NativeScript/nativescript-core/ui/label/index.ios.ts

import { Label as LabelDefinition } from ".";
import { Background } from "../styling/background";
import {
	Length,
	borderTopWidthProperty,
	borderRightWidthProperty,
	borderBottomWidthProperty,
	borderLeftWidthProperty,
	paddingTopProperty,
	paddingRightProperty,
	paddingBottomProperty,
	paddingLeftProperty,
} from "../styling/style-properties";
import { booleanConverter } from "../core/view-base";
import { View, CSSType } from "../core/view";
import { TextBase, whiteSpaceProperty, WhiteSpace } from "../text-base";
import { layout } from "../../utils/utils";

import { ios } from "../styling/background";

enum FixedSize {
	NONE = 0,
	WIDTH = 1,
	HEIGHT = 2,
	BOTH = 3,
}

@CSSType("Label")
export class Label extends TextBase implements LabelDefinition {
	nativeViewProtected: TNSLabel;
	private _fixedSize: FixedSize;

	public createNativeView() {
		const view = TNSLabel.new();
		view.userInteractionEnabled = true;

		return view;
	}

	get ios(): TNSLabel {
		return this.nativeTextViewProtected;
	}

	get textWrap(): boolean {
		return this.style.whiteSpace === "normal";
	}
	set textWrap(value: boolean) {
		if (typeof value === "string") {
			value = booleanConverter(value);
		}

		this.style.whiteSpace = value ? "normal" : "nowrap";
	}

	_requestLayoutOnTextChanged(): void {
		if (this._fixedSize === FixedSize.BOTH) {
			return;
		}
		if (
			this._fixedSize === FixedSize.WIDTH &&
			!this.textWrap &&
			this.getMeasuredHeight() > 0
		) {
			// Single line label with fixed width will skip request layout on text change.
			return;
		}
		super._requestLayoutOnTextChanged();
	}

	public onMeasure(
		widthMeasureSpec: number,
		heightMeasureSpec: number
	): void {
		let nativeView = this.nativeTextViewProtected;
		if (nativeView) {
			const width = layout.getMeasureSpecSize(widthMeasureSpec);
			const widthMode = layout.getMeasureSpecMode(widthMeasureSpec);

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

			this._fixedSize =
				(widthMode === layout.EXACTLY
					? FixedSize.WIDTH
					: FixedSize.NONE) |
				(heightMode === layout.EXACTLY
					? FixedSize.HEIGHT
					: FixedSize.NONE);

			let nativeSize;
			if (this.textWrap) {
				// https://github.com/NativeScript/NativeScript/issues/4834
				// NOTE: utils.measureNativeView(...) relies on UIView.sizeThatFits(...) that
				// seems to have various issues when laying out UILabel instances.
				// We use custom measure logic here that relies on overriden
				// UILabel.textRectForBounds:limitedToNumberOfLines: in TNSLabel widget.
				nativeSize = this._measureNativeView(
					width,
					widthMode,
					height,
					heightMode
				);
			} else {
				// https://github.com/NativeScript/NativeScript/issues/6059
				// NOTE: _measureNativeView override breaks a scenario with StackLayout that arranges
				// labels horizontally (with textWrap=false) e.g. we are measuring label #2 within 356px,
				// label #2 needs more, and decides to show ellipsis(...) but because of this its native size
				// returned from UILabel.textRectForBounds:limitedToNumberOfLines: logic becomes 344px, so
				// StackLayout tries to measure label #3 within the remaining 12px which is wrong;
				// label #2 with ellipsis should take the whole 356px and label #3 should not be visible at all.
				nativeSize = layout.measureNativeView(
					nativeView,
					width,
					widthMode,
					height,
					heightMode
				);
			}

			let labelWidth = nativeSize.width;

			if (this.textWrap && widthMode === layout.AT_MOST) {
				labelWidth = Math.min(labelWidth, width);
			}

			const measureWidth = Math.max(labelWidth, this.effectiveMinWidth);
			const measureHeight = Math.max(
				nativeSize.height,
				this.effectiveMinHeight
			);

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

			this.setMeasuredDimension(widthAndState, heightAndState);
		}
	}

	private _measureNativeView(
		width: number,
		widthMode: number,
		height: number,
		heightMode: number
	): { width: number; height: number } {
		const view = <UILabel>this.nativeTextViewProtected;

		const nativeSize = view.textRectForBoundsLimitedToNumberOfLines(
			CGRectMake(
				0,
				0,
				widthMode === 0 /* layout.UNSPECIFIED */
					? Number.POSITIVE_INFINITY
					: layout.toDeviceIndependentPixels(width),
				heightMode === 0 /* layout.UNSPECIFIED */
					? Number.POSITIVE_INFINITY
					: layout.toDeviceIndependentPixels(height)
			),
			0
		).size;

		nativeSize.width = layout.round(
			layout.toDevicePixels(nativeSize.width)
		);
		nativeSize.height = layout.round(
			layout.toDevicePixels(nativeSize.height)
		);

		return nativeSize;
	}

	[whiteSpaceProperty.setNative](value: WhiteSpace) {
		const nativeView = this.nativeTextViewProtected;
		switch (value) {
			case "normal":
				nativeView.lineBreakMode = NSLineBreakMode.ByWordWrapping;
				nativeView.numberOfLines = 0;
				break;
			case "nowrap":
			case "initial":
				nativeView.lineBreakMode = NSLineBreakMode.ByTruncatingTail;
				nativeView.numberOfLines = 1;
				break;
		}
	}

	_redrawNativeBackground(value: UIColor | Background): void {
		if (value instanceof Background) {
			ios.createBackgroundUIColor(
				this,
				(color: UIColor) => {
					const cgColor = color ? color.CGColor : null;
					this.nativeTextViewProtected.layer.backgroundColor = cgColor;
				},
				true
			);
		}

		this._setNativeClipToBounds();
	}

	[borderTopWidthProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const border = nativeView.borderThickness;
		nativeView.borderThickness = {
			top: layout.toDeviceIndependentPixels(this.effectiveBorderTopWidth),
			right: border.right,
			bottom: border.bottom,
			left: border.left,
		};
	}

	[borderRightWidthProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const border = nativeView.borderThickness;
		nativeView.borderThickness = {
			top: border.top,
			right: layout.toDeviceIndependentPixels(
				this.effectiveBorderRightWidth
			),
			bottom: border.bottom,
			left: border.left,
		};
	}

	[borderBottomWidthProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const border = nativeView.borderThickness;
		nativeView.borderThickness = {
			top: border.top,
			right: border.right,
			bottom: layout.toDeviceIndependentPixels(
				this.effectiveBorderBottomWidth
			),
			left: border.left,
		};
	}

	[borderLeftWidthProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const border = nativeView.borderThickness;
		nativeView.borderThickness = {
			top: border.top,
			right: border.right,
			bottom: border.bottom,
			left: layout.toDeviceIndependentPixels(
				this.effectiveBorderLeftWidth
			),
		};
	}

	[paddingTopProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const padding = nativeView.padding;
		nativeView.padding = {
			top: layout.toDeviceIndependentPixels(this.effectivePaddingTop),
			right: padding.right,
			bottom: padding.bottom,
			left: padding.left,
		};
	}

	[paddingRightProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const padding = nativeView.padding;
		nativeView.padding = {
			top: padding.top,
			right: layout.toDeviceIndependentPixels(this.effectivePaddingRight),
			bottom: padding.bottom,
			left: padding.left,
		};
	}

	[paddingBottomProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const padding = nativeView.padding;
		nativeView.padding = {
			top: padding.top,
			right: padding.right,
			bottom: layout.toDeviceIndependentPixels(
				this.effectivePaddingBottom
			),
			left: padding.left,
		};
	}

	[paddingLeftProperty.setNative](value: Length) {
		const nativeView = this.nativeTextViewProtected;
		const padding = nativeView.padding;
		nativeView.padding = {
			top: padding.top,
			right: padding.right,
			bottom: padding.bottom,
			left: layout.toDeviceIndependentPixels(this.effectivePaddingLeft),
		};
	}
}

Label.prototype.recycleNativeView = "auto";