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[PDF.js] Set light and dark theme manually

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")
                    pdfViewerIFrame.onload = () => {
                        // 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] Allow PDF documents to disable copying in the viewer

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")
                    pdfViewerIFrame.onload = () => {
                        //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] Prevent loading default pdf

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.

pdfViewer = document.getElementById("pdf-js-viewer");

pdfViewer.onload = () => {
          pdfViewer.contentWindow.PDFViewerApplicationOptions.set(
            "defaultUrl",
            ""
          );
};