31 lines
962 B
TypeScript
31 lines
962 B
TypeScript
import { NormalizedZoomValue, PointerCoords, Zoom } from "../types";
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export const getNewZoom = (
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newZoomValue: NormalizedZoomValue,
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prevZoom: Zoom,
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canvasOffset: { left: number; top: number },
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zoomOnViewportPoint: PointerCoords = { x: 0, y: 0 },
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): Zoom => {
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return {
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value: newZoomValue,
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translation: {
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x:
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zoomOnViewportPoint.x -
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canvasOffset.left -
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(zoomOnViewportPoint.x - canvasOffset.left - prevZoom.translation.x) *
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(newZoomValue / prevZoom.value),
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y:
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zoomOnViewportPoint.y -
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canvasOffset.top -
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(zoomOnViewportPoint.y - canvasOffset.top - prevZoom.translation.y) *
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(newZoomValue / prevZoom.value),
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},
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};
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};
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export const getNormalizedZoom = (zoom: number): NormalizedZoomValue => {
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const normalizedZoom = parseFloat(zoom.toFixed(2));
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const clampedZoom = Math.max(0.1, Math.min(normalizedZoom, 10));
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return clampedZoom as NormalizedZoomValue;
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};
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