37 lines
1.4 KiB
TypeScript
37 lines
1.4 KiB
TypeScript
|
import type { Directive, DirectiveBinding } from 'vue';
|
|||
|
|
|
|||
|
|
const addWaterMarker: Directive = (str: string, parentNode: any, font: any, textColor: string) => {
|
|||
|
|
// 创建一个canvas元素
|
|||
|
|
let can: HTMLCanvasElement = document.createElement('canvas');
|
|||
|
|
// 将canvas元素添加到父元素中
|
|||
|
|
parentNode.appendChild(can);
|
|||
|
|
// 设置canvas元素的宽高
|
|||
|
|
can.width = 205;
|
|||
|
|
can.height = 140;
|
|||
|
|
// 隐藏canvas元素
|
|||
|
|
can.style.display = 'none';
|
|||
|
|
// 获取canvas元素的2d上下文
|
|||
|
|
let cans = can.getContext('2d') as CanvasRenderingContext2D;
|
|||
|
|
// 旋转canvas元素
|
|||
|
|
cans.rotate((-20 * Math.PI) / 180);
|
|||
|
|
// 设置canvas元素的字体和文字颜色
|
|||
|
|
cans.font = font || '16px Microsoft JhengHei';
|
|||
|
|
cans.fillStyle = textColor || 'rgba(180, 180, 180, 0.3)';
|
|||
|
|
// 设置canvas元素的文本对齐方式和基线
|
|||
|
|
cans.textAlign = 'left';
|
|||
|
|
cans.textBaseline = 'Middle' as CanvasTextBaseline;
|
|||
|
|
// 在canvas元素上绘制文本
|
|||
|
|
cans.fillText(str, can.width / 10, can.height / 2);
|
|||
|
|
// 将父元素的背景图片设置为canvas元素的dataURL
|
|||
|
|
parentNode.style.backgroundImage = `url("${can.toDataURL('image/png')}")`;
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
const waterMarker: Directive = {
|
|||
|
|
mounted(el: DirectiveBinding, binding: DirectiveBinding) {
|
|||
|
|
// 调用addWaterMarker函数，给元素添加水印
|
|||
|
|
addWaterMarker(binding.value.text, el, binding.value.font, binding.value.textColor);
|
|||
|
|
},
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
export default waterMarker;
|