Global Variables vs onUpdate Calculations Efficiency

Avoid globals.  They can have side effects in this case if you ever add a background service, the scope can be an issue..

What you may want to do is declare them in your view class, like this:

class SLeanView extends Ui.WatchFace {
	var width,height,centerW,centerH;
	var radius;
	var largeF,largeH,mediumF,mediumH,secW;
	var smallF,smallH;
	var iconF,iconW;
	var timeY,secY,iconY,batY,hrY,stepY;
	var secX,dateX;

What I then do is set their values in onLayout().  You have the dc at that time, so you can use things like dc.getHeight(), dc.getFontHeight, dc.getTextWidthInPixels, to determine the x/y for things, spacing between lines, width of a string for seconds, etc.

I should have said exactly where above the functions...the variables are actually in the class like below.

With that said would you still recommend moving them down into the onUpdate section or leave them like they are? Am I saving any battery by having them outside the onUpdate?

class GarminWatchFaceView extends WatchUi.WatchFace {
var dH = System.getDeviceSettings().screenHeight;
var dM = dH/2;
var tR1 = dH*.11;
var tR1L = dH*.36;

....

function initialize() {
WatchFace.initialize();
}

function onLayout(dc) {
}

function onShow() {
}

function onUpdate(dc) {
dc.setColor(Graphics.COLOR_TRANSPARENT, backColor);
dc.clear();
dc.setColor(gridColor, Graphics.COLOR_TRANSPARENT);
dc.setPenWidth(gridThickness);
dc.drawLine(0,lH1,dH,lH1);

.....

Thanks for the help.