initHeader

frontend/src/directives/modules/waterMarker.ts

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+/*
+  需求：给整个页面添加背景水印。
+
+  思路：
+    1、使用 canvas 特性生成 base64 格式的图片文件，设置其字体大小，颜色等。
+    2、将其设置为背景图片，从而实现页面或组件水印效果
+  
+  使用：设置水印文案，颜色，字体大小即可
+  <div v-waterMarker="{text:'版权所有',textColor:'rgba(180, 180, 180, 0.4)'}"></div>
+*/
+
+import type { Directive, DirectiveBinding } from "vue";
+const addWaterMarker: Directive = (str: string, parentNode: any, font: any, textColor: string) => {
+  // 水印文字，父元素，字体，文字颜色
+  let can: HTMLCanvasElement = document.createElement("canvas");
+  parentNode.appendChild(can);
+  can.width = 205;
+  can.height = 140;
+  can.style.display = "none";
+  let cans = can.getContext("2d") as CanvasRenderingContext2D;
+  cans.rotate((-20 * Math.PI) / 180);
+  cans.font = font || "16px Microsoft JhengHei";
+  cans.fillStyle = textColor || "rgba(180, 180, 180, 0.3)";
+  cans.textAlign = "left";
+  cans.textBaseline = "Middle" as CanvasTextBaseline;
+  cans.fillText(str, can.width / 10, can.height / 2);
+  parentNode.style.backgroundImage = "url(" + can.toDataURL("image/png") + ")";
+};
+
+const waterMarker = {
+  mounted(el: DirectiveBinding, binding: DirectiveBinding) {
+    addWaterMarker(binding.value.text, el, binding.value.font, binding.value.textColor);
+  }
+};
+
+export default waterMarker;