[FEATURE] Add canvas panel plugin by adrianSepiol · Pull Request #729 · perses/plugins

adrianSepiol · 2026-07-15T17:20:23Z

Description

Introduces the canvas panel plugin — a free-form network diagram editor for building weathermap-style dashboards. Users can place nodes, connect them with edges, and overlay background shapes or images. Node and edge colors can be driven by query-bound thresholds, and edge thickness can scale with metric values.

Screenshots

Here's a walkthrough of the main interactions:

Example weather map created in canvas:

Adding a node:

Screen.Recording.2026-07-20.at.15.26.09.mov

After creating a node, you can specify its label and position, add a link, bind a query to it, and use the query value in the label or derive the color from thresholds.

Adding an edge:

Screen.Recording.2026-07-20.at.15.26.45.mov

Edges are created by dragging from one node to another. They can be bidirectional and, like nodes, can have a query bound to them.

Zoom, pan, and resize:

Screen.Recording.2026-07-20.at.15.32.35.mov

Adding backgrounds:

adding.background.mov

Multiple backgrounds can be added with an image or a solid color at varying opacity levels. If "Global" is selected, the background always fills the entire view regardless of pan/zoom; otherwise it is scoped to a specified area.

Checklist

Pull request has a descriptive title and context useful to a reviewer.
Pull request title follows the [<catalog_entry>] <commit message> naming convention using one of the
following catalog_entry values: FEATURE, ENHANCEMENT, BUGFIX, BREAKINGCHANGE, DOC,IGNORE.
All commits have DCO signoffs.

UI Changes

Changes that impact the UI include screenshots and/or screencasts of the relevant changes.
Code follows the UI guidelines.

Signed-off-by: Adrian Sepiół <a.sepiol@sap.com> [ENHANCEMENT] update panel schema re-exports to use @perses-dev/plugin-system panelEditorSchema and buildPanelEditorSchema have moved from @perses-dev/spec to @perses-dev/plugin-system. Signed-off-by: Adrian Sepiół <a.sepiol@sap.com>

jgbernalp · 2026-07-24T08:53:36Z

@@ -0,0 +1,20 @@
+{
+  "kind": "Canvas",


It appears to me that this is a nodes panel rather than a canvas. Unless we are thinking about adding other things different from nodes in the future.

Yes, We would like to develop it further with new things. I think adding background is one of the things that is already here and fits more into "canvas" than "nodes" plugin.

jgbernalp · 2026-07-24T08:59:53Z

First of all, awesome job @adrianSepiol!

Would be there an option to create a graph (nodes and connections) based on a query? for example network topology charts have queries that return a list of nodes and their connections. In that case could this panel create a graph from that information in addition to the manual placement of nodes?

adrianSepiol · 2026-07-30T13:01:32Z

First of all, awesome job @adrianSepiol!

Would be there an option to create a graph (nodes and connections) based on a query? for example network topology charts have queries that return a list of nodes and their connections. In that case could this panel create a graph from that information in addition to the manual placement of nodes?

That is something we also discussed and would like to work on in the future, but the idea is to make this work with this spec for the first iteration and then add new functionalities gradually.

ibakshay

Great job Adrian! My agent found some nits.

ibakshay · 2026-08-18T10:16:38Z

+        {displayNodes.map((node) => {
+          const onNodePointerDown = (event: PointerEvent<SVGRectElement>): void => {
+            const unselectedId = selectNode(event, node.id);
+            if (unselectedId !== null) {
+              selectItems(new Set([unselectedId]));
+            } else {
+              startMove();
+            }
+          };
+          const onNodePointerMove = (event: PointerEvent<SVGRectElement>): void => {
+            updateMove(event, node.id);
+          };
+          const onNodeMouseEnter = (): void => {
+            if (mode.type !== 'dragging-edge') {
+              hoverNode(node.id);
+            }
+          };
+          const onNodeMouseLeave = (): void => unhoverNode(node.id);
+          const onCrossDragStart = (anchor: AnchorPoint, x: number, y: number): void => {
+            beginEdgeDrag(node.id, anchor, x, y);
+            startDragEdge();
+          };
+          return (
+            <EditorNode
+              key={node.id}
+              node={node}
+              isHovered={hoveredId === node.id}
+              isSelected={selectedIds.has(node.id)}
+              snapTarget={dragEdge?.snapTargetId === node.id}
+              isDragging={mode.type === 'dragging-edge'}
+              onPointerDown={onNodePointerDown}
+              onPointerMove={onNodePointerMove}
+              onMouseEnter={onNodeMouseEnter}
+              onMouseLeave={onNodeMouseLeave}
+              onCrossDragStart={onCrossDragStart}
+            />
+          );
+        })}


[SUGGESTION] Rule: rerender-no-inline-components — No Inline Components

Inside the displayNodes.map(...) loop (line 213), several inline handler functions are defined (onNodePointerDown, onNodePointerMove, onNodeMouseEnter, onNodeMouseLeave, onCrossDragStart). These create new function references on every render, preventing EditorNode from being memoized.

Fix: Extract a dedicated <EditorNodeWrapper key={node.id} node={node} ... /> component that receives only primitives/stable references. This way, individual nodes only re-render when their own props change. For a canvas with many nodes, this materially impacts performance during pointer-move events.

ibakshay · 2026-08-18T10:16:38Z

+        {displayEdges.map((edge) => {
+          const onEdgeClick = (event: PointerEvent<SVGLineElement>): void => {
+            event.stopPropagation();
+            selectItems(new Set([edge.id]));
+          };
+          const onEndpointPointerDown = (
+            event: PointerEvent<SVGCircleElement>,
+            end: 'source' | 'target',
+            fixedX: number,
+            fixedY: number,
+            fixedNodeId: string,
+            fixedAnchor: AnchorPoint
+          ): void => {
+            if (beginEndpointDrag(event, edge.id, end, fixedX, fixedY, fixedNodeId, fixedAnchor)) {
+              startDragEdge();
+            }
+          };
+          return (
+            <EditorEdge
+              key={edge.id}
+              edge={edge}
+              isSelected={!selectionBoundingBox && selectedIds.has(edge.id)}
+              isDragging={mode.type === 'dragging-edge'}
+              nsPrefix={`${NS_PREFIX}-${edge.id}`}
+              nodeById={nodeById}
+              onEdgeClick={onEdgeClick}
+              onEndpointPointerDown={onEndpointPointerDown}
+            />
+          );


[SUGGESTION] Rule: rerender-no-inline-components — No Inline Components

Same issue for displayEdges.map(...) (line 252) — inline onEdgeClick and onEndpointPointerDown handlers are created per edge per render.

Fix: Extract a wrapper component that receives stable callbacks and only re-renders when its own edge changes.

ibakshay · 2026-08-18T10:16:38Z

+        />
+      </g>
+
+      {showLegend && (


[NOTE] Rule: rendering-conditional-render — Use Ternaries Instead of &&

&& is used for conditional rendering (e.g. {showLegend && (<ThresholdLegend .../>)} at CanvasPanel.tsx:88, {bwd && <EdgeArrowMarker .../>} at EdgeLines.tsx:110). When the left operand is falsy but not null/undefined/false, it can render "0" or "". In this codebase it's safe since the values are booleans/objects, but ternaries are more explicit.

Fix: Replace with ternary, e.g. {showLegend ? <ThresholdLegend ... /> : null}.

(Also applies to canvas/src/components/shared/EdgeLines.tsx:110)

ibakshay · 2026-08-18T10:16:38Z

+export function PanelEdgeLayer({ spec, seriesByQueryIndex, k, paletteColors }: PanelEdgeLayerProps): ReactElement {
+  const nodes = spec.nodes ?? [];
+  const edges = spec.edges ?? [];
+  const nodeById = new Map(nodes.map((n) => [n.id, n]));


[NOTE] Rule: js-index-maps — Build Maps for Repeated Lookups

const nodeById = new Map(nodes.map((n) => [n.id, n])) is created on every render without useMemo. Since PanelEdgeLayer re-renders on zoom changes, this map is rebuilt every time even though spec.nodes hasn't changed.

Fix: Wrap in useMemo(() => new Map(nodes.map(...)), [nodes]).

ibakshay · 2026-08-18T10:16:38Z

+  return {
+    palette: chartsTheme.thresholds.palette,
+    selection: muiTheme.palette.warning.main,
+    connection: muiTheme.palette.info.main,
+    snapHighlight: muiTheme.palette.success.main,
+    background: muiTheme.palette.background.paper,
+    divider: muiTheme.palette.divider,
+    text: muiTheme.palette.text.primary,
+    labelBackground: muiTheme.palette.background.paper,
+    labelBorder: muiTheme.palette.divider,
+    labelText: muiTheme.palette.text.primary,
+    nodeStroke: muiTheme.palette.background.paper,
+    nodeDefaultFill: muiTheme.palette.primary.main,
+  };


[NOTE] Rule: rerender-derived-state-no-effect — Avoid Recreating Objects Each Render

useCanvasTheme (line 32) creates a new object literal on every call (lines 35-48). Since it's used in both EditorNode and EditorEdge (called every frame during drag), this causes unnecessary object allocation.

Fix: Memoize the return value: return useMemo(() => ({ palette: ..., ... }), [muiTheme, chartsTheme]).

ibakshay · 2026-08-18T10:40:30Z

[SUGGESTION] please add a "info" message in the panel for the end users when the canvas is empty. Otherwise, it looks blank. Otherwise, the panel looks blank.

shahrokni · 2026-08-18T11:51:51Z

+	Color           string        `json:"color,omitempty" yaml:"color,omitempty"`
+}


Is this hex color code?

shahrokni · 2026-08-18T11:56:35Z

+	X2                  *float64      `json:"x2,omitempty" yaml:"x2,omitempty"`
+	Y2                  *float64      `json:"y2,omitempty" yaml:"y2,omitempty"`


Why do they have suffix '2'? Is this the edge's middle point?

shahrokni · 2026-08-18T12:00:31Z

+	X        float64  `json:"x" yaml:"x"`
+	Y        float64  `json:"y" yaml:"y"`


It seems we are repeating 'X' and 'Y' everywhere. Could it have its own struct like Position or Coordinate or it would be too much? Not sure though. Forget it if it is an overkill. Your call.

shahrokni · 2026-08-18T12:04:37Z

+	LabelPosition   LabelPosition `json:"labelPosition,omitempty" yaml:"labelPosition,omitempty"`
+	LabelPadding    float64       `json:"labelPadding,omitempty" yaml:"labelPadding,omitempty"`
+	Icon            string        `json:"icon,omitempty" yaml:"icon,omitempty"`
+	Link            string        `json:"link,omitempty" yaml:"link,omitempty"`


Wouldn't URL be a more appropriate name?

While a URL (Uniform Resource Locator) is the address of a resource on the web, a Link (or Hyperlink) is an element on the page that will take a user to another page.

https://www.geeksforgeeks.org/computer-networks/difference-between-url-and-link/

ibakshay · 2026-08-18T12:09:07Z

In the edge settings, please add full names for north, south, ... instead of short abbreviations.

shahrokni · 2026-08-18T12:22:54Z

+        <TextField
+          label="X"
+          size="small"
+          type="number"
+          value={Math.round(background.x)}
+          onChange={onIntFieldChange('x')}
+          sx={{ width: 80 }}
+          disabled={background.global}
+        />
+        <TextField
+          label="Y"
+          size="small"
+          type="number"
+          value={Math.round(background.y)}
+          onChange={onIntFieldChange('y')}
+          sx={{ width: 80 }}
+          disabled={background.global}
+        />
+        <TextField
+          label="Width"
+          size="small"
+          type="number"
+          value={Math.round(background.width)}
+          slotProps={{ htmlInput: { min: 1 } }}
+          onChange={onIntFieldChange('width', 1)}
+          sx={{ width: 80 }}
+          disabled={background.global}
+        />
+        <TextField
+          label="Height"
+          size="small"
+          type="number"
+          value={Math.round(background.height)}
+          slotProps={{ htmlInput: { min: 1 } }}
+          onChange={onIntFieldChange('height', 1)}
+          sx={{ width: 80 }}
+          disabled={background.global}
+        />


I have not tested this part yet to understand what it exactly does.
However, my very first impression is that the repetitive part could be shortened using a loop over an array of x, y, height, and width. It seems 90% of these Text fields are identical.

⚠️ I will come back to this part later during the test to understand what it does.

shahrokni · 2026-08-18T12:42:21Z

+  function parseImageFit(value: string): BackgroundSpec['imageFit'] {
+    return IMAGE_FIT_OPTIONS.includes(value as BackgroundSpec['imageFit'])
+      ? (value as BackgroundSpec['imageFit'])
+      : undefined;
+  }


It seems this function guarantees that what is received complies with BackgroundSpec['imageFit'] otherwise it returns undefined.

Checking the rest of the PR I see it has been used in a Select with limited and expected options (Menu Items). So, the question would be why we need this, if it is always dealing with a set of deterministic values? The function would make sense if a free text input was also an option. Am I missing something?

<Select<BackgroundSpec['imageFit']> label="Image fit" value={background.imageFit ?? 'cover'} onChange={(e) => onChange({ ...background, imageFit: parseImageFit(e.target.value ?? '') })} MenuProps={{ PaperProps: { style: { maxHeight: 240 } } }} > <MenuItem value="cover">Cover</MenuItem> <MenuItem value="contain">Contain</MenuItem> <MenuItem value="stretch">Stretch</MenuItem> </Select>

adrianSepiol force-pushed the feature/canvas-panel-plugin branch 7 times, most recently from 3ea64b7 to 39b9803 Compare July 16, 2026 13:20

adrianSepiol force-pushed the feature/canvas-panel-plugin branch from 39b9803 to d73e5e2 Compare July 17, 2026 07:54

Merge branch 'main' into feature/canvas-panel-plugin

0c35389

adrianSepiol marked this pull request as ready for review July 20, 2026 13:42

adrianSepiol requested review from a team, AntoineThebaud and Nexucis as code owners July 20, 2026 13:42

adrianSepiol requested review from shahrokni and removed request for a team July 20, 2026 13:42

jgbernalp reviewed Jul 24, 2026

View reviewed changes

ibakshay reviewed Aug 18, 2026

View reviewed changes

shahrokni reviewed Aug 18, 2026

View reviewed changes

		Color string `json:"color,omitempty" yaml:"color,omitempty"`
		}

		X2 *float64 `json:"x2,omitempty" yaml:"x2,omitempty"`
		Y2 *float64 `json:"y2,omitempty" yaml:"y2,omitempty"`

Uh oh!

Conversation

adrianSepiol commented Jul 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Screenshots

Checklist

UI Changes

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

jgbernalp commented Jul 24, 2026

Uh oh!

adrianSepiol commented Jul 30, 2026

Uh oh!

ibakshay left a comment • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

ibakshay commented Aug 18, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

shahrokni Aug 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

ibakshay commented Aug 18, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

adrianSepiol commented Jul 15, 2026 •

edited

Loading

ibakshay left a comment •

edited

Loading

shahrokni Aug 18, 2026 •

edited

Loading