Bar: inflate rects by 0.33px to avoid artifacts (#9399)

* Bar: inflate rects by 0.33px to avoid artifacts
* Update fixture
* YAGNI

src/elements/element.bar.js

@@ -1,5 +1,5 @@
 import Element from '../core/core.element';
-import {isObject} from '../helpers';
+import {isObject, _limitValue} from '../helpers';
 import {addRoundedRectPath} from '../helpers/helpers.canvas';
 import {toTRBL, toTRBLCorners} from '../helpers/helpers.options';
 
@@ -67,7 +67,7 @@ function startEnd(v, start, end) {
 }
 
 function skipOrLimit(skip, value, min, max) {
-  return skip ? 0 : Math.max(Math.min(value, max), min);
+  return skip ? 0 : _limitValue(value, min, max);
 }
 
 function parseBorderWidth(bar, maxW, maxH) {
@@ -156,6 +156,20 @@ function addNormalRectPath(ctx, rect) {
   ctx.rect(rect.x, rect.y, rect.w, rect.h);
 }
 
+function inflateRect(rect, amount, refRect = {}) {
+  const x = rect.x !== refRect.x ? -amount : 0;
+  const y = rect.y !== refRect.y ? -amount : 0;
+  const w = (rect.x + rect.w !== refRect.x + refRect.w ? amount : 0) - x;
+  const h = (rect.y + rect.h !== refRect.y + refRect.h ? amount : 0) - y;
+  return {
+    x: rect.x + x,
+    y: rect.y + y,
+    w: rect.w + w,
+    h: rect.h + h,
+    radius: rect.radius
+  };
+}
+
 export default class BarElement extends Element {
 
   constructor(cfg) {
@@ -176,20 +190,21 @@ export default class BarElement extends Element {
     const options = this.options;
     const {inner, outer} = boundingRects(this);
     const addRectPath = hasRadius(outer.radius) ? addRoundedRectPath : addNormalRectPath;
+    const inflateAmount = 0.33;
 
     ctx.save();
 
     if (outer.w !== inner.w || outer.h !== inner.h) {
       ctx.beginPath();
-      addRectPath(ctx, outer);
+      addRectPath(ctx, inflateRect(outer, inflateAmount, inner));
       ctx.clip();
-      addRectPath(ctx, inner);
+      addRectPath(ctx, inflateRect(inner, -inflateAmount, outer));
       ctx.fillStyle = options.borderColor;
       ctx.fill('evenodd');
     }
 
     ctx.beginPath();
-    addRectPath(ctx, inner);
+    addRectPath(ctx, inflateRect(inner, inflateAmount, outer));
     ctx.fillStyle = options.backgroundColor;
     ctx.fill();
 

test/fixtures/controller.bar/borderColor/border+dpr.js

@@ -0,0 +1,35 @@
+module.exports = {
+  threshold: 0,
+  tolerance: 0,
+  config: {
+    type: 'bar',
+    data: {
+      labels: [0, 1, 2, 3, 4, 5, 6],
+      datasets: [
+        {
+          // option in dataset
+          data: [5, 4, 3, 2, 3, 4, 5],
+        },
+      ]
+    },
+    options: {
+      events: [],
+      devicePixelRatio: 1.5,
+      barPercentage: 1,
+      categoryPercentage: 1,
+      backgroundColor: 'black',
+      borderColor: 'black',
+      borderWidth: 8,
+      scales: {
+        x: {display: false},
+        y: {display: false}
+      }
+    }
+  },
+  options: {
+    canvas: {
+      height: 256,
+      width: 501
+    }
+  }
+};

test/fixtures/controller.bar/borderRadius/no-spacing.js

@@ -0,0 +1,33 @@
+module.exports = {
+  threshold: 0.01,
+  config: {
+    type: 'bar',
+    data: {
+      labels: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
+      datasets: [
+        {
+          data: [9, 25, 13, 17, 12, 21, 20, 19, 6, 12, 14, 20],
+          categoryPercentage: 1,
+          barPercentage: 1,
+          backgroundColor: '#2E5C76',
+          borderWidth: 2,
+          borderColor: '#377395',
+          borderRadius: 5,
+        },
+      ]
+    },
+    options: {
+      devicePixelRatio: 1.25,
+      scales: {
+        x: {display: false},
+        y: {display: false}
+      }
+    }
+  },
+  options: {
+    canvas: {
+      height: 256,
+      width: 512
+    }
+  }
+};

test/fixtures/scale.category/ticks-from-data.js

@@ -4,19 +4,13 @@ module.exports = {
     type: 'bar',
     data: {
       datasets: [{
-        data: [10, 5, 0, 25, 78]
+        data: [10, 5, 0, 25, 78],
+        backgroundColor: 'transparent'
       }],
       labels: ['tick1', 'tick2', 'tick3', 'tick4', 'tick5']
     },
     options: {
       indexAxis: 'y',
-      elements: {
-        bar: {
-          backgroundColor: '#AAAAAA80',
-          borderColor: '#80808080',
-          borderWidth: {bottom: 6, left: 15, top: 6, right: 15}
-        }
-      },
       scales: {
         x: {display: false},
         y: {display: true}
@@ -24,6 +18,10 @@ module.exports = {
     }
   },
   options: {
-    spriteText: true
+    spriteText: true,
+    canvas: {
+      width: 128,
+      height: 256
+    }
   }
 };