80 lines
2.2 KiB
TypeScript
80 lines
2.2 KiB
TypeScript
import type { Dispatch } from "@commands/dispatcher";
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import { commandIds } from "@commands/ids";
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import type { GlobalPointerConsumer, GlobalWheelConsumer, PointerInputEvent, WheelInputEvent } from "./pointer";
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export type ViewportPointerPanHandler = {
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pointerDown(event: PointerInputEvent): boolean;
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pointerMove(event: PointerInputEvent): boolean;
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pointerUp(event: PointerInputEvent): boolean;
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};
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export function createViewportPointerPanHandler(options: {
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globalConsumer: GlobalPointerConsumer;
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dispatch: Dispatch;
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getCurrentZoom: () => number;
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canPan?: (event: PointerInputEvent) => boolean;
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}): ViewportPointerPanHandler {
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let activePointerId: number | undefined;
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let lastPosition: PointerInputEvent["position"] | undefined;
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const canPan = options.canPan ?? defaultCanPan;
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return {
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pointerDown(event) {
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if (options.globalConsumer(event)) return true;
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if (!canPan(event)) return false;
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activePointerId = event.pointerId;
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lastPosition = event.position;
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return true;
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},
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pointerMove(event) {
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if (activePointerId !== event.pointerId || !lastPosition) return false;
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const zoom = options.getCurrentZoom();
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const screenDelta = {
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x: event.position.x - lastPosition.x,
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y: event.position.y - lastPosition.y,
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};
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lastPosition = event.position;
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options.dispatch(commandIds.viewportPan, {
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delta: {
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x: -screenDelta.x / zoom,
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y: -screenDelta.y / zoom,
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},
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});
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return true;
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},
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pointerUp(event) {
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if (activePointerId !== event.pointerId) return false;
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activePointerId = undefined;
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lastPosition = undefined;
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return true;
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},
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};
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}
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function defaultCanPan(event: PointerInputEvent) {
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return event.pointerType !== "mouse" || (event.buttons & 4) === 4;
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}
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export function handleViewportWheel(options: {
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event: WheelInputEvent;
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globalConsumer: GlobalWheelConsumer;
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dispatch: Dispatch;
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currentZoom: number;
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}): boolean {
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if (options.globalConsumer(options.event)) return true;
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const zoomFactor = Math.exp(-options.event.delta.y * 0.001);
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options.dispatch(commandIds.viewportZoomAroundPoint, {
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zoom: options.currentZoom * zoomFactor,
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point: options.event.position,
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});
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return true;
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}
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