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Magnification in .NET MAUI PDF Viewer (SfPdfViewer)

7 Mar 20265 minutes to read

Give users precise control over how PDF content is displayed — from pinch-to-zoom on touch screens to setting an exact zoom percentage in code. You can also lock the view to predefined zoom modes like Fit to Page or Fit to Width to optimize readability for different document types.

Adjusting the Zoom Factor

You can control the zoom level using the ZoomFactor property. Refer to the following code example.

<syncfusion:SfPdfViewer x:Name="PdfViewer" DocumentSource="{Binding PdfDocumentStream}" ZoomFactor ="3" />
PdfViewer.ZoomFactor = 3;

You can also retrieve the current zoom level using the same property.

Setting Minimum and Maximum Zoom Limits

By default, the zoom range varies by platform:

  • Mobile (Android/iOS): 1.0 to 4.0
  • Desktop (Windows/macOS): 0.25 to 4.0

To restrict zoom levels, use the MinZoomFactor and MaxZoomFactor properties.

The following code example explains restricting the zoom factor between 0.5 and 2.

<syncfusion:SfPdfViewer x:Name="PdfViewer" DocumentSource="{Binding PdfDocumentStream}"  MinZoomFactor = “0.5” MaxZoomFactor ="2" />
PdfViewer.MinZoomFactor = 0.5;
PdfViewer.MaxZoomFactor = 2;

NOTE

If the ZoomFactor is set outside the defined MinZoomFactor and MaxZoomFactor range, it will be ignored.

You can download a sample project demonstrating magnification features here.

Zoom Modes

The PDF Viewer supports the following zoom modes via the ZoomMode property:

  1. Default – Restores the viewer to the last user-set zoom level. This is the initial mode when a document is loaded.
  2. Fit to Page – Displays the entire page within the viewport.
  3. Fit to Width – Expands the page to fill the width of the viewer.

The default value is ZoomMode.Default.

Zoom Mode via Built-In Toolbar

Desktop Toolbar

The built-in toolbar includes a magnification dropdown showing the current zoom percentage. Users can select predefined zoom levels or choose Fit to Page / Fit to Width.

Desktop Zoom Mode Combo Box

Mobile Toolbar

On mobile, the magnification tool appears only after the zoom factor changes. Users can then select Fit to Page or Fit to Width. Once selected, the icon disappears until the zoom factor changes again.

Mobile Zoom Mode Combo box

Programmatically Setting Zoom Mode

Fit to Page

You can change the SfPdfViewer.ZoomMode using the ZoomMode.FitToPage enumeration. It will magnify the PDF document so that the entire PDF page is visible in the view port.
Refer to the following code example: 

<Syncfusion:PdfViewer x:Name="pdfViewer" ZoomMode="FitToPage"/>
// To apply fit-to-page zoom mode. 
pdfViewer.ZoomMode = ZoomMode.FitToPage;

Fit to Width

You can change the SfPdfViewer.ZoomMode using the ZoomMode.FitToWidth enumeration. It will magnify the PDF document so that the widest page of the PDF document fits the width of the view port.
Refer to the following code example:

<Syncfusion:PdfViewer x:Name="pdfViewer" ZoomMode="FitToWidth"/>
// To apply fit-to-page zoom mode. 
pdfViewer.ZoomMode = ZoomMode.FitToWidth;

NOTE

When the ZoomFactor is manually changed, the ZoomMode resets to Default. You can reapply the desired zoom mode afterward.

Maintain Zoom Level in Single Page View Mode

In single-page view mode, the zoom level resets to default each time you navigate to a new page. To maintain a consistent zoom factor throughout the document, enable the PersistZoomOnPageChange property. This applies whether navigation is triggered by the built-in toolbar controls or programmatic APIs.
The default value of PersistZoomOnPageChange is False.

Enable PersistZoomOnPageChange

You can enable persistent zoom by setting the PersistZoomOnPageChange property to True. When enabled, the viewer preserves the numeric ZoomFactor when switching pages in SinglePage layout and applies that same zoom to the destination page. Refer to the following code example:

<syncfusion:SfPdfViewer x:Name="PdfViewer"
                        PageLayoutMode="SinglePage"
                        PersistZoomOnPageChange="True" />
// Enable persistence and set an initial zoom
PdfViewer.PageLayoutMode = PageLayoutMode.SinglePage;
PdfViewer.PersistZoomOnPageChange = true;

Disable PersistZoomOnPageChange

Set PersistZoomOnPageChange to False to keep the viewer’s default behavior. When disabled, navigating to a different page resets the viewer to the default zoom level unless you explicitly set a zoom after navigation. Refer to the following example:

<syncfusion:SfPdfViewer x:Name="PdfViewer"
                        PageLayoutMode="SinglePage"
                        PersistZoomOnPageChange="False" />
// Disable persistence
PdfViewer.PersistZoomOnPageChange = false;

See Also