• It's said that the essence of good Software Engineering is reuse (plagiarism?) so in developing my own analog clock faces, I have been looking through the code of many of the clocks in the BangleApps repository. In trying to get clock faces to render as quickly as possible, I found that the use of the Espruino graphics operation transformVertices from the builtin Graphics class helped enormously. Using the Github search facility, I found only two apps using the operation in BangleApps - neither are Analog Clocks - hence I hope the following example may be of interest. The example uses the the transformVertices operation in implementing the drawRotRect function used in the Beeb Clock (reuse in action).The function places a rectangle rotated around the centre of the clock dial at a parameterised distance from the centre of the clock. I have used it for the following Bold Clock influenced face:

    The following are the functions to draw the dial and the hands of this clock.

        var cx = g.getWidth()/2;
        var cy = g.getHeight()/2
        Graphics.prototype.drawRotRect = function(w, r1, r2, angle) {
            var w2=w/2, h=r2-r1, theta=angle*Math.PI/180;
            return this.fillPoly(this.transformVertices([-w­2,0,-w2,-h,w2,-h,w2,0], 
        function dial() {
            for (let a=0;a<360;a+=6)
            if (a % 90 == 0) 
            else if (a % 30 == 0)
    let hourHand = g.drawRotRect.bind(g,6,6,66);
     let minuteHand = g.drawRotRect.bind(g,3,6,100);
     let secondhand = g.drawRotRect.bind(g,2,3,100);

    This example uses a rectangle, however, the approach can just as easily be applied to polygons representing more complex hands.

  • looks very interesting - thank you very much!

    What always surprises me is the remark "Note: This is only available in !devices with low flash memory with !'Original' Espruino boards" at the end of many method descriptions - but the Bangle.js 2 is neither an original Espruino board nor has it low flash memory, right?