@itwin/core-frontend/lib/cjs/render/CanvasDecoration.d.ts

iTwin.js frontend components

/** @packageDocumentation
 * @module Rendering
 */
import { XAndY } from "@itwin/core-geometry";
import { BeButtonEvent, BeWheelEvent } from "../tools/Tool";
/** A [Decoration]($docs/learning/frontend/ViewDecorations#canvas-decorations) that is drawn onto the
 * [2d canvas](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D) on top of a ScreenViewport.
 * CanvasDecorations may be pickable by implementing [[pick]].
 * @public
 * @extensions
 */
export interface CanvasDecoration {
    /**
     * Required method to draw this decoration into the supplied [CanvasRenderingContext2D](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D). This method is called every time a frame is rendered.
     * @param ctx The CanvasRenderingContext2D for the [[ScreenViewport]] being rendered.
     * @note Before this this function is called, the state of the CanvasRenderingContext2D is [saved](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/save),
     * and it is [restored](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/restore) when this method returns. Therefore,
     * it is *not* necessary for implementers to save/restore themselves.
     */
    drawDecoration(ctx: CanvasRenderingContext2D): void;
    /**
     * Optional view coordinates position of this overlay decoration. If present, [ctx.translate](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/translate) is called
     * with this point before [[drawDecoration]] is called.
     */
    position?: XAndY;
    /** Optional method to provide feedback when mouse events occur on this decoration.
     * @param pt The position of the mouse in the ScreenViewport
     * @return true if the mouse is inside this decoration.
     * @note If this method is not present, no mouse events are directed to this decoration.
     */
    pick?(pt: XAndY): boolean;
    /** Optional method to be called whenever this decorator is picked and the mouse first enters this decoration. */
    onMouseEnter?(ev: BeButtonEvent): void;
    /** Optional method to be called whenever the mouse leaves this decoration. */
    onMouseLeave?(): void;
    /** Optional method to be called whenever the mouse moves inside this decoration. */
    onMouseMove?(ev: BeButtonEvent): void;
    /** Optional method to be called whenever the mouse moves inside this decoration that determines whether the event is forwarded to the active tool.
     * @return true if the event was *not* handled by this decoration and should be forwarded to the active tool.
     */
    propagateMouseMove?(ev: BeButtonEvent): boolean;
    /**
     * Optional method to be called whenever this decorator is picked and a mouse button is pressed or released inside this decoration.
     * @return true if the event was handled by this decoration and should *not* be forwarded to the active tool.
     * @note This method is called for both mouse up and down events. If it returns `true` for a down event, it should also return `true` for the
     * corresponding up event.
     */
    onMouseButton?(ev: BeButtonEvent): boolean;
    /**
     * Optional method to be called when the mouse wheel is rolled with the pointer over this decoration.
     * @return true to indicate that the event has been handled and should not be propagated to default handler
     */
    onWheel?(ev: BeWheelEvent): boolean;
    /** Cursor to use when mouse is inside this decoration. Default is "pointer". */
    decorationCursor?: string;
}
/** An array of [[CanvasDecoration]]s.
 * @public
 * @extensions
 */
export type CanvasDecorationList = CanvasDecoration[];
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