Improve Histogram.svelte

- Add bold axis labels
- Labels defined as element props xlabel and ylabel
- Label offset dynamic to plot height (10 percent)
- Add adjustable gaps between bars

web/frontend/src/Status.root.svelte

@@ -152,7 +152,8 @@
                     <Histogram
                         width={colWidth1 - 25} height={300}
                         data={$mainQuery.data.topUsers.sort((a, b) => b.count - a.count).map(({ count }, idx) => ({ count, value: idx }))}
-                        label={(x) => x < $mainQuery.data.topUsers.length ? $mainQuery.data.topUsers[Math.floor(x)].name : '0'} />
+                        label={(x) => x < $mainQuery.data.topUsers.length ? $mainQuery.data.topUsers[Math.floor(x)].name : '0'}
+                        xlabel="User Name" ylabel="Number of Jobs" />
                 {/key}
             </div>
         </Col>
@@ -173,7 +174,8 @@
                 <Histogram
                     width={colWidth1 - 25} height={300}
                     data={$mainQuery.data.topProjects.sort((a, b) => b.count - a.count).map(({ count }, idx) => ({ count, value: idx }))}
-                    label={(x) => x < $mainQuery.data.topProjects.length ? $mainQuery.data.topProjects[Math.floor(x)].name : '0'} />
+                    label={(x) => x < $mainQuery.data.topProjects.length ? $mainQuery.data.topProjects[Math.floor(x)].name : '0'}
+                    xlabel="Project Code" ylabel="Number of Jobs" />
             {/key}
         </Col>
         <Col class="px-4 py-2">
@@ -192,7 +194,8 @@
                 {#key $mainQuery.data.stats}
                     <Histogram
                         width={colWidth2 - 25} height={300}
-                        data={$mainQuery.data.stats[0].histDuration} />
+                        data={$mainQuery.data.stats[0].histDuration}
+                        xlabel="Current Runtime in Hours [h]" ylabel="Number of Jobs" />
                 {/key}
             </div>
         </Col>
@@ -201,7 +204,8 @@
             {#key $mainQuery.data.stats}
                 <Histogram
                     width={colWidth2 - 25} height={300}
-                    data={$mainQuery.data.stats[0].histNumNodes} />
+                    data={$mainQuery.data.stats[0].histNumNodes}
+                    xlabel="Allocated Nodes" ylabel="Number of Jobs" />
             {/key}
         </Col>
     </Row>

web/frontend/src/plots/Histogram.svelte

@@ -20,6 +20,8 @@
     export let data
     export let width
     export let height
+    export let xlabel
+    export let ylabel
     export let min = null
     export let max = null
     export let label = formatNumber
@@ -72,9 +74,11 @@
     }
 
     function render() {
-        const h = height - paddingTop - paddingBottom
+        const labelOffset =  Math.floor(height * 0.1)
+        const h = height - paddingTop - paddingBottom - labelOffset
         const w = width - paddingLeft - paddingRight
-        const barWidth = Math.ceil(w / (maxValue + 1))
+        const barGap = 5
+        const barWidth = Math.ceil(w / (maxValue + 1)) - barGap
 
         if (Number.isNaN(barWidth))
             return
@@ -83,9 +87,14 @@
         const getCanvasY = (count) => (h - (count / maxCount) * h) + paddingTop
 
         // X Axis
-        ctx.font = `${fontSize}px ${fontFamily}`
+        ctx.font = `bold ${fontSize}px ${fontFamily}`
         ctx.fillStyle = 'black'
+        if (xlabel != '') {
+            let textWidth = ctx.measureText(xlabel).width
+            ctx.fillText(xlabel, Math.floor((width / 2) - (textWidth / 2) + barGap), height - Math.floor(labelOffset / 2))
+        }
         ctx.textAlign = 'center'
+        ctx.font = `${fontSize}px ${fontFamily}`
         if (min != null && max != null) {
             const stepsizeX = getStepSize(max - min, w, 75)
             let startX = 0
@@ -94,19 +103,28 @@
 
             for (let x = startX; x < max; x += stepsizeX) {
                 let px = ((x - min) / (max - min)) * (w - barWidth) + paddingLeft + (barWidth / 2.)
-                ctx.fillText(`${formatNumber(x)}`, px, height - paddingBottom + 15)
+                ctx.fillText(`${formatNumber(x)}`, px, height - paddingBottom - Math.floor(labelOffset / 2))
             }
         } else {
             const stepsizeX = getStepSize(maxValue, w, 120)
             for (let x = 0; x <= maxValue; x += stepsizeX) {
-                ctx.fillText(label(x), getCanvasX(x), height - paddingBottom + 15)
+                ctx.fillText(label(x), getCanvasX(x), height - paddingBottom - Math.floor(labelOffset / 2))
             }
         }
 
         // Y Axis
         ctx.fillStyle = 'black'
         ctx.strokeStyle = '#bbbbbb'
+        ctx.font = `bold ${fontSize}px ${fontFamily}`
+        if (ylabel != '') {
+            ctx.save()
+            ctx.translate(15, Math.floor(h / 2))
+            ctx.rotate(-Math.PI / 2)
+            ctx.fillText(ylabel, 0, 0)
+            ctx.restore()
+        }
         ctx.textAlign = 'right'
+        ctx.font = `${fontSize}px ${fontFamily}`
         ctx.beginPath()
         const stepsizeY = getStepSize(maxCount, h, 50)
         for (let y = stepsizeY; y <= maxCount; y += stepsizeY) {
@@ -130,10 +148,10 @@
         // Fat lines left and below plotting area
         ctx.strokeStyle = 'black'
         ctx.beginPath()
-        ctx.moveTo(0, height - paddingBottom)
+        ctx.moveTo(0, height - paddingBottom - labelOffset)
-        ctx.lineTo(width, height - paddingBottom)
+        ctx.lineTo(width, height - paddingBottom - labelOffset)
         ctx.moveTo(paddingLeft, 0)
-        ctx.lineTo(paddingLeft, height- paddingBottom)
+        ctx.lineTo(paddingLeft, height - Math.floor(labelOffset / 2))
         ctx.stroke()
     }