Function applyPreset

Source

export function applyPreset(presetKey) {
    let preset = presets[presetKey];
    if (!preset) return;

    let width = reactiveState.cellGridWidth;
    let height = reactiveState.cellGridHeight;
    let newCells;

    if (presetKey === "random") {
        newCells = generateRandomCells(width, height);
    } else {
        const cells = preset.cells;

        let minX = Infinity,
            maxX = -Infinity;
        let minY = Infinity,
            maxY = -Infinity;
        cells.forEach(([x, y]) => {
            minX = Math.min(minX, x);
            maxX = Math.max(maxX, x);
            minY = Math.min(minY, y);
            maxY = Math.max(maxY, y);
        });
        const originalCenterX = (minX + maxX) / 2;
        const originalCenterY = (minY + maxY) / 2;
        const gridCenterX = Math.floor(width / 2);
        const gridCenterY = Math.floor(height / 2);
        const dx = Math.round(gridCenterX - originalCenterX);
        const dy = Math.round(gridCenterY - originalCenterY);
        const adjustedCells = cells.map(([x, y]) => [x + dx, y + dy]);
        newCells = generateCells(width, height, adjustedCells);
    }

    const newCellsFlat = new Uint8Array(newCells.flat());
    let changedCellsAlive = new Set();
    let changedCellsDead = new Set();

    // Calculate difference
    sharedState.cells.forEach((cell, i) => {
        if (cell === 0 && newCellsFlat[i] === 1) {
            changedCellsAlive.add(i);
        } else if (cell === 1 && newCellsFlat[i] === 0) {
            changedCellsDead.add(i);
        }
    });

    pushHistory({
        setCellsAlive: changedCellsAlive,
        setCellsDead: changedCellsDead,
        actionName: "Apply Preset",
    });

    sharedState.cells = newCellsFlat;
}
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