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Expand Clickable Area of Chart Points

Environment

Product Progress Kendo UI Chart for jQuery
Operating System Windows 10 64bit
Visual Studio version Visual Studio 2017
Preferred Language JavaScript

Description

Sometimes the Chart produces series of points that are too small to be reliably clicked or touched. How can I expand these?

Solution

It is possible to expand the active area by adding a transparent element as part of the visual configuration.

The following example demonstrates how to achieve this behavior in a Bar Charts series.

    <div id="chart"></div>
    <div id="log">Click on the area next to a point...</div>
    <script>
      $("#chart").kendoChart({
        series: [{
          type: "column",
          data: [1, 2, 3],
          visual: function(e) {
            var marker = e.createVisual();
            var group = new kendo.drawing.Group();

            // A transparent rectangle that serves as a touch zone
            var touch = kendo.drawing.Path.fromRect(e.rect, {
              transform: kendo.geometry.transform()
              .scale(1.5, 2, e.rect.center()),

              // Comment the following line to see it
              stroke: null,

              fill: {
                color: "#fff",
                opacity: 0
              }
            });

            group.append(touch, marker);
            return group;
          },
          tooltip: {
            visible: true
          }
        }],
        seriesClick: function(e) {
          $("#log").text("Clicked " + e.value);
        }
      });
    </script>

The following example demonstrates how to expand the clickable or touchable area of points in a line series.

    <div id="chart"></div>
    <div id="log">Click on the area next to a point...</div>
    <script>
      $("#chart").kendoChart({
        series: [{
          type: "line",
          data: [1, 2, 3],
          markers: {
              visual: function(e) {
                var marker = e.createVisual();
                var group = new kendo.drawing.Group();

                // A transparent rectangle that serves as a touch zone
                var touch = kendo.drawing.Path.fromRect(e.rect, {
                  transform: kendo.geometry.transform()
                  .scale(10, 10, e.rect.center()),

                  // Comment the following line to see it
                  stroke: null,

                  fill: {
                    color: "#fff",
                    opacity: 0
                  }
                });

                group.append(touch, marker);
                return group;
              }
          },
          tooltip: {
            visible: true
          }
        }],
        seriesClick: function(e) {
          $("#log").text("Clicked " + e.value);
        }
      });
    </script>

See Also

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