NativeScript/nativescript-core/ui/layouts/absolute-layout/index.ios.ts

import { AbsoluteLayoutBase } from "./absolute-layout-common";
import { View } from "../../core/view";
import { Length } from "../../styling/style-properties";
import { layout } from "../../../utils/utils";

export * from "./absolute-layout-common";

export class AbsoluteLayout extends AbsoluteLayoutBase {
	onLeftChanged(view: View, oldValue: Length, newValue: Length) {
		this.requestLayout();
	}

	onTopChanged(view: View, oldValue: Length, newValue: Length) {
		this.requestLayout();
	}

	public onMeasure(
		widthMeasureSpec: number,
		heightMeasureSpec: number
	): void {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);

		let measureWidth = 0;
		let measureHeight = 0;

		const width = layout.getMeasureSpecSize(widthMeasureSpec);
		const widthMode = layout.getMeasureSpecMode(widthMeasureSpec);

		const height = layout.getMeasureSpecSize(heightMeasureSpec);
		const heightMode = layout.getMeasureSpecMode(heightMeasureSpec);

		const childMeasureSpec = layout.makeMeasureSpec(0, layout.UNSPECIFIED);

		this.eachLayoutChild((child, last) => {
			let childSize = View.measureChild(
				this,
				child,
				childMeasureSpec,
				childMeasureSpec
			);
			measureWidth = Math.max(
				measureWidth,
				child.effectiveLeft + childSize.measuredWidth
			);
			measureHeight = Math.max(
				measureHeight,
				child.effectiveTop + childSize.measuredHeight
			);
		});

		measureWidth +=
			this.effectiveBorderLeftWidth +
			this.effectivePaddingLeft +
			this.effectivePaddingRight +
			this.effectiveBorderRightWidth;
		measureHeight +=
			this.effectiveBorderTopWidth +
			this.effectivePaddingTop +
			this.effectivePaddingBottom +
			this.effectiveBorderBottomWidth;

		measureWidth = Math.max(measureWidth, this.effectiveMinWidth);
		measureHeight = Math.max(measureHeight, this.effectiveMinHeight);

		const widthAndState = View.resolveSizeAndState(
			measureWidth,
			width,
			widthMode,
			0
		);
		const heightAndState = View.resolveSizeAndState(
			measureHeight,
			height,
			heightMode,
			0
		);

		this.setMeasuredDimension(widthAndState, heightAndState);
	}

	public onLayout(
		left: number,
		top: number,
		right: number,
		bottom: number
	): void {
		super.onLayout(left, top, right, bottom);

		const insets = this.getSafeAreaInsets();
		this.eachLayoutChild((child, last) => {
			const childWidth = child.getMeasuredWidth();
			const childHeight = child.getMeasuredHeight();

			const childLeft =
				this.effectiveBorderLeftWidth +
				this.effectivePaddingLeft +
				child.effectiveLeft +
				insets.left;
			const childTop =
				this.effectiveBorderTopWidth +
				this.effectivePaddingTop +
				child.effectiveTop +
				insets.top;
			const childRight =
				childLeft +
				childWidth +
				child.effectiveMarginLeft +
				child.effectiveMarginRight;
			const childBottom =
				childTop +
				childHeight +
				child.effectiveMarginTop +
				child.effectiveMarginBottom;

			View.layoutChild(
				this,
				child,
				childLeft,
				childTop,
				childRight,
				childBottom
			);
		});
	}
}