Restrict zoom percentage on mobile devices
The Syncfusion® ASP.NET Core PDF Viewer allows developers to cap zoom ranges on phones and tablets by adjusting the maxZoom and minZoom properties after the documentLoad event fires. Setting device-specific limits prevents excessive pinch-zooming, keeps pages readable, and avoids stuttering caused by rendering at extreme scales.
<div style="width:100%;height:600px">
<ejs-pdfviewer id="pdfviewer"
style="height:600px"
documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf">
</ejs-pdfviewer>
</div>
<script>
function documentLoad() {
var viewer = document.getElementById('pdfviewer').ej2_instances[0];
if (ej2_base_1.Browser.isDevice && !viewer.enableDesktopMode) {
viewer.maxZoom = 200;
viewer.minZoom = 10;
}
else {
viewer.zoomMode = 'Default';
}
}
</script><div style="width:100%;height:600px">
<ejs-pdfviewer id="pdfviewer"
style="height:600px"
serviceUrl="/api/PdfViewer"
documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf">
</ejs-pdfviewer>
</div>
<script>
function documentLoad() {
var viewer = document.getElementById('pdfviewer').ej2_instances[0];
if (ej2_base_1.Browser.isDevice && !viewer.enableDesktopMode) {
viewer.maxZoom = 200;
viewer.minZoom = 10;
}
else {
viewer.zoomMode = 'Default';
}
}
</script>By enforcing these limits, mobile users can zoom between 10% and 200%, which avoids blurry rendering or performance drops caused by extreme zoom levels. Adjust the thresholds to suit the document content but keep minZoom less than or equal to maxZoom so the viewer maintains a valid range.