Perspectives

Experimental: Perspectives were introduced in Theia 1.74 and are experimental. The API is likely to change in upcoming releases, and the feature is not yet exposed as a regular part of the UI. This page therefore only gives an overview. For the current details, see PerspectiveService in @theia/core/lib/browser/perspective-service.

A perspective is a named arrangement of views in the Theia workbench. Instead of asking users to move views around manually to get a layout that fits a certain kind of work, an application can offer a perspective that already places the relevant views in the intended shell areas.

Switching Perspectives

Every application has a built-in Default perspective, which corresponds to the layout it starts with. Perspectives are switched with the command Switch Perspective (Experimental), which opens a quick pick with all registered perspectives. While the feature is experimental, this command and Reset Perspective (Experimental), which restores the original arrangement of the active perspective, are only available from the command palette and are not contributed to any menu. Layout changes a user makes are remembered per perspective.

The ID of the active perspective is available in the context key activePerspectiveId, so menu items, toolbar items and keybindings can be bound to a specific perspective.

Contributing a Perspective

A perspective is contributed by implementing PerspectiveContribution and registering a descriptor that maps view IDs to shell areas (main, left, right, bottom).

@injectable()
export class ReviewPerspectiveContribution implements PerspectiveContribution {

    registerPerspectives(service: PerspectiveService): void {
        service.registerPerspective({
            id: 'review',
            label: nls.localize('my-ext/perspective/review', 'Review'),
            viewPlacements: new Map<string, ApplicationShell.Area>([
                [SCM_VIEW_CONTAINER_ID, 'left'],
                [PROBLEMS_WIDGET_ID, 'bottom']
            ])
        });
    }
}

The contribution is bound by first binding the class to itself and then binding the contribution symbol to that service, via bind(ReviewPerspectiveContribution).toSelf().inSingletonScope() followed by bind(PerspectiveContribution).toService(ReviewPerspectiveContribution). Besides the view placements, a descriptor can declare which view should end up focused in an area, which areas start collapsed, and hooks that run when the perspective is entered or left. Note that only views contributed via AbstractViewContribution can be placed this way, because other widgets may have side effects when being created.

Injecting PerspectiveService gives access to the active perspective and to a change event, and allows switching or resetting perspectives programmatically.

Example: The AI First Perspective

The Theia IDE ships an AI First perspective as a practical example. It is implemented by AIFirstPerspectiveContribution in the @theia/ai-ide package, see the end user documentation for how it looks and behaves.