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Tag: PDF.js

PDF.js

[PDF.js] Get PDF Viewer when it’s available in DOM and fully initialized

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https://github.com/mozilla/pdf.js/wiki/Third-party-viewer-usage

<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html?file=" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

            displayPdf: async function (id) { 
                const pdfArrayBuffer= await getPdf(id)
                const pdfViewerIFrame = await getPdfViewer()
                await pdfViewerIFrame.contentWindow.PDFViewerApplication.initializedPromise
                await pdfViewerIFrame.contentWindow.PDFViewerApplication.open(pdfArrayBuffer)
            },

            getPdfViewer: function (id = 'pdf-js-viewer') {
                return new Promise((resolve, reject) => {
                    let pdfViewerIFrame = document.getElementById(id)
                    //if already loaded in DOM, return it
                    if (pdfViewerIFrame?.contentWindow?.PDFViewerApplication) {
                        resolve(pdfViewerIFrame)
                    } else {
                        //if not loaded yet, set up eventListener
                        document.addEventListener("webviewerloaded", async () => {
                            pdfViewerIFrame = document.getElementById(id)
                            resolve(pdfViewerIFrame)
                        })
                    }
                })
            }

This logic helped me to get the PDFViewerApplication in every situation correctly, for example when reloading the page with F5 or when having the PDF viewer already loaded and just wanting to open another PDF file.

PDF.js

[PDF.js] Set filename when downloading pdf

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When using a blob or base64 data to open a file in PDF.js, the viewer is not able to get the correct filename. So when downloading the pdf using the download button inside the viewer, it will always download as document.pdf. To manually set a filename, you can use the setTitleUsingUrl function.

<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html?file=" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

let pdfViewerIFrame = document.getElementById("pdf-js-viewer")
pdfViewerIFrame.contentWindow.PDFViewerApplication.setTitleUsingUrl("myFilename")

More info here: https://github.com/mozilla/pdf.js/issues/10435

PDF.js

[PDF.js] Set light and dark theme manually

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The new PDF.js viewer design Photon supports a light and a dark mode. By default, the theme is set automatically. To overwrite this, you can set the viewerCssTheme property.

I’ve embedded my PDF viewer in an iFrame like this:

<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

By setting the viewerCssTheme property, you are able to change the PDF viewer theme. It can be modified using the PDFViewerApplicationOptions.set() function and there are three possible values. The property has to be set before the Viewer is initialized. To archive this, you can listen to the event webviewerloaded (read more about it here). In my case, I also had to call _forceCssTheme() after that.

                document.addEventListener("webviewerloaded", async () => {
                    let pdfViewerIFrame = document.getElementById("pdf-js-viewer")
                    // https://github.com/mozilla/pdf.js/blob/master/web/app_options.js
                    pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("viewerCssTheme", 1)       // 0=automatic theme, 1=light theme, 2=dark theme 
                    pdfViewerIFrame.contentWindow.PDFViewerApplication._forceCssTheme()
                })

PDF.js

[PDF.js] Allow PDF documents to disable copying in the viewer

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With pull request 11789, the PDF Viewer respects the PDF property Content Copying, if the viewer option enablePermissions is set to true.

I’ve embedded my viewer in an iFrame like this:

<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

The enablePermissions property can be modified using the PDFViewerApplicationOptions.set() function. The property has to be set before the Viewer is initialized. To archive this, you can listen to the event webviewerloaded (read more about it here). 

                document.addEventListener("webviewerloaded", async () => {
                    let pdfViewerIFrame = document.getElementById("pdf-js-viewer")
                    //https://github.com/mozilla/pdf.js/blob/master/web/app_options.js
                    pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("enablePermissions", true) //allow PDF documents to disable copying in the viewer
                    pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("defaultUrl", "") //prevent loading default pdf
                    }
                })

PDF.js

[PDF.js] Prevent loading default pdf

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This can be done by appending ?file= to the src path, like it is mentionend here.

<!-- "?file=" prevents loading the default document -->
<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html?file=" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

Or by setting the variable defaultUrl to blank using the onload event.

document.addEventListener("webviewerloaded", async () => {
   let pdfViewerIFrame = document.getElementById("pdf-js-viewer")
   //https://github.com/mozilla/pdf.js/blob/master/web/app_options.js
   pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("defaultUrl", "") //prevent loading default pdf
})