projection: begin the exact-path public epoch

The public tree and its history contain only the listed paths. Earlier projection history remains preserved internally.

Source-Sha: 913fde029b935671833254797f0f20f1eb9fabba

Policy-Sha: 913fde029b935671833254797f0f20f1eb9fabba

Tree-Digest: 180ae530c1058a2a5c89837bdce2d323ae83e669e38590ca72e75b8d92b7262f

desktop/qml/LineGraph.qml

@@ -0,0 +1,45 @@
+import QtQuick
+
+Canvas {
+    id: root
+    property var values: []
+    property real ceiling: 100
+    property color lineColor: Theme.red
+    property color fillColor: Theme.tint(lineColor, 0.12)
+    property bool grid: true
+
+    onValuesChanged: requestPaint()
+    onWidthChanged: requestPaint()
+    onHeightChanged: requestPaint()
+    onCeilingChanged: requestPaint()
+
+    onPaint: {
+        const ctx = getContext("2d")
+        ctx.reset()
+        if (grid) {
+            ctx.strokeStyle = Theme.divider
+            ctx.lineWidth = 1
+            for (let y = 0; y <= 4; ++y) {
+                ctx.beginPath(); ctx.moveTo(0, y * height / 4); ctx.lineTo(width, y * height / 4); ctx.stroke()
+            }
+        }
+        if (!values || values.length < 2) return
+        const top = Math.max(1, ceiling)
+        const step = width / Math.max(1, values.length - 1)
+        ctx.beginPath()
+        for (let i = 0; i < values.length; ++i) {
+            const x = i * step
+            const y = height - Math.min(top, Math.max(0, Number(values[i]))) / top * height
+            if (i === 0) ctx.moveTo(x, y); else ctx.lineTo(x, y)
+        }
+        ctx.lineTo(width, height); ctx.lineTo(0, height); ctx.closePath()
+        ctx.fillStyle = fillColor; ctx.fill()
+        ctx.beginPath()
+        for (let j = 0; j < values.length; ++j) {
+            const x2 = j * step
+            const y2 = height - Math.min(top, Math.max(0, Number(values[j]))) / top * height
+            if (j === 0) ctx.moveTo(x2, y2); else ctx.lineTo(x2, y2)
+        }
+        ctx.strokeStyle = lineColor; ctx.lineWidth = 2; ctx.stroke()
+    }
+}