生成一张带有网站标题、简介和二维码的海报，并下载。方便进行分享。
// ==UserScript==
// @name 网站二维码海报
// @namespace QRCode post for website
// @description 生成一张带有网站标题、简介和二维码的海报，并下载。方便进行分享。
// @match *://*/*
// @grant GM_download
// @grant GM_registerMenuCommand
// @require https://cdnjs.cloudflare.com/ajax/libs/qrcodejs/1.0.0/qrcode.min.js
// @noframes
// @version 0.0.2
// @author -
// @description 2020/5/9 下午8:59:19
// ==/UserScript==
const makerQRCode = ()=>{
const qrcodepostmaker = document.createElement('div');
qrcodepostmaker.id = 'qrcodepostmaker';
qrcodepostmaker.style.display = 'none';
document.body.appendChild(qrcodepostmaker);
const textComputer = (text, style, width, ctx) => {
if(text.replace(/\s/g, '').length === 0) { return [] }
ctx.font = style;
let temp = 0;
const row = [];
for (let i = 0; i <= text.length; i++) {
if (ctx.measureText(text.substring(temp, i)).width >= width) {
row.push(text.substring(temp, i-1));
temp = i-1;
}else if(i === text.length){
row.push(text.substring(temp, i));
}
}
return row;
};
const textWriter = (
textArr,
Style,
align,
color,
borderColor,
fontSize,
lineHeight,
pos,
ctx
) => {
ctx.font = Style;
ctx.textAlign = align;
ctx.fillStyle = color;
ctx.strokeStyle = borderColor;
for (const text of textArr) {
pos.y += fontSize * lineHeight;
// ctx.strokeText(text, pos.x, pos.y);
ctx.fillText(text, pos.x, pos.y);
}
return pos;
};
const makerQRPost = () => {
const canvas = document.querySelector('#qrcodepostmaker > canvas');
const ctx = canvas.getContext('2d');
const QRCodeData = ctx.getImageData(0, 0, canvas.width, canvas.height);
const title = document.title;
const desc = document.head.querySelector('meta[name="description"]') ? document.head.querySelector('meta[name="description"]').content : '';
const cardWidth = 360;
const lineHeight = 1.6;
const margin = 36;
const titleStyle = 'Bold 18px "Microsoft YaHei"';
const descStyle = '16px "Microsoft YaHei"';
const titleArray = textComputer(
title,
titleStyle,
cardWidth - margin * 2,
ctx
);
const descArray = textComputer(desc, descStyle, cardWidth - margin * 2, ctx);
const cardHeight = margin * 2.5
+ 18 * titleArray.length * lineHeight
+ 16 * descArray.length * lineHeight
+ (descArray.length ? margin/2 : 0)
+ 300;
canvas.width = cardWidth;
canvas.height = cardHeight;
const myGradient = ctx.createLinearGradient(0, 0, 0, cardHeight);
myGradient.addColorStop(0, "#2980B9");
myGradient.addColorStop(0.5, "#6DD5FA");
myGradient.addColorStop(1, "#FFFFFF");
ctx.fillStyle = myGradient;
ctx.fillRect(0, 0, cardWidth, cardHeight);
ctx.fillStyle = "#FFFFFF";
ctx.beginPath();
ctx.arc(margin*0.4, cardHeight - margin*5, margin, 0, Math.PI*2, true);
ctx.arc(cardWidth-margin*0.4, cardHeight - margin*3, margin*0.8, 0, Math.PI*2, true);
ctx.fillRect(0, cardHeight - margin*5, cardWidth/2, margin*5);
ctx.fillRect(cardWidth/2, cardHeight - margin*3, cardWidth/2, margin*3);
ctx.fill();
const titleEnd = textWriter(
titleArray,
titleStyle,
'center',
'black',
'rgba(255, 255, 255, 0.6)',
18,
lineHeight,
{ x: cardWidth / 2, y: margin },
ctx
);
const descEnd = textWriter(
descArray,
descStyle,
'left',
'black',
'rgba(255, 255, 255, 0.6)',
16,
lineHeight,
{ x: margin, y: titleEnd.y+margin/2 },
ctx
);
ctx.fillStyle = 'white';
ctx.fillRect((cardWidth-288)/2, descEnd.y + margin - 24, 288, 288);
ctx.putImageData(QRCodeData, (cardWidth-256)/2, descEnd.y + margin);
textWriter(
['（长按识别二维码进行访问）'],
descStyle,
'center',
'rgba(0, 0, 0, 0.6)',
'rgba(255, 255, 255, 0.6)',
16,
lineHeight,
{ x: cardWidth / 2, y: descEnd.y + margin + 256 },
ctx
);
GM_download(canvas.toDataURL("image/png"), title+'.png')
qrcodepostmaker.parentNode.removeChild(qrcodepostmaker)
};
let tryTimes = 30;
const makeQRCode = window.setInterval(() => {
try {
new QRCode(
document.getElementById('qrcodepostmaker'),
window.location.href
);
window.clearInterval(makeQRCode);
makerQRPost();
} catch (error) {
console.log(error)
tryTimes--;
if (!tryTimes) {
window.clearInterval(makeQRCode);
alert('没能成功载入功能库，请刷新重试~');
}
}
}, 200);
}
GM_registerMenuCommand('生成二维码海报', makerQRCode)