Merge pull request #14877 from papagian/feature-histogram-min-max

Optionally set histogram x-axis min/max

public/app/plugins/panel/graph/axes_editor.html

@@ -67,6 +67,17 @@
 			<input type="number" class="gf-form-input max-width-8" ng-model="ctrl.panel.xaxis.buckets" placeholder="auto" ng-change="ctrl.render()" ng-model-onblur bs-tooltip="'Number of buckets'" data-placement="right">
 		</div>
 
+		<div class="gf-form-inline" ng-if="ctrl.panel.xaxis.mode === 'histogram'">
+			<div class="gf-form">
+				<label class="gf-form-label width-6">X-Min</label>
+				<input type="number" class="gf-form-input width-5" placeholder="auto" empty-to-null ng-model="ctrl.panel.xaxis.min" ng-change="ctrl.render()" ng-model-onblur>
+			</div>
+			<div class="gf-form">
+				<label class="gf-form-label width-6">X-Max</label>
+				<input type="number" class="gf-form-input width-5" placeholder="auto" empty-to-null ng-model="ctrl.panel.xaxis.max" ng-change="ctrl.render()" ng-model-onblur>
+			</div>
+		</div>
+
 		<div>
 			<br/>
 			<h5 class="section-heading">Y-Axes</h5>

public/app/plugins/panel/graph/graph.ts

@@ -337,9 +337,17 @@ class GraphElement {
         let bucketSize: number;
 
         if (this.data.length) {
-          const histMin = _.min(_.map(this.data, s => s.stats.min));
-          const histMax = _.max(_.map(this.data, s => s.stats.max));
+          let histMin = _.min(_.map(this.data, s => s.stats.min));
+          let histMax = _.max(_.map(this.data, s => s.stats.max));
           const ticks = panel.xaxis.buckets || this.panelWidth / 50;
+          if (panel.xaxis.min != null) {
+            const isInvalidXaxisMin = tickStep(panel.xaxis.min, histMax, ticks) <= 0;
+            histMin = isInvalidXaxisMin ? histMin : panel.xaxis.min;
+          }
+          if (panel.xaxis.max != null) {
+            const isInvalidXaxisMax = tickStep(histMin, panel.xaxis.max, ticks) <= 0;
+            histMax = isInvalidXaxisMax ? histMax : panel.xaxis.max;
+          }
           bucketSize = tickStep(histMin, histMax, ticks);
           options.series.bars.barWidth = bucketSize * 0.8;
           this.data = convertToHistogramData(this.data, bucketSize, this.ctrl.hiddenSeries, histMin, histMax);

public/app/plugins/panel/graph/histogram.ts

@@ -43,6 +43,10 @@ export function convertValuesToHistogram(values: number[], bucketSize: number, m
   }
 
   for (let i = 0; i < values.length; i++) {
+    // filter out values outside the min and max boundaries
+    if (values[i] < min || values[i] > max) {
+      continue;
+    }
     const bound = getBucketBound(values[i], bucketSize);
     histogram[bound] = histogram[bound] + 1;
   }