AddedPaddingValues.kt

package com.moriatsushi.compose

import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.runtime.Stable
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.LayoutDirection

operator fun PaddingValues.plus(other: PaddingValues): PaddingValues {
    return AddedPaddingValues(this, other)
}

@Stable
private class AddedPaddingValues(
    private val first: PaddingValues,
    private val second: PaddingValues,
) : PaddingValues {
    override fun calculateBottomPadding(): Dp {
        return first.calculateBottomPadding() +
            second.calculateBottomPadding()
    }

    override fun calculateLeftPadding(layoutDirection: LayoutDirection): Dp {
        return first.calculateLeftPadding(layoutDirection) +
            second.calculateLeftPadding(layoutDirection)
    }

    override fun calculateRightPadding(layoutDirection: LayoutDirection): Dp {
        return first.calculateRightPadding(layoutDirection) +
            second.calculateRightPadding(layoutDirection)
    }

    override fun calculateTopPadding(): Dp {
        return first.calculateTopPadding() +
            second.calculateTopPadding()
    }

    override fun toString(): String {
        return "($first + $second)"
    }

    override fun equals(other: Any?): Boolean {
        if (this === other) {
            return true
        }
        if (other !is AddedPaddingValues) {
            return false
        }
        return first == other.first && second == other.second
    }

    override fun hashCode(): Int {
        var result = first.hashCode()
        result = 31 * result + second.hashCode()
        return result
    }
}