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| 1 | +import Data from "../../modules/data.js" |
| 2 | + |
| 3 | +export function init(id, options) { |
| 4 | + const el = document.getElementById(id); |
| 5 | + if (el === null) { |
| 6 | + return; |
| 7 | + } |
| 8 | + const watermark = { el, options }; |
| 9 | + createWatermark(watermark); |
| 10 | + |
| 11 | + const observer = ob => { |
| 12 | + ob.observe(el, { |
| 13 | + childList: true, |
| 14 | + attributes: true, |
| 15 | + subtree: true |
| 16 | + }); |
| 17 | + } |
| 18 | + |
| 19 | + const observerCallback = records => { |
| 20 | + ob.disconnect(); |
| 21 | + updateWatermark(records, watermark); |
| 22 | + observer(ob); |
| 23 | + }; |
| 24 | + |
| 25 | + const ob = new MutationObserver(observerCallback); |
| 26 | + observer(ob); |
| 27 | + watermark.ob = ob; |
| 28 | + |
| 29 | + Data.set(id, watermark); |
| 30 | +} |
| 31 | + |
| 32 | +export function update(id, options) { |
| 33 | + const watermark = Data.get(id); |
| 34 | + watermark.options = options; |
| 35 | + |
| 36 | + createWatermark(watermark); |
| 37 | +} |
| 38 | + |
| 39 | +export function dispose(id) { |
| 40 | + const watermark = Data.get(id); |
| 41 | + Data.remove(id); |
| 42 | + |
| 43 | + if (watermark) { |
| 44 | + const { ob } = watermark; |
| 45 | + ob.disconnect(); |
| 46 | + |
| 47 | + delete watermark.ob; |
| 48 | + } |
| 49 | +} |
| 50 | + |
| 51 | +const updateWatermark = (records, watermark) => { |
| 52 | + for (const record of records) { |
| 53 | + for (const dom of record.removedNodes) { |
| 54 | + if (dom.classList.contains('bb-watermark-bg')) { |
| 55 | + createWatermark(watermark); |
| 56 | + return; |
| 57 | + } |
| 58 | + } |
| 59 | + |
| 60 | + if (record.target.classList.contains('bb-watermark-bg')) { |
| 61 | + createWatermark(watermark); |
| 62 | + return; |
| 63 | + } |
| 64 | + } |
| 65 | +} |
| 66 | + |
| 67 | +const createWatermark = watermark => { |
| 68 | + const { el, options } = watermark; |
| 69 | + const defaults = { |
| 70 | + gap: 40, |
| 71 | + fontSize: 16, |
| 72 | + text: 'BootstrapBlazor', |
| 73 | + rotate: -40, |
| 74 | + color: '#0000004d' |
| 75 | + }; |
| 76 | + |
| 77 | + for (const key in options) { |
| 78 | + if (options[key] === void 0 || options[key] === null) { |
| 79 | + delete options[key]; |
| 80 | + } |
| 81 | + } |
| 82 | + |
| 83 | + const bg = getWatermark({ ...defaults, ...options }); |
| 84 | + const div = document.createElement('div'); |
| 85 | + const { base64, styleSize } = bg; |
| 86 | + div.style.backgroundImage = `url(${base64})`; |
| 87 | + div.style.backgroundSize = `${styleSize}px ${styleSize}px`; |
| 88 | + div.style.backgroundRepeat = 'repeat'; |
| 89 | + div.style.pointerEvents = 'none'; |
| 90 | + div.style.opacity = '1'; |
| 91 | + div.style.position = 'absolute'; |
| 92 | + div.style.inset = '0'; |
| 93 | + div.style.zIndex = '999'; |
| 94 | + div.classList.add("bb-watermark-bg"); |
| 95 | + |
| 96 | + const mark = el.querySelector('.bb-watermark-bg'); |
| 97 | + if (mark) { |
| 98 | + mark.remove(); |
| 99 | + } |
| 100 | + el.appendChild(div); |
| 101 | +} |
| 102 | + |
| 103 | +const getWatermark = props => { |
| 104 | + const canvas = document.createElement('canvas'); |
| 105 | + const devicePixelRatio = window.devicePixelRatio || 1; |
| 106 | + |
| 107 | + const fontSize = props.fontSize * devicePixelRatio; |
| 108 | + const font = fontSize + 'px serif'; |
| 109 | + const ctx = canvas.getContext('2d'); |
| 110 | + |
| 111 | + ctx.font = font; |
| 112 | + const { width } = ctx.measureText(props.text); |
| 113 | + const canvasSize = Math.max(100, width) + props.gap * devicePixelRatio; |
| 114 | + canvas.width = canvasSize; |
| 115 | + canvas.height = canvasSize; |
| 116 | + ctx.translate(canvas.width / 2, canvas.height / 2); |
| 117 | + |
| 118 | + ctx.rotate((Math.PI / 180) * props.rotate); |
| 119 | + ctx.fillStyle = props.color; |
| 120 | + ctx.font = font; |
| 121 | + ctx.textAlign = 'center'; |
| 122 | + ctx.textBaseline = 'middle'; |
| 123 | + |
| 124 | + ctx.fillText(props.text, 0, 0); |
| 125 | + return { |
| 126 | + base64: canvas.toDataURL(), |
| 127 | + size: canvasSize, |
| 128 | + styleSize: canvasSize / devicePixelRatio, |
| 129 | + }; |
| 130 | +} |
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