154.dae7ac5c.js

(window.webpackJsonp=window.webpackJsonp||[]).push([[154],{510:function(n,t,o){"use strict";o.r(t);var a=o(7),e=Object(a.a)({},(function(){var n=this,t=n._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":n.$parent.slotKey}},[t("h1",{attrs:{id:"canvas-background"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#canvas-background"}},[n._v("#")]),n._v(" Canvas background")]),n._v(" "),t("p",[n._v("In some use cases you would want a background image or color over the whole canvas. There is no built-in support for this, the way you can achieve this is by writing a custom plugin.")]),n._v(" "),t("p",[n._v("In the two example plugins underneath here you can see how you can draw a color or image to the canvas as background. This way of giving the chart a background is only necessary if you want to export the chart with that specific background.\nFor normal use you can set the background more easily with "),t("a",{attrs:{href:"https://www.w3schools.com/cssref/css3_pr_background.asp",target:"_blank",rel:"noopener noreferrer"}},[n._v("CSS"),t("OutboundLink")],1),n._v(".")]),n._v(" "),t("tabs",[t("tab",{attrs:{name:"Color"}},[t("chart-editor",{attrs:{code:"// <block:setup:1>\nconst data = {\n  labels: [\n    'Red',\n    'Blue',\n    'Yellow'\n  ],\n  datasets: [{\n    label: 'My First Dataset',\n    data: [300, 50, 100],\n    backgroundColor: [\n      'rgb(255, 99, 132)',\n      'rgb(54, 162, 235)',\n      'rgb(255, 205, 86)'\n    ],\n    hoverOffset: 4\n  }]\n};\n// </block:setup>\n\n// <block:plugin:2>\n// Note: changes to the plugin code is not reflected to the chart, because the plugin is loaded at chart construction time and editor changes only trigger an chart.update().\nconst plugin = {\n  id: 'customCanvasBackgroundColor',\n  beforeDraw: (chart, args, options) => {\n    const {ctx} = chart;\n    ctx.save();\n    ctx.globalCompositeOperation = 'destination-over';\n    ctx.fillStyle = options.color || '#99ffff';\n    ctx.fillRect(0, 0, chart.width, chart.height);\n    ctx.restore();\n  }\n};\n// </block:plugin>\n\n// <block:config:0>\nconst config = {\n  type: 'doughnut',\n  data: data,\n  options: {\n    plugins: {\n      customCanvasBackgroundColor: {\n        color: 'lightGreen',\n      }\n    }\n  },\n  plugins: [plugin],\n};\n// </block:config>\n\nmodule.exports = {\n  actions: [],\n  config: config,\n};\n"}})],1),n._v(" "),t("tab",{attrs:{name:"Image"}},[t("chart-editor",{attrs:{code:"// <block:setup:1>\nconst data = {\n  labels: [\n    'Red',\n    'Blue',\n    'Yellow'\n  ],\n  datasets: [{\n    label: 'My First Dataset',\n    data: [300, 50, 100],\n    backgroundColor: [\n      'rgb(255, 99, 132)',\n      'rgb(54, 162, 235)',\n      'rgb(255, 205, 86)'\n    ],\n    hoverOffset: 4\n  }]\n};\n// </block:setup>\n\n// <block:plugin:2>\n// Note: changes to the plugin code is not reflected to the chart, because the plugin is loaded at chart construction time and editor changes only trigger an chart.update().\nconst image = new Image();\nimage.src = 'https://www.chartjs.org/img/chartjs-logo.svg';\n\nconst plugin = {\n  id: 'customCanvasBackgroundImage',\n  beforeDraw: (chart) => {\n    if (image.complete) {\n      const ctx = chart.ctx;\n      const {top, left, width, height} = chart.chartArea;\n      const x = left + width / 2 - image.width / 2;\n      const y = top + height / 2 - image.height / 2;\n      ctx.drawImage(image, x, y);\n    } else {\n      image.onload = () => chart.draw();\n    }\n  }\n};\n// </block:plugin>\n\n// <block:config:0>\nconst config = {\n  type: 'doughnut',\n  data: data,\n  plugins: [plugin],\n};\n// </block:config>\n\nmodule.exports = {\n  actions: [],\n  config: config,\n};\n"}})],1)],1)],1)}),[],!1,null,null,null);t.default=e.exports}}]);