第一步：新建paintingSeal.js文件，文件内容如下：
"use strict";
let Seal = {
//签章颜色定义
colors: ['red', 'blue', '#000'],
//签章字体定义
fonts: ['宋体', 'YouYuan', 'KaiTi'],
baseConf: {
color: null,
font: null,
},
commonMethod(cType, fType) {
let color = null;
color = this.colors[cType];
if (color === undefined || color == 'undefined') {
color = this.colors[0];
}
let font = this.fonts[fType];
if (font === undefined || font == 'undefined') {
font = this.fonts[0];
}
this.baseConf.color = color;
this.baseConf.font = font;
},
/**
*
* @param company 公司名称
* @param sType 横向文
* @param seaNo 下弦文
* @param cType 颜色 0.红 1. 蓝色 2.其他
* @param fType 字体 0.宋体
*/
companySeal: function (company, sType, seaNo, cType, fType) {
var canvas = document.createElement("canvas");
var context = canvas.getContext('2d');
canvas.width = 200;
canvas.height = 200;
this.commonMethod(cType, fType);
let width = canvas.width / 2;
let height = canvas.height / 2;
//画圆方法
drawCircle()
draw5Start(width, height)
drawTitle();
writeCompany()
writeSeaNo()
//返回图片base64
return canvas.toDataURL();
function drawCircle() {
context.lineWidth = 5;
context.strokeStyle = Seal.baseConf.color;
context.beginPath();
context.arc(width, height, 90, 0, Math.PI * 2); //宽、高、半径
context.stroke();
}
function draw5Start(sx, sy) {
context.save();
context.fillStyle = Seal.baseConf.color;
context.translate(sx, sy); //移动坐标原点
context.rotate(Math.PI); //旋转
context.beginPath(); //创建路径
var dig = (Math.PI / 5) * 4;
for (var i = 0; i < 5; i++) {
//画五角星的五条边
var x = Math.sin(i * dig);
var y = Math.cos(i * dig);
context.lineTo(x * 20, y * 20);
}
context.closePath();
context.stroke();
context.fill();
context.restore();
}
function drawTitle() {
context.font = '12px ' + Seal.baseConf.font;
context.textBaseline = "middle"; //设置文本的垂直对齐方式
context.textAlign = "center"; //设置文本的水平对对齐方式
context.lineWidth = 1;
context.strokeStyle = Seal.baseConf.color;
context.strokeText(sType, width, height + 45);
}
function writeCompany() {
context.translate(width, height); // 平移到此位置,
context.font = '18px ' + Seal.baseConf.font;
var count1 = company.length; // 字数
var angle1 = (6 * Math.PI) / (5 * (count1 - 1)); // 字间角度
var chars1 = company.split("");
var c1;
for (var i = 0; i < count1; i++) {
c1 = chars1[i]; // 需要绘制的字符
if (i == 0) {
context.rotate((19 * Math.PI) / 21);
} else {
context.rotate(angle1);
}
context.save();
context.translate(75, 0); // 平移到此位置,此时字和x轴垂直，公司名称和最外圈的距离
context.rotate(Math.PI / 2); // 旋转90度,让字平行于x轴
context.strokeText(c1, 0, 0); // 此点为字的中心点
context.restore();
}
}
function writeSeaNo() {
context.translate(0, 0); // 平移到此位置,
context.font = '12px ' + Seal.baseConf.font;
var count = seaNo.length; // 字数
var angle = (-3 * Math.PI) / (5 * (count - 1)); // 字间角度
var chars = seaNo.split("");
var c;
for (var i = 0; i < count; i++) {
c = chars[i]; // 需要绘制的字符
if (i == 0) {
context.rotate((7 * Math.PI) / 10);
} else {
context.rotate(angle);
}
context.save();
context.translate(80, 0); // 平移到此位置,此时字和x轴垂直，公司名称和最外圈的距离
context.rotate((Math.PI * 3) / 2); // 旋转90度,让字平行于x轴
context.strokeText(c, 0, 0); // 此点为字的中心点
context.restore();
}
}
},
/**
*
* @param company 公司名称
* @param sType 横向文
* @param seaNo 下弦文
* @param cType 颜色 0.红 1. 蓝色 2.其他
* @param fType 字体 0.宋体
*/
companyEllipse: function (company, sType, seaNo, cType, fType) {
//椭圆长轴半径
var radiusX = 200;
//短轴半径
var radiusY = 125;
this.commonMethod(cType, fType);
var color = Seal.baseConf.color;
var font = Seal.baseConf.font;
var canvas = document.createElement("canvas");
canvas.width = 200;
canvas.height = 200;
canvas.width = 2 * radiusX + 5;
canvas.height = 2 * radiusY + 5;
var context = canvas.getContext('2d');
writeFont(true, company);
writeFont(false, seaNo);
writeTitle();
drawEllipse();
return canvas.toDataURL();
function drawEllipse() {
context.ellipse(radiusX + context.lineWidth + 1, radiusY + context.lineWidth + 1, radiusX, radiusY, 0, 0, Math.PI * 2);
//背景透明
context.fillStyle = "rgba(255, 255, 255, 0)";
context.strokeStyle = color;
context.lineWidth = 5;
context.fill();
context.stroke();
}
function writeFont(isTop, words) {
var totalArcAng = 270;
let f = ""
//字体长度
if (!isTop) {
totalArcAng = 90;
f = "20px " + font
} else {
f = "30px " + font
}
var fontTextLen = words.length;
var radiusWidth = radiusX + context.lineWidth;
var radiusHeight = radiusY + context.lineWidth;
//从边线向中心的移动因子
var minRat = 1.1;
//起始角度
var startAngle = isTop == true ? -90 - totalArcAng / 2 : 90 - totalArcAng / 2;
var step = 0.5;
var alCount = Math.ceil(totalArcAng / step) + 1;
var angleArr = new Array(alCount);
var arcLenArr = new Array(alCount);
var num = 0;
var accArcLen = 0;
angleArr[num] = startAngle;
arcLenArr[num] = accArcLen;
num++;
var angR = startAngle * Math.PI / 180;
var lastX = radiusX * Math.cos(angR) + radiusWidth;
var lastY = radiusY * Math.sin(angR) + radiusHeight;
for (var i = startAngle + step; num < alCount; i += step) {
angR = i * Math.PI / 180;
var x = radiusX * Math.cos(angR) + radiusWidth;
var y = radiusY * Math.sin(angR) + radiusHeight;
accArcLen += Math.sqrt((lastX - x) * (lastX - x) + (lastY - y) * (lastY - y));
angleArr[num] = i;
arcLenArr[num] = accArcLen;
lastX = x;
lastY = y;
num++;
}
var arcPer = accArcLen / fontTextLen;
for (var i = 0; i < fontTextLen; i++) {
var arcL = i * arcPer + arcPer / 2;
var ang = 0;
for (var p = 0; p < arcLenArr.length - 1; p++) {
if (arcLenArr[p] <= arcL && arcL <= arcLenArr[p + 1]) {
ang = (arcL >= ((arcLenArr[p] + arcLenArr[p + 1]) / 2)) ? angleArr[p + 1] : angleArr[p];
break;
}
}
angR = (ang * Math.PI / 180);
var x = radiusX * Math.cos(angR) + radiusX;
var y = radiusY * Math.sin(angR) + radiusY;
var qxang = Math.atan2(radiusY * Math.cos(angR), -radiusX * Math.sin(angR));
var fxang = qxang + Math.PI / 2;
var subIndex = isTop == true ? i : fontTextLen - 1 - i;
var c = words[subIndex];
var w = 25; var h = 31;
if (!isTop) {
w = 2; h = 10;
}
x += (h * minRat) * Math.cos(fxang);
y += (h * minRat) * Math.sin(fxang);
if (isTop) {
x += -w / 2 * Math.cos(qxang);
y += -w / 2 * Math.sin(qxang);
} else {
x += w / 2 * Math.cos(qxang);
y += w / 2 * Math.sin(qxang);
}
context.save()
context.translate(x, y);
if (isTop == true) {
context.rotate((fxang * 180 / Math.PI - 90) * Math.PI / 180)
} else {
context.rotate((fxang * 180 / Math.PI + 180 - 90) * Math.PI / 180)
}
context.translate(-x, -y)
context.fillStyle = color;
context.font = f;
context.fillText(c, x, y);
context.restore();
}
}
function writeTitle() {
context.fillStyle = color;
context.font = 'bolder 24px ' + Seal.baseConf.font;
context.textAlign = 'center';
context.fillText(sType, radiusX, radiusY + 65);
context.restore();
}
}
}
export default Seal
第二步：导入新建的js文件
import Seal from "当前文件路径（需要自己改哦，别直接复制运行哟）";
第三步：使用
圆形公章：
let src = Seal.companySeal(
"公司名字",
"横向文",
"下弦文",
0,
0
);
注：src为base64图片字符串，直接可用img标签加载
椭圆公章：
let src = Seal.companyEllipse(
"公司名字",
"横向文",
"下弦文",
0,
0
);
src和上面的一样哟，代码就到此为止了，大家可直接使用。
