API Reference > imodeljs-frontend > Views > Viewport Viewport Class A Viewport renders the contents of one or more Models onto an HTMLCanvasElement. It holds a ViewState object that defines its viewing parameters. ViewTools may modify the ViewState object. Changes to the ViewState are only reflected in a Viewport after the Viewport.synchWithView method is called. In general, because the Viewport essentially takes control of its attached ViewState, changes to the ViewState should be made indirectly through the Viewport's own API. Doing so ensures that synchronization between the Viewport and its ViewState is reliable and automatic. For example: To change the set of categories or models displayed in the Viewport, use Viewport.changeCategoryDisplay and Viewport.changeModelDisplay rather than modifying the ViewState's CategorySelectorState or ModelSelectorState directly. To change the ViewFlags, set Viewport.viewFlags rather than modifying the ViewState's DisplayStyleState directly. To modify the DisplayStyleState:const style = viewport.displayStyle.clone(); style.backgroundColor = ColorDef.red.clone(); // or any other desired modifications viewport.displayStyle = style; As changes to ViewState are made, Viewports also hold a stack of previous copies of it, to allow for undo/redo (i.e. View Previous and View Next) of viewing tools. Changes to a Viewport's state can be monitored by attaching an event listener to a variety of specific events. Most such events are triggered only once per frame, just before the Viewport's contents are rendered. For example, if the following sequence of events occurs: First frame is rendered ViewFlags are modified ViewFlags are modified again Second frame is rendered The Viewport.onDisplayStyleChanged event will be invoked exactly once, when the second frame is rendered. see ViewManager Extended by ScreenViewport Implements IDisposable Methods Name Description addViewedModels(models: Id64Arg): Promise<void> Adds a set of models to the set of those currently displayed in this viewport. changeBackgroundMapProps(props: BackgroundMapProps): void Modify a subset of the background map display settings. Beta changeCategoryDisplay(categories: Id64Arg, display: boolean, enableAllSubCategories: boolean = false): void Enable or disable display of elements belonging to a set of categories specified by Id. changeModelDisplay(models: Id64Arg, display: boolean): boolean Add or remove a set of models from those models currently displayed in this viewport. changeView(view: ViewState, _opts?: ViewChangeOptions): void Change the ViewState of this Viewport changeViewedModel2d(baseModelId: Id64String, options?: ChangeViewedModel2dOptions & ViewChangeOptions): Promise<void> Attempt to change the 2d Model this Viewport is displaying, if its ViewState is a ViewState2d. changeViewedModels(modelIds: Id64Arg): boolean Attempt to replace the set of models currently viewed by this viewport, if it is displaying a SpatialView clearAlwaysDrawn(): void Clear the set of always-drawn elements. clearNeverDrawn(): void Clear the set of never-drawn elements. cssPixelsToDevicePixels(cssPixels: number): number Convert a number in CSS pixels to device pixels using this Viewport's device pixel ratio. Beta determineVisibleDepthRange(rect?: ViewRect, result?: DepthRangeNpc): DepthRangeNpc | undefined Computes the range of npc depth values for a region of the screen dispose(): void dropSubCategoryOverride(id: Id64String): void Remove any SubCategoryOverride for the specified subcategory. getAuxCoordOrigin(result?: Primitives.Point3d): Point3d getAuxCoordRotation(result?: Matrix3d): Matrix3d getContrastToBackgroundColor(): ColorDef Get a color that will contrast to the current background color of this Viewport. getFrustum(sys: CoordSystem = CoordSystem.World, adjustedBox: boolean = true, box?: Frustum): Frustum Get an 8-point Frustum corresponding to the 8 corners of the Viewport in the specified coordinate system. getPixelDataNpcPoint(pixels: Pixel.Buffer, x: number, y: number, out?: Primitives.Point3d): Point3d | undefined Get the point at the specified x and y location in the pixel buffer in npc coordinates Beta getPixelDataWorldPoint(pixels: Pixel.Buffer, x: number, y: number, out?: Primitives.Point3d): Point3d | undefined Get the point at the specified x and y location in the pixel buffer in world coordinates Beta getPixelSizeAtPoint(point?: Primitives.Point3d): number Get the width of a pixel (a unit vector in the x direction in view coordinates) at a given point in world coordinates, returning the result in meters (world units). getSubCategoryAppearance(id: Id64String): SubCategoryAppearance Query the symbology with which geometry belonging to a specific subcategory is rendered within this viewport. getSubCategoryOverride(id: Id64String): SubCategoryOverride | undefined Query the symbology overrides applied to geometry belonging to a specific subcategory when rendered within this viewport. getWorldFrustum(box?: Frustum): Frustum Get a copy of the current (unadjusted) frustum of this viewport, in world coordinates. invalidateDecorations(): void Mark the current set of decorations invalid, so that they will be recreated on the next render frame. Beta isSubCategoryVisible(id: Id64String): boolean Determine whether geometry belonging to a specific SubCategory is visible in this viewport, assuming the containing Category is displayed. npcToView(pt: Point3d, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.Npc to CoordSystem.View npcToViewArray(pts: Point3d[]): void Convert an array of points from CoordSystem.Npc to CoordSystem.View npcToWorld(pt: XYAndZ, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.Npc to CoordSystem.World npcToWorldArray(pts: Point3d[]): void Convert an array of points from CoordSystem.Npc to CoordSystem.World overrideSubCategory(id: Id64String, ovr: SubCategoryOverride): void Override the symbology of geometry belonging to a specific subcategory when rendered within this viewport. pixelsFromInches(inches: number): number Converts inches to pixels based on screen DPI. readImage(rect: ViewRect = new ViewRect(0, 0, -1, -1), targetSize: Point2d = Point2d.createZero(), flipVertically: boolean = false): ImageBuffer | undefined Read the current image from this viewport from the rendering system. readPixels(rect: ViewRect, selector: Pixel.Selector, receiver: Pixel.Receiver, excludeNonLocatable: boolean = false): void Read selected data about each pixel within a rectangular region of this Viewport. Beta replaceViewedModels(modelIds: Id64Arg): Promise<void> Attempt to replace the set of models currently viewed by this viewport, if it is displaying a SpatialView scroll(screenDist: XAndY, options?: ViewChangeOptions): void Scroll the view by a given number of pixels. setAlwaysDrawn(ids: Id64Set, exclusive: boolean = false): void Specify the Ids of a set of elements which should always be rendered within this view, regardless of category and subcategory visibility. setAnimator(animator?: Animator): void Set or clear the animator for this Viewport. Beta setFeatureOverrideProviderChanged(): void Notifies this viewport that the internal state of its FeatureOverrideProvider has changed such that its setNeverDrawn(ids: Id64Set): void Specify the Ids of a set of elements which should never be rendered within this view. setStandardRotation(id: StandardViewId): void Orient this viewport to one of the StandardView rotations. setupFromView(pose?: ViewPose): ViewStatus Establish the parameters of this Viewport from the current information in its ViewState setupViewFromFrustum(inFrustum: Frustum): boolean Shortcut to call view.setupFromFrustum and then Viewport.setupFromView synchWithView(_options?: ViewChangeOptions | boolean): void Call Viewport.setupFromView on this Viewport and then apply optional behavior. turnCameraOn(lensAngle?: Angle): ViewStatus Turn the camera on if it is currently off. updateChangeFlags(newView: ViewState): void Protected Invoked from finishUndoRedo, applyViewState, and changeView to potentially recompute change flags based on differences between current and new ViewState. view4dToWorld(input: Point4d, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.View as a Point4d to CoordSystem.View view4dToWorldArray(viewPts: Point4d[], worldPts: Point3d[]): void Convert an array of points from CoordSystem.View as Point4ds to CoordSystem.World viewToNpc(pt: Point3d, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.View to CoordSystem.Npc viewToNpcArray(pts: Point3d[]): void Convert an array of points from CoordSystem.View to CoordSystem.Npc viewToWorld(input: XYAndZ, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.View to CoordSystem.World viewToWorldArray(pts: Point3d[]): void Convert an array of points from CoordSystem.View to CoordSystem.World viewsModel(modelId: Id64String): boolean Returns true if this Viewport is currently displaying the model with the specified Id. worldToNpc(pt: XYAndZ, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.World to CoordSystem.Npc worldToNpcArray(pts: Point3d[]): void Convert an array of points from CoordSystem.World to CoordSystem.Npc worldToView(input: XYAndZ, out?: Primitives.Point3d): Point3d Convert a point from CoordSystem.World to CoordSystem.View worldToView4d(input: XYAndZ, out?: Point4d): Point4d Convert a point from CoordSystem.World to CoordSystem.View as Point4d worldToView4dArray(worldPts: Point3d[], viewPts: Point4d[]): void Convert an array of points from CoordSystem.World to CoordSystem.View, as Point4ds worldToViewArray(pts: Point3d[]): void Convert an array of points from CoordSystem.World to CoordSystem.View zoom(newCenter: Point3d | undefined, factor: number, options?: ViewChangeOptions): void Zoom the view by a scale factor, placing the new center at the given point (world coordinates). zoomToElementProps(elementProps: ElementProps[], options?: ViewChangeOptions & ZoomToOptions): void Zoom the view to a show the tightest box around a given set of ElementProps. zoomToElements(ids: Id64Arg, options?: ViewChangeOptions & ZoomToOptions): Promise<void> Zoom the view to a show the tightest box around a given set of elements. zoomToPlacementProps(placementProps: PlacementProps[], options?: ViewChangeOptions & ZoomToOptions): void Zoom the view to a show the tightest box around a given set of PlacementProps. zoomToVolume(volume: LowAndHighXYZ | LowAndHighXY, options?: ViewChangeOptions): void Zoom the view to a volume of space in world coordinates. Properties Name Type Description alwaysDrawn Accessor ReadOnly Id64Set | undefined Ids of a set of elements which should always be rendered within this view, regardless of category and subcategory visibility. auxCoordSystem Accessor ReadOnly AuxCoordSystemState backgroundMapSettings Accessor BackgroundMapSettings The settings controlling how a background map is displayed within a view. Beta continuousRendering Accessor boolean Enables or disables continuous rendering. devicePixelRatio Accessor ReadOnly number The device pixel ratio used by this Viewport. Beta displayStyle Accessor DisplayStyleState The display style controller how the contents of this viewport are rendered. emphasisSettings Accessor Settings The settings that control how emphasized elements are displayed in this Viewport. Beta featureOverrideProvider Accessor FeatureOverrideProvider | undefined An object which can customize the appearance of Viewport.Features within a viewport. hilite Accessor Settings The settings that control how elements are hilited in this Viewport. iModel Accessor ReadOnly IModelConnection The iModel of this Viewport isAlwaysDrawnExclusive Accessor ReadOnly boolean Returns true if the set of elements in the Viewport.alwaysDrawn set are the only elements rendered within this view. isCameraOn Accessor ReadOnly boolean True if this is a 3d view with the camera turned on. isDisposed Accessor ReadOnly boolean Returns true if this Viewport's Viewport.dispose method has been invoked. isFadeOutActive Accessor boolean Enables or disables "fade-out" mode. isGridOn Accessor ReadOnly boolean Determine whether the Grid display is currently enabled in this Viewport. neverDrawn Accessor ReadOnly Id64Set | undefined Ids of a set of elements which should not be rendered within this view. numReadyTiles number The number of tiles which were ready and met the desired level-of-detail for display in the view as of the most recently-drawn frame. numRequestedTiles Accessor ReadOnly number The number of outstanding requests for tiles to be displayed in this viewport. numSelectedTiles number The number of tiles selected for display in the view as of the most recently-drawn frame. onAlwaysDrawnChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's set of always-drawn elements changes. Beta onChangeView BeEvent<(vp: Viewport, previousViewState: ViewState) => void> Event invoked immediately when Viewport.changeView is called to replace the current ViewState with a different one. Beta onDisplayStyleChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's DisplayStyleState or its members change. Beta onFeatureOverrideProviderChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's FeatureOverrideProvider changes, or the internal state of the provider changes such that the overrides needed to be recomputed. Beta onFeatureOverridesChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's FeatureSymbology.Overrides change. Beta onNeverDrawnChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's set of never-drawn elements changes. Beta onRender BeEvent<(vp: Viewport) => void> Called when the visible contents of the viewport are redrawn. onViewChanged BeEvent<(vp: Viewport) => void> Event called whenever this viewport is synchronized with its ViewState. onViewedCategoriesChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's set of displayed categories changes. Beta onViewedCategoriesPerModelChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's set of PerModelCategoryVisibility.Overrides changes. Beta onViewedModelsChanged BeEvent<(vp: Viewport) => void> Event called on the next frame after this viewport's set of displayed models changes. Beta onViewportChanged BeEvent<(vp: Viewport, changed: ChangeFlags) => void> Event called on the next frame after any of the viewport's ChangeFlags changes. Beta onViewUndoRedo BeEvent<(vp: Viewport, event: ViewUndoEvent) => void> Event called after reversing the most recent change to the Viewport from the undo stack or reapplying the most recently undone change to the Viewport from the redo stack. Beta rotation Accessor ReadOnly Matrix3d This viewport's rotation matrix. undoDelay Static BeDuration Don't allow entries in the view undo buffer unless they're separated by more than this amount of time. view Accessor ReadOnly ViewState The ViewState for this Viewport viewDelta Accessor ReadOnly Vector3d The vector between the opposite corners of this viewport's extents. viewFlags Accessor ViewFlags The ViewFlags that determine how the contents of this Viewport are rendered. viewRect Accessor ReadOnly ViewRect Get the rectangle of this Viewport in CoordSystem.View coordinates. worldToViewMap Accessor ReadOnly Map4d Provides conversions between world and view coordinates. Defined in core/frontend/src/Viewport.ts Line 576 Last Updated: 13 June, 2024