node文字生成图片的示例代码

今天老板提了需求，要在服务端生成邀请卡，嗯…，简单的说就是把要这张：

变成差多这样的：

后端搞ruby的哥们搞了个html转图片，说转得太慢了，我就把这坑接下来了

所以睡前就倒腾了下，搞了个简单的实现

解决思路

文字转svg -> svg转png -> 合并图片

相关*

1. images node.js 轻量级跨平台图像编解码库，不需要额外安装依赖
2. text-to-svg 文字转svg
3. svg2png svg转png图片

示例代码

'use strict';

const fs = require('fs');
const images = require('images');
const texttosvg = require('text-to-svg');
const svg2png = require("svg2png");
const promise = require('bluebird');

promise.promisifyall(fs);

const texttosvg = texttosvg.loadsync('fonts/文泉驿微米黑.ttf');

const sourceimg = images('./i/webwxgetmsgimg.jpg');
const swidth = sourceimg.width();
const sheight = sourceimg.height();

const svg1 = texttosvg.getsvg('魏长青-人人讲app', {
 x: 0,
 y: 0,
 fontsize: 24,
 anchor: 'top',
});

const svg2 = texttosvg.getsvg('邀请您参加', {
 x: 0,
 y: 0,
 fontsize: 16,
 anchor: 'top',
});

const svg3 = texttosvg.getsvg('人人讲课程', {
 x: 0,
 y: 0,
 fontsize: 32,
 anchor: 'top',
});

promise.coroutine(function* generateinvitationcard() {
 const targetimg1path = './i/1.png';
 const targetimg2path = './i/2.png';
 const targetimg3path = './i/3.png';
 const targetimg4path = './i/qrcode.jpg';
 const [buffer1, buffer2, buffer3] = yield promise.all([
  svg2png(svg1),
  svg2png(svg2),
 svg2png(svg3),
 ]);

 yield promise.all([
  fs.writefileasync(targetimg1path, buffer1),
  fs.writefileasync(targetimg2path, buffer2),
  fs.writefileasync(targetimg3path, buffer3),
 ]);

 const target1img = images(targetimg1path);
 const t1width = target1img.width();
 const t1height = target1img.height();
 const offsetx1 = (swidth - t1width) / 2;
 const offsety1 = 200;

 const target2img = images(targetimg2path);
 const t2width = target2img.width();
 const t2height = target2img.height();
 const offsetx2 = (swidth - t2width) / 2;
 const offsety2 = 240;

 const target3img = images(targetimg3path);
 const t3width = target3img.width();
 const t3height = target3img.height();
 const offsetx3 = (swidth - t3width) / 2;
 const offsety3 = 270;

 const target4img = images(targetimg4path);
 const t4width = target4img.width();
 const t4height = target4img.height();
 const offsetx4 = (swidth - t4width) / 2;
 const offsety4 = 400;

 images(sourceimg)
 .draw(target1img, offsetx1, offsety1)
 .draw(target2img, offsetx2, offsety2)
 .draw(target3img, offsetx3, offsety3)
 .draw(target4img, offsetx4, offsety4)
 .save('./i/card.png', { quality : 90 });
})().catch(e => console.error(e));

注意事项

text-to-svg需要中文字体的支持，不然中文会乱码

在我的破电脑上执行一次只花了500多毫秒，感觉足够了，分享出来希望能给大家一个参照

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。