excalidraw/src/points.ts

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2020-03-17 11:01:11 -07:00
import { Point } from "./types";
export function getSizeFromPoints(points: readonly Point[]) {
const xs = points.map(point => point[0]);
const ys = points.map(point => point[1]);
return {
width: Math.max(...xs) - Math.min(...xs),
height: Math.max(...ys) - Math.min(...ys),
};
}
export function rescalePoints(
dimension: 0 | 1,
nextDimensionSize: number,
prevPoints: readonly Point[],
): Point[] {
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const prevDimValues = prevPoints.map(point => point[dimension]);
const prevMaxDimension = Math.max(...prevDimValues);
const prevMinDimension = Math.min(...prevDimValues);
const prevDimensionSize = prevMaxDimension - prevMinDimension;
const dimensionScaleFactor = nextDimensionSize / prevDimensionSize;
let nextMinDimension = Infinity;
const scaledPoints = prevPoints.map(prevPoint =>
prevPoint.map((value, currentDimension) => {
if (currentDimension !== dimension) {
return value;
}
const scaledValue = value * dimensionScaleFactor;
nextMinDimension = Math.min(scaledValue, nextMinDimension);
return scaledValue;
}),
);
const translation = prevMinDimension - nextMinDimension;
const nextPoints = scaledPoints.map(
scaledPoint =>
scaledPoint.map((value, currentDimension) => {
return currentDimension === dimension ? value + translation : value;
}) as [number, number],
);
return nextPoints;
}