Cropping PDF pages in Android

With the Apryse library you can crop pages manually or automatically, as well as reset document pages to their original size. The UserCropDialogFragment allows a user to adjust the page's crop box which can then be applied to a subset of pages or to all the pages in a document.

Show user crop pages dialog

To show a user crop pages dialog in your activity, create a new instance of UserCropDialogFragment by calling newInstance() and setting the PDFViewCtrl:

Java

private PDFViewCtrl mPdfViewCtrl;
// ...
public void showUserCropDialog(FragmentManager fragmentManager) {
    UserCropDialogFragment fragment = UserCropDialogFragment.newInstance();
    fragment.setPdfViewCtrl(mPdfViewCtrl);
    // Set a custom style for this dialog
    fragment.setStyle(DialogFragment.STYLE_NO_TITLE, R.style.PDFTronAppTheme);
    // Show the dialog
    fragment.show(fragmentManager, "user_crop_pages_dialog");
}

Kotlin

private var mPdfViewCtrl: PDFViewCtrl? = null
// ...
fun showUserCropDialog(fragmentManager: FragmentManager) {
    val fragment = UserCropDialogFragment.newInstance()
    fragment.setPdfViewCtrl(mPdfViewCtrl!!)
    // Set a custom style for this dialog
    fragment.setStyle(DialogFragment.STYLE_NO_TITLE, R.style.PDFTronAppTheme)
    // Show the dialog
    fragment.show(fragmentManager, "user_crop_pages_dialog")
}

In order to view user cropped pages in PDFViewCtrl make sure you set Page.e_user_crop as the default page box:

Java

mPdfViewCtrl.setPageBox(Page.e_user_crop);

Kotlin

mPdfViewCtrl?.setPageBox(Page.e_user_crop)

You can also set a listener via setOnUserCropDialogDismissListener(...) to be notified when the user crop dialog is dismissed.

UserCropDialogFragment does not crop pages permanently, it may not handled well by other PDF viewer. To crop pages permanently, see cropping pages permanently

Automatically crop pages

You can also automatically crop the edges of the document based on the position of the content. To do this, you can simply call the utility method UserCropUtilities.AutoCropInBackgroundTask and pass in your activity and PDFViewCtrl.

Example

Java

UserCropUtilities.AutoCropInBackgroundTask autoCropTask =
    new UserCropUtilities.AutoCropInBackgroundTask(getContext(), mPdfViewCtrl,
        new UserCropUtilities.AutoCropInBackgroundTask.AutoCropTaskListener() {
            @Override
            public void onAutoCropTaskDone() {
                // Auto crop task was finished or cancelled
            }
        });

Kotlin

val autoCropTask = UserCropUtilities.AutoCropInBackgroundTask(context, mPdfViewCtrl,
    UserCropUtilities.AutoCropInBackgroundTask.AutoCropTaskListener {
        // Auto crop task was finished or cancelled
    })

Remove user defined crop boxes

If you wish to remove user defined cropping for a given page you can call the utility method UserCropUtilities.removeUserCropFromPage(Page).

Permanently crop pages

Cropping pages using the above methods are at user-level. User-level page-cropping may not be handled well by other PDF viewers. To apply crop pages permanently use UserCropUtilities.cropDoc(PDFDoc).