Add ChipText composable

/*

 * Copyright (C) 2024 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.android.systemui.statusbar.chips.ui.compose

import androidx.compose.foundation.layout.sizeIn

import androidx.compose.material3.LocalTextStyle

import androidx.compose.material3.Text

import androidx.compose.runtime.Composable

import androidx.compose.runtime.remember

import androidx.compose.ui.Modifier

import androidx.compose.ui.draw.drawWithContent

import androidx.compose.ui.geometry.Offset

import androidx.compose.ui.geometry.Size

import androidx.compose.ui.graphics.Brush

import androidx.compose.ui.graphics.Color

import androidx.compose.ui.platform.LocalDensity

import androidx.compose.ui.res.dimensionResource

import androidx.compose.ui.text.TextLayoutResult

import androidx.compose.ui.text.TextStyle

import androidx.compose.ui.text.rememberTextMeasurer

import com.android.systemui.res.R

/**

 * Renders text within a status bar chip. The text is only displayed if more than 50% of its width

 * can fit inside the bounds of the chip. If there is any overflow,

 * [R.dimen.ongoing_activity_chip_text_fading_edge_length] is used to fade out the edge of the text.

 */

@Composable

fun ChipText(

    text: String,

    backgroundColor: Color,

    modifier: Modifier = Modifier,

    color: Color = Color.Unspecified,

    style: TextStyle = LocalTextStyle.current,

    minimumVisibleRatio: Float = 0.5f,

) {

    val density = LocalDensity.current

    val textMeasurer = rememberTextMeasurer()

    val textFadeLength =

        dimensionResource(id = R.dimen.ongoing_activity_chip_text_fading_edge_length)

    val maxTextWidthDp = dimensionResource(id = R.dimen.ongoing_activity_chip_max_text_width)

    val maxTextWidthPx = with(density) { maxTextWidthDp.toPx() }

    val textLayoutResult = remember(text, style) { textMeasurer.measure(text, style) }

    val willOverflowWidth = textLayoutResult.size.width > maxTextWidthPx

    if (isSufficientlyVisible(maxTextWidthPx, minimumVisibleRatio, textLayoutResult)) {

        Text(

            text = text,

            style = style,

            softWrap = false,

            color = color,

            modifier =

                modifier

                    .sizeIn(maxWidth = maxTextWidthDp)

                    .then(

                        if (willOverflowWidth) {

                            Modifier.overflowFadeOut(

                                with(density) { textFadeLength.roundToPx() },

                                backgroundColor,

                            )

                        } else {

                            Modifier

                        }

                    ),

        )

    }

}

private fun Modifier.overflowFadeOut(fadeLength: Int, color: Color): Modifier = drawWithContent {

    drawContent()

    val brush =

        Brush.horizontalGradient(

            colors = listOf(Color.Transparent, color),

            startX = size.width - fadeLength,

            endX = size.width,

        )

    drawRect(

        brush = brush,

        topLeft = Offset(size.width - fadeLength, 0f),

        size = Size(fadeLength.toFloat(), size.height),

    )

}

/**

 * Returns `true` if at least [minimumVisibleRatio] of the text width fits within the given

 * [maxAvailableWidthPx].

 */

@Composable

private fun isSufficientlyVisible(

    maxAvailableWidthPx: Float,

    minimumVisibleRatio: Float,

    textLayoutResult: TextLayoutResult,

): Boolean {

    val widthPx = textLayoutResult.size.width

    return (maxAvailableWidthPx / widthPx) > minimumVisibleRatio

}