Hack 10 Pace Your Reading or Present a Slideshow in Acrobat or Reader

You can make Acrobat or Reader advance a document at a preset interval, making it easy to maintain a given reading pace or to present slides.

If you are sitting down for a long, on-screen read, consider adding this "cruise control" feature to Acrobat/Reader. It turns PDF pages at an adjustable pace. Acrobat and Reader already have a similar "slideshow" feature, but it works only when viewing PDFs in Full Screen mode.

In Acrobat or Reader 6.0, also try the View Automatically Scroll feature. It smoothly scrolls the pages across the screen.

1.11.1 Acrobat/Reader Full-Screen Slideshow

If you have a PDF photo album [Hack #48] or slideshow presentation, you can configure Acrobat/Reader to automatically advance through the pages at a timed pace. Select Edit Preferences . . . General . . . Full Screen (Acrobat/Reader 6 Windows) or Edit Preferences . . . Full Screen (Acrobat/Reader 5 Windows) or Acrobat Preferences . . . Full Screen (Acrobat/Reader 6 Macintosh). Set the page advance, looping, and navigation options as shown in Figure 1-11, and click OK. Open your PDF, select Window Full Screen View (Acrobat/Reader 6 for Windows or Macintosh) or View Full Screen (Acrobat/Reader 5), and the slideshow begins. To exit Full Screen mode, press Ctrl-L (Windows) or Command-L (Mac).

Figure 1-11. Configuring Acrobat/Reader's Full Screen mode to show slides

You can also use this slideshow feature as a "cruise control" for on-screen reading. However, the Full Screen mode hides document bookmarks and application menus, and adjusting its timing is a multistep burden.

1.11.2 JavaScript Page Turner

The following JavaScript for Acrobat and Reader provides a more flexible page turner. You can run it outside of Full Screen mode, and its timing is easier to adjust.

Visit http://www.pdfhacks.com/page_turner/ to download the JavaScript in Example 1-3. Unzip it, and then copy it into your Acrobat or Reader JavaScripts directory. [Hack #96] explains where to find this directory on your platform. Restart Acrobat/Reader, and page_turner.js will add new items to your View menu.

Example 1-3. JavaScript for turning pages

// page_turner.js, version 1.0

// visit: http://www.pdfhacks.com/page_turner/



var pt_wait= 3000; // three seconds; set to taste

var pt_step= 1000; // adjust speed in steps of one second

var pt_timeout= 0;

var pt_our_doc= 0;

var pt_our_path= 0;



function PT_Stop( ) {

  if( pt_timeout!= 0 ) {

    // stop turning pages

    app.clearInterval( pt_timeout );



    pt_timeout= 0;

    pt_our_doc= 0;

    pt_our_path= 0;

  }

}



function PT_TurnPage( ) {

  if( this!= pt_our_doc ||

      this.path!= pt_our_path )

  { // Acrobat's state has changed; stop turning pages

    PT_Stop( );

  }

  else if( 0< this.pageNum &&

           this.pageNum== this.numPages- 1 )

  {

    app.execMenuItem("FirstPage"); // return to the beginning

  }

  else {

    // this works better than this.pageNum++ when

    // using 'continuous facing pages' viewing mode

    app.execMenuItem("NextPage");

  }

}



function PT_Start( wait ) {

  if( pt_timeout== 0 ) {

    // start turning pages

    pt_our_path= this.path;

    pt_our_doc= this;

    pt_timeout= app.setInterval( 'PT_TurnPage( )', wait );

  }

}



////

// add menu items to the Acrobat/Reader View menu



app.addMenuItem( {

cName: "-",              // menu divider

cParent: "View",         // append to the View menu

cExec: "void(0);" 

} );



app.addMenuItem( {

cName: "Start Page Turner &4",

cParent: "View",

cExec: "PT_Start( pt_wait );",

//

// "event" is an object passed to us upon execution;

// in this context, event.target is the currently active document;

// event.rc is the return code: success <==> show menu item

cEnable: "event.rc= ( event.target!= null && pt_timeout== 0 );"

} );



app.addMenuItem( {

cName: "Slower",

cParent: "View",

cExec: "PT_Stop( ); pt_wait+= pt_step; PT_Start( pt_wait );",

cEnable: "event.rc= ( event.target!= null && pt_timeout!= 0 );"

} );



app.addMenuItem( {

cName: "Faster",

cParent: "View",

cExec: "if(pt_step< pt_wait) { PT_Stop( ); pt_wait-= pt_step; PT_Start(pt_wait);

 }",

cEnable: "event.rc= (event.target != null && pt_timeout!= 0 && pt_step< pt_wait);"

} );



app.addMenuItem( {

cName: "Stop Page Turner",

cParent: "View",

cExec: "PT_Stop( );",

cEnable: "event.rc= ( event.target != null && pt_timeout!= 0 );"

} );

1.11.3 Running the Hack

After you restart Acrobat, open a PDF document. Select View Start Page Turner and it will begin to advance the PDF pages at the pace set in the script's pt_wait variable. Adjust this pace by selecting View Faster or View Slower. As the script runs, use the Page Down and Page Up keys to fast-forward or rewind the PDF. Stop the script by selecting View Stop Page Turner.

After starting the page turner and setting its speed, activate Acrobat/Reader's Full Screen mode for maximum page visibility. Select Window Full Screen View (Acrobat/Reader 6) or View Full Screen (Acrobat/Reader 5). The Page Down and Page Up keys still work as expected. Press Ctrl-L (Windows) or Command-L (Mac) to exit Full Screen mode.