AsposePdfPagesToPng

Convert a PDF-file to PNG.

function AsposePdfPagesToPng(
    fileBlob,
    fileName,
    fileNameResult,
    resolution
)

Parameters:

• fileBlob Blob object
• fileName file name
• fileNameResult result file name template (for sample: “ResultPdfToPng{0:D2}.png” where {0}, {0:D2}, {0:D3}, {0:Dn} - format page number)
• resolution image resolution, default 300 dpi

Return: JSON object

• errorCode - code error (0 no error)
• errorText - text error ("" no error)
• filesCount - png files count
• filesNameResult - array of result filenames

Web Worker example:

  /*Create Web Worker*/
  const AsposePDFWebWorker = new Worker("AsposePDFforJS.js");
  AsposePDFWebWorker.onerror = evt => console.log(`Error from Web Worker: ${evt.message}`);
  AsposePDFWebWorker.onmessage = evt => document.getElementById('output').textContent = 
    (evt.data == 'ready') ? 'loaded!' :
      (evt.data.json.errorCode == 0) ? 
        `Files(pages) count: ${evt.data.json.filesCount.toString()}\n${evt.data.params.forEach(
          (element, index) => DownloadFile(evt.data.json.filesNameResult[index], "image/png", element) ) ?? ""}` : 
        `Error: ${evt.data.json.errorText}`;

  /*Event handler*/
  const ffileToPng = e => {
    const file_reader = new FileReader();
    file_reader.onload = event => {
      /*Convert a PDF-file to PNG with template "ResultPdfToPng{0:D2}.png" ({0}, {0:D2}, {0:D3}, ... format page number),
        resolution 150 DPI and save - Ask Web Worker*/
      AsposePDFWebWorker.postMessage(
        { "operation": 'AsposePdfPagesToPng', "params": [event.target.result, e.target.files[0].name, "ResultPdfToPng{0:D2}.png", 150] },
        [event.target.result]
      );
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };

  /*Make a link to download the result file*/
  const DownloadFile = (filename, mime, content) => {
      mime = mime || "application/octet-stream";
      var link = document.createElement("a"); 
      link.href = URL.createObjectURL(new Blob([content], {type: mime}));
      link.download = filename;
      link.innerHTML = "Click here to download the file " + filename;
      document.body.appendChild(link); 
      document.body.appendChild(document.createElement("br"));
      return filename;
    }

Simple example:

  var ffileToPng = function (e) {
    const file_reader = new FileReader();
    file_reader.onload = (event) => {
      /*Convert a PDF-file to PNG with template "ResultPdfToPng{0:D2}.png" ({0}, {0:D2}, {0:D3}, ... format page number), resolution 150 DPI and save*/
      const json = AsposePdfPagesToPng(event.target.result, e.target.files[0].name, "ResultPdfToPng{0:D2}.png", 150);
      if (json.errorCode == 0) {
        document.getElementById('output').textContent = "Files(pages) count: " + json.filesCount.toString();
        /*Make links to result files*/
        for (let fileIndex = 0; fileIndex < json.filesCount; fileIndex++) DownloadFile(json.filesNameResult[fileIndex], "image/png");
      }
      else document.getElementById('output').textContent = json.errorText;
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };