Question

I want to add keyboard control for the tiny scrollbar script. i am not very good at javascript. i know that i can use jquery keypress() function to intercept arrow keys(38,40) and then scroll the overview div by changing its css top property.

I can do this outside of the tinyscrollbar plugin but i would love to use the functions that is already inside the plugin to do that.

Any direction on how to start this will be a big help.thanks.

for more information, check tinyscrollbar code here. And more info and demos here.

Answer 1

I added a new function to the plugin and used it to update scroll on keydown event.

Code added to the plugin:

// define the added function
 jQuery.fn.tinyscrollbar_updatescroll = function(sScroll)
{
    return jQuery( this ).data( 'tsb' ).updatescroll( sScroll ); 
};
// end of added function definition

function Scrollbar( root, options )
{
    var oSelf       = this
    ,   oWrapper    = root
    ,   oViewport   = { obj: jQuery( '.viewport', root ) }
    ,   oContent    = { obj: jQuery( '.overview', root ) }
    ,   oScrollbar  = { obj: jQuery( '.scrollbar', root ) }
    ,   oTrack      = { obj: jQuery( '.track', oScrollbar.obj ) }
    ,   oThumb      = { obj: jQuery( '.thumb', oScrollbar.obj ) }
    ,   sAxis       = options.axis === 'x'
    ,   sDirection  = sAxis ? 'left' : 'top'
    ,   sSize       = sAxis ? 'Width' : 'Height'
    ,   iScroll     = 0
    ,   iPosition   = { start: 0, now: 0 }
    ,   iMouse      = {}
    ,   touchEvents = 'ontouchstart' in document.documentElement
    ;

    function initialize()
    {
        oSelf.update();
        setEvents();

        return oSelf;
    }

    // the new added function using the wheel function
    this.updatescroll = function( sScroll )
    {
        if( oContent.ratio < 1 )
        {

            iScroll -= sScroll;
            iScroll = Math.min( ( oContent[ options.axis ] - oViewport[ options.axis ] ), Math.max( 0, iScroll ));

            oThumb.obj.css( sDirection, iScroll / oScrollbar.ratio );
            oContent.obj.css( sDirection, -iScroll );

        }
    };
    // end of added function

the code outside the plugin:

jQuery('body').keydown(function (event) {
    if (event.keyCode == 38) {
      // up arrow
      $('#scrollbar1').tinyscrollbar_updatescroll(40);
    } else if (event.keyCode == 40) {
     // down arrow
     $('#scrollbar1').tinyscrollbar_updatescroll(-40);
    }
  });

the tinyscrollbar_updatescroll scrolls the content to the current position plus the amount sent to it. the original tinyscrollbar_update function scrolls the content to a certain position given in pixels.