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Merged
siarheihuzarevich merged 1 commit into from
Nov 29, 2025
Merged

feat(background): add support for custom and complex SVG patterns #256

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30 changes: 19 additions & 11 deletions projects/f-examples/extensions/background-example/background-example.component.html
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@@ -1,15 +1,23 @@
<f-flow fDraggable (fLoaded)="onLoaded()">
@if (background === 'circle') {
<f-background>
<f-circle-pattern></f-circle-pattern>
</f-background>
} @else if (background === 'rect') {
<f-background>
<f-rect-pattern></f-rect-pattern>
</f-background>
<f-flow fDraggable (fLoaded)="loaded()">
@switch (background()) {
@case ('circle') {
<f-background>
<f-circle-pattern />
</f-background>
}
@case ('rect') {
<f-background>
<f-rect-pattern />
</f-background>
}
@case ('custom') {
<f-background>
<custom-background-example />
</f-background>
}
}
<f-canvas>
<f-connection fOutputId="output1" fInputId="input1" fBehavior="floating"></f-connection>
<f-canvas fZoom>
<f-connection fOutputId="output1" fInputId="input1" fBehavior="floating" />
<div fNode [fNodePosition]="{ x: 0, y: 0 }" fDragHandle>
<div fNodeOutput fOutputId="output1" class="right"></div>
I'm a node
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16 changes: 8 additions & 8 deletions projects/f-examples/extensions/background-example/background-example.component.ts
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@@ -1,26 +1,26 @@
import { ChangeDetectionStrategy, Component, ViewChild } from '@angular/core';
import { ChangeDetectionStrategy, Component, signal, viewChild } from '@angular/core';
import { FCanvasComponent, FFlowModule } from '@foblex/flow';
import { MatFormField, MatLabel } from '@angular/material/form-field';
import { MatOption } from '@angular/material/core';
import { MatSelectModule } from '@angular/material/select';
import { FlowBackground } from './custom-background-example/custom-background-example';

@Component({
selector: 'background-example',
styleUrls: ['./background-example.component.scss'],
templateUrl: './background-example.component.html',
changeDetection: ChangeDetectionStrategy.OnPush,
standalone: true,
imports: [FFlowModule, MatFormField, MatLabel, MatOption, MatSelectModule],
imports: [FFlowModule, MatFormField, MatLabel, MatOption, MatSelectModule, FlowBackground],
})
export class BackgroundExampleComponent {
@ViewChild(FCanvasComponent, { static: true })
public fCanvas!: FCanvasComponent;
private readonly _canvas = viewChild.required(FCanvasComponent);

public background = 'circle';
protected readonly background = signal('custom');

public backgroundOptions = ['circle', 'rect', 'none'];
protected readonly backgroundOptions = ['circle', 'rect', 'custom', 'none'];

public onLoaded(): void {
this.fCanvas.resetScaleAndCenter(false);
protected loaded(): void {
this._canvas()?.resetScaleAndCenter(false);
}
}
8 changes: 8 additions & 0 deletions ...es/extensions/background-example/custom-background-example/custom-background-example.html
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@@ -0,0 +1,8 @@
<svg:pattern #circlePattern id="circleGrid" patternUnits="userSpaceOnUse">
<svg:circle #circle></svg:circle>
</svg:pattern>
<svg:pattern #rectPattern patternUnits="userSpaceOnUse">
<svg:rect width="100%" height="100%" fill="url(#circleGrid)"></svg:rect>
<svg:line x1="0" y1="0" x2="100%" y2="0" stroke-width="2"></svg:line>
<svg:line x1="0" y1="0" x2="0" y2="100%" stroke-width="2"></svg:line>
</svg:pattern>
117 changes: 117 additions & 0 deletions ...ples/extensions/background-example/custom-background-example/custom-background-example.ts
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@@ -0,0 +1,117 @@
import {
ChangeDetectionStrategy,
Component,
DestroyRef,
ElementRef,
inject,
input,
numberAttribute,
OnInit,
viewChild,
} from '@angular/core';
import {
F_BACKGROUND_PATTERN,
FChannel,
FChannelHub,
FFlowModule,
IFBackgroundPattern,
notifyOnStart,
} from '@foblex/flow';
import {
ITransformModel,
PointExtensions,
SizeExtensions,
TransformModelExtensions,
} from '@foblex/2d';

@Component({
selector: 'custom-background-example',
templateUrl: './custom-background-example.html',
changeDetection: ChangeDetectionStrategy.OnPush,
standalone: true,
imports: [FFlowModule],
providers: [{ provide: F_BACKGROUND_PATTERN, useExisting: FlowBackground }],
})
export class FlowBackground implements OnInit, IFBackgroundPattern {
private readonly _destroyRef = inject(DestroyRef);
private readonly _elementReference = inject(ElementRef);

private readonly _stateChanges = new FChannel();

public get hostElement(): HTMLElement {
return this._elementReference.nativeElement;
}

public readonly size = input(80, { transform: numberAttribute });
public readonly circleSize = input(16, { transform: numberAttribute });

private _transform = TransformModelExtensions.default();

private _position = PointExtensions.initialize();

private _size = SizeExtensions.initialize(this.size(), this.size());
private _radius = this.circleSize();

private readonly _circlePattern = viewChild<ElementRef<SVGPatternElement>>('circlePattern');
private readonly _circlePatternCircle = viewChild<ElementRef<SVGCircleElement>>('circle');

private readonly _rectPattern = viewChild<ElementRef<SVGPatternElement>>('rectPattern');

public ngOnInit(): void {
this._listenStateChanges();
}

private _listenStateChanges(): void {
new FChannelHub(this._stateChanges)
.pipe(notifyOnStart())
.listen(this._destroyRef, () => this._redraw());
}

private _redraw(): void {
this._calculatePattern();
this._redrawPattern();
}

private _calculatePattern(): void {
this._position.x = this._transform.position.x + this._transform.scaledPosition.x;
this._position.y = this._transform.position.y + this._transform.scaledPosition.y;
this._size = SizeExtensions.initialize(
this.size() * this._transform.scale,
this.size() * this._transform.scale,
);
this._radius = this.circleSize() * this._transform.scale;
}

private _redrawPattern(): void {
this._redrawRectPattern();
this._redrawCirclePattern();
}

private _redrawRectPattern(): void {
this._rectPattern()?.nativeElement.setAttribute('x', `${this._position.x}`);
this._rectPattern()?.nativeElement.setAttribute('y', `${this._position.y}`);
this._rectPattern()?.nativeElement.setAttribute('width', `${this._size.width}`);
this._rectPattern()?.nativeElement.setAttribute('height', `${this._size.height}`);
}

private _redrawCirclePattern(): void {
this._circlePattern()?.nativeElement.setAttribute('width', `${this._radius}`);
this._circlePattern()?.nativeElement.setAttribute('height', `${this._radius}`);
this._redrawCircleElement();
}

private _redrawCircleElement(): void {
this._circlePatternCircle()?.nativeElement.setAttribute('r', `${this._transform.scale}`);
this._circlePatternCircle()?.nativeElement.setAttribute('cx', `${this._transform.scale / 2}`);
this._circlePatternCircle()?.nativeElement.setAttribute('cy', `${this._transform.scale / 2}`);
}

public setTransform(transform: ITransformModel): void {
this._transform = transform;
this._refresh();
}

private _refresh(): void {
this._stateChanges.notify();
}
}
2 changes: 1 addition & 1 deletion projects/f-flow/package.json
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@@ -1,6 +1,6 @@
{
"name": "@foblex/flow",
"version": "17.9.7",
"version": "17.9.8",
"description": "An Angular library designed to simplify the creation and manipulation of dynamic flow. Provides components for flows, nodes, and connections, automating node manipulation and inter-node connections.",
"main": "index.js",
"types": "index.d.ts",
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6 changes: 2 additions & 4 deletions ...ow/src/domain/f-background/add-pattern-to-background/add-pattern-to-background.request.ts
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Expand Up @@ -2,8 +2,6 @@ import { IFBackgroundPattern } from '../../../f-backgroud';

export class AddPatternToBackgroundRequest {
static readonly fToken = Symbol('AddPatternToBackgroundRequest');
constructor(
public fPattern: IFBackgroundPattern | undefined,
) {
}

constructor(public fPattern: IFBackgroundPattern | undefined) {}
}
31 changes: 20 additions & 11 deletions ...nd/add-pattern-to-background.execution.ts → ...o-background/add-pattern-to-background.ts
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Expand Up @@ -13,9 +13,7 @@ let uniqueId = 0;
*/
@Injectable()
@FExecutionRegister(AddPatternToBackgroundRequest)
export class AddPatternToBackgroundExecution
implements IExecution<AddPatternToBackgroundRequest, void>
{
export class AddPatternToBackground implements IExecution<AddPatternToBackgroundRequest, void> {
private readonly _store = inject(FComponentsStore);
private readonly _browser = inject(BrowserService);

Expand All @@ -24,21 +22,32 @@ export class AddPatternToBackgroundExecution
}

public handle(request: AddPatternToBackgroundRequest): void {
const children = request.fPattern?.hostElement.getElementsByTagName('pattern') || [];
const pattern = children.length ? children[0] : undefined;
if (pattern) {
const defs = createSVGElement('defs', this._browser);
pattern.id = 'f-background-pattern-' + uniqueId++;
request.fPattern?.hostElement.remove();
defs.appendChild(pattern);
const patterns = this._getPatterns(request.fPattern?.hostElement);
if (!patterns?.length) {
return;
}
const defs = createSVGElement('defs', this._browser);
request.fPattern?.hostElement.remove();

patterns.forEach((pattern) => {
defs.append(pattern);
});

if (patterns.length) {
this._backgroundElement?.firstChild?.appendChild(defs);
patterns[patterns.length - 1].id = 'f-background-pattern-' + uniqueId++;
const lastPatternId = patterns[patterns.length - 1].id;
const rect = createSVGElement('rect', this._browser);
rect.setAttribute('fill', 'url(#' + pattern.id + ')');
rect.setAttribute('fill', 'url(#' + lastPatternId + ')');
rect.setAttribute('width', '100%');
rect.setAttribute('height', '100%');
this._backgroundElement.firstChild?.appendChild(rect);
const transform = this._store.fCanvas?.transform || TransformModelExtensions.default();
request.fPattern?.setTransform(transform);
}
}

private _getPatterns(element?: HTMLElement | SVGElement | undefined): SVGPatternElement[] {
return Array.from(element?.getElementsByTagName('pattern') || []);
}
}
2 changes: 1 addition & 1 deletion projects/f-flow/src/domain/f-background/add-pattern-to-background/index.ts
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@@ -1,3 +1,3 @@
export * from './add-pattern-to-background.execution';
export * from './add-pattern-to-background';

export * from './add-pattern-to-background.request';
5 changes: 2 additions & 3 deletions projects/f-flow/src/domain/f-background/providers.ts
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@@ -1,4 +1,4 @@
import { AddPatternToBackgroundExecution } from './add-pattern-to-background';
import { AddPatternToBackground } from './add-pattern-to-background';
import { AddBackgroundToStoreExecution } from './add-background-to-store';
import { RemoveBackgroundFromStoreExecution } from './remove-background-from-store';
import { SetBackgroundTransformExecution } from './set-background-transform';
Expand All @@ -8,10 +8,9 @@ import { SetBackgroundTransformExecution } from './set-background-transform';
* It includes executions for adding, removing, and setting the background in the FComponentsStore.
*/
export const F_BACKGROUND_FEATURES = [

AddBackgroundToStoreExecution,

AddPatternToBackgroundExecution,
AddPatternToBackground,

RemoveBackgroundFromStoreExecution,

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28 changes: 23 additions & 5 deletions public/markdown/examples/background.md
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Expand Up @@ -2,17 +2,35 @@

## Description

This guide demonstrates how to add a background to the [canvas](./docs/f-canvas-component). To enable this feature, you need to add the [f-background component](./docs/f-background-component) inside the [f-flow component](./docs/f-flow-component).
There are two default patterns: ‘rect’ and ‘circle’, but you can also create your own custom pattern (instructions are available in the [f-background documentation](./docs/f-background-component)).
The background feature allows you to render an SVG pattern underneath all nodes and connections on the [canvas](./docs/f-canvas-component).
It is useful for creating grids, subtle textures, or branded backgrounds that stay fixed while the user interacts with the flow.

To enable a background, place the [f-background component](./docs/f-background-component) **inside** the [f-flow component](./docs/f-flow-component).
The `f-background` component is responsible for defining and attaching the SVG pattern that will be used as the canvas background.

Backgrounds can work in three modes:

- **`rect`** – built-in rectangular pattern (useful for grid-like backgrounds);
- **`circle`** – built-in circular pattern;
- **`custom`** – a mode that lets you provide your **own SVG pattern**, so you can build complex or branded backgrounds (multiple patterns, custom shapes, textures, etc.).

The `custom` mode is configured via standard SVG `<pattern>` elements and a custom component.
Detailed instructions and API for creating custom patterns are described in the [f-background documentation](./docs/f-background-component).

## Example

The example below shows how to:

- wrap `f-canvas` with `f-flow`;
- add `f-background` to enable a background;
- switch between the built-in `rect` and `circle` patterns;
- use the new `custom` mode with a custom background implementation.

::: ng-component <background-example></background-example> [height]="600"
[component.html] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/extensions/background-example/background-example.component.html
[component.ts] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/extensions/background-example/background-example.component.ts
[component.scss] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/extensions/background-example/background-example.component.scss
[custom.html] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/extensions/background-example/custom-background-example/custom-background-example.html
[custom.ts] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/extensions/background-example/custom-background-example/custom-background-example.ts
[common.scss] <<< https://raw.githubusercontent.com/Foblex/f-flow/main/projects/f-examples/_flow-common.scss
:::



8 changes: 6 additions & 2 deletions src/app/examples.config.ts
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Expand Up @@ -883,13 +883,17 @@ function extensionGroup() {
link: 'background',
text: 'Background',
description:
'Add background shapes and frames to structure the canvas. Layering and styling patterns in Angular.',
'Add SVG background patterns to the flow diagrams in Angular, using built-in rect and circle presets or a fully custom pattern for complex, branded backgrounds.',
image: './previews/examples/background-example.light.png',
image_dark: './previews/examples/background-example.dark.png',
image_width: 821,
image_height: 600,
image_type: 'image/png',
date: new Date('2024-10-06 14:49:44'),
date: new Date('2025-11-29 14:49:44'),
badge: {
text: 'Updated',
type: 'info',
},
},
]);
}
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