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View Code? Open in Web Editor NEWJavaScript用canvans 画圆形 椭圆公章 正方形 长方形私章
JavaScript用canvans 画圆形 椭圆公章 正方形 长方形私章
大佬可以弄成class模块化 npm安装导入吗?
`//椭圆签章
companyEllipse: function (company,name,nameb,serNo,fType,cType) {
//椭圆长轴半径
var radiusX = 140;
//短轴半径
var radiusY = 90;
this.commonMethod(cType,fType);
var color = FXQ.baseConf.color;
var font = FXQ.baseConf.font;
//var canvas = document.getElementById('canvas');
var canvas = document.createElement("canvas");
var context = canvas.getContext('2d');
canvas.width = 300;
canvas.height = 300;
canvas.width = 2 * radiusX + 5;
canvas.height = 2 * radiusY + 5;
writeFont(true,company);
writeFont(false,serNo);
writeTitle(name);
writeTitleb(nameb);
drawEllipse();
drowImageToCanvas(context,0,0);
// canvas对象绘制图片
function drowImageToCanvas(context,x,y) {
var img = new Image();
//指定图片的URL
img.src = "/fg.png";
//浏览器加载图片完毕后再绘制图片
img.onload = function(){
context.save();
context.drawImage(img,0,0);
context.restore();
};
}
function writeFont(isTop,words) {
var totalArcAng = 180;
font = "20px "+font
//字体长度
if (!isTop) {
totalArcAng = 60;
font = "10px "+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 = 0.9;
//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 = font;
context.fillText(c,x,y);
context.restore();
}
}
function writeTitle(name) {
context.fillStyle = color;
context.font = '20px SimSun';
context.textAlign = 'center';
context.fillText(name,radiusX,radiusY+10);
context.restore();
}
function writeTitleb(nameb) {
context.fillStyle = color;
context.font = '20px SimSun';
context.textAlign = 'center';
context.fillText(nameb,radiusX,radiusY+55);
context.restore();
}
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 = 3;
context.fill();
context.stroke();
}
//返回图片base64
return canvas.toDataURL();
},`
drowImageToCanvas函数,图片是存在的,加了代码没有效果,请问如何解决,感谢。
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