javascript - 同步使用 ImageMagic

Question

尝试使用imagemagick

需要同步使用imagemagick。

即下一个代码应该只在图像转换完成后执行(无论错误还是成功)

我只看到一个解决方案 deasync :

const ImageMagick = require('imagemagick');
const Deasync = require('deasync');

var finished = false;
ImageMagick.convert(
  [
    source,
    path_to
  ],
  function(err, stdout){
    finished = true;
});

Deasync.loopWhile(function(){return !finished;});

// the next code performed only after image convertion will be done

是否有任何变体如何同步使用 imagemagick？

Answer 1

Node.js 是单线程的，所以你应该尽量避免让函数像这样同步。您可能只需在回调函数中执行您的代码。

const ImageMagick = require('imagemagick');

ImageMagick.convert(
  [
    source,
    path_to
  ],
  function(err, stdout){
    // the next code performed only after image convertion will be done
});

或者你可以使用 Promise 和 await，但是你的整个函数将是异步的

const ImageMagic = require('imagemagick');

function convertImage(source, path_to){
    return new Promise((resolve, reject) => {
        ImageMagick.convert(
            [
                source,
                path_to
            ],
            function(err, stdout){
                if(err) {
                    reject(err)
                }
                resolve(stdout);
            });
    })
}

async function doStuff(){
    // start the image convert
    let stdout = await convertImage(source, path_to);
    // now the function will go on when the promise from convert image is resolved
    // the next code performed only after image convertion will be done
}