Category Archives: Gauges

A week of Learning

Working on the gauge in CodePenSome may be wondering if I’ve gone off on holiday, as I normally post here on an almost daily basis. Well, if you regularly read the comments sections you’ll see I’ve been heavily involved in answering questions, but more importantly I’ve taken one step back and two steps forward on this gauge thing. Read on.

But firstly – WIN SOMETHING! You’ve probably heard me talk about my pal Peter Oakes in Canada – he has an excellent YouTube Channel in which he talks about IOT – well, he’s just launched a competition and the prizes look pretty damned impressive indeed. Take a quick looks over here – you might want to participate…. https://www.hackster.io/contests/IOT2020

Thanks:  Before going any further, I’d like to take this opportunity to thank some people in there without naming names – for several donations received this week – you have no idea how this helps motivation, knowing that your work is appreciated. Thank you, guys!

The Gauge: Now - regular visitors will know I’ve been doing a lot of work on Node-Red-Dashboard-compatible widgets recently as I really do think this is the way forward for mobile access to DIY home control systems and also for desktop and wall access via touch displays -  but one thing that has bothered me up to now was the clumsiness of some of my coding – global variables all over the place, a lot of opportunity for interference from one node to another etc. Everything just works but the perfectionist in me wants to “do the job properly”.

So earlier this week I took a step back, seeing what “proper programmers” had done with turning these widgets into “objects”, with clean interfacing to the outside world. Well, trust me, it isn’t that easy. I asked around as to how I might encapsulate my Javascript into an object, exposing only those bits that needed to be exposed. No-one I know well enough to ask for help, could help in this particular instance! So, I took a step back, grabbed some coffee and thanks to my friend Google, I’m pleased to say I’m getting somewhere.

Shortly you will see my gauge once again featured in these pages but the way it is done and bits you’ll need to look at have been dramatically changed as has the chance of unwanted interaction – and the overhead has been substantially reduced due to a series of insights which have followed each other – and some of them I’m sure some others have missed. Read on.

So first off, I made a gauge with pretty colours – you’ll see it elsewhere in this blog. It works – why take it any further?

Well, the gauge features nice, smoothly moving needles and other bits. What’s wrong with that?  Every time the needle is updated in the existing design, the entire gauge has to be re-drawn. This is not uncommon but just felt wrong to me. To tackle this I had to understand LAYERS. It turns out that if you make the position of CANVASSES absolute, you can put one on top of another (you also need to understand zIndex but that’s easy). If you can do that, then you can draw the gauge backdrop including the text and pretty-coloured segments once only on the bottom layer and only then clear and update the top layer, say, 50 times a second with needle updates etc. That saves some calculating.

But now I needed two CANVAS items which looks a little odd when setting up so I worked out how to create both, totally in Javascript. That led to another problem, in Node-Red you can’t just put your CANVAS elements in the top left corner of the page BODY – it won’t work. I then reasoned that both CANVASSES could sit inside a DIV on top of each others – and indeed they can. So now all that is needed in HTML is to define a DIV and the Javascript will do the rest.

That still left me with a mass of messy Javascript - and the thought of explaining what was and what was not relevant to end users in the blog here was keeping me awake. That’s when I started looking into this whole object encapsulation thing. 2 days ago that was a distant world, something for the future. Today, I wonder why I waited so long to take the effort to learn. I had to learn some new tricks in the process – however, when you eventually see the new gauge, setting it up will be as easy as this.

var gauge1= new petesGauge;

gauge1.init({
  container: "myDiv",
  });


gauge1.value1(90);

Define a gauge, point it to a DIV at which point it appears magically – and then dynamically set a value which will slowly change in front of your eyes. No other information exposed to the outside world, no need to do anything other than set up an empty DIV and add a link to the Javascript compressed library.

Part of the magic here is in the encapsulation I’ve learned to handle – but also of course there are many defaults. In the top section you’ll be able to override defaults and turns things on and off if you want – and in the bottom section there will be several settable items – the value of two gauge needles, the value of set points, visibility of LEDs etc. All easy to use options.

I’m on the right path – I understand what I’m doing but I’ve only so much time to code this up.

If anyone fancies themselves a whiz at JS Objects, I’ve fathomed out how to get and set global vars in the object with simple methods – no problem but can i hell interact externally with internal vars – happy to have a chat with anyone interested in enlightening me.

jsFiddle helped me get this far but the best tool for the job IMHO apart from lack of formatting – is CodePen – you can make code changes dynamically and see changes in real time – what a difference this makes. Oh and I realised the one thing missing from my LCD display (not shown above) is the overspill of side lighting typically seen on real LCD displays. That’s coming soon.

New Toys: I’ve also discovered (thanks to MrShark) Atom this week which promises to be a great editor both in Windows and on my little SBCs.  My MINT installation, apart from falling to bits visually after a “sleep” operation, continues to function well on the laptop and I’ve received some nice new DIN rail brackets from China which can screw onto the back of a perspex sheet for mounting boards and supplies. More on all of this later. Incidentally for those wondering, my testbed wireless Orange Pi Zero and twin NanoPi M3 units are still sitting on the bench, still working perfectly despite disconnecting the WIFI several times deliberately.

Desktop Touch Controller: And on another subject, how is my Desktop Pi Touch Controller doing? For some time Desktop Controllernow I’ve had a 5” touch screen attached to a Raspberry Pi 2, using Node-Red Dashboard as a simple controller for my office – to turn lights on and off and keep an eye on temperatures etc.  Works a treat using Chromium in “kiosk mode” – but two things have annoyed me – one being that menu from Node-Red Dashboard – the second being the ability of the browser to fail occasionally due to connection issues and put up a stupid message instead of trying to reconnect.  Well, I may have cracked both of these as for the last few days the little unit has been sitting there rock-solidly doing it’s job.

The annoying Node-Red-Dashboard unwanted menu problem (well I only have one page on this unit – why do I want a menu) was solved simply by a reader who wrote in to suggest this added to the style.

#toolbar {display:none;}

Yes, that’s it – simple as that. Gone – space retrieved.

The second came from here. http://www.labs.bristolmuseums.org.uk/running-google-chrome-in-kiosk-mode-tips-tricks-and-workarounds/

So I have a couple of templates on the page – one at the top with my CSS and some useful Javascript – the second at the bottom.

I’ve added this to the top

<body onClick=”location.reload()”>

and this to the bottom.

<script type=”text/javascript”> $(function() { setTimeout(function () { if($(“#VisitorStoriesHelpText”).length>0){ $(‘body’).attr(“onClick”,””) } }, 1 * 1 * 1000);}); </script>

And yes, I know that body code is really not appropriate in a Node-Red template – but guess what… it seems to work. I’ve not had an issue with the display for days now. May be a fluke of course – but fingers crossed.

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What, ANOTHER Gauge?

Now, before you say anything – this gauge is different to the rest.. It is all mine and it EVOLVING (last update Feb 03) if you’ve seen this blog entry before today…

Gauges: Peter Scargill's GaugeI’ve spent a lot of time ploughing through code, some of it years old (SteelSeries) and though many of these designs are beautiful, most are not that well supported if at all and some comprise libraries that are kitchen sink jobs that take some learning, so much so that recently, in a fit of peak, after failing to figure out how to add a simple second dial or eliminate the wasted space of that metal outer ring in SteelSeries (it is easy to make it disappear but not the space it occupies) that I decided to “give it a go” myself.

What you see here is not finished but it works (and is a lot prettier when you see it running).  It scales without internal adjustments other than the gauge size as I need something that will easily adapt to differing Node-Red template blocks.

Images: There are several images on my site – don’t use them permanently please – grab them for yourself – they likely will change anyway.

As the dials move below the (circular) set-points the LEDS will go on and off – one triggers BELOW the set-point (heat), the other ABOVE (dehumidifier).

In the process of making this I’ve made a number of dials and centres – all in PowerPoint – very simple.

Centre 1 by Peter ScargillCentre 2 by Peter ScargillCentre 2 by Peter Scargill

I call these three metalCarvedCentre.png, greenCarveCentre.png and greyCentre.png respectively. I don’t plan to make a lot as there must be millions of needles and centres out there already.

tmpFF04Glowing rings are easy to add… and I’m working on an LCD display background image that’s hopefully a little more convincing than the canvas-manufactured version I’m using right now.

Glowing rings by Peter Scargill - in PowerPoint

If you poke the test values, you should see the gauge needles move smoothly to their destination. So I’m really happy about (and this happens a LOT it seems) having to update the whole thing every 20ms for animation when all I want is to update the dials (and an LCD panel eventually) – but I can’t find LAYERS anywhere.

What I HAVE done elsewhere is use Z-laying with multiple canvases to achieve layering as you will see in the link below. Originally I had 3 layers – the background, the bits that change and the knob over the needle – all of which SHOULD have worked perfectly – but for reasons beyond me the knob didn’t always show. I moved it in with the dial and all is well – so only two identical canvas units are needed. This seems like a good general way forward. I will change my main dial code to follow this pattern eventually when I've pondered what effect this will have on interfacing.  Anyway, I put this together from scratch and it seems to work ok, Take a look at this.. https://jsfiddle.net/scargill/r4qstas2/6/

tmp42D9

A timer runs constantly but does nothing unless a change is made  and the values are then incremented or decremented until they  match the required values.

I think this will make a fine addition to the visual tools we have but still needs much tidying up so no comments about code quality please.

Fonts: Fonts are always a thing – and the normal web ones are today considered to be utterly pants. So – TTF fonts are good but also large – so I found this online convertor. You simply drag a TTF file of your choosing (clearly if for commercial purposes, you need to make sure it is free) and you get the option to download from a link – it works. So I wanted a nice dot matrix font for the little display here – and I found “Dots all for Now JL” which is pretty but also 44K. I ran it through the convertor and in less than a minute I was up and running with a font that is only 7k.

To use the font, I did this..

<style type="text/css">
@font-face {
font-family: "DOTMAT";
src: url("/myfonts/dotsalfn.woff") format('woff');
}
</style>

and then just referred to DOTMAT as you would any font. Now there are all sorts of warnings on the web about ensuring fonts are loaded first and working with CANVAS etc. – but somehow, in Node-Red, it all just works… which is nice and keeps the code simple.

And that’s it for now. I’m working on improving the code.

[{"id":"22bad52a.82347a","type":"ui_template","z":"c552e8d2.712b48","group":"40cf30b4.d9549","name":"MyGauge","order":0,"width":"6","height":"6","format":"<style>\n  @font-face {\n    font-family: \"DOTMAT\";\n    src: url(\"/myfonts/dotsalfn.woff\") format('woff');\n  } \n</style>\n\n<script>\n  var showNeedle2 = true;\nvar showLED1 = true;\nvar showLED2 = true;\nvar needleWidth1 = 1;\nvar needleWidth2 = 1;\n\nvar set1 = 0;\nvar set2 = 0;\nvar value1 = 0;\nvar value2 = 0;\n\nvar setpoint1 = -1;\nvar setpoint2 = -1;\nvar degrees = -1;\nvar degrees2 = -1;\n\nvar title = \"Pete's Aircon\";\nvar subTitle = \"Hmm1\";\nvar ledTitle1 = \"DEHUM\";\nvar ledTitle2 = \"HEATING\";\n\nvar needle1 = new Image();\nvar needle2 = new Image();\nvar centre = new Image();\n\n\n\nvar direction1 = 1;\nvar direction2 = 1;\n\n(function(scope) {\n  scope.$watch('msg', function(msg) {\n    if (typeof(msg.value1) != \"undefined\") value1 = msg.value1;\n    if (typeof(msg.value2) != \"undefined\") value2 = msg.value2;\n    if (typeof(msg.set1) != \"undefined\") set1 = msg.set1;\n    if (typeof(msg.set2) != \"undefined\") set2 = msg.set2;\n  });\n})(scope);\n\n\n\n\nfunction n(n) {\n  return n > 9 ? \"\" + n : \"0\" + n;\n}\n\n\nfunction init() {\n  needle1.src = \"http://www.scargill.net/things/needles/redCurvedNeedle.png\";\n  needle2.src = \"http://www.scargill.net/things/needles/greenCurvedNeedle.png\";\n  centre.src = \"http://www.scargill.net/things/needles/greyCarvedCentre.png\";\n  canvas = document.getElementById(\"fred\");\n  ctx = canvas.getContext(\"2d\");\n  cX = Math.floor(canvas.width / 2);\n  cY = Math.floor(canvas.height / 2);\n  dX = cX / 175; // divisor for centrepiece sizing\n  dY = cY / 175;\n\n  setInterval(draw, 50);\n\n}\n\n// draw a wedge\nfunction drawWedge(percent, color, count) {\n  var arcRadians = ((percent / 100) * 360) * (Math.PI / 180),\n    startAngle = totalArc,\n    endAngle = totalArc - arcRadians;\n  ctx.save();\n  ctx.beginPath();\n  ctx.moveTo(cX, cY);\n  ctx.arc(cX, cY, radius_outer, startAngle, endAngle, true);\n  /** cut out the inner section by going in the opposite direction **/\n  ctx.fillStyle = color;\n  ctx.arc(cX, cY, radius_inner, endAngle, startAngle, false);\n  ctx.closePath();\n  ctx.fill()\n  ctx.restore();\n  totalArc -= arcRadians;\n}\n\nfunction drawbit(i, colr) {\n  if (i & 1) drawWedge(1.1, colr, i);\n  else drawWedge(0.2, \"#cccccc\", i);\n}\n\n// draw the donut one wedge at a time\nfunction drawDonut() {\n  var r, g, b;\n  b = 0;\n  g = 0;\n  r = 255;\n  for (var i = 0; i < 100; i++) {\n    var r, g, b;\n    if (i < 40) {\n      g += 8;\n    }\n    if ((i > 40) && (i < 70)) {\n      g -= 8;\n      r -= 12;\n    }\n    if (i > 70) {\n      g -= 8;\n      b += 12;\n    }\n    drawbit(i, \"rgba(\" + r + \",\" + g + \",\" + b + \",1)\");\n  }\n}\n\nfunction roundRect(ctx, x, y, width, height, radius, fill, stroke) {\n  if (typeof stroke == 'undefined') {\n    stroke = true;\n  }\n  if (typeof radius === 'undefined') {\n    radius = 5;\n  }\n  if (typeof radius === 'number') {\n    radius = {\n      tl: radius,\n      tr: radius,\n      br: radius,\n      bl: radius\n    };\n  } else {\n    var defaultRadius = {\n      tl: 0,\n      tr: 0,\n      br: 0,\n      bl: 0\n    };\n    for (var side in defaultRadius) {\n      radius[side] = radius[side] || defaultRadius[side];\n    }\n  }\n  ctx.beginPath();\n  ctx.moveTo(x + radius.tl, y);\n  ctx.lineTo(x + width - radius.tr, y);\n  ctx.quadraticCurveTo(x + width, y, x + width, y + radius.tr);\n  ctx.lineTo(x + width, y + height - radius.br);\n  ctx.quadraticCurveTo(x + width, y + height, x + width - radius.br, y + height);\n  ctx.lineTo(x + radius.bl, y + height);\n  ctx.quadraticCurveTo(x, y + height, x, y + height - radius.bl);\n  ctx.lineTo(x, y + radius.tl);\n  ctx.quadraticCurveTo(x, y, x + radius.tl, y);\n  ctx.closePath();\n  if (fill) {\n    ctx.fill();\n  }\n  if (stroke) {\n    ctx.stroke();\n  }\n}\n\nfunction drawCircle() {\n  ctx.save();\n  /** outer ring **/\n  ctx.beginPath();\n  ctx.moveTo(cX, cY);\n  ctx.shadowBlur = 5 * dX;\n  ctx.shadowColor = \"rgba(40,40,40,1)\";\n  ctx.arc(cX, cY, radius + (8 * dX), 0, 2 * Math.PI, false);\n  ctx.arc(cX, cY, radius + (6 * dX), 0, 2 * Math.PI, true);\n  ctx.closePath();\n  ctx.fillStyle = \"rgba(40,40,40,1)\";\n  ctx.fill();\n  ctx.restore();\n  \n  \n  // do an arc of numbers...\n   ctx.save();\n    ctx.translate(canvas.width / 2, canvas.height / 2);\n    ctx.rotate(-140 * (Math.PI / 180));\n    ctx.font = \"bold \" + String(Math.floor(cX / 13)) + \"px Helvetica\";\n    ctx.textAlign = 'center';\n    ctx.fillStyle = '#000000';\n    for (var a=0;a<=100; a+=10)\n    {\n    ctx.rotate(23 * (Math.PI / 180));\n    ctx.fillText(n(a), 0, -(cY*0.65)); \n    }\n    ctx.restore();\n  \n\n  ctx.save();\n\n  if (showLED1 == true) {\n    /** Sub label 1 **/\n    ctx.font = \"bold \" + String(Math.floor(cX / 14)) + \"px Helvetica\";\n\n    // ctx.font = \"bold \" + String(Math.floor(cX / 14)) + \"px Helvetica\";\n    ctx.textAlign = 'center';\n    ctx.fillStyle = '#8A8A8A';\n    ctx.fillText(ledTitle2, cX + (cX / 2.5), cY - (cY / 9), (cX / 1));\n    if (degrees < setpoint2) {\n      ctx.beginPath(); // red led - size and scale need to be related to canvas - currently fixed\n      ctx.arc(cX + (cX / 2.5), cY, (cX / 15), 0, 2 * Math.PI, false);\n      ctx.closePath();\n      ctx.shadowBlur = 20;\n      ctx.shadowColor = \"rgba(255,0,0,1)\";\n      ctx.fillStyle = \"rgba(255,0,0,1)\";\n      ctx.fill();\n      ctx.restore();\n    } else {\n      ctx.beginPath(); // red led - size and scale need to be related to canvas - currently fixed\n      ctx.arc(cX + (cX / 2.5), cY, (cX / 15), 0, 2 * Math.PI, false);\n      ctx.closePath();\n      ctx.fillStyle = \"rgba(140,40,40,1)\";\n      ctx.fill();\n      ctx.lineWidth = 2 * dX;\n      ctx.strokeStyle = 'rgba(40,0,0,0.6)';\n      ctx.stroke();\n      ctx.restore();\n    }\n  }\n  if (showLED2 == true) {\n    /** Sub label 1 **/\n    ctx.font = \"bold \" + String(Math.floor(cX / 14)) + \"px Helvetica\";\n    ctx.textAlign = 'center';\n    ctx.fillStyle = '#8A8A8A';\n    ctx.fillText(ledTitle1, cX - (cX / 2.5), cY - (cY / 9), (cX / 1));\n\n    if (degrees2 > setpoint1) {\n      ctx.save(); // green led - size and scale need to be related to canvas - currently fixed\n      ctx.beginPath();\n      ctx.arc(cX - (cX / 2.5), cY, (cX / 15), 0, 2 * Math.PI, false);\n      ctx.closePath();\n      ctx.shadowBlur = 20;\n      ctx.shadowColor = \"rgba(0,200,0,1)\";\n      ctx.fillStyle = \"rgba(0,200,0,1)\";\n      ctx.fill();\n      ctx.restore();\n    } else {\n      ctx.save(); // green led - size and scale need to be related to canvas - currently fixed\n      ctx.beginPath();\n      ctx.arc(cX - (cX / 2.5), cY, (cX / 15), 0, 2 * Math.PI, false);\n      ctx.closePath();\n      ctx.fillStyle = \"rgba(40,110,40,1)\";\n      ctx.fill();\n      ctx.lineWidth = 2 * dX;\n      ctx.strokeStyle = 'rgba(0,40,0,0.6)';\n      ctx.stroke();\n      ctx.restore();\n    }\n  }\n\n  /** Main label **/\n  ctx.save();\n\n  ctx.beginPath;\n  roundRect(ctx, cX - (cX / 1.7), cY + (cY / 3), cX + (cX / 5.1), cY - (cY / 1.5), dX * 10, true);\n  ctx.clip()\n\n  ctx.beginPath;\n  ctx.strokeStyle = 'black';\n  ctx.lineWidth = 5;\n  ctx.shadowBlur = 15;\n  ctx.shadowColor = 'black';\n  ctx.shadowOffsetX = 0;\n  ctx.shadowOffsetY = 0;\n  ctx.fillStyle = \"rgba(255, 255, 180, .8)\";\n  roundRect(ctx, cX - (cX / 1.7) - 4, cY + (cY / 3) - 4, cX + (cX / 5.1) + 8, cY - (cY / 1.5) + 8, dX * 10, true);\n\n  ctx.restore();\n  ctx.save();\n\n  ctx.font = \"bold \" + String(Math.floor(cX / 8)) + \"px DOTMAT\";\n  ctx.textAlign = 'center';\n  ctx.fillStyle = '#8A8A8A';\n  ctx.fillText(title, cX, cY + (cY / 2.05));\n\n  /** Sub label **/\n  ctx.font = \"bold \" + String(Math.floor(cX / 12)) + \"px Helvetica\";\n  ctx.textAlign = 'center';\n  ctx.fillStyle = '#8A8A8A';\n  ctx.fillText(subTitle, cX, cY + (cY / 1.65));\n  ctx.restore();\n}\n\nfunction draw() {\n\n  if ((set1 == setpoint1) && (set2 == setpoint2) && (value1 == degrees) && (value2 == degrees2)) return;\n\n  if (set1 > setpoint1) setpoint1++;\n  else if (set1 < setpoint1) setpoint1--;\n  if (set2 > setpoint2) setpoint2++;\n  else if (set2 < setpoint2) setpoint2--;\n\n  if (value1 > degrees) degrees++;\n  else if (value1 < degrees) degrees--;\n  if (value2 > degrees2) degrees2++;\n  else if (value2 < degrees2) degrees2--;\n\n\n  width = 18 * dX,\n    radius = cX * .9,\n    radius_outer = cX * .9,\n    radius_inner = (radius - width) - (11 * dX),\n    kerning = 0.04,\n    color_alpha = 0.3;\n  totalArc = .47; // starting point for the arc\n\n  ctx.save();\n  // Radii of the white glow.\n  innerRadius = 20 * dX;\n  outerRadius = canvas.height / 2;\n  gradient = ctx.createRadialGradient(canvas.width / 2, canvas.height / 2, innerRadius, canvas.width / 2, canvas.height / 2, outerRadius);\n  gradient.addColorStop(0, 'white');\n  gradient.addColorStop(1, '#bbbbbb');\n  ctx.arc(canvas.width / 2, canvas.height / 2, canvas.height / 2 - (10 * dX), 0, 2 * Math.PI);\n  ctx.fillStyle = gradient;\n  ctx.fill();\n  ctx.restore();\n\n  drawCircle();\n  drawDonut();\n  \n  // Humid Circle\n  ctx.save();\n  ctx.beginPath();\n  ctx.translate(canvas.width / 2, canvas.height / 2);\n  tdegrees = -204 + (degrees2 * 227 / 100)\n    ctx.rotate((233 / 100 * setpoint1 - 118) * (Math.PI / 180));\n    ctx.beginPath();\n    ctx.arc(0, -(cY*0.82),cY*0.05, 0, 2 * Math.PI, false);\n    ctx.fillStyle = 'green';\n    ctx.fill();\n    ctx.lineWidth = 1.5;\n    ctx.strokeStyle = '#ffffff';\n    ctx.stroke();\n  ctx.restore();\n\n  // Temperature Circle\n  ctx.save(); \n  ctx.beginPath();\n  ctx.translate(canvas.width / 2, canvas.height / 2);\n  tdegrees = -204 + (degrees2 * 227 / 100)\n  ctx.rotate((233 / 100 * setpoint2 - 118) * (Math.PI / 180));\n  //ctx.beginPath();\n    ctx.arc(0, -(cY*0.82),cY*0.05, 0, 2 * Math.PI, false);\n    ctx.fillStyle = 'red';\n    ctx.fill();\n    ctx.lineWidth = 1.5;\n    ctx.strokeStyle = '#ffffff';\n    ctx.stroke();\n  ctx.restore();\n\n  // Save the current drawing state\n  ctx.save();\n  ctx.beginPath();\n  ctx.translate(canvas.width / 2, canvas.height / 2);\n  tdegrees = -204 + (degrees * 227 / 100)\n  ctx.rotate(tdegrees * (Math.PI / 180));\n\n  // shadow on lines??\n  ctx.shadowBlur = 4;\n  ctx.shadowColor = \"rgba(0,0,0,0.2)\";\n  ctx.shadowOffsetX = 5 * dX;\n  ctx.shadowOffsetY = 5 * dX;\n\n\n  ctx.drawImage(needle1, (canvas.width / 7) - (canvas.width / 4), -(canvas.height * needleWidth1 / 80), (canvas.height / 2), (canvas.width * needleWidth1 / 40));\n  // Restore the previous drawing state\n  ctx.restore();\n\n  if (showNeedle2 == true) {\n    // Save the current drawing state\n    ctx.save();\n    ctx.beginPath();\n    ctx.translate(canvas.width / 2, canvas.height / 2);\n    tdegrees = -204 + (degrees2 * 227 / 100)\n    ctx.rotate(tdegrees * (Math.PI / 180));\n    // shadow on lines??\n    ctx.shadowBlur = 4;\n    ctx.shadowColor = \"rgba(0,0,0,0.2)\";\n    ctx.shadowOffsetX = 5 * dX;\n    ctx.shadowOffsetY = 5 * dX;\n    ctx.drawImage(needle2, (canvas.width / 7) - (canvas.width / 4), -(canvas.height * needleWidth2 / 80), (canvas.height / 2), (canvas.width * needleWidth2 / 40));\n    ctx.restore();\n  }\n  ctx.save();\n  ctx.beginPath();\n  ctx.translate(canvas.width / 2, canvas.height / 2);\n  // draw the centre bit then restore the previous drawing state\n  ctx.drawImage(centre, (0 - (centre.height / 4)) * dX, (0 - (centre.width / 4)) * dY, (centre.height / 2) * dX, (centre.width / 2) * dY);\n  ctx.restore();\n  subTitle = \"Temp=\" + n(Math.floor(degrees)) + \"c \" + \"Hum=\" + n(Math.floor(degrees2)) + \"% \";\n}\n\ninit();\n\n</script>\n\n<canvas id = \"fred\"\nwidth = 310 height = 310 > </canvas>","storeOutMessages":true,"fwdInMessages":true,"x":980,"y":2480,"wires":[[]]},{"id":"fbecd5a1.989ac8","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"22","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2340,"wires":[["9f9e89fe.db3518"]]},{"id":"6e98eeac.504cf","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"35","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2380,"wires":[["9f9e89fe.db3518"]]},{"id":"9f9e89fe.db3518","type":"function","z":"c552e8d2.712b48","name":"msg.value1","func":"msg.value1=msg.payload;\nreturn msg;","outputs":1,"noerr":0,"x":790,"y":2360,"wires":[["22bad52a.82347a"]]},{"id":"10d0f056.a552e","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"11","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2420,"wires":[["9eb8ebf8.be3108"]]},{"id":"ae37427b.2f8b3","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"60","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2460,"wires":[["9eb8ebf8.be3108"]]},{"id":"9eb8ebf8.be3108","type":"function","z":"c552e8d2.712b48","name":"msg.value2","func":"msg.value2=msg.payload;\nreturn msg;","outputs":1,"noerr":0,"x":790,"y":2440,"wires":[["22bad52a.82347a"]]},{"id":"2251f312.3a575c","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"10","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2500,"wires":[["7c5ad2de.3c767c"]]},{"id":"ae3f6f46.2aed8","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"20","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2540,"wires":[["7c5ad2de.3c767c"]]},{"id":"7c5ad2de.3c767c","type":"function","z":"c552e8d2.712b48","name":"msg.set1","func":"msg.set1=msg.payload;\nreturn msg;","outputs":1,"noerr":0,"x":780,"y":2520,"wires":[["22bad52a.82347a"]]},{"id":"4a2ac4f5.5906dc","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"30","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2580,"wires":[["f6ffef5f.562ca"]]},{"id":"8f5b3775.03c018","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"40","payloadType":"str","repeat":"","crontab":"","once":false,"x":630,"y":2620,"wires":[["f6ffef5f.562ca"]]},{"id":"f6ffef5f.562ca","type":"function","z":"c552e8d2.712b48","name":"msg.set2","func":"msg.set2=msg.payload;\nreturn msg;","outputs":1,"noerr":0,"x":780,"y":2600,"wires":[["22bad52a.82347a"]]},{"id":"40cf30b4.d9549","type":"ui_group","z":"","name":"testa","tab":"66a97521.af8dac","disp":true,"width":"6"},{"id":"66a97521.af8dac","type":"ui_tab","z":"","name":"testa","icon":"dashboard"}]
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Thermometers

Thermometers for Node-Red

Three thermometers in a row for Node-Red (or as many or few as you like really) for Node-Red Dashboard. Another fine example of simple gauges and unlike some it is easy to make multiple gauges on one page – I will demonstrate three.

Here is the library source, I grabbed the larger one and saved as gauges-min.js in my /myjs folder – see previous blogs for setting this up with Node-Red.

Here is the code for one – and a flow example with three independent units.

You can of course alter the colours to whatever you want.

thermometer flow for Node-Red

The code for one template:

<script src="/myjs/gauge.min.js"></script>

<script>
  (function(scope){ 
            scope.$watch('msg', function(msg) {
               if (typeof(msg.payload) != "undefined") { gauge2.value=msg.payload; gauge2.draw(); }
            });
    })(scope);

var gauge2 = new LinearGauge({
    renderTo: 'mycanvas',
    valueBox: false,
    highlights: [ 
            {"from": 0, "to": 10, "color": "rgba(50, 50, 200, .75)"},
            {"from": 10, "to": 20, "color": "rgba(50, 200, 200, .75)"},
            {"from": 20, "to": 30, "color": "rgba(50, 200, 50, .75)"},
            {"from": 30, "to": 50, "color": "rgba(200, 200, 50, .75)"},
            {"from": 50, "to": 100, "color": "rgba(200, 50, 50, .75)"}
            ],
    barWidth: 10,
    units: "°C",
    borderShadowWidth: 0,
    borders: false,
    value: 35
}).draw();

</script>

<canvas id="mycanvas" 
    data-type="linear-gauge"
    data-width="106"
    data-height="270"
    data-units="°C"
    data-min-value="0"
    data-start-angle="90"
    data-ticks-angle="180"
    data-value-box="false"
    data-max-value="220"
    data-major-ticks="0,20,40,60,80,100,120,140,160,180,200,220"
    data-minor-ticks="2"
    data-stroke-ticks="true"
    data-color-plate="#fff"
    data-border-shadow-width="0"
    data-borders="false"
    data-needle-type="arrow"
    data-needle-width="2"
    data-needle-circle-size="7"
    data-needle-circle-outer="true"
    data-needle-circle-inner="false"
    data-animation-duration="1500"
    data-animation-rule="linear"
    data-bar-width="10"
    data-value="35"
></canvas>

The sample flow above

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gauge4.draw(); }\n            });\n    })(scope);\n\nvar gauge4 = new LinearGauge({\n    renderTo: 'mycanvas3',\n    valueBox: false,\n    highlights: [ \n            {\"from\": 0, \"to\": 10, \"color\": \"rgba(50, 50, 200, .75)\"},\n            {\"from\": 10, \"to\": 20, \"color\": \"rgba(50, 200, 200, .75)\"},\n            {\"from\": 20, \"to\": 30, \"color\": \"rgba(50, 200, 50, .75)\"},\n            {\"from\": 30, \"to\": 50, \"color\": \"rgba(200, 200, 50, .75)\"},\n            {\"from\": 50, \"to\": 100, \"color\": \"rgba(200, 50, 50, .75)\"}\n            ],\n    barWidth: 10,\n    units: \"°C\",\n    borderShadowWidth: 0,\n    borders: false,\n    value: 35\n}).draw();\n\n</script>\n\n<canvas id=\"mycanvas3\" \n    data-type=\"linear-gauge\"\n    data-width=\"106\"\n    data-height=\"270\"\n    data-units=\"°C\"\n    data-min-value=\"0\"\n    data-start-angle=\"90\"\n    data-ticks-angle=\"180\"\n    data-value-box=\"false\"\n    data-max-value=\"220\"\n    data-major-ticks=\"0,20,40,60,80,100,120,140,160,180,200,220\"\n    data-minor-ticks=\"2\"\n    data-stroke-ticks=\"true\"\n    data-color-plate=\"#fff\"\n    data-border-shadow-width=\"0\"\n    data-borders=\"false\"\n    data-needle-type=\"arrow\"\n    data-needle-width=\"2\"\n    data-needle-circle-size=\"7\"\n    data-needle-circle-outer=\"true\"\n    data-needle-circle-inner=\"false\"\n    data-animation-duration=\"1500\"\n    data-animation-rule=\"linear\"\n    data-bar-width=\"10\"\n    data-value=\"35\"\n></canvas>\n","storeOutMessages":false,"fwdInMessages":false,"x":960,"y":2200,"wires":[[]]},{"id":"7df32c36.100ef4","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"20","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2100,"wires":[["ddc888ba.e45578"]]},{"id":"54305565.bdfd7c","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"60","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2140,"wires":[["ddc888ba.e45578"]]},{"id":"7907996d.21af38","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"10","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2180,"wires":[["27cb8298.0e94de"]]},{"id":"583f639c.99440c","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"90","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2220,"wires":[["27cb8298.0e94de"]]},{"id":"c8fdd54c.823418","type":"ui_template","z":"c552e8d2.712b48","group":"33279d5b.72b122","name":"controller","order":0,"width":"2","height":"5","format":"<script src=\"/myjs/gauge.min.js\"></script>\n\n<script>\n  (function(scope){ \n            scope.$watch('msg', function(msg) {\n               if (typeof(msg.payload) != \"undefined\") { gauge2.value=msg.payload; gauge2.draw(); }\n            });\n    })(scope);\n\nvar gauge2 = new LinearGauge({\n    renderTo: 'mycanvas',\n    valueBox: false,\n    highlights: [ \n            {\"from\": 0, \"to\": 10, \"color\": \"rgba(50, 50, 200, .75)\"},\n            {\"from\": 10, \"to\": 20, \"color\": \"rgba(50, 200, 200, .75)\"},\n            {\"from\": 20, \"to\": 30, \"color\": \"rgba(50, 200, 50, .75)\"},\n            {\"from\": 30, \"to\": 50, \"color\": \"rgba(200, 200, 50, .75)\"},\n            {\"from\": 50, \"to\": 100, \"color\": \"rgba(200, 50, 50, .75)\"}\n            ],\n    barWidth: 10,\n    units: \"°C\",\n    borderShadowWidth: 0,\n    borders: false,\n    value: 35\n}).draw();\n\n</script>\n\n<canvas id=\"mycanvas\" \n    data-type=\"linear-gauge\"\n    data-width=\"106\"\n    data-height=\"270\"\n    data-units=\"°C\"\n    data-min-value=\"0\"\n    data-start-angle=\"90\"\n    data-ticks-angle=\"180\"\n    data-value-box=\"false\"\n    data-max-value=\"220\"\n    data-major-ticks=\"0,20,40,60,80,100,120,140,160,180,200,220\"\n    data-minor-ticks=\"2\"\n    data-stroke-ticks=\"true\"\n    data-color-plate=\"#fff\"\n    data-border-shadow-width=\"0\"\n    data-borders=\"false\"\n    data-needle-type=\"arrow\"\n    data-needle-width=\"2\"\n    data-needle-circle-size=\"7\"\n    data-needle-circle-outer=\"true\"\n    data-needle-circle-inner=\"false\"\n    data-animation-duration=\"1500\"\n    data-animation-rule=\"linear\"\n    data-bar-width=\"10\"\n    data-value=\"35\"\n></canvas>\n","storeOutMessages":false,"fwdInMessages":false,"x":960,"y":2040,"wires":[[]]},{"id":"8cc2ade9.5db9b","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"5","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2020,"wires":[["c8fdd54c.823418"]]},{"id":"277f033f.43ecbc","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"48","payloadType":"num","repeat":"","crontab":"","once":false,"x":770,"y":2060,"wires":[["c8fdd54c.823418"]]},{"id":"33279d5b.72b122","type":"ui_group","z":"","name":"LCD Test","tab":"34cddaf3.8a9cd6","disp":true,"width":"6"},{"id":"34cddaf3.8a9cd6","type":"ui_tab","z":"","name":"testz","icon":"dashboard"}]
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Yet Another Gauge

tmp6CBFThis one has been long in coming because despite my quickly evolving knowledge of Javascript and Canvas, that last leap – getting variable information out of a canvas and back into Node-Red – has kept me on edge for a couple of days now.  Dave (DCEEJAY) pointed me to various solutions all of which failed for me but then this morning he came up with a winner. I’ll go into detail in this article.

The gauge is simple enough – very much like the ones that Node-Red Dashboard already has – but it is adjustable (hmm, that’s a thought – I have suggested the Node-Red guys add a tick option to make the existing gauges adjustable. For now – this is it.

So – this started off as one of the examples from RGraph – you’ll need to include those libraries as previously. So note that the units used (degrees C) can be changed to anything you want – percentage or whatever. That is in the setup and is the entry marked “unitsPost”.

We have the by now familiar function(scope) function which allows us to inject values into the gauge – in this case msg.payload sets the gauge value.

We also have a special function which returns variable “value” to Node-Red on mouse up. This is the piece of the puzzle that has kept me going for days.  We also have a function which occurs on mouse up that grabs the current gauge value and stores it in “value”.  In the template itself, I’ve un-ticked “pass through messages” so that clicking or touching the gauge returns the new value of the gauge  - but injecting values does NOT product an output.

Now why is that last point important. Well, put such a gauge up on your computer screen and also on a secondary screen or phone – and watch what happens. Adjust one and…. nothing – the OTHER screen shows no change – oh dear. You need to inject the output back into the input for this to happen and unless you un-tick that box – the gauge will disappear up it’s own bum! For reasons beyond me you can’t connect a template’s output back to it’s input – so I just use an empty function to do that – well, empty other than I take the opportunity to put the value under the function just for effect.

I’ve made this to fit a 6*4 block. You can make it smaller by adjusting the size of the canvas, the gutter offsets and font size – but I could only manage to get one on a given tab without some unexplained interaction so I left the gauge this size which is handy for fingers on a typical phone.

tmp25CC

A view of the code:

<script src="/myjs/RGraph/RGraph.common.core.js"></script>
<script src="/myjs/RGraph/RGraph.common.dynamic.js"></script>
<script src="/myjs/RGraph/RGraph.semicircularprogress.js"></script>

<script>
    var value=0;

    (function(scope){
        scope.$watch('msg', function(msg) {
               if (typeof(msg.payload) != "undefined") { ssp.value=msg.payload; ssp.grow(); }
        });
  
})(scope);

this.scope.action = function() {
    return value;
}
    
    var ssp = new RGraph.SemiCircularProgress({
        id: 'newgauge1',
        min: 0,
        max: 100,
        value: 86,
        options: {
            gutterTop: 2,
            gutterLeft: 20,
            gutterRight: 5,
            gutterBottom: 70,
            unitsPost: '°C',
            labelsCenterSize: 40,
            labelsCenterValign: 'center',
            labelsMinSize: 10,
            labelsMinOffsetAngle:-0.1,
            labelsMinOffsetx:0,
            labelsMinOffsety:0,
            labelsMaxSize: 10,
            labelsMaxOffsetAngle:0.1,
            labelsMaxOffsetx:0,
            labelsMaxOffsety:0,
            adjustable: true,
            textAccessiblePointerevents: false,
            colors: ['Gradient(#224499:white)'],
            anglesStart: RGraph.PI - 0.5,
            anglesEnd: RGraph.TWOPI + 0.5
        }
    }).grow();
  
ssp.canvas.onmouseup = function (e)
{
    var obj   = e.target.__object__;
    value=obj.value;
}  
 </script>

<canvas ng-mouseup="send({payload:action()})" class="knob" id="newgauge1" width="300" height="200">
    [No canvas support]
</canvas>

The actual flow for copying into Node-Red:

[{"id":"3cbe837a.faf1dc","type":"ui_template","z":"c552e8d2.712b48","group":"33279d5b.72b122","name":"controller","order":0,"width":"6","height":"4","format":"<script src=\"/myjs/RGraph/RGraph.common.core.js\"></script>\n<script src=\"/myjs/RGraph/RGraph.common.dynamic.js\"></script>\n<script src=\"/myjs/RGraph/RGraph.semicircularprogress.js\"></script>\n\n<script>\n    var value=0;\n\n    (function(scope){\n        scope.$watch('msg', function(msg) {\n               if (typeof(msg.payload) != \"undefined\") { ssp.value=msg.payload; ssp.grow(); }\n        });\n  \n})(scope);\n\nthis.scope.action = function() {\n    return value;\n}\n    \n    var ssp = new RGraph.SemiCircularProgress({\n        id: 'newgauge1',\n        min: 0,\n        max: 100,\n        value: 86,\n        options: {\n            gutterTop: 2,\n            gutterLeft: 20,\n            gutterRight: 5,\n            gutterBottom: 70,\n            unitsPost: '°C',\n            labelsCenterSize: 40,\n            labelsCenterValign: 'center',\n            labelsMinSize: 10,\n            labelsMinOffsetAngle:-0.1,\n            labelsMinOffsetx:0,\n            labelsMinOffsety:0,\n            labelsMaxSize: 10,\n            labelsMaxOffsetAngle:0.1,\n            labelsMaxOffsetx:0,\n            labelsMaxOffsety:0,\n            adjustable: true,\n            textAccessiblePointerevents: false,\n            colors: ['Gradient(#224499:white)'],\n            anglesStart: RGraph.PI - 0.5,\n            anglesEnd: RGraph.TWOPI + 0.5\n        }\n    }).grow();\n  \nssp.canvas.onmouseup = function (e)\n{\n    var obj   = e.target.__object__;\n    value=obj.value;\n}  \n </script>\n\n<canvas ng-mouseup=\"send({payload:action()})\" class=\"knob\" id=\"newgauge1\" width=\"300\" height=\"200\">\n    [No canvas support]\n</canvas>","storeOutMessages":true,"fwdInMessages":false,"x":940,"y":1880,"wires":[["5ea77ad6.1b8064","8dc0930c.a5aaf"]]},{"id":"ecf3d231.ddba3","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"40","payloadType":"str","repeat":"","crontab":"","once":false,"x":770,"y":1880,"wires":[["8dc0930c.a5aaf"]]},{"id":"d9c0b1d6.35dbb","type":"inject","z":"c552e8d2.712b48","name":"","topic":"","payload":"80","payloadType":"str","repeat":"","crontab":"","once":false,"x":770,"y":1920,"wires":[["8dc0930c.a5aaf"]]},{"id":"5ea77ad6.1b8064","type":"debug","z":"c552e8d2.712b48","name":"","active":true,"console":"false","complete":"false","x":1130,"y":1880,"wires":[]},{"id":"8dc0930c.a5aaf","type":"function","z":"c552e8d2.712b48","name":"pass thru","func":"node.status({fill:\"blue\",shape:\"dot\",text:msg.payload});\n\nreturn msg;","outputs":1,"noerr":0,"x":940,"y":1940,"wires":[["3cbe837a.faf1dc"]]},{"id":"33279d5b.72b122","type":"ui_group","z":"","name":"LCD Test","tab":"34cddaf3.8a9cd6","disp":true,"width":"6"},{"id":"34cddaf3.8a9cd6","type":"ui_tab","z":"","name":"testz","icon":"dashboard"}]
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RGraph with Node-Red

RGraph GaugeHaving gone from spending countless hours staring at HTML5 CANVAS, I’m now at the “meh” stage as it starts to dawn on my how it works.

And so it was that I stumbled on RGraph – or put another way, Christmas for widget-lovers.

If you’ve been following these blog entries you’ll know that Node-Red has TEMPLATES in the UI – and that you can put your own stuff into the templates and that recently the fog has lifted on getting variables in and out of the templates.

In recent blogs I’ve been constantly improving a thermostat control page and that took me off looking for a gauge with two pointers – one to show temperature, the other to show humidity.

And that’s when I stumbled upon RGraph. If you read this – and understand it – you will open the doors to a boatload of gauges, thermometers, charts and graphs so tuck in:

First things first, if you’ve already played with Node-Red in here you will likely have made a /myjs folder (home/pi/.node-red/public/myjs or similar – defined in your Node-Red settings.js file) to put various Javascript files in. Well, add this lot in a sub-folder called RGraph – you can call it freddy if you like but I thought it reasonable to use the name the way they use it. I grabbed the latest stable version from here. Inside there is a folder called RGraph – and inside that is a folder called libraries – I grabbed the contents of that folder and put it inside my /public/RGraph folder. It may be there is a use for other stuff in there – but for now that’s all I’ve taken.

So – then I dropped in a template – made it 6*6 and inside that template I put this lot – code shown below.

Now, if you don’t like my colours – change them. You can change just about anything including the size but you may need to adjust the font size if you do that. Experiment!

To change the two pointers – which I’ve chosen to call temperature and humidity – you might use them for petrol and oil – or whatever….I simply pass MSG as is common in Node-Red – but not msg.template – instead msg.temperature and msg.humidity – you can call them whatever you like.

The point of this is not to demonstrate my crap taste in colours – once you follow what I’ve done here – that entire, massive library of CANVAS-related gauges and charts is yours for the taking!  You can make the gauges interactive – but as I had two, not one pointers in this example, I skipped that. Details are in the extensive RGraph documentation.  Copy me and drop them an encouraging lines to say MORE IOT PLEASE!!

Oh and if you don’t like animation – where I say “grow” say “draw”.

(As an aside, I got this working today as well - https://www.codeproject.com/Articles/304874/HTML-Canvas-Aqua-Gauge)  very pretty but doesn’t scale well.

Prerequisites: Far too often in blogs like this we “assume” that everyone is keeping up – if not – may I suggest a quick look at this page I put up specifically to give a little background – which might help explain this article.

<script src="/myjs/RGraph/RGraph.common.core.js" ></script>
<script src="/myjs/RGraph/RGraph.gauge.js" ></script>

<script language="javascript" type="text/javascript">

           (function(scope){ 
                scope.$watch('msg', function(msg) {
                   gauge3.value=[msg.temperature,msg.humidity];
                   gauge3.grow();
                });
            })(scope);
            
            var gauge3 = new RGraph.Gauge({
                id: 'cvs',
                min: 0,
                max: 100,
                value: [23,60],
                options: {
                    titleTop: 'Temperature',
                    titleTopSize: '16',
                    titleTopFont: 'Impact',
                    titleTopColor: '#ff8888',
                    titleTopPos: 0.25,
                    titleBottom: 'Humidity',
                    titleBottomSize: '14',
                    titleBottomFont: 'Impact',
                    titleBottomColor: '#8888ff',
                    titleBottomPos: 0.3,
                    backgroundColor: 'black',
                    backgroundGradient: true,
                    centerpinColor: '#666',
                    needleSize: [null, 50],
                    needleColors: ['Gradient(transparent:yellow:orange:#ff8888:#ff8888)', 
                                    'Gradient(transparent:cyan:green:blue:blue)'],
                    textColor: 'white',
                    tickmarksBigColor: 'white',
                    tickmarksMediumColor: 'white',
                    tickmarksSmallColor: 'white',
                    borderWidth: 1,
                    borderOuter: '#666',
                    borderInner: '#3333',
                    colorsRanges: [
                                    [0,10,'rgba(0,0,255,0.6)'], 
                                    [10,20,'rgba(0,128,255,0.6)'], 
                                    [20,30,'rgba(0,255,255,0.6)'], 
                                    [30,40,'rgba(0,255,128,0.6)'], 
                                    [40,50,'rgba(0,255,0,0.6)'], 
                                    [50,60,'rgba(128,255,0,0.6)'], 
                                    [60,70,'rgba(255,255,0,0.6)'], 
                                    [70,80,'rgba(255,128,0,0.6)'],                                                                                                                                                 
                                    [80,90,'rgba(255,64,0,0.6)'],   
                                    [90,100,'rgba(255,0,0,1']
                                  ],
                    textAccessible: true
                }
            });
            gauge3.grow();

    </script>

    <canvas id="cvs" width="300" height="300">[No canvas support]</canvas>
 
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