Angular Signature Pad | ng-hub-ui-signature
Accessible Angular signature field that stores mouse, touch and pen input as scalable SVG form values, with undo, redo and PNG export.
Styles
Mixins and styles
Override the `--hub-signature-*` design tokens in a single include, without coupling the consumer to the component's DOM. Every parameter is OPTIONAL and defaults to `null`: only the parameters you pass are emitted, so the tokens you leave alone keep resolving through their own defaults. An include with no arguments would therefore emit nothing at all, which reads as a broken build rather than as a no-op — so it raises a `@warn` instead of failing silently. Token-based and self-contained (no Bootstrap dependencies).
Theming with hub-signature-theme
Sign with the keyboard: arrow keys move the pen, holding Shift moves it further, Space or Enter lowers and lifts it, and Escape discards the stroke in progress.
| Mixin | Parameters | Description |
|---|---|---|
| Theming | ||
hub-signature-theme() | $background, $color, $border-color, $border-radius, $focus-border-color, $border-width, $focus-shadow, $font-size, $label-color, $label-font-size, $actions-gap | One-call theming for `<hub-signature>` |
CSS variables
Theme every pixel with 11 CSS variables. Override them at :root or scope them to a wrapper.
Signature
Design tokens read by this component. Override them on the host element (or any ancestor) to customize; every default falls back to the ng-hub-ui-ds layer.
| Variable | Default | Type | Description |
|---|---|---|---|
--hub-signature-bg | var(--hub-input-bg, var(--hub-sys-surface, #fff)) | color | Drawing-surface background |
--hub-signature-color | var(--hub-input-color, var(--hub-sys-text-primary, #212529)) | color | Field text colour |
--hub-signature-border-color | var(--hub-input-border-color, var(--hub-sys-border, #ced4da)) | color | Drawing-surface border colour |
--hub-signature-border-width | var(--hub-input-border-width, 1px) | length | Drawing-surface border thickness |
--hub-signature-border-radius | var(--hub-input-border-radius, var(--hub-ref-radius-md, 0.375rem)) | length | Drawing-surface corner radius |
--hub-signature-focus-border-color | var(--hub-input-focus-border-color, var(--hub-sys-color-primary, #0d6efd)) | color | Border colour while the surface holds keyboard focus |
--hub-signature-focus-shadow | var(--hub-input-focus-box-shadow, 0 0 0 0.25rem rgb(13 110 253 / 25%)) | shadow | Focus ring around the drawing surface |
--hub-signature-label-color | var(--hub-label-color, var(--hub-sys-text-primary, #212529)) | color | Field label colour |
--hub-signature-label-font-size | var(--hub-label-font-size, var(--hub-ref-font-size-sm, 0.875rem)) | length | Field label font size |
--hub-signature-font-size | var(--hub-input-font-size, 1rem) | length | Field font size |
--hub-signature-actions-gap | var(--hub-ref-space-2, 0.5rem) | length | Gap between the clear / undo / redo actions |
Styling and theming
Load the forms stylesheet
The chrome around the canvas is not the signature's. Its root element is class="hub-field hub-signature" and the label row, the helper text, the validation feedback and the ? mark that opens it are all defined in ng-hub-ui-forms, so @use 'ng-hub-ui-forms/styles'; belongs in the application's global stylesheet, once. Skip it and the canvas still looks right while the text under it falls back to unstyled body copy and the ? mark, glyph and circle included, is left as an empty button. Add @use 'ng-hub-ui-utils/styles/tooltip'; too when the field uses formTextType="tooltip": the bubble is appended to <body>, out of reach of the sheet above. Neither is replaced by ng-hub-ui-signature/styles, which forwards the theming mixin and emits no chrome.
Match the form theme
The field inherits the forms token family and accepts a local signature token override. Validation is part of that inheritance: the invalid and valid states colour the drawing surface from the shared --hub-form-* contract, so a signature turns red alongside the inputs around it rather than printing a message under a canvas that still looks fine.
Examples:
Inheriting the form theme
Skin the form once and the signature follows: its slots default through --hub-input-* for the drawing surface and --hub-label-* for the label, so not one --hub-signature-* rule is needed. Note the asymmetry — this works from a wrapper because those tokens are read through var() off the inherited value, while --hub-signature-* is declared on the field element itself and would have to be overridden there.
Sign with the keyboard: arrow keys move the pen, holding Shift moves it further, Space or Enter lowers and lifts it, and Escape discards the stroke in progress.
Code
Import:
Template:
Component: