View mode

There are a few view modes which can be adjusted to provide an optimal presentation such as layout, fit, or reflow. Additionally, you can present a view mode dialog allowing a user to change these settings.

Layout

Page layout/presentation mode

PDFViewCtrl supports a number of page layouts (presentation modes), as listed below:

Page presentation mode	Description
SINGLE	Displays one page at a time, swiping left and right to change pages.
SINGLE_CONT	Displays one page at a time, scrolling up and down to change pages.
SINGLE_VERT	Displays one page at a time, swiping up and down to change pages.
FACING	Displays two pages at a time, with odd-numbered pages on left, swiping left and right to change pages.
FACING_CONT	Displays pages in two columns, with odd-numbered pages on left, scrolling up and down to change pages.
FACING_VERT	Displays two pages at a time, with odd-numbered pages on left, swiping up and down to change pages.
FACING_COVER	Displays two pages at a time, with odd-numbered pages on right, swiping left and right to change pages.
FACING_COVER_CONT	Display pages in two columns, with odd-numbered pages on right, scrolling up and down to change pages.
FACING_COVER_VERT	Displays two pages at a time, with odd-numbered pages on right, swiping up and down to change pages.

Set the page presentation mode

You can set page presentation mode in your PDFViewCtrl by using PDFViewCtrl.setPagePresentationMode(PagePresentationMode):

Java

mPdfViewCtrl.setPagePresentationMode(PDFViewCtrl.PagePresentationMode.FACING);

Kotlin

mPdfViewCtrl.pagePresentationMode = PDFViewCtrl.PagePresentationMode.FACING

Fit

Page fit & default zoom mode in Android

PDFViewCtrl's page view mode controls the default zoom level of pages and documents. New documents will automatically open at the zoom level specified by the mode.

If you configured PDFViewCtrl by using [AppUtils.setupPDFViewCtrl](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/utils/AppUtils.html#setupPDFViewCtrl(PDFViewCtrl, com.pdftron.pdf.config.PDFViewCtrlConfig)), the page view mode and zoom level is maintained automatically. Click here to learn more about setting up PDFViewCtrl.

Page view modes

PDFViewCtrl supports the following page view modes:

Page view mode	Description	Screenshot-portrait	Screenshot-landscape
PageViewMode.FIT_PAGE	The zoom is set so that the entire page is visible without scrolling.
PageViewMode.FIT_WIDTH	The zoom is set so that the page's width matches the viewer's width.
PageViewMode.FIT_HEIGHT	The zoom is set so that the page's height matches the viewer's height.
PageViewMode.ZOOM	The viewer's zoom is not adjusted based on the page.

Set the default page fit mode

You can set a default page fit mode in your PDFViewCtrl by using setPageRefViewMode(PageViewMode).

Set the page fit mode dynamically

If you want to dynamically change the page fit mode, use setPageViewMode(PageViewMode). Note that when the user flips the page, the page view mode will be automatically reset to the default mode set by setPageRefViewMode.

Java

mPdfViewCtrl.setPageViewMode(PDFViewCtrl.PageViewMode.FIT_WIDTH);

Kotlin

mPdfViewCtrl.pageViewMode = PDFViewCtrl.PageViewMode.FIT_WIDTH

It is also possible to maintain the zoom level when switching pages.

PDFViewCtrl allows users to zoom in and out with touch gestures. To maintain zoom level when flipping pages, call setMaintainZoomEnabled(boolean). Note that when you double tap PDFViewCtrl will end zooming and reset the page view mode to preferred page view mode. To set preferred page view mode, callsetPreferredViewMode(PageViewMode).

Java

private PDFViewCtrl mPdfViewCtrl;
// ...
private void zoomSettingSample() throws PDFNetException {
    // Enable maintain zoom level
    mPdfViewCtrl.setMaintainZoomEnabled(true);
    // Set preferred view mode to PageViewMode.FIT_PAGE
    mPdfViewCtrl.setPreferredViewMode(PDFViewCtrl.PageViewMode.FIT_PAGE);
    // Set PageViewMode.FIT_PAGE to current page view mode
    mPdfViewCtrl.setPageViewMode(PDFViewCtrl.PageViewMode.FIT_PAGE);
}

Kotlin

private var mPdfViewCtrl: PDFViewCtrl? = null
// ...
private fun zoomSettingSample() {
    // Enable maintain zoom level
    mPdfViewCtrl!!.isMaintainZoomEnabled = true
    // Set preferred view mode to PageViewMode.FIT_PAGE
    mPdfViewCtrl!!.preferredViewMode = PDFViewCtrl.PageViewMode.FIT_PAGE
    // Set PageViewMode.FIT_PAGE to current page view mode
    mPdfViewCtrl!!.pageViewMode = PDFViewCtrl.PageViewMode.FIT_PAGE
}

Reflow

Reflow document mode in Android

For Android, available in the full version of the library only. See Apryse full or standard?

Reflow makes the document more flexible and easier to read, especially on small devices. Apryse is able to extract the reflowable layout of each page in a PDF document to an HTML file. First, we explain how simple it is to show a widget that allows the user to swipe left or right through the pages of the document to see reflowable document pages. Then, we provide the methods necessary for converting a hard-layout PDF page to an HTML document page.

Show reflow pager

ReflowControl is a ViewPager that allows the user to flip left and right through the reflowable layout of pages in a PDF document.

Implementation

To set up your layout with ReflowControl, add a <ReflowControl> element to your XML layout. For example, if each page in the swipe view should consume the entire layout, then your layout looks like this:

<com.pdftron.pdf.controls.ReflowControl xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/reflow_pager" android:layout_width="match_parent" android:layout_height="match_parent" />

Then, you need to attach a PDFDoc to the reflow pager:

Java

ReflowControl reflowControl = (ReflowControl) findViewById(R.id.reflow_pager);
reflowControl.setup(pdfDoc);

Kotlin

val reflowControl = findViewById(R.id.reflow_pager) as ReflowControl
reflowControl.setup(pdfDoc)

Scrolling direction

Java

// horizontal (default)
reflowControl.setOrientation(ReflowControl.HORIZONTAL);
// vertical
reflowControl.setOrientation(ReflowControl.VERTICAL);

Kotlin

// horizontal (default)
reflowControl.orientation = ReflowControl.HORIZONTAL;
// vertical
reflowControl.orientation = ReflowControl.VERTICAL;

That is everything you need to have a simple reflow pager. Next, we will go through advanced features.

Post-processing color

If you want to map each original color to a new color (for example for handling night mode) you need to pass an OnPostProcessColorListener listener to the ReflowControl.

To do so, you can provide an OnPostProcessColorListener listener when setting up the ReflowControl:

Java

ReflowControl reflowControl = (ReflowControl) findViewById(R.id.reflow_pager);
reflowControl.setup(pdfDoc, mOnPostProcessColorListener);

Kotlin

val reflowControl = findViewById(R.id.reflow_pager) as ReflowControl
reflowControl.setup(pdfDoc, mOnPostProcessColorListener)

For example, OnPostProcessColorListener can be defined by PDFViewCtrl as:

Java

final ReflowControl.OnPostProcessColorListener mOnPostProcessColorListener =
    new ReflowControl.OnPostProcessColorListener() {
        @Override
        public ColorPt getPostProcessedColor(ColorPt cp) {
            if (mPDFViewCtrl != null) {
                return mPDFViewCtrl.getPostProcessedColor(cp);
            }
            return cp;
        }
    };

Kotlin

val mOnPostProcessColorListener = ReflowControl.OnPostProcessColorListener { cp ->
    if (mPDFViewCtrl != null) {
      mPDFViewCtrl.getPostProcessedColor(cp)
    } else cp
  }

Alternatively you can set a listener:

Java

ReflowControl reflowControl = (ReflowControl) findViewById(R.id.reflow_pager);
reflowControl.setup(pdfDoc);
reflowControl.setOnPostProcessColorListener(mOnPostProcessColorListener);

Kotlin

val reflowControl = findViewById(R.id.reflow_pager) as ReflowControl
reflowControl.setup(pdfDoc)
reflowControl.setOnPostProcessColorListener(mOnPostProcessColorListener)

Notify the reflow pager that the document has been modified

To refresh the reflow pager to show the latest changes on your document, you should let the reflow pager know that the document has been modified:

Java

void notifyReflowModified(ReflowControl reflowControl) {
    if (reflowControl != null && reflowControl.isReady()) {
        reflowControl.notifyPagesModified();
    }
}

Kotlin

fun notifyReflowModified(reflowControl: ReflowControl?) {
    if (reflowControl != null && reflowControl.isReady) {
        reflowControl.notifyPagesModified()
    }
}

Set the text size

It is possible to change the size of reflowable text. The default text size is 100; valid values are 5, 10, 25, 50, 75, 100, 125, 150, 200, 400, 800, and 1600. See the following code as an example:

Java

void changeReflowSize(ReflowControl reflowControl, int percent) {
    if (reflowControl != null && reflowControl.isReady()) {
        reflowControl.setTextSizeInPercent(percent);
    }
}

Kotlin

fun changeReflowSize(reflowControl: ReflowControl?, percent: Int) {
    if (reflowControl != null && reflowControl.isReady) {
        reflowControl.textSizeInPercent = percent
    }
}

Alternatively, you can zoom in/out to change the reflowable text size:

Java

void zoomReflow(ReflowControl reflowControl, boolean zoomIn) {
    if (reflowControl != null && reflowControl.isReady()) {
        if (zoomIn) {
            reflowControl.zoomIn();
        } else {
            reflowControl.zoomOut();
        }
    }
}

Kotlin

fun zoomReflow(reflowControl: ReflowControl?, zoomIn: Boolean) {
    if (reflowControl != null && reflowControl.isReady) {
        if (zoomIn) {
            reflowControl.zoomIn()
        } else {
            reflowControl.zoomOut()
        }
    }
}

Assuming the current text size is 100%, by calling zoomReflow(reflowControl, true) and zoomReflow(reflowControl, false) the new text size will be 125% and 75% of the original size, respectively.

Set background color

There are three methods to change the background color:

setDayMode(): no background

setNightMode(): night background

setCustomColorMode(int): customized background

Set right-to-left direction

You can support right-to-left (RTL) languages by setting the direction of reflowable text by calling setRightToLeftDirection(isRtlMode)

Generate a reflow page

It is not necessary to use a reflow pager to create a reflowable layout of PDF pages. It is also possible to extract the reflowable layout by creating an HTML file from a specific page of the document using the ReflowProcessor class. The first step is to let the Core know you are going to use reflow by calling initialize(). Please note that this method clears all existing reflowable data. Thus, preferably put this call in your Application or Activity.

When reflow processor has been initialized, it is possible to turn reflow on by calling [getReflow(Page, RequestHandler, Object)](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/ReflowProcessor.html#getReflow(com.pdftron.pdf.Page, com.pdftron.pdf.RequestHandler, java.lang.Object)) and passing a RequestHandler callback in order to be notified once the reflowable HTML file is ready::

Java

void getReflowPage(PDFViewCtrl pdfViewCtrl, final int pageNum) throws Exception {
    final PDFDoc doc = pdfViewCtrl.getDoc();
    pdfViewCtrl.docLockRead(new PDFViewCtrl.LockRunnable() {
        @Override
        public void run() throws Exception {
            Page page = doc.getPage(pageNum);
            ReflowProcessor.getReflow(page, mRequestHandler, pageNum);
        }
    });
}
RequestHandler mRequestHandler = new RequestHandler(new RequestHandler.RequestHandlerCallback() {
    @Override
    public void RequestHandlerProc(RequestHandler.JobRequestResult result, String outFilename, Object customData) {
        if (result == RequestHandler.JobRequestResult.FINISHED) {
            // int pageNum = (int) customData;
            // A reflowable HTML file with a page number of pageNum is located at outFilename
        }
    }
});

Kotlin

fun getReflowPage(pdfViewCtrl: PDFViewCtrl, pageNum: Int) {
    val doc = pdfViewCtrl.doc
    pdfViewCtrl.docLockRead {
        val page = doc.getPage(pageNum)
        ReflowProcessor.getReflow(page, mRequestHandler, pageNum)
    }
}
var mRequestHandler = RequestHandler(RequestHandlerCallback { result, outFilename, customData ->
    if (result == JobRequestResult.FINISHED) { // int pageNum = (int) customData;
        // A reflowable HTML file with a page number of pageNum is located at outFilename
    }
})

To cancel all reflow requests, call cancelAllRequests().

Finally, if you want to clear all HTML files created in the cache, you may need to call clearCache().

Dialog

View mode dialog

ViewModePickerDialogFragment allows users to: pick page layout mode, select page color mode, rotate pages, and crop pages.

Show view mode dialog

To show a view mode dialog in your activity, create a new instance of ViewModePickerDialogFragment by calling newInstance(PagePresentationMode, boolean, boolean, int):

Java

private PDFViewCtrl mPdfViewCtrl;
// ...
public void showViewModeDialog(FragmentManager fragmentManager) {
  ViewModePickerDialogFragment dialog = ViewModePickerDialogFragment.newInstance(mPdfViewCtrl.getPagePresentationMode(), false, false, 0);
  // Set a custom style for this dialog
  dialog.setStyle(DialogFragment.STYLE_NORMAL, com.pdftron.pdf.tools.R.style.PDFTronAppTheme);
  // Show the dialog
  dialog.show(fragmentManager, "view_mode_picker");
}

Kotlin

private var mPdfViewCtrl: PDFViewCtrl? = null
// ...
fun showViewModeDialog(fragmentManager: FragmentManager) {
  val dialog = ViewModePickerDialogFragment.newInstance(mPdfViewCtrl?.pagePresentationMode, false, false, 0)
  // Set a custom style for this dialog
  dialog.setStyle(DialogFragment.STYLE_NORMAL, com.pdftron.pdf.tools.R.style.PDFTronAppTheme)
  // Show the dialog
  dialog.show(fragmentManager, "view_mode_picker")
}

Set view mode dialog listener

In order to let users pick PDF page presentation mode, color mode, etc. you need to set a ViewModePickerDialogFragmentListener by calling setViewModePickerDialogFragmentListener. Implement each method in the listener to change page presentation mode, color mode, reflow, etc.

Java

dialog.setViewModePickerDialogFragmentListener(new ViewModePickerDialogFragment.ViewModePickerDialogFragmentListener() {
   /**
    * Called when a view mode has been selected.
    *
    * @param viewMode The selected view mode
    */
    @Override
    public void onViewModeSelected(String viewMode) {
        // Implement functionality for each view mode selected
        // ...
    }

    /**
      * Called when a color mode has been selected.
      *
      * @param colorMode The color mode
      * @return True if the dialog should be dismissed
      */
    @Override
    public boolean onViewModeColorSelected(int colorMode) {
        return false;
    }

    /**
      * Called when a custom color mode is selected
      *
      * @param bgColor  The selected background color
      * @param txtColor The selected text color
      * @return True if the dialog should be dismissed
      */
    @Override
    public boolean onCustomColorModeSelected(int bgColor, int txtColor) {
        return false;
    }

    /**
      * Called when the dialog has been dismissed.
      */
    @Override
    public void onViewModePickerDialogFragmentDismiss() {
        // Do something when the dialog is dismissed
    }

    /**
      * The implementation should zoom in/out reflow
      *
      * @param flagZoomIn True if zoom in; False if zoom out
      * @return The text size raging from 0 to 100
      */
    @Override
    public int onReflowZoomInOut(boolean flagZoomIn) {
        return 0;
    }

    /**
      * The implementation should check tab conversion and shows the alert if needed.
      *
      * @param messageID      The message ID
      * @param allowConverted True if conversion is allowed
      * @return True if handled
      */
    @Override
    public boolean checkTabConversionAndAlert(int messageID, boolean allowConverted) {
        return false;
    }
});

Kotlin

dialog.setViewModePickerDialogFragmentListener(object : ViewModePickerDialogFragment.ViewModePickerDialogFragmentListener {
  /**
    * Called when a view mode has been selected.
    *
    * @param viewMode The selected view mode
    */
  override fun onViewModeSelected(viewMode: String) {
    // Implement functionality for each view mode selected
    // ...
  }

  /**
    * Called when a color mode has been selected.
    *
    * @param colorMode The color mode
    * @return True if the dialog should be dismissed
    */
  override fun onViewModeColorSelected(colorMode: Int): Boolean {
    return false
  }

  /**
    * Called when a custom color mode is selected
    *
    * @param bgColor The selected background color
    * @param txtColor The selected text color
    * @return True if the dialog should be dismissed
    */
  override fun onCustomColorModeSelected(bgColor: Int, txtColor: Int): Boolean {
    return false
  }

  /**
    * Called when the dialog has been dismissed.
    */
  override fun onViewModePickerDialogFragmentDismiss() {
    // Do something when the dialog is dismissed
  }

  /**
    * The implementation should zoom in/out reflow
    *
    * @param flagZoomIn True if zoom in; False if zoom out
    * @return The text size raging from 0 to 100
    */
  override fun onReflowZoomInOut(flagZoomIn: Boolean): Int {
    return 0
  }

  /**
    * The implementation should check tab conversion and shows the alert if needed.
    *
    * @param messageID The message ID
    * @param allowConverted True if conversion is allowed
    * @return True if handled
    */
  override fun checkTabConversionAndAlert(messageID: Int, allowConverted: Boolean): Boolean {
    return false
  }
})

In onViewModeSelected(String), the selected view mode values are defined in PdfViewCtrlSettingsManager and include the following:

View Mode	Description	Value
KEY_PREF_VIEWMODE_CONTINUOUS_VALUE	Single page in continuous mode is selected.	"continuous"
KEY_PREF_VIEWMODE_SINGLEPAGE_VALUE	Single page presentation mode is selected.	"singlepage"
KEY_PREF_VIEWMODE_FACING_VALUE	Facing two pages presentation mode is selected.	"facing"
KEY_PREF_VIEWMODE_FACINGCOVER_VALUE	Facing two pages with odd page number on right side of PDF is selected.	"facingcover"
KEY_PREF_VIEWMODE_FACING_CONT_VALUE	In continuous mode, Facing two pages presentation mode is selected.	"facing_cont"
KEY_PREF_VIEWMODE_FACINGCOVER_CONT_VALUE	In continuous mode, Facing two pages with odd page number on right side of PDF is selected.	"facingcover_cont"
KEY_PREF_VIEWMODE_ROTATION_VALUE	Rotate pdf pages is selected.	"rotation"
KEY_PREF_VIEWMODE_USERCROP_VALUE	User-level crop pages is selected.	"user_crop"

To learn about setting page presentation mode, see PDFViewCtrl page presentation mode .

To learn about setting page color mode, see PDFViewCtrl color modes .

To learn about reflow, see reflow .

To learn about cropping pages, see crop page dialog .