 'transparent',
+    hidden: true
+  }, {
+    data: Utils.numbers(numberCfg),
+    borderColor: innerDataset.backgroundColor[2],
+    backgroundColor: 'transparent',
+    hidden: true
+  }]
+};
+// </block:setup>
+
+// <block:annotation1:1>
+const annotation1 = {
+  type: 'label',
+  content: innerChart.canvas,
+  xValue: 1,
+  yValue: 135,
+  enter: (ctx) => setCursor(ctx, 'pointer'),
+  leave: (ctx) => setCursor(ctx, 'default'),
+  click: clickOnInnerChart
+};
+// </block:annotation1>
+
+// <block:annotation2:2>
+const annotation2 = {
+  type: 'label',
+  content: (ctx) => [innerChart.data.labels[getVisibleDatasetIndex(ctx)],
+    'items trend'],
+  callout: {
+    enabled: true,
+    position: 'bottom',
+    margin: 0
+  },
+  font: {
+    size: 16
+  },
+  backgroundColor: 'white',
+  borderWidth: 1,
+  xAdjust: -60,
+  xValue: (ctx) => point(ctx).x,
+  yAdjust: -60,
+  yValue: (ctx) => point(ctx).y
+};
+// </block:annotation2>
+
+// <block:annotation3:3>
+const annotation3 = {
+  type: 'label',
+  content: ['Click on a slice of the pie chart', 'to see the data in the main chart'],
+  color: 'rgba(0, 0, 0, 0.5)',
+  xValue: 3.2,
+  yValue: 150,
+};
+// </block:annotation3>
+
+/* <block:config:0> */
+const config = {
+  type: 'line',
+  data,
+  options: {
+    scales: {
+      y: {
+        beginAtZero: true,
+        min: 0,
+        max: 160
+      }
+    },
+    plugins: {
+      annotation: {
+        annotations: {
+          annotation1,
+          annotation2,
+          annotation3
+        }
+      }
+    }
+  }
+};
+/* </block:config> */
+
+// <block:utils:4>
+function clickOnInnerChart(ctx, event) {
+  event.x = event.x - ctx.element.x;
+  event.y = event.y - ctx.element.y;
+  const elements = innerChart.getElementsAtEventForMode(event, 'point', {}, true);
+  if (elements.length) {
+    const first = elements[0];
+    ctx.chart.setDatasetVisibility(getVisibleDatasetIndex(ctx), false);
+    ctx.chart.show(first.index);
+  }
+}
+
+function getVisibleDatasetIndex(ctx) {
+  const chart = ctx.chart;
+  for (let i = 0; i < chart.data.datasets.length; i++) {
+    if (chart.isDatasetVisible(i)) {
+      return i;
+    }
+  }
+  return 0;
+}
+
+function point(ctx) {
+  const dataset = ctx.chart.data.datasets[getVisibleDatasetIndex(ctx)];
+  const values = dataset.data.filter((value, i) => i > dataset.data.length - 4);
+  const y = Math.max(...values);
+  const x = dataset.data.lastIndexOf(y);
+  return {x, y};
+}
+
+function setCursor(ctx, type) {
+  ctx.chart.canvas.style.cursor = type;
+}
+// </block:utils>
+
+const actions = [
+  {
+    name: 'Randomize',
+    handler: function(chart) {
+      chart.data.datasets.forEach(function(dataset, i) {
+        dataset.data = dataset.data.map(() => Utils.rand(MIN, MAX));
+      });
+      chart.update();
+      innerChart.data.datasets.forEach(function(dataset, i) {
+        dataset.data = dataset.data.map(() => Utils.rand(MIN, MAX));
+      });
+      innerChart.update();
+    }
+  }
+];
+
+module.exports = {
+  actions: actions,
+  config: config
+};
+```

docs/scripts/utils.js

@@ -1,7 +1,8 @@
+import {Chart} from 'chart.js';
 import {valueOrDefault} from 'chart.js/helpers';
 
 // Adapted from http://indiegamr.com/generate-repeatable-random-numbers-in-js/
-var _seed = Date.now();
+let _seed = Date.now();
 
 export function srand(seed) {
   _seed = seed;
@@ -50,6 +51,21 @@ export function getImage() {
   return img;
 }
 
+let pieChart = null;
+
+export function getChart() {
+  if (pieChart) {
+    return pieChart;
+  }
+  const canvas = document.createElement('canvas');
+  canvas.width = 100;
+  canvas.height = 100;
+  canvas.style.visibility = 'hidden';
+  document.body.appendChild(canvas);
+  pieChart = createChart(canvas);
+  return pieChart;
+}
+
 export function getSpiral() {
   const canvas = document.createElement('canvas');
   canvas.width = 150;
@@ -88,3 +104,27 @@ export function getHouse() {
   ctx.stroke();
   return canvas;
 }
+
+function createChart(canvas) {
+  return new Chart(canvas, {
+    type: 'pie',
+    data: {
+      labels: ['Bought', 'Sold', 'Rented'],
+      datasets: [{
+        data: [42, 33, 25],
+        backgroundColor: ['#3366cc', '#dc3912', '#ff9900']
+      }]
+    },
+    options: {
+      responsive: false,
+      animation: false,
+      plugins: {
+        autocolors: false,
+        version: false,
+        legend: false,
+        title: false,
+        subtitle: false
+      }
+    }
+  });
+}