New sample: Progressive Line With Easing

docs/.vuepress/config.js

@@ -250,6 +250,7 @@ module.exports = {
             'animations/drop',
             'animations/loop',
             'animations/progressive-line',
+            'animations/progressive-line-easing',
           ]
         },
         {

docs/samples/animations/progressive-line-easing.md

@@ -0,0 +1,172 @@
+# Progressive Line With Easing
+
+```js chart-editor
+
+// <block:data:2>
+const data = [];
+const data2 = [];
+let prev = 100;
+let prev2 = 80;
+for (let i = 0; i < 1000; i++) {
+  prev += 5 - Math.random() * 10;
+  data.push({x: i, y: prev});
+  prev2 += 5 - Math.random() * 10;
+  data2.push({x: i, y: prev2});
+}
+// </block:data>
+
+// <block:animation:1>
+let easing = helpers.easingEffects.easeOutQuad;
+let restart = false;
+const totalDuration = 5000;
+const duration = (ctx) => easing(ctx.index / data.length) * totalDuration / data.length;
+const delay = (ctx) => easing(ctx.index / data.length) * totalDuration;
+const previousY = (ctx) => ctx.index === 0 ? ctx.chart.scales.y.getPixelForValue(100) : ctx.chart.getDatasetMeta(ctx.datasetIndex).data[ctx.index - 1].getProps(['y'], true).y;
+const animation = {
+  x: {
+    type: 'number',
+    easing: 'linear',
+    duration: duration,
+    from: NaN, // the point is initially skipped
+    delay(ctx) {
+      if (ctx.type !== 'data' || ctx.xStarted) {
+        return 0;
+      }
+      ctx.xStarted = true;
+      return delay(ctx);
+    }
+  },
+  y: {
+    type: 'number',
+    easing: 'linear',
+    duration: duration,
+    from: previousY,
+    delay(ctx) {
+      if (ctx.type !== 'data' || ctx.yStarted) {
+        return 0;
+      }
+      ctx.yStarted = true;
+      return delay(ctx);
+    }
+  }
+};
+// </block:animation>
+
+// <block:config:0>
+const config = {
+  type: 'line',
+  data: {
+    datasets: [{
+      borderColor: Utils.CHART_COLORS.red,
+      borderWidth: 1,
+      radius: 0,
+      data: data,
+    },
+    {
+      borderColor: Utils.CHART_COLORS.blue,
+      borderWidth: 1,
+      radius: 0,
+      data: data2,
+    }]
+  },
+  options: {
+    animation,
+    interaction: {
+      intersect: false
+    },
+    plugins: {
+      legend: false,
+      title: {
+        display: true,
+        text: () => easing.name
+      }
+    },
+    scales: {
+      x: {
+        type: 'linear'
+      }
+    }
+  }
+};
+// </block:config>
+
+// <block:actions:2>
+function restartAnims(chart) {
+  chart.stop();
+  const meta0 = chart.getDatasetMeta(0);
+  const meta1 = chart.getDatasetMeta(1);
+  for (let i = 0; i < data.length; i++) {
+    const ctx0 = meta0.controller.getContext(i);
+    const ctx1 = meta1.controller.getContext(i);
+    ctx0.xStarted = ctx0.yStarted = false;
+    ctx1.xStarted = ctx1.yStarted = false;
+  }
+  chart.update();
+}
+
+const actions = [
+  {
+    name: 'easeOutQuad',
+    handler(chart) {
+      easing = helpers.easingEffects.easeOutQuad;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeOutCubic',
+    handler(chart) {
+      easing = helpers.easingEffects.easeOutCubic;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeOutQuart',
+    handler(chart) {
+      easing = helpers.easingEffects.easeOutQuart;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeOutQuint',
+    handler(chart) {
+      easing = helpers.easingEffects.easeOutQuint;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeInQuad',
+    handler(chart) {
+      easing = helpers.easingEffects.easeInQuad;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeInCubic',
+    handler(chart) {
+      easing = helpers.easingEffects.easeInCubic;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeInQuart',
+    handler(chart) {
+      easing = helpers.easingEffects.easeInQuart;
+      restartAnims(chart);
+    }
+  },
+  {
+    name: 'easeInQuint',
+    handler(chart) {
+      easing = helpers.easingEffects.easeInQuint;
+      restartAnims(chart);
+    }
+  },
+];
+// </block:actions>
+
+module.exports = {
+  config,
+  actions
+};
+
+```

docs/scripts/helpers.js

@@ -1,4 +1,4 @@
 // Add helpers needed in samples here.
 // Usable through `helpers[name]`.
-export {color, getHoverColor} from '../../dist/helpers.esm';
+export {color, getHoverColor, easingEffects} from '../../dist/helpers.esm';