scrolling performance

Ok, so first of all, scowling WHAT?  Scrolling through glances, scrolling through pages when you are in full screen mode, having text scroll right to left?

If you mean scrolling text horizontally, I've had ok results using a 50 ms update timer (which is the fastest timer possible), and scrolling by 2 pixels for every update. (This is on the lower-resolution MIP devices - on AMOLED devices, you may have to scroll by more 2 than pixels per update to get an acceptable scroll speed.)

Here's some example code and a video captured from the simulator:

https://forums.garmin.com/developer/connect-iq/f/discussion/258627/anybody-have-example-of-sliding-text/1235847#1235847

Here's a video of a real device:

forums.garmin.com/.../1497375

I've got a view in my widget which need to display lot's of lines of info.

I scroll through it with next/prev (scrolling vertically, but can be changed to be right/left if needed)

but for now it's painlessly slow

You want to post the code for how you are doing this now for help with speeding it up.

here are the main parts :

function onUpdate(dc) {
        //System.println("view hour onUpdate");
        // Call the parent onUpdate function to redraw the layout
        View.onUpdate(dc);
          
         // clear the screen
        dc.setColor(Graphics.COLOR_BLACK, Graphics.COLOR_BLACK);
        dc.clear();

        // drawing !
		dc.setColor(Gfx.COLOR_WHITE, Gfx.COLOR_TRANSPARENT);
        //TODO: check scroll bug ?

        var tides = _tideData[5]["data"];
        if (tides != null) {
            var y = _scrollpos;
            //System.println("elem : "+ tides.size());
            
            for(var h = 0; h < tides.size(); h++) {              
                // color for current hur
                y = drawHourly(dc,mWidth * 0.1 , y /* h *30 + _scrollpos  /*64*/ , tides[h]);                    
            }       
        }
            
        //System.println("view hour onUpdate - out");
    }

and more elements : 

    function scrollup() {
        _scrollpos += 60;
        if (_scrollpos> 0) {  // 24*80 ?
            _scrollpos = 0;
        }
        System.println("scroll : " + _scrollpos);
        WatchUi.requestUpdate();
    }

       function scrolldown() {
        _scrollpos -= 60;
        if (_scrollpos< -1900) {
            _scrollpos = -1900;
        } 
        System.println("scroll : " +_scrollpos);
        WatchUi.requestUpdate();
    }
    
    
      // scroll down
	function onNextPage() {
        //System.println("openTideWidgetHourViewDelegate scroll down");
        _view.scrolldown();
        
        return true;       
    }
    
    

hope this can help

This looks pretty optimized to me. A suggestion would be to define your `tides` variable somewhere other than onUpdate(), so that you don't have to keep retrieving the same value every time the user scrolls.

If the scroll is taking a long time, your drawHourly function must be doing some pretty time consuming things. Have you tried optimizing that?

How can I profile to optimisze it ?

have  try this, but didn't understand how to interprete/use the result !