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Set image as a marker

Viewing 8 posts - 1 through 8 (of 8 total)
  • March 22, 2017 at 11:57 am #14640

    NehaSingh

    Hello, i wanted to know that can we set an image as a marker. i am using splineGraph and i want to

      replace the circle marker with an image

    . Please reply as soon as possible.

    March 22, 2017 at 5:56 pm #14645

    Suyash Singh

    @nehasingh,

    As of now markers can have only five possible values – “circle”, “square”, “triangle” , “cross” & “none”. However, you can position images in place of markers by adding few lines of code. Please checkout the code snippet below for the same.

    addMarkerImages(chart);

function addMarkerImages(chart){
  for(var i = 0; i < chart.data[0].dataPoints.length; i++){
    customMarkers.push($("<img>").attr("src", chart.data[0].dataPoints[i].markerImageUrl)
                       .css("display", "none")
                       .css("height", 30)
                       .css("width", 30)
                       .appendTo($("#chartContainer>.canvasjs-chart-container"))
                      );        
    positionMarkerImage(customMarkers[i], i);
  }    
}

function positionMarkerImage(customMarker, index){ 
  var pixelX = chart.axisX[0].convertValueToPixel(chart.options.data[0].dataPoints[index].x);
  var pixelY = chart.axisY[0].convertValueToPixel(chart.options.data[0].dataPoints[index].y);
  
  customMarker.css({"position": "absolute", 
                    "display": "block",
                    "top": pixelY - customMarker.height()/2,
                    "left": pixelX - customMarker.width()/2
                   });
}

    Also, please take a look at this JSFiddle for a complete code. For further insight, please refer this how to section for positioning images over chart.

    Chart with image as marker

    —
    Suyash Singh
    Team CanvasJS

    March 22, 2017 at 10:33 pm #14647

    NehaSingh

    Hello @Suyash Singh, Thanks a lot for the quick response..
    This works perfectly….
    you guys have done a superb job..
    This saved me a lot of time..

    March 22, 2017 at 11:13 pm #14648

    NehaSingh     
    <!DOCTYPE HTML>
<html>

    <head>
        <style>
            img{
                pointer-events: none;
            }
        </style>
        <script type="text/javascript" src="https://canvasjs.com/assets/script/jquery-1.11.1.min.js"></script>  
        <script type="text/javascript" src="https://cdn.canvasjs.com/jquery.canvasjs.min.js"></script>
        <script type="text/javascript">
            window.onload = function () {
                var dps = [{x: 0, y: 0, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}];
                /*[{x: 1, y: 10, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 2, y: 13, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 3, y: 18, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 4, y: 20, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 5, y: 17, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 6, y: 10, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 7, y: 13, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 8, y: 18, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 9, y: 20, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}, 
                 {x: 10, y: 47, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"}]; */  //dataPoints. 
                var chart = new CanvasJS.Chart("chartContainer", {
                    theme: "theme2", //theme1
                    backgroundColor: "transparent",
                    title: {
                        text: "Live Data"
                    },
                    axisX: {
                        title: "Velocity"
                    },
                    axisY: {
                        title: "Distance"
                    },
                    data: [
                        {
                            type: "spline",
                            markerType: "none",
                            dataPoints: dps
                        }
                    ]
                });

                chart.render();

                var xVal = dps.length + 1;
                var yVal = 15;
                var updateInterval = 1000;

                var updateChart = function () {

                    yVal = yVal + Math.round(5 + Math.random() * (-5 - 5));
                    dps.push({x: xVal,y: yVal, markerImageUrl:  "http://i.imgur.com/TUmQf5n.png"});
                   

                    xVal++;
                    if (dps.length > 10)
                    {
                        dps.shift();
                    }

                    chart.render();

                    // update chart after specified time. 

                };

                setInterval(function () {
                    updateChart();
                }, updateInterval);

                var customMarkers = [];

                addMarkerImages(chart);

                function addMarkerImages(chart) {
                    for (var i = 0; i < chart.data[0].dataPoints.length; i++) {

                        customMarkers.push($("<img>").attr("src", chart.data[0].dataPoints[i].markerImageUrl)
                                .css("display", "none")
                                .css("height", 40)
                                .css("width", 50)
                                .appendTo($("#chartContainer>.canvasjs-chart-container"))
                                );
                        positionMarkerImage(customMarkers[i], i);
                    }
                }

                function positionMarkerImage(customMarker, index) {
                    var pixelX = chart.axisX[0].convertValueToPixel(chart.options.data[0].dataPoints[index].x);
                    var pixelY = chart.axisY[0].convertValueToPixel(chart.options.data[0].dataPoints[index].y);

                    customMarker.css({"position": "absolute",
                        "display": "block",
                        "top": pixelY - customMarker.height() / 2,
                        "left": pixelX - customMarker.width() / 2
                    });
                }

                $(window).resize(function () {
                    for (var i = 0; i < chart.data[0].dataPoints.length; i++) {
                        positionMarkerImage(customMarkers[i], i);
                    }
                });
            };
        </script>	
    </head>
    <body>
        <div id="chartContainer" style="height: 300px; width: 100%;"></div>
    </body>
</html>

    This is what i have done so far. For static data it is working fine, when i am trying to do it for dynamic data, don’t now why the dps.push function is not working. The graph is created but the image doesn’t appears. Please suggest what is wrong here. i am almost there.

    • This reply was modified 7 years, 9 months ago by NehaSingh. Reason: remove Extra code for better understanding
    March 23, 2017 at 1:49 am #14651

    NehaSingh

    And I also wanted to ask that I am using this for a college project and it is offline. I just read that trial version is only for 30 days so will I be able to use this after that???
    Can I use it offline… or it will stop working after the trial period.

    March 23, 2017 at 8:32 pm #14660

    Suyash Singh

    @nehasingh

    For dynamic data, updating the position of image after adding new dataPoint has to be handled. Please take a look at below code snippet for the same.

    var updateChart = function () {
  yVal = yVal + Math.round(5 + Math.random() * (-5 - 5));
  dps.push({ x: xVal,y: yVal });
  xVal++;
  if (dps.length > 10)
  {
    dps.shift();
  }
  chart.render();
  addMarkerImage(chart);
};

function addMarkerImage(chart) {
  var data = chart.options.data[0];
  for(var i = 0; i < data.dataPoints.length; i++) {
    customMarkers.push($("<img>").attr("src", data.markerImageUrl)
                       .css("display", "none")
                       .css("height", 20)
                       .css("width", 20)
                       .appendTo($("#chartContainer>.canvasjs-chart-container"))
                      );   
    positionMarkerImage(customMarkers[i], i);
  }            
}

function positionMarkerImage(customMarker, index){ 
  var pixelX = chart.axisX[0].convertValueToPixel(chart.options.data[0].dataPoints[index].x);
  var pixelY = chart.axisY[0].convertValueToPixel(chart.options.data[0].dataPoints[index].y);

  customMarker.css({"position": "absolute", 
                    "display": "block",
                    "top": pixelY - customMarker.height()/2,
                    "left": pixelX - customMarker.width()/2
                   });
}

var updateId = setInterval(function () { updateChart();}, updateInterval);

    Please refer to this JSFiddle for complete code.

    Dynamic line chart with image as marker

    Regarding your query about the Trial Version, our sales team have already mailed you and they will be assisting you further with your requirements.

    —
    Suyash Singh
    Team CanvasJS

    April 3, 2017 at 12:40 pm #14725

    NehaSingh

    Hello,

    I am going through few problems.
    1. I am showing live data from my database which is being updated every 2 seconds. Now after some time the marker disappears. For first few minutes it is displayed but not after that, is there any range? the line works fine. only i am not able to see the marker.

    2. i am using an image as a marker but i want to show the image only for the current position and the rest of the points should be any simple marker type. Is there any way to do that?

    Hoping to hear from you soon.

    April 3, 2017 at 4:35 pm #14726

    Suyash Singh

    @nehasingh,

    1. Default Markers are automatically disabled when number of dataPoints are more. You can manually override the automatic disabling/enabling of markers by setting markerSize to a value equal to or greater than zero. 

    {
  .
  .
  data: [{
    markerSize: 10,
    .
    .
  }]
}

    Please have a look at this JSFiddle for complete code.

    2. You can show the marker image only for current dataPoint by placing the marker Image on top of the last dataPoint every time the chart is updated. Please have a look at this below code snippet for the same.

    var updateChart = function () {
  yVal = yVal + Math.round(5 + Math.random() * (-5 - 5));
  dps.push({ x: xVal,y: yVal });
  xVal++;
  if (dps.length > 10)
  {
    dps.shift();
  }
  chart.render();

  // Position image marker over the last/ current dataPoint
  positionMarkerImage(imageMarker, chart.options.data[0].dataPoints.length - 1);
};

function positionMarkerImage(imageMarker, index){ 
  var pixelX = chart.axisX[0].convertValueToPixel(chart.options.data[0].dataPoints[index].x);
  var pixelY = chart.axisY[0].convertValueToPixel(chart.options.data[0].dataPoints[index].y);

  imageMarker.css({"position": "absolute", 
                   "display": "block",
                   "top": pixelY - imageMarker.height()/2,
                   "left": pixelX - imageMarker.width()/2
                  });
}

var updateId = setInterval(function () { updateChart();}, updateInterval);

    Please refer to this JSFiddle for complete code on the same.

    Dynamic chart with image as marker

    ___
    Suyash Singh
    Team CanvasJS

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