Zooming

This guide shows how to programmatically manage the zoom scale of a PDF page.

Manual Zooming

PdfFragment allows you to programmatically zoom to a certain scale or to an area of a PDF document page using a convenient zooming API.

• PdfFragment#zoomTo(RectF, int, long) allows you to zoom to a specific RectF on the given page.
• PdfFragment#zoomTo(int, int, int, float, long) lets you zoom to a focus point at the given scale.

ℹ️ Note: Both methods take PDF page coordinates. To find out more on that topic, see the guide on coordinate space conversion.

You can also easily get the current zoom level of a page by calling PdfFragment#getZoomScale.

Disable Zooming

Zooming can be disabled by setting maxZoomScale of PdfConfiguration to 1. It’s important to set this value before creating the view:

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val configuration = PdfConfiguration.Builder()
    .maxZoomScale(1.0f)
    .build()

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final PdfConfiguration configuration = new PdfConfiguration.Builder()
    .maxZoomScale(1.0f)
    .build();

Starting the Document at a Given Scale

A document can be started at an already pre-determined scale (on the given page). Note that rotating the screen resets the scale. The property that controls this is startZoomScale in PdfConfiguration:

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val configuration = PdfConfiguration.Builder()
    .startZoomScale(3.0f)
    .build()

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final PdfConfiguration configuration = new PdfConfiguration.Builder()
    .startZoomScale(3.0f)
    .build();